JP6315830B2 - Disconnection direction determination device, disconnection direction determination method, and disconnection section identification system - Google Patents

Description

  The present invention relates to a disconnection direction determination device, a disconnection direction determination method, and a disconnection section identification system that detect a direction in which a disconnection of a distribution line has occurred.

  A disconnection detection device for detecting disconnection of a distribution line in a distribution network has been developed. For example, there is a method of detecting disconnection on the upstream side (power supply side) from the voltage detection point by detecting the voltage of each phase of the distribution line (for example, Patent Document 1). Further, there is a method of detecting a line current of each phase of the distribution line and detecting a disconnection on the downstream side (load side) based on the phase difference of each line current (for example, Patent Document 2).

JP 2007-282252 A JP 2009-81905 A

  The inventors of the present application have developed a disconnection detection device capable of detecting both an upstream disconnection and a downstream disconnection (Japanese Patent Application No. 2014-178846). In this case, depending on whether the configuration for detecting the disconnection on the upstream side detects a disconnection or the configuration for detecting the disconnection on the downstream side detects a disconnection, a disconnection has occurred on the upstream side of the disconnection detection device, or on the downstream side. It is possible to determine whether a disconnection has occurred. That is, along with the detection of the disconnection, the direction in which the disconnection has occurred can be determined.

  However, when a distributed power source or a rotating machine is connected to the distribution network in which the disconnection detection device is disposed, the direction in which the disconnection occurs may be erroneously determined. For example, even when a disconnection occurs on the upstream side of the disconnection detection device, the voltage on the downstream side of the disconnection position may be held by the distributed power source or the rotating machine, and the change in voltage may be reduced. In this case, the configuration for detecting the upstream disconnection cannot detect the disconnection. On the other hand, the configuration for detecting the disconnection on the downstream side may detect the disconnection by mistake. In this case, it is erroneously determined that the disconnection has occurred on the downstream side, even though the disconnection has occurred on the upstream side of the disconnection detection device.

  The present invention has been conceived under the circumstances described above, and an object of the present invention is to provide a disconnection direction determination device that can more accurately determine the direction in which a disconnection has occurred.

  In order to solve the above problems, the present invention takes the following technical means.

  The disconnection direction determination device provided by the first aspect of the present invention is a disconnection direction determination device that determines the direction in which a disconnection occurs when any one of the three-phase distribution lines is disconnected. A vector that generates a line current vector of each phase based on a current signal detected by an electrical signal detector disposed on a distribution line, and generates a voltage vector of each phase based on a voltage signal detected by the electrical signal detector Generation means, actual voltage change vector generation means for generating an actual voltage change vector, which is a change vector obtained by subtracting the voltage vector of each phase before disconnection from the voltage vector of each phase after disconnection, and occurrence of disconnection A change vector obtained by subtracting the line current vector of each phase after occurrence of disconnection from the previous line current vector of each phase is generated. By calculating, an estimated voltage change vector generating means for generating an estimated voltage change vector, a degree of coincidence between the measured voltage change vector and the estimated voltage change vector is calculated, and based on the degree of coincidence, a disconnection is detected on the upstream side. And a coincidence degree judging means for judging whether or not a disconnection has occurred on the downstream side.

  In a preferred embodiment of the present invention, the coincidence degree determination means determines that a disconnection has occurred on the downstream side when the coincidence degree is equal to or greater than a predetermined threshold value, and It is determined that a disconnection has occurred on the upstream side.

  In a preferred embodiment of the present invention, the degree of coincidence is calculated based on a phase difference between the measured voltage change vector of each phase and the estimated voltage change vector of each phase.

  In a preferred embodiment of the present invention, the degree of coincidence is calculated based on a difference in magnitude between the measured voltage change vector of each phase and the estimated voltage change vector of each phase.

In a preferred embodiment of the present invention, the degree of coincidence ρ is defined as ΔVabr, ΔVbcr, ΔVcar as the actually measured voltage change vectors of the respective phases, and ΔVabg, ΔVbcg, ΔVcag as the estimated voltage change vectors of the respective phases. In this case, it is calculated based on the following formula.

  In a preferred embodiment of the present invention, the threshold value is “0”.

  In a preferred embodiment of the present invention, the coincidence degree judging means transforms the actually measured voltage change vector of each phase into a first vector and transforms the estimated voltage change vector of each phase into a second vector. The degree of coincidence is calculated based on the first vector and the second vector.

In a preferred embodiment of the present invention, the degree of coincidence ρ is defined as ΔVabr, ΔVbcr, ΔVcar as the actually measured voltage change vectors of the respective phases, and ΔVabg, ΔVbcg, ΔVcag as the estimated voltage change vectors of the respective phases. In this case, it is calculated based on the following formula.

  In a preferred embodiment of the present invention, the estimated voltage change vector generation means generates an estimated voltage change vector by multiplying a line impedance per unit distance as a line impedance of the distribution line, and generates the estimated voltage change The vector is normalized and output, and the measured voltage change vector generation means normalizes and outputs the generated measured voltage change vector.

  In preferable embodiment of this invention, the disconnection determination means which determines whether the disconnection of either of the said three-phase distribution line generate | occur | produced is further provided.

  In a preferred embodiment of the present invention, the disconnection determining means is a current change vector which is a change vector of a line current vector based on a reference voltage for each phase based on the electrical signal detected by the electrical signal detector. A current change vector generation means for generating a disconnection, and a disconnection determination means for determining whether or not a break has occurred in the distribution line based on each current change vector generated by the current change vector generation means. .

  In a preferred embodiment of the present invention, the current change vector generation means generates a line current vector for each phase based on the current signal detected by the electrical signal detector, and the voltage detected by the electrical signal detector. A second vector generating means for generating a voltage vector for each phase based on the signal, and using the voltage vector for each phase, the line current vector for each phase is converted into a vector based on a reference voltage for each phase; And calculating means for calculating a change vector of the line current vector of each phase after the conversion.

In a preferred embodiment of the present invention, the disconnection determining means is configured such that each current change vector generated by the current change vector generating means is
(1) A phase difference of a current change vector of a phase whose phase advances with respect to a current change vector of a certain phase, and a current change vector of the certain phase with respect to a current change vector of a phase whose phase is later than the certain phase Of the first threshold value θ ₁ or more and the second threshold value θ ₂ or less, respectively.
(2) the magnitudes of all current change vectors are greater than or equal to a predetermined threshold I ₀ ;
(3) Not applicable when all of the following (3-1) to (3-2) are satisfied,
(3-1) The phase difference between the current change vector having the maximum size among the current change vectors and the other current change vectors is about 60 °, respectively.
(3-2) The magnitude of the maximum current change vector is about twice the magnitude of the other current change vectors.
If all the conditions are satisfied, it is determined that a disconnection has occurred.

In a preferred embodiment of the present invention, it further comprises a zero-phase voltage detecting means for detecting a zero-phase voltage, and the disconnection judging means is in addition to the conditions (1) to (3),
(4) The zero-phase voltage is not less than a predetermined threshold value V ₀ .
If all the conditions are satisfied, it is determined that a disconnection has occurred.

  The disconnection section specifying system provided by the second aspect of the present invention includes a plurality of disconnection direction determination devices provided by the first aspect of the present invention, and the disconnection direction determination device arranged on the distribution line. When determining the direction in which the disconnection occurs, the disconnection direction determination device comprises a management device that transmits information about disconnection by communication, the management device based on the received information about the disconnection, A section in which the disconnection of the distribution line occurs is specified.

  A method provided by the third aspect of the present invention is a method for determining a direction in which a disconnection of a distribution line has occurred, wherein a first electric signal detector disposed on the distribution line detects an electric signal. A second step of generating a line current vector of each phase and a voltage vector of each phase based on the electrical signal detected in the first step, and a third step of storing each detected vector A step of generating an actually measured voltage change vector that is a change vector obtained by subtracting the voltage vector of each phase before occurrence of disconnection from the voltage vector of each phase after occurrence of disconnection; and the step before occurrence of disconnection By generating a change vector obtained by subtracting the line current vector of each phase after occurrence of disconnection from the line current vector of each phase, and multiplying this by the line impedance of the distribution line, an estimated voltage change vector is obtained. And the degree of coincidence between the measured voltage change vector and the estimated voltage change vector is calculated, and based on the degree of coincidence, a disconnection has occurred on the upstream side, or a disconnection has occurred on the downstream side. And a sixth step of determining whether or not.

  According to the present invention, when disconnection occurs, the measured voltage change vector, which is a change vector obtained by subtracting the voltage vector of each phase before disconnection from the voltage vector of each phase after disconnection, and each phase before disconnection occurs. An estimated voltage change vector is generated by multiplying the change vector obtained by subtracting the line current vector of each phase after occurrence of disconnection from the line current vector of this line by the line impedance of the distribution line. Then, the degree of coincidence between the measured voltage change vector and the estimated voltage change vector is calculated, and based on the degree of coincidence, it is determined whether a disconnection has occurred on the upstream side or a disconnection has occurred on the downstream side. That is, the disconnection direction is determined based on whether or not the actual voltage change at the time of disconnection is the same as the voltage change when the disconnection occurs on the downstream side. Therefore, the disconnection direction can be determined more accurately than when the configuration for detecting the disconnection on the upstream side detects the disconnection or the configuration for detecting the disconnection on the downstream side detects the disconnection.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

It is a figure for demonstrating the disconnection detection apparatus which concerns on 1st Embodiment. It is a block diagram which shows the internal structure of the disconnection determination part which concerns on 1st Embodiment. It is a figure for demonstrating the case where the connection of a transformer is (DELTA) delta connection. It is a figure for demonstrating the state which a disconnection generate | occur | produced. It is a figure for demonstrating the state which the single phase load fluctuation | variation generate | occur | produced. It is a figure for demonstrating the state which the three-phase load fluctuation | variation generate | occur | produced. It is a figure for demonstrating the case where the connection of a transformer is (DELTA) Y connection. It is a figure which shows the vector at the time of load fluctuation. It is a figure for demonstrating the case where the connection of a transformer is a Ydelta connection. It is a figure which shows the vector at the time of load fluctuation. It is a figure which shows the change vector of the voltage at the time of disconnection generation | occurrence | production. It is a flowchart for demonstrating a disconnection direction determination process. It is a figure for demonstrating the state which the two-phase load fluctuation | variation generate | occur | produced. It is a figure which shows the vector at the time of two-phase load fluctuation | variation. It is a block diagram which shows the internal structure of the disconnection determination part which concerns on 2nd Embodiment. It is a figure for demonstrating a disconnection area identification system.

  Embodiments of the present invention will be specifically described below with reference to the drawings.

  FIG. 1 is a diagram for explaining the disconnection detection apparatus A according to the first embodiment, and shows a state where the disconnection detection apparatus A is arranged on a three-phase distribution line. The three phases consist of an a phase, a b phase, and a c phase. The b phase current is delayed in phase from the a phase current, and the c phase current is advanced in phase from the a phase current.

  The disconnection detection device A detects disconnection of the distribution line. This embodiment demonstrates the case where the disconnection detection apparatus A detects the disconnection of the three-phase distribution line which consists of the a-phase distribution line a, the b-phase distribution line b, and the c-phase distribution line c. Moreover, the disconnection detection apparatus A can also determine the direction in which the disconnection has occurred. That is, the disconnection detection device A corresponds to the “disconnection direction determination device” of the present invention.

Loads are connected between the distribution lines a, b, and c via the transformer B, respectively. A load Lab is connected between the distribution line a and the distribution line b, a load Lbc is connected between the distribution line b and the distribution line c, and a load Lca is connected between the distribution line c and the distribution line a. Is connected. An instrumental current transformer CT1 is disposed on the distribution line a, an instrumental current transformer CT2 is disposed on the distribution line b, and an instrumental current transformer CT3 is disposed on the distribution line c. . The instrument current transformers CT1, CT2 and CT3 detect currents flowing through the respective distribution lines. Current signals i _a , i _b , and _ic detected by the instrument current transformers CT1, CT2, and CT3, respectively, are input to the disconnection detection device A. Instead of the instrument current transformers CT1, CT2, CT3, other current detection devices (for example, photocurrent measurement) may be used. An instrument transformer PT1 is arranged between the distribution line a and the distribution line b, and an instrument transformer PT2 is arranged between the distribution line b and the distribution line c. An instrument transformer PT3 is disposed between c and the distribution line a. The instrument transformers PT1, PT2, PT3 detect line voltages between the distribution lines, respectively. The voltage signals v _ab , v _bc and v _ca detected by the instrument transformers PT1, PT2 and PT3 are input to the disconnection detection device A. Instead of the instrument transformers PT1, PT2, PT3, other voltage detection devices (for example, capacitor partial pressure) may be used.

  Circuit breakers CB1, CB2, CB3 are provided downstream of the instrument current transformers CT1, CT2, CT3 and the instrument transformers PT1, PT2, PT3. The circuit breakers CB1, CB2, and CB3 block currents flowing through the distribution lines a, b, and c, respectively, in response to the disconnection command input from the disconnection detection device A. The circuit breakers CB1, CB2, and CB3 may be provided upstream of the instrument current transformers CT1, CT2, and CT3 and the instrument transformers PT1, PT2, and PT3.

Breaking detection device A, the current transformer CT1, CT2, the current signal is input from each _{CT3 i a, i b, i} c, and a voltage signal are input from the potential transformer PT1, PT2, PT3 A disconnection is detected based on v _ab , v _{bc, and} v _ca, and a disconnection command for opening the circuit breakers CB1, CB2, and CB3 that are normally closed is output. Moreover, the disconnection detection apparatus A determines the direction in which the disconnection occurred when the disconnection is detected. The disconnection detection device A includes a disconnection direction determination unit 1, a disconnection determination unit 2, a cutoff command unit 3, and a communication unit 4.

  The disconnection determination unit 2 determines whether a disconnection has occurred. FIG. 2 is a block diagram illustrating an internal configuration of the disconnection determination unit 2. As illustrated in FIG. 2, the disconnection determination unit 2 includes a current change vector generation unit 21, a downstream disconnection determination unit 22, an effective value calculation unit 23, and an upstream disconnection determination unit 24.

The current change vector generation unit 21 generates a change vector of the line current vector of each phase voltage reference based on the input voltage signals v _ab , v _bc, v _ca and the current signals i _a , i _{b, ic.} Output. The current change vector generation unit 21 includes a vector generation unit 211, a calculation unit 212, and a storage unit 213.

The vector generator 211 generates a line current vector and a line voltage vector for each phase. The a-phase line current vector is Ia, the b-phase line current vector is Ib, the c-phase line current vector is Ic, the a-phase line voltage vector for the b-phase is Vab, and the b-phase line-to-c phase The voltage vector is represented as Vbc, and the line voltage vector of the c phase with respect to the a phase is represented as Vca. Vector generation unit 211 converts the current signal i _a respectively input from the current transformer CT1, CT2, CT3, i _b, a i _c into a digital signal, to remove the harmonic components by the low pass filter, respectively amplitude And the phase are detected, and line current vectors Ia, Ib, and Ic are generated based on these. The vector generation unit 211 converts the voltage signals v _ab , v _bc , and v _ca input from the instrument transformers PT1, PT2, and PT3, respectively, into digital signals, removes harmonic components with a low-pass filter, The amplitude and phase are detected, and line voltage vectors Vab, Vbc, Vca are generated based on these. The vector generation unit 211 outputs the generated line current vectors Ia, Ib, Ic and the line voltage vectors Vab, Vbc, Vca to the calculation unit 212. The “vector generation unit 211” corresponds to “second vector generation means” of the present invention.

  The calculation unit 212 converts the line current vectors Ia, Ib, and Ic input from the vector generation unit 211 into vectors based on each phase voltage, and generates and outputs a change vector. The calculation unit 212 converts the line current vectors Ia, Ib, and Ic input from the vector generation unit 211 into vectors based on each line voltage using the line voltage vectors Vab, Vbc, and Vca, and the phase is 30 °. By delaying, it is converted to a vector based on each phase voltage. Then, the line current vectors Ia, Ib, and Ic converted to the respective phase voltage reference vectors are stored in the storage unit 213, and the line current vector before a predetermined time (for example, several tens of milliseconds) is read from the storage unit 213. . The calculation unit 212 receives the line current vectors Ia ′, Ib, Ic input from the vector generation unit 211 and converted into vectors based on the respective phase voltages, from the line current vectors Ia ′, Ib ′, Current change vectors ΔIa (= Ia′−Ia), ΔIb (= Ib′−Ib), ΔIc (= Ic′−Ic) are calculated by subtracting from Ic ′ and output to downstream disconnection determination unit 22. .

  Note that when the line current vectors Ia, Ib, and Ic are converted into vectors based on the respective line voltages, for example, the line current vector Ib is converted with reference to the line voltage vector Vab. The phase of the current vector Ic may be delayed by 120 °. In addition, first, change vectors of the line current vectors Ia, Ib, and Ic may be generated, converted into vectors for each phase voltage reference, and output.

  Note that the configuration of the current change vector generation unit 21 is not limited to that described above, and any configuration that generates the current change vectors ΔIa, ΔIb, ΔIc based on each phase voltage may be used. Further, an analog filter may be provided before the vector generation unit 211. The vector generation unit 211 generates line current vectors Ia, Ib, Ic and line voltage vectors Vab, Vbc, Vca every predetermined time, and the operation unit 212 inputs the line current vectors Ia ′, Ib ′, The current change vectors ΔIa, ΔIb, ΔIc may be calculated from Ic ′ and the line current vectors Ia, Ib, Ic input this time.

  The downstream disconnection determination unit 22 determines the occurrence of disconnection on the downstream side (load side) from the position where the instrument current transformers CT1, CT2, CT3 and the instrument transformers PT1, PT2, PT3 are arranged, and the disconnection occurs. The distribution line is identified, and is realized by, for example, a microcomputer. The downstream disconnection determination unit 22 makes a determination based on the current change vectors ΔIa, ΔIb, ΔIc of each phase voltage reference input from the current change vector generation unit 21. The downstream disconnection determination unit 22 determines that a disconnection has occurred on the downstream side when the current change vectors ΔIa, ΔIb, ΔIc of each phase voltage reference satisfy a predetermined condition. When the downstream disconnection determination unit 22 determines that a disconnection has occurred on the downstream side, the downstream disconnection determination unit 22 outputs information about the occurrence of the disconnection and the distribution line in which the disconnection has occurred to the disconnection command unit 3 and the communication unit 4. Further, the downstream disconnection determination unit 22 outputs a signal indicating that a disconnection has occurred to the disconnection direction determination unit 1.

  Below, the conditions for the downstream disconnection judgment part 22 to judge a downstream disconnection are demonstrated.

  If no disconnection occurs on the downstream side and the load connected to the distribution line does not change, the line current vectors Ia, Ib, and Ic do not change. Therefore, the current change vectors ΔIa, ΔIb, and ΔIc (reference values for each phase voltage) Hereinafter, “vectors ΔIa, ΔIb, ΔIc” are all zero vectors. When the disconnection occurs on the downstream side, the line current vectors Ia, Ib, and Ic change, so the vectors ΔIa, ΔIb, and ΔIc also change. However, the vectors ΔIa, ΔIb, ΔIc also change when the load connected between the distribution lines of each phase varies. The downstream disconnection determination unit 22 determines that a disconnection has occurred on the downstream side from the characteristics of the vectors ΔIa, ΔIb, and ΔIc. Specifically, the downstream disconnection determination unit 22 conditionally stores the characteristics of the vectors ΔIa, ΔIb, ΔIc when the disconnection occurs on the downstream side, and the vectors ΔIa, ΔIb, ΔIc match the conditions. By determining whether or not to do so, the occurrence of a disconnection on the downstream side is determined.

  The connection of the transformer B (see FIG. 1) interposed between the distribution line and the load includes a ΔΔ connection, a YY connection, a ΔY connection, a YΔ connection, and the like. In this embodiment, the disconnection can be determined regardless of the connection of the transformer B.

FIG. 3 shows a case where the connection of the transformer B is a ΔΔ connection, and FIG. 3 (a) shows the transformer B and the load connected to the distribution lines a, b, and c shown in FIG. Yes. In FIG. 3A, the vector of the current flowing through the load Lab is Iab, the vector of the current flowing through the load Lbc is Ibc, and the vector of the current flowing through the load Lca is Ica. As shown in FIG. 3A, the line current vector Ia of the a-phase distribution line a, the line current vector Ib of the b-phase distribution line b, and the line current vector Ic of the c-phase distribution line c are respectively
Ia = Iab-Ica
Ib = Ibc-Iab
Ic = Ica-Ibc
It becomes. For convenience of calculation, the transformation ratio of the transformer B is “1”. When the transformation ratio is not “1”, the vectors ΔIa, ΔIb, and ΔIc are obtained by dividing the magnitude by the transformation ratio, but the conditions are the same regardless of whether the line is disconnected or the load is changed. , ΔIb, ΔIc are respectively divided by the transformation ratio. Therefore, there is no problem even if the transformation ratio is calculated as “1”.

FIG. 3B shows the current and voltage vectors in the three-phase equilibrium state. The phase voltage vector Va of the a phase, the phase voltage vector Vb of the b phase, and the phase voltage vector Vc of the c phase are 120 degrees apart from each other (indicated by thick arrows in FIG. 3B). . The a-phase line voltage vector Vab for the b-phase, the b-phase line voltage vector Vbc for the c-phase, and the c-phase line voltage vector Vca for the a-phase are respectively
Vab = Va−Vb
Vbc = Vb−Vc
Vca = Vc−Va
(Indicated by broken-line arrows in FIG. 3B). Assuming that the current is advanced in phase θ from the voltage, current vectors Iab, Ibc, and Ica are indicated by thin line arrows in FIG.

When current vectors Iab, Ibc, and Ica are expressed with reference to phase voltage vector Va of a phase,
When current vectors Iab, Ibc, and Ica are expressed with reference to phase voltage vector Vb of b phase,
When current vectors Iab, Ibc, and Ica are expressed with reference to phase voltage vector Vc of c phase,
It becomes.

FIG. 4A shows a state in which disconnection occurs in the a-phase distribution line a. When disconnection occurs in the distribution line a, no current flows through the distribution line a, so the line current vector Ia becomes a zero vector. The same current flows through the loads Lab and Lca, and this current vector is a vector having the same phase and different magnitude as the current vector Ibc, and can be expressed as αIbc. Therefore,
Ia = 0
Ib = Ibc + αIbc
Ic = −Ibc−αIbc
It becomes.

Therefore, the current change vectors ΔIa, ΔIb, ΔIc before and after the disconnection are
ΔIa = (Iab−Ica) − (0) = Iab−Ica
ΔIb = (Ibc−Iab) − (Ibc + αIbc) = − Iab−αIbc
ΔIc = (Ica−Ibc) − (− Ibc−αIbc) = Ica + αIbc
And expressed with reference to the phase voltage vector of each phase,
It becomes.

When the line current vector based on each phase voltage is set to I and the vectors βVa, βVb, βVc are replaced with the vector I, respectively,
It becomes. In an actual power system, α becomes a value close to “0” due to a power failure due to insufficient voltage at the time of disconnection. FIG. 4B shows the vectors ΔIa, ΔIb, ΔIc at the time of disconnection.

  Next, vectors ΔIa, ΔIb, ΔIc at the time of single-phase load fluctuation will be described.

FIG. 5A shows a single-phase load fluctuation and shows a state where the load Lab is disconnected. In this case, as is apparent from FIG.
Ia = -Ica
Ib = Ibc
Ic = Ica-Ibc
It becomes.

Therefore, the current change vectors ΔIa, ΔIb, ΔIc before and after the load change are
ΔIa = (Iab−Ica) − (− Ica) = Iab
ΔIb = (Ibc−Iab) − (Ibc) = − Iab
ΔIc = (Ica−Ibc) − (Ica−Ibc) = 0
And expressed with reference to the phase voltage vector of each phase,
It becomes.

When the line current vector based on each phase voltage is set to I and the vectors βVa, βVb, βVc are replaced with the vector I, respectively,
It becomes. FIG. 5B shows the vectors ΔIa, ΔIb, ΔIc when the single-phase load fluctuates.

  Next, vectors ΔIa, ΔIb, ΔIc at the time of three-phase load fluctuation will be described.

FIG. 6A shows a three-phase load fluctuation, and shows a state in which the loads Lab, Lbc, and Lca are disconnected. In this case, as is apparent from FIG.
Ia = 0
Ib = 0
Ic = 0
It becomes.

Therefore, the current change vectors ΔIa, ΔIb, ΔIc before and after the load change are
ΔIa = (Iab−Ica) − (0) = Iab−Ica
ΔIb = (Ibc−Iab) − (0) = Ibc−Iab
ΔIc = (Ica−Ibc) − (0) = Ica−Ibc
And expressed with reference to the phase voltage vector of each phase,
It becomes.

When the line current vector based on each phase voltage is set to I and the vectors βVa, βVb, βVc are replaced with the vector I, respectively,
It becomes. FIG. 6B shows the vectors ΔIa, ΔIb, ΔIc when the three-phase load fluctuates.

  Next, the case where the connection of the transformer B is a ΔY connection will be described.

FIG. 7 shows a case where the connection of the transformer B is a ΔY connection, and FIG. 7 (a) shows the transformer B and the load connected to the distribution lines a, b, and c shown in FIG. Yes. Similarly to FIG. 3A, in FIG. 7A, the current vector flowing through the load Lab is Iab, the current vector flowing through the load Lbc is Ibc, and the current vector flowing through the load Lca is Ica. As shown in FIG. 7A, the line current vector Ia of the a-phase distribution line a, the line current vector Ib of the b-phase distribution line b, and the line current vector Ic of the c-phase distribution line c are respectively
Ia = Iab + Ibc-2Ica
Ib = Ibc + Ica-2Iab
Ic = Ica + Iab-2Ibc
It becomes.

FIG. 7B shows current and voltage vectors in a three-phase equilibrium state. The phase voltage vector Va of the a phase, the phase voltage vector Vb of the b phase, and the phase voltage vector Vc of the c phase are 120 degrees apart from each other (indicated by bold arrows in FIG. 7B). . The a-phase line voltage vector Vab for the b-phase, the b-phase line voltage vector Vbc for the c-phase, and the c-phase line voltage vector Vca for the a-phase are respectively
Vab = Va−Vb
Vbc = Vb−Vc
Vca = Vc−Va
(Indicated by a broken-line thick arrow in FIG. 7B). The voltage vector applied to the load Lab is Vab ′, the voltage vector applied to the load Lbc is Vbc ′, the voltage vector applied to the load Lca is Vca ′, and the phase is 30 with respect to the line voltage vectors Vab, Vbc, Vca, respectively. Go forward. Assuming that the current is advanced in phase θ from the voltage, current vectors Iab, Ibc, Ica are indicated by thin line arrows in FIG.

When current vectors Iab, Ibc, and Ica are expressed with reference to phase voltage vector Va of a phase,
When current vectors Iab, Ibc, and Ica are expressed with reference to phase voltage vector Vb of b phase,
When current vectors Iab, Ibc, and Ica are expressed with reference to phase voltage vector Vc of c phase,
It becomes.

  When the connection of the transformer B is the ΔY connection, the vectors ΔIa, ΔIb, ΔIc at the time of the disconnection are the same as those in FIG.

  Next, vectors ΔIa, ΔIb, ΔIc at the time of single-phase load fluctuation will be described.

When the load Lab is disconnected and Iab = 0,
Ia = Ibc-2Ica
Ib = Ibc + Ica
Ic = Ica-2Ibc
It becomes.

Therefore, the current change vectors ΔIa, ΔIb, ΔIc before and after the load change are
ΔIa = (Iab + Ibc-2Ica) − (Ibc-2Ica) = Iab
ΔIb = (Ibc + Ica−2Iab) − (Ibc + Ica) = − 2Iab
ΔIc = (Ica + Iab−2Ibc) − (Ica−2Ibc) = Iab
And expressed with reference to the phase voltage vector of each phase,
It becomes.

When the line current vector based on each phase voltage is set as I and the vectors γVa, γVb, and γVc are replaced with the vector I, respectively,
It becomes. FIG. 8A shows the vectors ΔIa, ΔIb, ΔIc when the single-phase load fluctuates.

  Next, vectors ΔIa, ΔIb, ΔIc at the time of three-phase load fluctuation will be described.

When the loads Lab, Lbc, and Lca are disconnected,
Ia = 0
Ib = 0
Ic = 0
It becomes.

Therefore, the current change vectors ΔIa, ΔIb, ΔIc before and after the load change are
ΔIa = (Iab + Ibc−2Ica) − (0) = − 3Ica
ΔIb = (Ibc + Ica−2Iab) − (0) = − 3Iab
ΔIc = (Ica + Iab−2Ibc) − (0) = − 3Ibc
And expressed with reference to the phase voltage vector of each phase,
It becomes.

When the line current vector based on each phase voltage is set as I and the vectors γVa, γVb, and γVc are replaced with the vector I, respectively,
It becomes. FIG. 8B shows the vectors ΔIa, ΔIb, ΔIc when the three-phase load fluctuates.

  Next, a case where the connection of the transformer B is a YΔ connection will be described.

FIG. 9 shows a case where the connection of the transformer B is a YΔ connection, and FIG. 9A shows the transformer B and the load connected to the distribution lines a, b, and c shown in FIG. Yes. Similarly to FIG. 3A, in FIG. 9A, the current vector flowing through the load Lab is Iab, the current vector flowing through the load Lbc is Ibc, and the current vector flowing through the load Lca is Ica. As shown in FIG. 9A, the line current vector Ia of the a-phase distribution line a, the line current vector Ib of the b-phase distribution line b, and the line current vector Ic of the c-phase distribution line c are respectively
Ia = (2/3) Iab- (1/3) Ibc- (1/3) Ica
Ib = (2/3) Ibc- (1/3) Ica- (1/3) Iab
Ic = (2/3) Ica- (1/3) Iab- (1/3) Ibc
It becomes.

  FIG. 9B shows current and voltage vectors in a three-phase equilibrium state. The phase voltage vector Va of the a phase, the phase voltage vector Vb of the b phase, and the phase voltage vector Vc of the c phase are 120 degrees apart from each other (indicated by thick arrows in FIG. 9B). . The a-phase line voltage vector Vab for the b-phase, the b-phase line voltage vector Vbc for the c-phase, and the c-phase line voltage vector Vca for the a-phase are equal to the phase voltage vectors Va, Vb, and Vc, respectively. . Assuming that the current is advanced in phase θ from the voltage, current vectors Iab, Ibc, and Ica are indicated by thin line arrows in FIG.

When current vectors Iab, Ibc, and Ica are expressed with reference to phase voltage vector Va of a phase,
When current vectors Iab, Ibc, and Ica are expressed with reference to phase voltage vector Vb of b phase,
When current vectors Iab, Ibc, and Ica are expressed with reference to phase voltage vector Vc of c phase,
It becomes.

  When the connection of the transformer B is the YΔ connection, the vectors ΔIa, ΔIb, ΔIc at the time of the disconnection are the same as those in FIG.

  Next, vectors ΔIa, ΔIb, ΔIc at the time of single-phase load fluctuation will be described.

When the load Lab is disconnected and Iab = 0,
Ia =-(1/3) Ibc- (1/3) Ica
Ib = (2/3) Ibc- (1/3) Ica
Ic = (2/3) Ica- (1/3) Ibc
It becomes.

Therefore, the current change vectors ΔIa, ΔIb, ΔIc before and after the load change are
ΔIa = (2/3) Iab− (1/3) Ibc− (1/3) Ica) − (− (1/3) Ibc− (1/3) Ica) = (2/3) Iab
ΔIb = ((2/3) Ibc− (1/3) Ica− (1/3) Iab) − ((2/3) Ibc − ((1/3)) Ica) = − (1/3) Iab
ΔIc = ((2/3) Ica− (1/3) Iab− (1/3) Ibc) − ((2/3) Ica− (1/3) Ibc) = − (1/3) Iab
And expressed with reference to the phase voltage vector of each phase,
It becomes.

When the line current vector based on each phase voltage is set to I and the vectors εVa, εVb, and εVc are replaced with the vector I, respectively,
It becomes. FIG. 10A shows the vectors ΔIa, ΔIb, ΔIc when the single-phase load fluctuates.

  Next, vectors ΔIa, ΔIb, ΔIc at the time of three-phase load fluctuation will be described.

When the loads Lab, Lbc, and Lca are disconnected,
Ia = 0
Ib = 0
Ic = 0
It becomes.

Therefore, the current change vectors ΔIa, ΔIb, ΔIc before and after the load change are
ΔIa = ((2/3) Iab− (1/3) Ibc− (1/3) Ica) − (0) = Iab
ΔIb = ((2/3) Ibc− (1/3) Ica− (1/3) Iab) − (0) = Ibc
ΔIc = ((2/3) Ica− (1/3) Iab− (1/3) Ibc) − (0) = Ica
And expressed with reference to the phase voltage vector of each phase,
It becomes.

When the line current vector based on each phase voltage is set to I and the vectors εVa, εVb, and εVc are replaced with the vector I, respectively,
It becomes. FIG. 10B shows the vectors ΔIa, ΔIb, ΔIc when the three-phase load fluctuates.

  When the connection of the transformer B is the YY connection, it is the same as the case of the ΔΔ connection. It should be noted that the two-phase load fluctuation occurs only in a very special state and hardly occurs in practice, and therefore, this embodiment does not assume a case where the two-phase load fluctuation occurs.

  As described above, the vectors ΔIa, ΔIb, and ΔIc have a case where a disconnection occurs on the downstream side (see FIG. 4B) and a case where a load change occurs (see FIGS. 5B and 6B). Different vectors are obtained in FIGS. 8A, 8B, 10A, and 10B. When the vectors ΔIa, ΔIb, and ΔIc become the vectors shown in FIG. 4B, it can be determined that a disconnection has occurred on the downstream side. However, when the load fluctuates, there is no problem considering that the load is approximately balanced. However, when the downstream side is disconnected, the load on the load side is not always balanced from the disconnection point, as shown in FIG. Deviations from the vector diagram may occur. It is also necessary to take into account that measurement errors occur in the instrument current transformers CT1, CT2, CT3 or the instrument transformers PT1, PT2, PT3. That is, even if these errors are included, the vectors ΔIa, ΔIb, ΔIc are the vectors shown in FIG. 4B, and FIG. 5B, FIG. 6B, FIG. It is necessary to set conditions that can be determined not to be the vectors shown in (b) and FIGS. 10 (a) and 10 (b).

In the present embodiment, the following conditions are set as conditions for determining the occurrence of downstream disconnection.
(1) Phase difference of a phase voltage reference current change vector of a phase whose phase is advanced from a phase with respect to a current change vector of a phase voltage reference of a phase, and a phase voltage reference current change of a phase lagging a phase The phase difference of the current change vector based on the phase voltage of a certain phase with respect to the vector is not less than the first threshold θ _{1 and not} more than the second threshold θ ₂ , respectively.
(2) The magnitude of the current change vector based on the phase voltage of all phases is equal to or greater than a predetermined threshold value I ₀ .
(3) Not applicable if all of the following conditions are met.
(3-1) The phase difference between the vector having the largest magnitude among the current change vectors based on the phase voltage of each phase and the other vectors is about 60 °.
(3-2) The size of the maximum vector is about twice the size of the other vectors.

In the present embodiment, a value of 5 ° to 30 ° is set as the first threshold θ ₁ , a value of 150 ° to 180 ° is set as the second threshold θ ₂ , and a value of several amperes is set as the predetermined threshold I _0. Is set.

The above condition (1) is that, for example, when the “certain phase” is the a phase, the phase difference between the current change vector based on the phase voltage of the a phase and the current change vector based on the phase voltage of the c phase is θ ₁ to θ _2. And the phase difference of the current change vector of the a-phase phase voltage reference to the current change vector of the b-phase phase voltage reference is in the range of θ ₁ to θ ₂ .

  The condition (3) above is that the vector does not correspond to the vectors shown in FIGS. 8 (a) and 10 (a). When no power failure occurs due to disconnection, that is, when α is (1/2), the vector shown in FIG. 4B and the vectors shown in FIGS. 8A and 10A can be discriminated. difficult. However, it is unlikely that no power outage will occur in the actual system. Therefore, when the vectors ΔIa, ΔIb, ΔIc correspond to the vectors shown in FIG. 8A or FIG. 10A, there is no problem even if it is determined that the load is not a disconnection but a load change. In the present embodiment, the condition (3-1) is determined based on whether each phase difference is within a range of 60 ° ± 5 °. Further, it is determined whether or not the condition (3-2) is within a range of 1.9 to 2 times.

  The conditions (1) to (3) described above are examples of conditions for determining the occurrence of downstream disconnection, and the conditions set in the downstream disconnection determination unit 22 are not limited thereto. The conditions for determining the occurrence of the downstream disconnection are based on the case where the disconnection occurs on the downstream side (see FIG. 4B) based on the vectors ΔIa, ΔIb, ΔIc, and the case where a load change occurs (see FIG. 4). 5 (b), FIG. 6 (b), FIG. 8 (a), (b), FIG. 10 (a), and (b)) may be used.

  The downstream disconnection determination unit 22 generates a disconnection on the downstream side of the distribution line when the vectors ΔIa, ΔIb, and ΔIc input from the current change vector generation unit 21 satisfy all the above conditions (1) to (3). Judge.

  In the above description, the vector diagrams of the vectors ΔIa, ΔIb, and ΔIc when the loads are disconnected as the load fluctuation occurs (FIGS. 5B, 6B, 8A, and 8A) ( b) and FIGS. 10A and 10B). When the load decreases, only the lengths of the vectors ΔIa, ΔIb, and ΔIc in each diagram are different. When the load increases, the directions of the vectors ΔIa, ΔIb, and ΔIc in each diagram are simply reversed by 180 °. is there. Therefore, these cases can also be distinguished from those at the time of occurrence of downstream disconnection using the above conditions (1) to (3).

Returning to FIG. 2, the effective value calculation unit 23 calculates effective values Vrmsab, Vrmsbc, and Vrmsca of the line voltages based on the input voltage signals v _ab , v _bc , and v _ca. The effective value calculation unit 23 outputs the calculated effective values Vrmsab, Vrmsbc, and Vrmsca to the upstream disconnection determination unit 24.

  The upstream disconnection determination unit 24 determines the occurrence of disconnection on the upstream side (power supply side) from the position where the instrument current transformers CT1, CT2, CT3 and the instrument transformers PT1, PT2, PT3 are arranged. The distribution line is identified, and is realized by, for example, a microcomputer. The upstream disconnection determination unit 24 makes a determination based on the effective values Vrmsab, Vrmsbc, and Vrmsca of each line voltage input from the effective value calculation unit 23. In normal times, the effective values Vrmsab, Vrmsbc, and Vrmsca are substantially similar values. However, when a disconnection occurs on the upstream side, the line voltage related to the disconnected distribution line decreases. For example, when disconnection occurs in the a-phase distribution line a, the effective values Vrmsab and Vrmsca are lowered. The upstream disconnection determining unit 24 determines that a disconnection has occurred on the upstream side when any two of the effective values Vrmsab, Vrmsbc, and Vrmsca are lower than the remaining one by a predetermined value or more. Further, the upstream disconnection determination unit 24 determines the disconnected distribution line according to which two values have decreased. When the upstream disconnection determination unit 24 determines that a disconnection has occurred on the upstream side, the upstream disconnection determination unit 24 outputs to the disconnection command unit 3 and the communication unit 4 information about the occurrence of the disconnection and the distribution line in which the disconnection has occurred. Further, the upstream disconnection determination unit 24 outputs a signal indicating that a disconnection has occurred to the disconnection direction determination unit 1.

Returning to FIG. 1, the disconnection direction determination unit 1 determines the direction in which the disconnection has occurred, and when a signal indicating that a disconnection has occurred is input from the disconnection determination unit 2, the instrument current transformer CT <b> 1. , CT2, the current signal is input from each _{CT3 i a, i b, i} c, and, on the basis of potential transformers PT1, PT2, from PT3 voltage signal v _ab respectively input, v _bc, the v _ca, The direction in which the disconnection has occurred is determined, and information indicating the determined disconnection direction is output to the communication unit 4. It can be considered that the “disconnection direction determination unit 1” in the disconnection detection device A corresponds to the “disconnection direction determination device” of the present invention.

  Since the disconnection determination unit 2 includes the downstream disconnection determination unit 22 and the upstream disconnection determination unit 24, the disconnection direction can be estimated depending on which one detects the disconnection. However, when a distributed power source or a rotating machine is connected downstream of the disconnection position, even if a disconnection occurs upstream of the disconnection detection device A, the voltage on the downstream side of the disconnection position is maintained and the voltage changes Therefore, the upstream disconnection determination unit 24 may not be able to detect disconnection. On the other hand, even in this case, since the downstream disconnection determination unit 22 can detect the disconnection, it erroneously determines that the disconnection has occurred on the downstream side. Therefore, in this embodiment, when the disconnection determination unit 2 determines that a disconnection has occurred, the disconnection direction determination unit 1 determines the direction in which the disconnection has occurred.

  When a disconnection occurs, a voltage change occurs both upstream and downstream from the disconnection position. The voltage fluctuation on the upstream side (power supply side) from the disconnection position is generated by disconnecting the load due to disconnection and eliminating the voltage drop generated by the current flowing through the load. FIG. 11A is an example of voltage change vectors ΔVab, ΔVbc, ΔVca on the upstream side of the disconnection position when the disconnection occurs in the a phase. On the other hand, the voltage fluctuation on the downstream side (load side) from the disconnection position occurs when an electric circuit constituted by the distribution line and the load is changed by disconnection. FIG. 11B is an example of voltage change vectors ΔVab, ΔVbc, ΔVca on the downstream side of the disconnection position when the disconnection occurs in the a phase. The disconnection direction determination unit 1 uses this difference to determine whether a disconnection has occurred on the upstream side or on the downstream side. Specifically, the voltage drop generated by the change in the current is calculated from the current vector changed at the time of disconnection, and the voltage change is estimated. That is, a voltage change (a voltage change on the upstream side of the disconnection position) when it is assumed that a disconnection has occurred on the downstream side is estimated (the estimated voltage change vector is as shown in FIG. 11A). . Then, the measured voltage change is compared with the estimated voltage change. If they match, it is determined that the disconnection has occurred on the downstream side, and if they do not match, it is determined that the disconnection has occurred on the upstream side. .

  As illustrated in FIG. 1, the disconnection direction determination unit 1 includes a vector generation unit 11, an actual measurement voltage change vector generation unit 12, an estimated voltage change vector generation unit 13, and a coincidence degree determination unit 14.

The vector generation unit 11 generates a line current vector and a phase voltage vector for each phase. The a-phase line current vector is Ia, the b-phase line current vector is Ib, the c-phase line current vector is Ic, the a-phase line voltage vector for the b-phase is Vab, and the b-phase line-to-c phase The voltage vector is represented as Vbc, and the line voltage vector of the c phase with respect to the a phase is represented as Vca. The vector generation unit 11 converts the current signals i _a , i _b , and _ic input from the instrument current transformers CT1, CT2, and CT3, respectively, into digital signals, removes harmonic components with a low-pass filter, and amplitudes respectively. And the phase are detected, and line current vectors Ia, Ib, and Ic are generated based on these. The vector generation unit 11 converts the voltage signals v _ab , v _bc , and v _ca input from the instrument transformers PT1, PT2, and PT3, respectively, into digital signals, removes harmonic components with a low-pass filter, The amplitude and phase are detected, and line voltage vectors Vab, Vbc, Vca are generated based on these. The vector generation unit 11 outputs the generated line voltage vectors Vab, Vbc, Vca to the measured voltage change vector generation unit 12, and outputs the generated line current vectors Ia, Ib, Ic to the estimated voltage change vector generation unit 13. . The “vector generation unit 11” corresponds to “vector generation means” of the present invention. Note that the vector generation unit 211 of the disconnection determination unit 2 may also be used without providing the vector generation unit 11.

  The actual voltage change vector generation unit 12 generates and outputs an actual voltage change vector that is a change vector before and after the disconnection of the line voltage vectors Vab, Vbc, and Vca input from the vector generation unit 11. The measured voltage change vector generation unit 12 stores the line voltage vectors Vab, Vbc, Vca input from the vector generation unit 11 in a storage unit (not shown). When a signal indicating that a disconnection has occurred is input from the disconnection determination unit 2, the actually measured voltage change vector generation unit 12 receives the line voltage vectors Vab, Vbc, Vca (disconnection generation) input from the vector generation unit 11. The line voltage vectors Vab ′, Vbc ′, and Vca ′ (phase line voltage vectors before the occurrence of disconnection) read from the storage unit are subtracted from the subsequent line voltage vectors), respectively, and the measured voltage change vector ΔVabr (= Vab−Vab ′), ΔVbcr (= Vbc−Vbc ′), ΔVcar (= Vca−Vca ′) are calculated, normalized, and output to the coincidence determination unit 14. Normalization is performed by dividing the measured voltage change vectors ΔVabr, ΔVbcr, and ΔVcar, which are the largest of the magnitudes of the measured voltage change vectors ΔVbrr, ΔVbcr, and ΔVcar. The measured voltage change vectors ΔVabr, ΔVbcr, and ΔVcar indicate voltages that have changed due to disconnection.

  The estimated voltage change vector generation unit 13 estimates a vector of a voltage change that is estimated to be generated when the load current disappears due to disconnection (that is, a voltage change when a disconnection occurs on the downstream side). The estimated voltage change vector generation unit 13 first generates change vectors before and after the disconnection of the line current vectors Ia, Ib, and Ic input from the vector generation unit 11. The estimated voltage change vector generation unit 13 stores the line current vectors Ia, Ib, and Ic input from the vector generation unit 11 in a storage unit (not shown). Then, when a signal indicating that a disconnection has occurred is input from the disconnection determination unit 2, the estimated voltage change vector generation unit 13 receives the line current vectors Ia, Ib, Ic (after the occurrence of the disconnection) input from the vector generation unit 11. Are subtracted from the line current vectors Ia ′, Ib ′, and Ic ′ (line current vectors before occurrence of disconnection) read from the storage unit, respectively, to obtain a current change vector ΔIa (= Ia′−Ia). ), ΔIb (= Ib′−Ib), ΔIc (= Ic′−Ic). Note that the current change vectors ΔIa, ΔIb, and ΔIc are not converted into vectors based on the respective phase voltages, unlike the calculation unit 212. Current change vectors ΔIa, ΔIb, and ΔIc indicate currents (load currents) that flow through the load lost due to disconnection. Next, the estimated voltage change vector generation unit 13 multiplies the current change vectors ΔIa, ΔIb, ΔIc by the line impedance (R + jX) per unit distance of the distribution lines a, b, c to thereby change the phase voltage. Vectors ΔVag (= (R + jX) × ΔIa), ΔVbg (= (R + jX) × ΔIb), and ΔVcg (= (R + jX) × ΔIc) are calculated. Then, in order to convert the phase voltage into the line voltage, the respective differences are calculated to be estimated voltage change vectors ΔVabg (= ΔVag−ΔVbg), ΔVbcg (= ΔVbg−ΔVcg), ΔVcag (= ΔVcg−ΔVag). After normalization, the result is output to the coincidence determination unit 14. Normalization is performed by dividing the estimated voltage change vectors ΔVabg, ΔVbcg, ΔVcag, respectively, which is the largest of the estimated voltage change vectors ΔVabg, ΔVbcg, ΔVcag. The estimated voltage change vectors ΔVabg, ΔVbcg, ΔVcag indicate a change in voltage due to the absence of a voltage drop due to a current that has flowed through the load lost due to disconnection, and indicate a change in voltage when a disconnection occurs on the downstream side. Yes.

  Instead of multiplying the line impedance (R + jX) per unit distance of the distribution lines a, b, and c, it is multiplied by a specific line impedance from the power source to the position where the disconnection detecting device A is arranged. (It is even better if it is a specific line impedance from the power source to the disconnection position). In this case, the measured voltage change vector generation unit 12 does not need to normalize the measured voltage change vectors ΔVabr, ΔVbcr, ΔVcar, and the estimated voltage change vector generation unit 13 needs to normalize the estimated voltage change vectors ΔVabg, ΔVbcg, ΔVcag. There is no. However, it is necessary to set different line impedances for each disconnection detecting device A.

  In the measured voltage change vector generation unit 12 and the estimated voltage change vector generation unit 13, the vector read from the storage unit when a disconnection occurs is assumed to be stored the same predetermined time (for example, several tens of milliseconds). Note that the vector may be continuously stored in the storage unit even after the disconnection occurs, and the vector after the disconnection may be read from the storage unit. That is, it suffices if a change vector can be generated from a vector before occurrence of disconnection and a vector after occurrence of disconnection.

  In the present embodiment, the measured voltage change vector generation unit 12 and the estimated voltage change vector generation unit 13 generate the measured voltage change vector and the estimated voltage change vector, respectively, as change vectors of the line voltage vector. It is not limited to this. The actually measured voltage change vector and the estimated voltage change vector may be generated as a change vector of the phase voltage vector.

The coincidence determination unit 14 includes the actual voltage change vectors ΔVabr, ΔVbcr, ΔVcar input from the actual voltage change vector generation unit 12 and the estimated voltage change vectors ΔVabg, ΔVbcg, ΔVcag input from the estimated voltage change vector generation unit 13. Are compared to determine the direction in which the disconnection occurs, and is realized by, for example, a microcomputer. The coincidence determination unit 14 first calculates a coincidence ρ that is an index indicating how similar the measured voltage change vectors ΔVabr, ΔVbcr, ΔVcar and the estimated voltage change vectors ΔVabg, ΔVbcg, ΔVcag are. In the present embodiment, the degree of coincidence ρ is calculated based on the following equation (1).

  ABSab indicates the degree of coincidence between the magnitude of the vector ΔVabr and the magnitude of the vector ΔVabg. The smaller one of the magnitude of the vector ΔVabr and the magnitude of the vector ΔVabg is divided by the larger one. Therefore, 0 <ABSab ≦ 1, and if the magnitude of the vector ΔVabr matches the magnitude of the vector ΔVabg, ABSab = 1. Similarly, ABSbc indicates the degree of coincidence between the magnitude of the vector ΔVbcr and the magnitude of the vector ΔVbcg, and 0 <ABSbc ≦ 1, and when the magnitude of the vector ΔVbcr and the magnitude of the vector ΔVbcg coincide with each other, ABSbc = 1. ABSca indicates the degree of coincidence between the magnitude of the vector ΔVcar and the magnitude of the vector ΔVcag, and 0 <ABSca ≦ 1, and when the magnitude of the vector ΔVcar and the magnitude of the vector ΔVcag coincide, ABSca = 1

The above equation (1) is calculated from the following equation (2). θab is a phase difference between the vector ΔVabr and the vector ΔVabg, and −1 ≦ cos θab ≦ 1. When the phase of the vector ΔVabr and the phase of the vector ΔVabg coincide with each other, θab = 0 and cos θab = 1. On the other hand, when the phase of the vector ΔVabr and the phase of the vector ΔVabg are shifted by 180 °, cos θab = −1. Similarly, θbc is a phase difference between the vector ΔVbcr and the vector ΔVbcg, and −1 ≦ cos θbc ≦ 1. When the phase of the vector ΔVbcr matches the phase of the vector ΔVbcg, θbc = 0 and cos θbc = 1. On the other hand, when the phase of the vector ΔVbcr and the phase of the vector ΔVbcg are shifted by 180 °, cos θbc = −1. Θca is a phase difference between the vector ΔVcar and the vector ΔVcag, and −1 ≦ cos θca ≦ 1. When the phase of the vector ΔVcar and the phase of the vector ΔVcag coincide with each other, θca = 0 and cos θca = 1. On the other hand, when the phase of the vector ΔVcar and the phase of the vector ΔVcag are shifted by 180 °, cos θca = −1. As can be seen from the following equation (2), the degree of coincidence ρ is obtained by multiplying the degree of coincidence of the vector size and the degree of coincidence of the phase for each phase, and adding the weights. The degree of coincidence ρ is −1 ≦ ρ ≦ 1, and when the measured voltage change vectors ΔVabr, ΔVbcr, ΔVcar and the estimated voltage change vectors ΔVabg, ΔVbcg, ΔVcag completely coincide with each other, ρ = 1 and are mutually inverted. In the case (complete disagreement), ρ = -1.

Note that the formula for calculating the degree of matching ρ is not limited to this. Any value may be used as long as it calculates a value for determining whether the actually measured voltage change vectors ΔVabr, ΔVbcr, ΔVcar and the estimated voltage change vectors ΔVabg, ΔVbcg, ΔVcag are the same or different. For example, focusing on the phase of each vector, the degree of coincidence ρ may be increased as the phase difference of the vector for each phase is closer to “0”. The following formula (3) calculates the degree of coincidence ρ by paying attention to the phase of each vector, and calculates the degree of coincidence of phases by dividing the inner product for each phase by the product of absolute values. The degree of coincidence ρ (−1 ≦ ρ ≦ 1) is calculated by taking the sum and dividing by 3.

Further, paying attention to the size of each vector, the degree of coincidence ρ may be increased as the difference in vector size for each phase is closer to “0”. The following equation (4) calculates the degree of coincidence ρ by paying attention to the size of each vector. The degree of coincidence of the vector size is calculated for each phase, and the sum of the three phases is calculated as 3. The degree of coincidence ρ (0 ≦ ρ ≦ 1) is calculated by dividing.

  However, when the degree of coincidence ρ is calculated only by the phase or when the degree of coincidence ρ is calculated only by the magnitude, the calculation of the degree of coincidence ρ is easy, but a threshold value is set for determining whether or not they coincide. Depending on how you do this, you may end up with a lot of wrong decisions. Therefore, it is desirable to calculate the degree of coincidence ρ in consideration of both the phase and the size. In this case, the degree of coincidence ρ as a whole vector can be calculated. For example, it is possible to suppress erroneous judgments that the two are the same when the sizes are similar but the phases are significantly different, or when the phases are similar but the sizes are completely different. Can do.

The following equation (5) calculates the degree of coincidence ρ by paying attention to both the phase and size of each vector. In the calculation of the degree of phase coincidence for each phase in the above equation (3), The degree of coincidence is multiplied (−1 ≦ ρ ≦ 1). In addition, said (1) Formula weights for every phase based on the ratio of the magnitude | size of each vector in following (5) Formula.

In addition, you may make it use the following (6) Formula which weighted for every phase in said (3) Formula.

Further, the degree of coincidence ρ may be calculated after the measured voltage change vectors ΔVabr, ΔVbcr, ΔVcar and the estimated voltage change vectors ΔVabg, ΔVbcg, ΔVcag are transformed into a state that can be easily compared. For example, vectors ΔVαβr, obtained by three-phase two-phase conversion (αβ conversion) of the measured voltage change vectors ΔVabr, ΔVbcr, ΔVcar and the estimated voltage change vectors ΔVabg, ΔVbcg, ΔVcag as shown in the following equations (7) and (8), respectively. ΔVαβg may be calculated, and the degree of coincidence ρ (−1 ≦ ρ ≦ 1) may be calculated using the following equation (9). The ΔVαβr corresponds to the “first vector” of the present invention, and the ΔVαβg corresponds to the “second vector” of the present invention. In this case, the degree of coincidence ρ is calculated after the measured voltage change vectors ΔVabr, ΔVbcr, ΔVcar and the estimated voltage change vectors ΔVabg, ΔVbcg, ΔVcag are each transformed into one vector, so the degree of coincidence ρ is easily calculated.

Instead of the above equation (9), the following equation (10) for calculating the degree of coincidence ρ focusing on the phase of the vector may be used. 11) Formula may be used. Further, the degree of coincidence ρ may be calculated by converting to another vector by a method other than the three-phase to two-phase conversion and using the vector after each conversion.

  Next, the coincidence determination unit 14 determines whether the coincidence ρ is “0” or more or less than “0”. When the degree of coincidence ρ is “0” or more, it is determined that the measured voltage change vectors ΔVabr, ΔVbcr, ΔVcar and the estimated voltage change vectors ΔVabg, ΔVbcg, ΔVcag match, and it is determined that a disconnection has occurred on the downstream side. . On the other hand, if the degree of coincidence ρ is less than “0”, it is determined that the measured voltage change vectors ΔVabr, ΔVbcr, ΔVcar and the estimated voltage change vectors ΔVabg, ΔVbcg, ΔVcag do not match, and a disconnection occurs on the upstream side. judge. The coincidence degree determination unit 14 outputs information indicating the determined disconnection direction to the communication unit 4.

  For example, when the measured voltage change vectors ΔVabr, ΔVbcr, ΔVcar are vectors indicated by broken lines in FIG. 11C, they are similar to the estimated voltage change vectors ΔVabg, ΔVbcg, ΔVcag indicated by solid lines, and the degree of coincidence ρ Becomes a large value. Therefore, it is determined that ρ ≧ 0, and it is determined that the disconnection has occurred on the downstream side. On the other hand, when the measured voltage change vectors ΔVabr, ΔVbcr, ΔVcar are vectors indicated by broken lines in FIG. 11D, they are not similar to the estimated voltage change vectors ΔVabg, ΔVbcg, ΔVcag indicated by solid lines, and the degree of coincidence ρ becomes a small value. Therefore, it is determined that ρ <0, and it is determined that the disconnection has occurred on the upstream side.

  In the present embodiment, the coincidence degree determination unit 14 compares the coincidence degree ρ with “0”, but the threshold value for comparison is not limited thereto. The degree of coincidence ρ is −1 ≦ ρ ≦ 1, and when ρ = 1, perfect coincidence, and when ρ = −1, complete coincidence. As the threshold value for comparison is set to a larger value, it is less likely to be determined to match, and as the threshold value is set to a smaller value, it is more likely to be determined to match. The threshold value for comparison may be appropriately determined by experiment so that the correct judgment can be made as much as possible. Even when the line impedance per unit distance is inaccurate, such as when the types and thicknesses of the distribution lines a, b, and c change in the middle, by setting the threshold value for comparison with the matching degree ρ to a small value The error can be made more tolerable.

  FIG. 12 is a flowchart for explaining the disconnection direction determination process performed by the disconnection direction determination unit 1. This process is started when the disconnection detection device A is activated.

First, the disconnection direction determination unit 1 acquires current signals i _a , i _b , and _ic from the instrument current transformers CT1, CT2, and CT3, respectively, and voltage signals v _ab from the instrument transformers PT1, PT2, and PT3, respectively. , V _bc , v _ca are acquired (S1). Based on the acquired signals, the vector generation unit 11 generates line current vectors Ia, Ib, Ic and line voltage vectors Vab, Vbc, Vca (S2).

  Next, the disconnection direction determination unit 1 determines whether a disconnection is detected (S3). Specifically, it is determined whether or not a signal indicating that a disconnection has occurred is input from the disconnection determination unit 2. When the disconnection is not detected (S3: NO), the line current vectors Ia, Ib, Ic and the line voltage vectors Vab, Vbc, Vca are written in the storage unit (S4), and the process returns to step S1. On the other hand, if a disconnection is detected (S3: YES), line current vectors Ia ', Ib', Ic 'and line voltage vectors Vab', Vbc ', Vca' are read from the storage unit (S5).

  Next, the measured voltage change vector generation unit 12 generates the measured voltage change vectors ΔVabr, ΔVbcr, ΔVcar, and the estimated voltage change vector generation unit 13 generates the estimated voltage change vectors ΔVabg, ΔVbcg, ΔVcag (S6). Then, the coincidence determination unit 14 calculates the coincidence ρ based on the equation (1) (S7).

  Next, the coincidence determination unit 14 determines whether or not the coincidence ρ is “0” or more (S8). When the coincidence degree ρ is equal to or greater than “0” (S8: YES), the coincidence degree determination unit 14 determines that the actually measured voltage change vectors ΔVabr, ΔVbcr, ΔVcar and the estimated voltage change vectors ΔVabg, ΔVbcg, ΔVcag match. It judges and outputs the information which shows that the disconnection generate | occur | produced in the downstream to the communication part 4 (S9). On the other hand, when the coincidence degree ρ is less than “0” (S8: NO), the coincidence degree determination unit 14 matches the measured voltage change vectors ΔVabr, ΔVbcr, ΔVcar and the estimated voltage change vectors ΔVabg, ΔVbcg, ΔVcag. It is determined that there is no disconnection, and information indicating that a disconnection has occurred upstream is output to the communication unit 4 (S10). In addition, the disconnection direction determination process which the disconnection direction determination part 1 performs is not limited to what was mentioned above.

  The interruption command unit 3 outputs an interruption command to the circuit breakers CB1, CB2, and CB3 based on information input from the disconnection determination unit 2. When the information indicating that the disconnection has occurred is input, the breaker command unit 3 outputs a breaker command to the breakers CB1 to CB3 to open the breakers CB1 to CB3.

  The communication part 4 transmits the information input from the disconnection determination part 2 and the disconnection direction determination part 1 to the management apparatus which is not shown in figure. The management device manages the state of the distribution line. When information indicating that a disconnection has occurred is input from the communication unit 4, the management device warns the occurrence of the disconnection with a buzzer and displays it on the monitor screen. . In addition, the information transmitted from the communication unit 4 to the management device includes information indicating whether the disconnection is downstream or upstream. Therefore, the management device determines which section of which distribution line the disconnection has occurred according to what information is input from which disconnection detection device A, and displays the determined content on the monitor screen. indicate.

  The processing performed by each part of the disconnection detection device A may be designed by a program, and the computer may function as the disconnection detection device A by executing the program. The program may be recorded on a recording medium and read by a computer.

  In the present embodiment, when the disconnection determination unit 2 detects the occurrence of a disconnection, the disconnection direction determination unit 1 determines the disconnection direction. The disconnection direction determination unit 1 generates an actually measured voltage change vector ΔVabr, ΔVbcr, ΔVcar indicating an actual voltage change due to disconnection by the actually measured voltage change vector generation unit 12, and the estimated voltage change vector generation unit 13 disconnects at the downstream side. Estimated voltage change vectors ΔVabg, ΔVbcg, and ΔVcag indicating the voltage change estimated when the error occurs are generated. Then, the coincidence determination unit 14 calculates a coincidence degree ρ between the measured voltage change vectors ΔVabr, ΔVbcr, ΔVcar and the estimated voltage change vectors ΔVabg, ΔVbcg, ΔVcag, and when the coincidence degree ρ is “0” or more, It is judged that they are coincident, it is judged that a disconnection has occurred on the downstream side, and if the degree of coincidence ρ is less than “0”, it is judged that they are not coincident and the disconnection has occurred on the upstream side judge. That is, the disconnection direction is determined based on whether or not the actual voltage change at the time of disconnection is the same as the voltage change when the disconnection occurs on the downstream side. Therefore, the direction in which the disconnection has occurred can be determined more accurately than the case where the configuration that detects the disconnection on the upstream side detects a disconnection or the configuration that detects the disconnection on the downstream side detects the disconnection. .

  Further, the coincidence determination unit 14 calculates the coincidence ρ based on the above (1). Since the above equation (1) calculates the degree of coincidence ρ for the entire vector in consideration of both the phase and the magnitude, it is possible to suppress misjudgment of coincidence. Therefore, erroneous determination of the disconnection direction can be suppressed. Further, since the threshold value to be compared with the matching degree ρ is “0”, the determination can be made based on whether the matching degree ρ is a positive value or a negative value. Therefore, determination is easy.

  The estimated voltage change vector generation unit 13 generates phase voltage change vectors ΔVag, ΔVbg, ΔVcg by multiplying the current change vectors ΔIa, ΔIb, ΔIc by the line impedance (R + jX) per unit distance. . Therefore, since the line impedance per unit distance may be set, it is not necessary to set a specific line impedance corresponding to the distance from the power source for each disconnection detection device A.

  Moreover, since the disconnection detection apparatus A includes the disconnection determination unit 2, it is possible to determine that a disconnection has occurred even if information on the occurrence of disconnection is not input from an external disconnection determination apparatus. The disconnection determination unit 2 can detect the upstream disconnection by the upstream disconnection determination unit 24 and can detect the downstream disconnection by the downstream disconnection determination unit 22. Therefore, the disconnection determination unit 2 can detect the occurrence of disconnection more reliably than when detecting disconnection in only one direction.

  Further, the downstream disconnection determination unit 22 determines whether or not the current change vectors ΔIa, ΔIb, and ΔIc of each phase voltage input input from the current change vector generation unit 21 satisfy the above conditions (1) to (3). When all the conditions are satisfied, it is determined that a disconnection has occurred on the downstream side. Although it is difficult to distinguish between load fluctuations and downstream disconnections based on line current vectors, they can be distinguished by differences in current change vectors of each phase voltage reference. Therefore, erroneous detection due to load fluctuation can be suppressed in downstream disconnection detection.

  In the present embodiment, the degree of coincidence ρ is compared with one threshold value, but the present invention is not limited to this. For example, two threshold values may be provided, and it may be determined whether they are coincident or not coincident. Specifically, when the degree of coincidence ρ is equal to or greater than a first threshold (for example, 0.3), the actually measured voltage change vectors ΔVabr, ΔVbcr, ΔVcar and the estimated voltage change vectors ΔVabg, ΔVbcg, ΔVcag match. It is determined that a disconnection has occurred on the downstream side. On the other hand, when the degree of coincidence ρ is less than a second threshold (for example, −0.3), it is determined that the actually measured voltage change vectors ΔVabr, ΔVbcr, ΔVcar and the estimated voltage change vectors ΔVabg, ΔVbcg, ΔVcag do not match. It is determined that the disconnection has occurred on the upstream side. If the degree of coincidence ρ is less than the first threshold value and greater than or equal to the second threshold value, it is determined whether it matches or does not match, and it is determined that the direction in which the disconnection has occurred is unknown. In this case, it can be suppressed that the disconnection direction is erroneously determined as the opposite direction.

  Moreover, although this embodiment demonstrated the case where the disconnection direction determination part 1 determined a disconnection direction, even when the upstream disconnection determination part 24 detected a disconnection, it is not restricted to this. For example, since the upstream disconnection determination unit 24 cannot detect the disconnection on the downstream side, when the upstream disconnection determination unit 24 detects the disconnection, the disconnection direction determination unit 1 does not determine the disconnection direction and the upstream It may be determined that a disconnection has occurred on the side. That is, the upstream disconnection determination unit 24 may output information indicating the disconnection direction (upstream side) to the communication unit 4 instead of outputting a signal indicating that the disconnection has occurred to the disconnection direction determination unit 1. Good.

  In this embodiment, the case where the instrument transformers PT1, PT2, and PT3 each detect the line voltage between the distribution lines has been described. However, the instrument transformers PT1, PT2, and PT3 each detect the phase voltage of the distribution line. You may make it do.

  In the present embodiment, the current change vectors ΔIa, ΔIb, ΔIc of each phase voltage reference are used to determine the occurrence of the disconnection on the downstream side, but the present invention is not limited to this. For example, each line voltage reference current change vector may be used. Alternatively, a current change vector based on a voltage obtained by adding a predetermined phase to each phase voltage (for example, a voltage obtained by shifting each phase voltage by 10 °) may be used. That is, a current change vector based on the reference voltage for each phase may be used.

  In the said 1st Embodiment, the case where the case where a two-phase load fluctuation arises was not assumed was demonstrated. Below, the case where the case where a two-phase load fluctuation arises is assumed is explained as a 2nd embodiment.

  First, vectors ΔIa, ΔIb, ΔIc at the time of two-phase load fluctuation when the connection of transformer B is a ΔΔ connection will be described.

FIG. 13A shows a two-phase load fluctuation, and shows a state where the load Lab and the load Lca are disconnected. In this case, as is apparent from FIG.
Ia = 0
Ib = Ibc
Ic = −Ibc
It becomes.

Therefore, the current change vectors ΔIa, ΔIb, ΔIc before and after the load change are
ΔIa = (Iab−Ica) − (0) = Iab−Ica
ΔIb = (Ibc−Iab) − (Ibc) = − Iab
ΔIc = (Ica−Ibc) − (− Ibc) = Ica
And expressed with reference to the phase voltage vector of each phase,
It becomes.

When the line current vector based on each phase voltage is set to I and the vectors βVa, βVb, βVc are replaced with the vector I, respectively,
It becomes. FIG. 13B shows the vectors ΔIa, ΔIb, ΔIc when the two-phase load fluctuates. In the vector diagram at the time of the disconnection shown in FIG. 4B, when α is “0”, the vector diagram is the same as FIG. 13B.

  Next, vectors ΔIa, ΔIb, ΔIc at the time of two-phase load fluctuation when the connection of transformer B is a ΔY connection will be described.

When the load Lab and the load Lca are disconnected and Iab = Ica = 0,
Ia = Ibc
Ib = Ibc
Ic = -2Ibc
It becomes.

Therefore, the current change vectors ΔIa, ΔIb, ΔIc before and after the load change are
ΔIa = (Iab + Ibc−2Ica) − (Ibc) = Iab−2Ica
ΔIb = (Ibc + Ica−2Iab) − (Ibc) = Ica−2Iab
ΔIc = (Ica + Iab−2Ibc) − (− 2Ibc) = Ica + Iab
And expressed with reference to the phase voltage vector of each phase,
It becomes.

When the line current vector based on each phase voltage is set as I and the vectors γVa, γVb, and γVc are replaced with the vector I, respectively,
It becomes. FIG. 14A shows the vectors ΔIa, ΔIb, ΔIc when the two-phase load fluctuates. Even the vector shown in FIG. 14A may satisfy all of the above conditions (1) to (3).

  Next, vectors ΔIa, ΔIb, ΔIc at the time of two-phase load fluctuation when the connection of transformer B is a YΔ connection will be described.

When the load Lab and the load Lca are disconnected and Iab = Ica = 0,
Ia =-(1/3) Ibc
Ib = (2/3) Ibc
Ic =-(1/3) Ibc
It becomes.

Therefore, the current change vectors ΔIa, ΔIb, ΔIc before and after the load change are
ΔIa = ((2/3) Iab− (1/3) Ibc− (1/3) Ica) − (− (1/3) Ibc)
= (2/3) Iab- (1/3) Ica
ΔIb = ((2/3) Ibc− (1/3) Ica− (1/3) Iab) − (2/3) Ibc
=-(1/3) Ica- (1/3) Iab
ΔIc = ((2/3) Ica− (1/3) Iab− (1/3) Ibc) − (− (1/3) Ibc)
= (2/3) Ica- (1/3) Iab
And expressed with reference to the phase voltage vector of each phase,
It becomes.

When the line current vector based on each phase voltage is set to I and the vectors εVa, εVb, and εVc are replaced with the vector I, respectively,
It becomes. FIG. 14B shows the vectors ΔIa, ΔIb, ΔIc when the two-phase load fluctuates. Even the vector shown in FIG. 14B may satisfy all of the above conditions (1) to (3).

  As described above, if occurrence of disconnection is determined under the above conditions (1) to (3), it is erroneously determined as disconnection when the two-phase load fluctuates. In the second embodiment, no erroneous determination is made in the case of a two-phase load fluctuation.

  FIG. 15 is a diagram for explaining the disconnection determination unit 2 ′ according to the second embodiment. In the same figure, the same code | symbol is attached | subjected to the same or similar element as the disconnection determination part 2 (refer FIG. 2) which concerns on 1st Embodiment.

  The disconnection determination unit 2 ′ shown in FIG. 15 is the same as that of the first embodiment in that the downstream disconnection determination unit 22 ′ uses the input from the zero-phase voltage sensor 7 to determine whether the downstream disconnection has occurred. It differs from the disconnection determination part 2 which concerns.

  The zero phase voltage sensor 7 is disposed on the distribution lines a, b, and c, and detects the zero phase voltage. The zero-phase voltage sensor 7 outputs the detected zero-phase voltage to the downstream disconnection determination unit 22 '.

The downstream disconnection determination unit 22 ′ also determines the occurrence of disconnection using the zero phase voltage input from the zero phase voltage sensor 7. Specifically, the downstream disconnection determination unit 22 ′ sets the following condition (4) in addition to the above conditions (1) to (3).
(4) The zero-phase voltage is equal to or higher than a predetermined threshold value V ₀ .

The zero-phase voltage is “0” in the three-phase equilibrium state, and is not affected by the load fluctuation. However, when a disconnection occurs, an unbalanced state occurs and the zero-phase voltage is not “0”. When the zero-phase voltage is equal to or higher than a predetermined threshold value V ₀ based on detection errors, a disconnection may have occurred. In the present embodiment, for example, a value of several volts is set as the predetermined threshold value V ₀ . Since the zero phase voltage may not be “0” due to the unbalance due to the fluctuation of the power system, the condition (1) to (3) is not determined based on the condition (4) alone. Judgment is also made. The downstream disconnection determination unit 22 ′ determines that a disconnection has occurred in the distribution line when all of the above conditions (1) to (4) are satisfied.

  When the two-phase load fluctuates, the above conditions (1) to (3) may be satisfied, but the above condition (4) is not satisfied. Therefore, in the second embodiment, it is possible to suppress erroneous determination that disconnection occurs when the two-phase load fluctuates.

  In the first and second embodiments, the case where the downstream disconnection is detected based on the current change vector has been described. However, the method for detecting the downstream disconnection is not limited to this. For example, the downstream disconnection may be detected based on the current vector. Further, a disconnection on the downstream side may be detected based on a change in impedance.

  In the first and second embodiments, the case where the upstream disconnection is detected based on the effective value of the line voltage has been described, but the method of detecting the upstream disconnection is not limited to this. For example, the upstream disconnection may be detected based on the instantaneous value of the line voltage. Further, a phase voltage may be used instead of the line voltage. Further, the disconnection on the upstream side may be detected using current, power, zero-phase voltage, or the like instead of voltage.

  In the first and second embodiments, the case where the disconnection determination unit 2 (2 ') can detect both the upstream disconnection and the downstream disconnection has been described. However, the present invention is not limited to this. The disconnection determination unit 2 (2 ') may detect only one of the upstream and downstream disconnections. That is, the disconnection determination unit 2 (2 ') only needs to be able to detect that a disconnection has occurred. Even in this case, when the disconnection occurs, the disconnection direction determination unit 1 determines the disconnection direction.

  Next, a disconnection section specifying system using the disconnection detection apparatus A will be described.

  FIG. 16 is a diagram for explaining the disconnection section identification system. The disconnection section specifying system includes disconnection detection devices A1, A2, A3,...

  The management device C manages the state of the distribution line, and receives information transmitted from each of the disconnection detection devices A1, A2, A3,. When each disconnection detecting device A1, A2, A3,... Detects a disconnection, the disconnection detection device A1, A2, A3,. The management device C identifies the section where the disconnection has occurred based on the information about the disconnection received from each of the disconnection detection devices A1, A2, A3,. Then, the occurrence of the disconnection and the section where the disconnection has occurred are displayed on the monitor screen and notified.

  For example, the management device C receives information indicating that a disconnection has occurred downstream from the disconnection detection devices A1 and A2, and has received information indicating that a disconnection has occurred upstream from the disconnection detection device A3. In this case, it is determined that a disconnection has occurred in the third section.

  The disconnection direction determination device, the disconnection direction determination method, and the disconnection section identification system according to the present invention are not limited to the above-described embodiments. The specific configuration of each part of the disconnection direction determination device, disconnection direction determination method, and disconnection section identification system according to the present invention can be varied in design in various ways.

A, A ′, A1, A2, A3 Disconnection detection device 1 Disconnection direction determination unit 11 Vector generation unit (vector generation unit)
DESCRIPTION OF SYMBOLS 12 Measured voltage change vector production | generation part 13 Estimated voltage change vector production | generation part 14 Matching degree judgment part 2,2 'Disconnection judgment part 21 Current change vector production | generation part 211 Vector production | generation part (2nd vector production | generation part)
212 arithmetic unit 213 storage unit 22, 22 ′ downstream disconnection determination unit (disconnection determination means)
23 RMS value calculation unit 24 Upstream disconnection determination unit 3 Interruption command unit 4 Communication unit 7 Zero-phase voltage sensor a, b, c distribution line CT1, CT2, CT3 Current transformer (electric signal detector)
PT1, PT2, PT3 Instrument transformer (electric signal detector)
B Transformer C Management device

Claims (16)

A disconnection direction determination device that determines a direction in which a disconnection occurs when any one of the three-phase distribution lines is disconnected,
A line current vector for each phase is generated based on the current signal detected by the electrical signal detector disposed on the distribution line, and a voltage vector for each phase is generated based on the voltage signal detected by the electrical signal detector. Vector generation means;
An actual voltage change vector generating means for generating an actual voltage change vector that is a change vector obtained by subtracting the voltage vector of each phase before the occurrence of disconnection from the voltage vector of each phase after the occurrence of disconnection;
By generating a change vector obtained by subtracting the line current vector of each phase after occurrence of disconnection from the line current vector of each phase before occurrence of disconnection, and multiplying this by the line impedance of the distribution line, the estimated voltage change An estimated voltage change vector generating means for generating a vector;
A degree of coincidence determining means for calculating a degree of coincidence between the measured voltage change vector and the estimated voltage change vector, and determining whether a disconnection has occurred on the upstream side or a disconnection has occurred on the downstream side based on the degree of coincidence; ,
A disconnection direction determination device characterized by comprising: The coincidence determination means determines that a disconnection has occurred on the downstream side when the coincidence is equal to or greater than a predetermined threshold, and determines that a disconnection has occurred on the upstream side when the coincidence is less than the predetermined threshold. ,
The disconnection direction determination apparatus according to claim 1. The degree of coincidence is calculated based on the phase difference between the measured voltage change vector of each phase and the estimated voltage change vector of each phase.
The disconnection direction determination apparatus according to claim 1 or 2. The degree of coincidence is calculated based on a difference in magnitude between the measured voltage change vector of each phase and the estimated voltage change vector of each phase.
The disconnection direction determination apparatus according to any one of claims 1 to 3. The degree of coincidence ρ is calculated based on the following equation when the measured voltage change vectors of the respective phases are ΔVabr, ΔVbcr, ΔVcar, and the estimated voltage change vectors of the respective phases are ΔVabg, ΔVbcg, ΔVcag. ,
The disconnection direction determination apparatus according to claim 2.
The threshold is “0”.
The disconnection direction determination apparatus according to claim 5. The degree-of-match determination means transforms the measured voltage change vector of each phase into a first vector, transforms the estimated voltage change vector of each phase into a second vector, and the first vector and the second vector And the degree of coincidence is calculated based on the vector of
The disconnection direction determination apparatus according to claim 1 or 2. The degree of coincidence ρ is calculated based on the following equation when the measured voltage change vectors of the respective phases are ΔVabr, ΔVbcr, ΔVcar, and the estimated voltage change vectors of the respective phases are ΔVabg, ΔVbcg, ΔVcag. ,
The disconnection direction determination apparatus according to claim 7.
The estimated voltage change vector generating means generates an estimated voltage change vector by multiplying the line impedance per unit distance as the line impedance of the distribution line, normalizes and outputs the generated estimated voltage change vector,
The measured voltage change vector generating means standardizes and outputs the generated measured voltage change vector.
The disconnection direction determination apparatus according to any one of claims 1 to 8. A disconnection determining means for determining whether any one of the three-phase distribution lines is disconnected;
The disconnection direction determination apparatus according to any one of claims 1 to 9. The disconnection determination means includes:
Based on the electrical signal detected by the electrical signal detector, a current change vector generating means for generating a current change vector that is a change vector of a line current vector with reference to a reference voltage for each phase;
Disconnection determination means for determining whether or not a disconnection has occurred in the distribution line based on each current change vector generated by the current change vector generation means;
With
The disconnection direction determination apparatus according to claim 10. The current change vector generation means includes
Second vector generating means for generating a line current vector for each phase based on the current signal detected by the electrical signal detector, and generating a voltage vector for each phase based on the voltage signal detected by the electrical signal detector. When,
Calculation means for converting the line current vector of each phase into a vector based on a reference voltage for each phase using the voltage vector of each phase and calculating a change vector of the line current vector of each phase after the conversion When,
With
The disconnection direction determination apparatus according to claim 11. The disconnection judging means has each current change vector generated by the current change vector generating means,
(1) A phase difference of a current change vector of a phase whose phase advances with respect to a current change vector of a certain phase, and a current change vector of the certain phase with respect to a current change vector of a phase whose phase is later than the certain phase Of the first threshold value θ ₁ or more and the second threshold value θ ₂ or less, respectively.
(2) the magnitudes of all current change vectors are greater than or equal to a predetermined threshold I ₀ ;
(3) Not applicable when all of the following (3-1) to (3-2) are satisfied,
(3-1) The phase difference between the current change vector having the maximum size among the current change vectors and the other current change vectors is about 60 °, respectively.
(3-2) The magnitude of the maximum current change vector is about twice the magnitude of the other current change vectors.
If all the conditions are satisfied, it is determined that a disconnection has occurred.
The disconnection direction determination apparatus according to claim 11 or 12. It further comprises a zero phase voltage detecting means for detecting a zero phase voltage,
In addition to the conditions (1) to (3), the disconnection determination means
(4) The zero-phase voltage is not less than a predetermined threshold value V ₀ .
If all the conditions are satisfied, it is determined that a disconnection has occurred.
The disconnection direction determination apparatus according to claim 13. A plurality of disconnection direction determination devices according to any one of claims 1 to 14, arranged on a distribution line,
When the disconnection direction determination device determines the direction in which the disconnection has occurred, a management device that transmits information about the disconnection by communication from the disconnection direction determination device;
With
The management device identifies a section where the disconnection of the distribution line has occurred based on the received information about the disconnection,
Disconnection section identification system. A method for determining the direction in which a disconnection of a distribution line has occurred,
A first step in which an electric signal detector disposed on the distribution line detects an electric signal;
A second step of generating a line current vector of each phase and a voltage vector of each phase based on the electrical signal detected in the first step;
A third step of storing each detected vector;
A fourth step of generating an actually measured voltage change vector that is a change vector obtained by subtracting the voltage vector of each phase before occurrence of disconnection from the voltage vector of each phase after occurrence of disconnection;
By generating a change vector obtained by subtracting the line current vector of each phase after occurrence of disconnection from the line current vector of each phase before occurrence of disconnection, and multiplying this by the line impedance of the distribution line, the estimated voltage change A fifth step of generating a vector;
A sixth step of calculating a degree of coincidence between the actually measured voltage change vector and the estimated voltage change vector, and determining, based on the degree of coincidence, whether a disconnection has occurred on the upstream side or a disconnection has occurred on the downstream side; ,
The disconnection direction determination method characterized by comprising.