JP4429766B2 - Voltage adjusting device and voltage adjusting method - Google Patents

Description

  The present invention relates to a voltage adjustment device that adjusts the voltage of a distribution line by switching taps of a transformer, for example, in preparation for a voltage drop of the distribution line, and a voltage adjustment method of the voltage adjustment device.

Since voltage stabilization in power supply is essential, for example, in substation equipment, voltage regulation of the distribution line is performed by a voltage regulator. In particular, when the distribution line from the transformer facility to the user is long, the voltage fluctuation also increases according to the load of the user. Therefore, when the substation equipment distributes power by lowering the voltage to the user's usage level using a transformer provided in the voltage regulator, tap switching of the transformer is automatically performed to maintain a specified voltage.
Japanese Patent Laid-Open No. 9-84266

  However, for example, the tap of the transformer in the voltage regulator disclosed in Patent Document 1 has been switched by contacting the movable contact with any of the plurality of taps of the transformer. Here, in order for the movable contact to move from one tap to another without interrupting the load on the output side, the movable contact must operate across the two taps. In order to avoid damage to the transformer due to a short circuit between the taps, the voltage regulator described above has a current limiting resistor or current limiting reactor inserted between the two taps when the movable contact extends over the two taps. Had to have a configuration. As described above, the voltage adjusting device in which the movable contact mechanically selects the tap has a complicated structure and the control of the tap switching time is not easy. For this reason, the above-described voltage adjusting device cannot be quickly adjusted with respect to a rapid voltage fluctuation caused by a motor load or the like at high cost.

  Further, the voltage regulator described above, for example, calculates a voltage drop to the user based on only one of the current and voltage of the distribution line, and switches the tap of the transformer to compensate for the voltage drop. . For this reason, it was not possible to sufficiently compensate for a large voltage fluctuation caused by a load that generates an induced electromotive force such as a motor.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a low-cost voltage regulator capable of quickly and sufficiently adjusting a voltage with respect to a load with a rapid and large voltage fluctuation, and the voltage. An object of the present invention is to provide a voltage adjustment method for an adjustment device.

Invention for solving the previous SL problems, which switches the tap of a transformer connected to the mains voltage regulator for adjusting the voltage of the distribution line, is turned on or off corresponding to each of the taps A switching relay attached, a bridging relay that bridges between the taps by changing from off to on, and a current that flows between the taps bridged by the bridging relay is limited. When switching between the current limiting means and the tap, the switching relay is changed from off to on while holding the switching relay in the on or off state before switching, Current-limiting bridge and holding the switching relay in the on or off state after switching, while changing the bridging relay of the current-limiting bridging means from on to off, Cancel the current bridge, It becomes provided with a control means, the.

  The control means of the voltage regulator changes the current between the taps by changing the bridging relay from off to on while maintaining the state of the switching relay, for example, at the initial switching of the tap. Bridge. Next, after changing the switching relay to a predetermined state in order to switch the tap, the control means changes the bridging relay from an on state to an off state at the end of the switching of the tap, for example. Release the current-limiting bridge. If the control means controls the switching relay and the bridging relay as described above at least at the initial stage of switching and at the end of switching, for example, while preventing the short circuit between the taps and protecting the transformer, for example, the output The voltage of the load can be adjusted without interrupting the load on the side.

In the voltage regulator, it is preferable that the current limiting means is a current limiting resistor connected in series with the bridging relay.
According to this voltage regulator, the current flowing between the taps bridged by the bridging relay is limited by the current limiting resistor. Thereby, the said transformer can be protected avoiding the short circuit between the said taps.

Further, in the voltage regulator, the voltage measuring device for measuring the voltage of the distribution line and / or the current measuring device for measuring the current of the distribution line, and the voltage measuring device and / or the current measuring device, respectively. Preferably, the apparatus further comprises tap selection means for selecting the tap based on the voltage and / or current.
If both the voltage and current of the distribution line are measured by the voltage measuring device and the current measuring device, for example, the power factor of the load on the output side can be obtained from the phase difference between the voltage and the current. For example, since the voltage drop of the distribution line changes according to the power factor, if the tap selection means calculates a voltage drop based on the power factor, the tap is effectively used to compensate for the voltage drop. You can choose.

Further, in the voltage adjustment device, the tap selection unit calculates a voltage drop at a predetermined point of the distribution line based on the current of the distribution line measured by the current measurement device, and the voltage of the distribution line It is preferable to include a calculation unit that subtracts a voltage drop and a predetermined voltage at the predetermined point, and a comparison unit that compares the absolute value of the subtraction value obtained by the calculation unit with a predetermined value.
If the predetermined point is, for example, a load on the output side of the distribution line, the calculation unit can calculate a voltage drop of the distribution line up to the load. Further, if the predetermined voltage is a voltage expected at the load on the output side, for example, the calculation unit can calculate the difference between the expected voltage and the actual voltage at the load. If the predetermined value is an allowable value of this difference, for example, the comparison unit can determine whether or not the actual voltage is within an allowable range. Therefore, the tap selection means can select the tap more effectively to compensate for the voltage drop.

Moreover, in this voltage regulator, it is preferable that the calculation unit calculates the voltage drop by multiplying the current of the distribution line measured by the current measuring device by the impedance of the distribution line. In the voltage regulator, the tap selection unit further includes a storage unit that stores data of a cross-sectional area of the distribution line and data of a length up to the predetermined point of the distribution line, and the calculation unit includes: It is preferable to calculate the impedance of the distribution line based on the data read from the storage unit.
The tap selection unit can read the data of the distribution line from the storage unit, calculate an impedance of the distribution line based on the data, and calculate the voltage drop using the impedance. Therefore, for example, if the data is input by an appropriate input unit and stored in the storage unit, the tap selection unit can more effectively select the tap to compensate for the voltage drop according to the data. .

In this voltage regulator, the tap selection means may select the tap that has increased or decreased by one step when the comparison unit determines that the absolute value of the subtraction value is greater than the predetermined value. preferable. Further, in this voltage regulator, the tap selection means is configured to increase or decrease the tap by one step when the comparison unit continues to determine that the absolute value of the subtraction value is greater than the predetermined value within a predetermined time. Is preferably selected. In the voltage regulator, it is preferable that the predetermined time is about 5 seconds to about 30 seconds. In the voltage regulator, the predetermined value is preferably about 20V to about 25V.
According to this voltage regulator, if the predetermined value is, for example, an allowable value of the difference between the voltage expected at the load on the output side of the distribution line and the actual voltage (absolute value of the subtraction value), When the comparison unit determines that the actual voltage is not within the allowable range, the tap is selected to increase or decrease the voltage of the voltage regulator. Therefore, the tap selection means can effectively select the tap to compensate for voltage fluctuation. In addition, if the tap is selected when the determination continues to be performed within the predetermined time, the determination becomes more reliable, so the tap can be selected more effectively.

  The invention for solving the above-mentioned problem is a voltage adjustment method of a voltage adjustment device for adjusting a voltage of the distribution line by switching a tap of a transformer to which the distribution line is connected by a switching relay, A current-limiting bridging start step for current-limiting bridging between the taps while holding the switching relay associated with each tap corresponding to the off-state in an on or off state before switching; A current limiting bridge releasing step of canceling the current limiting bridge while maintaining the relay in an on or off state after switching. In addition, the voltage adjustment method may further include a tap selection step of selecting the tap based on the voltage of the distribution line and / or the current of the distribution line prior to the step of starting the current limiting bridge. Is preferred. In the voltage adjustment method, the tap selection step calculates a voltage drop at a predetermined point of the distribution line based on the current of the distribution line, and calculates the voltage drop and the predetermined point at the predetermined point from the voltage of the distribution line. It is preferable to subtract the voltage and compare the absolute value of the subtraction value with a predetermined value. In the voltage adjustment method, it is preferable that the tap selection step selects the tap that has increased or decreased by one step when it is determined that the absolute value of the subtraction value is greater than the predetermined value. In the voltage adjustment method, the tap selection step selects the tap that has increased or decreased by one step when the absolute value of the subtraction value is determined to be larger than the predetermined value within a predetermined time. It is preferable.

  It is possible to provide a low-cost voltage adjustment device capable of quickly and sufficiently adjusting a voltage with respect to a load with a rapid and large voltage fluctuation, and a voltage adjustment method for the voltage adjustment device.

=== Configuration of Voltage Regulator ===
<<<< Switching relay, bridging relay, current limiting resistor >>>>
As illustrated in the circuit diagram of FIG. 1, the voltage regulator 10 of the present embodiment mainly includes a regulation transformer (transformer) 20, a series transformer 30, and switching relays 41, 42, 43, 44, a relay 50 for bridging, and a relay circuit 70 including current limiting resistors (current limiting means, first current limiting resistor, second current limiting resistor) 61 and 62. Here, the adjustment transformer 20 is connected to the distribution lines S and T as the input side of the voltage regulator 10. The series transformer 30 is connected to the distribution lines S and T as the output side of the voltage regulator 10. Further, the switching relays 41, 42, 43, and 44 are provided in the adjustment transformer 20 and switch taps described later. The bridging relay 50 bridges the taps, and the current limiting resistors 61 and 62 limit the current between the taps.

  Note that a voltage of 420 V is applied between the input side terminals UV of the voltage adjusting device 10 of the present embodiment, and a voltage of 420 V to 540 V is output between the output side terminals uv as described later. In addition, the voltage regulator 10 according to the present embodiment, for example, supplies electric power having a voltage of about 400 V to a general user through a distribution line of about 1.5 km with a current of about 30 A at a light load and about 80 A at a heavy load. It can be applied to the supplying system.

  The adjustment transformer 20 includes a first tap (A1) 21 having a potential of 420V, a second tap (A2) 22 having a potential of 280V, a third tap (A3) 23 having a potential of 140V, and a potential of 0V. There are a total of four taps 21, 22, 23, 24 of the fourth tap (A4) 24.

  The relay circuit 70 will be described. For the first tap (A1) 21 and the third tap (A3) 23, the first switching relay (Ry1) is set so that the potential on the intermediate side (X1, see FIG. 1) of the relay circuit 70 is 420V or 140V. ) 41, the first relay circuit 71 is formed. Here, the first switching relay (Ry1) 41 is configured to connect one of A1 and X1 and between A3 and X1 in FIG.

  In the present embodiment, for the following explanation, the state of the first switching relay (Ry1) 41 that connects between A1 and X1 and cuts off between A3 and X1 is turned on, and conversely between A1 and X1 The state of the first switching relay (Ry1) 41 that shuts off and connects between A3 and X1 is turned off. That is, when the first switching relay (Ry1) 41 is in the on state, a potential of 420 V is generated on the intermediate side X1, and when the first switching relay (Ry1) 41 is in the off state, the intermediate side X1 has A potential of 140V is generated. A fourth switching relay (Ry4) 44 is connected to the intermediate side X1 and the output side B1 (see FIG. 1) of the relay circuit 70, and the fourth switching relay (Ry4) 44 is According to the on or off state, X1 and B1 are connected or disconnected.

  For the second tap (A2) 22 and the fourth tap (A4) 24, the second switching relay (Ry2) is set so that the potential on the intermediate side (X2, see FIG. 1) of the relay circuit 70 is 280V or 0V. ) 42 is formed through the second relay circuit 72. Here, the second switching relay (Ry2) 42 is configured to connect one of A2 and X2 and between A4 and X2 in FIG.

  In the present embodiment, the second switching relay (Ry2) 42 that connects A2 and X2 and cuts off A4 and X2 is turned on for the following explanation, and conversely, A2 and X2 are connected. The state of the second switching relay (Ry2) 42 that shuts off and connects A4 and X2 is turned off. That is, when the second switching relay (Ry2) 42 is on, a potential of 280 V is generated on the intermediate side X2, and when the second switching relay (Ry2) 42 is off, the intermediate side X2 A potential of 0V is generated. Further, a third switching relay (Ry3) 43 is connected to the intermediate side X2 and the output side B4 (see FIG. 1) of the relay circuit 70, and the third switching relay (Ry3) 43 is According to the on or off state, X2 and B4 are connected or disconnected.

  The intermediate side X1 and the output side B3 (see FIG. 1) of the relay circuit 70 are connected to the current-limiting resistor 61 and the bridging relay (Ry5) 50 connected in series with each other. A current limiting resistor 62 and a bridging relay (Ry5) 50 connected in series are connected to the side X2 and the output side B2 of the relay circuit 70 (see FIG. 1). Here, the bridging relay (Ry5) 50 is configured to connect or block between X1 and B3 and between X2 and B2 in FIG.

  The series transformer 30 has a function of transforming the potential 0V to 420V on the output side (for example, B1 in FIG. 1) of the relay circuit 70 to 0V to 120V, which is 1 / 3.5, for example. The output from the series transformer 30 is added to the voltage 420V between the input side terminals UV, and the voltage between the output side terminals uv becomes 420V to 540V.

  As illustrated in the circuit diagram of FIG. 1, the voltage regulator 10 of the present embodiment includes an instrument transformer (PT, voltage measuring device) 90 for measuring the voltage between the output terminals uv, And a current transformer (CT, current measuring device) 100 for measuring the current flowing at the output terminal u.

  Further, as illustrated in the circuit diagram of FIG. 1, the operations of the switching relays 41, 42, 43, 44, the bridging relay 50, the instrument transformer 90, and the current transformer 100 of this embodiment are as follows. The control board 110 on which a predetermined circuit is formed is controlled. Next, a circuit formed on the control board 110 will be described.

<<<< Control means, tap selection means >>>>
As illustrated in the block diagram of FIG. 2, the circuit formed on the control board 110 (FIG. 1) includes the control unit 200 that controls the relays 41, 42, 43, 44, 50, and the like described above. Yes.

  As will be described later, the control unit 200 turns on or off the switching relays 41, 42, 43, and 44 and the bridging relay 50 for a predetermined time at a predetermined timing. This time is counted by the timer 210. In the on / off control, the control unit 200 causes the voltage transformer (PT) 90 and the current transformer (CT) 100 to measure voltage and current, respectively. The voltage and current are transmitted to the control unit 200 via an appropriate AC / DC converter. The control unit 200 performs an appropriate calculation on the voltage and current and data on the distribution lines S and T read from the memory (storage unit) 220 such as a ROM or a RAM, and the control unit 200 outputs the load 120 from the output terminals u and v. The voltage drop of the distribution lines S and T up to (see FIG. 1) is calculated. In accordance with the expected value of the voltage at the load 120, which is further calculated based on this voltage drop, the control unit 200 selects the taps 21, 22, 23, 24 to be switched, and the switching relays 41, 42, 43, 44 and the bridging relay 50 are turned on or off.

As will be described later, the control unit 200 performs a predetermined series of operations from the time when the voltage transformer 90 and the current transformer 100 measure the voltage and current to the time when the expected value of the voltage at the load 120 is calculated. It has a function to repeat in the cycle.
Such an operation of the control unit 200 is realized based on an appropriate program stored in the memory 220.

=== Voltage adjustment method ===
<<< Tap selection operation >>>
As illustrated in the flowchart of FIG. 3, first, the control unit 200 causes the timer 210 to start measuring time (S101). When the control unit 200 that causes the voltage transformer (PT) 90 and the current transformer (CT) 100 to constantly measure voltage and current respectively receives current (I) data from the current transformer (CT) 100, The current (I) is multiplied by the impedance (Z) of the distribution lines S and T, and the voltage drop (VD) of the distribution lines S and T from the output terminals u and v to the load 120 is calculated (S102). . Here, the impedance (Z) of the distribution lines S and T is stored in the memory 220 in advance, and the control unit 200 may read the impedance (Z) from the memory 220 in step S102. Alternatively, the line type (cross-sectional area) and length of the distribution lines S and T are stored in the memory 220, and the control unit 200 reads out the line type and length from the memory 220 in step S102, and the impedance (Z ) May be calculated.

  In addition, the control unit 200 that has received the voltage (V) data from the instrument transformer (PT) 90 determines, based on the voltage (V), the voltage drop (VD) and the expected value of the voltage at the load 120 (predetermined voltage). , E) are subtracted to calculate a subtraction value (D) (S103). The expected value (E) is a so-called reference voltage in the load 120, and is 365V, 375V, 385V, 395V, 405V, or 415V in the present embodiment. The expected value (E) may be stored in the memory 220 in advance and read from the memory 220 at the time of calculation in step S103.

  Next, the control unit 200 determines whether or not the absolute value (DA) of the subtraction value (D) is greater than the allowable fluctuation value (predetermined value, VC) (S104). If it is determined that the absolute value (DA) of the subtraction value (D) is equal to or less than the allowable fluctuation value (VC) (S104: N), the control unit 200 continues the operation after step S108 described later. Note that the variation allowable value (VC) of this embodiment is 20V to 25V. This variation allowable value (VC) may be stored in advance in the memory 220 and read from the memory 220 at the time of determination in step S104.

  If it is determined that the absolute value (DA) of the subtraction value (D) is larger than the allowable variation value (VC) (S104: Y), the control unit 200 refers to the timer 210 and starts from step S101. It is determined whether the elapsed time (T) is equal to or longer than a predetermined time (TC) (S105). The predetermined time (TC) in the present embodiment is 5 to 30 seconds. The predetermined time (TC) may be stored in advance in the memory 220 and read from the memory 220 at the time of determination in step S105. If it is determined that the elapsed time (T) is less than the predetermined time (TC) (S105: N), the control unit 200 continues the operation after step S102.

  If it is determined that the elapsed time (T) is equal to or longer than the predetermined time (TC) (S105: Y), if the subtraction value (D) is a positive value (S106: D> 0), the control unit 200 The taps 21, 22, and 23 that have risen by one step are selected, and on / off signals corresponding to switching to the respective taps 21, 22, and 23, which will be described later, are sent to the switching relays 41, 42, 43, and 44 and the bridge. (S107) and the timer 210 is reset (S108). On the other hand, when the subtraction value (D) is a negative value (S106: D <0), the control unit 200 selects the taps 22, 23, 24 that are lowered by one step, and each of the taps 22, 23, An on / off signal corresponding to the switching to 24 is transmitted to the switching relays 41, 42, 43, 44 and the bridging relay 50 (S109), and the timer 210 is reset (S110).

  In the present embodiment, the control unit 200 and an appropriate program that causes the control unit 200 to perform the operations of steps S101 to S110 correspond to the tap selection unit. Further, the control unit 200 and an appropriate program for causing the control unit 200 to perform the operations of steps S102 and S103 correspond to the calculation unit in the tap selection unit. Further, the control unit 200 and an appropriate program for causing the control unit 200 to perform the operation of step S105 correspond to the comparison unit in the tap selection unit.

<<< Tap switching operation from 420 V to 460 V >>>
An operation in which the control unit 200 (FIG. 2) switches from the fourth tap 24 to the third tap 23 in order to switch the voltage between the output terminals uv from 420 V to 460 V will be described.

  In the time domain T1 in the diagram of FIG. 4, the first switching relay (Ry1) 41 is in the off state, the second switching relay (Ry2) 42 is in the off state, and the third switching relay (Ry3). 43 is in an on state, the fourth switching relay (Ry4) 44 is in an off state, and the bridging relay (Ry5) 50 is in an off state. This is abbreviated as, for example, (Ry1, Ry2, Ry3, Ry4, Ry5) = (OFF, OFF, ON, OFF, OFF). In this case, the potential in the loop (see the arrow in FIG. 5) from A4 to the series transformer 30 via X2 and B4 and from the series transformer 30 to the input side terminal V is 0V everywhere. That is, the fourth tap (A4) 24 is selected, and the voltage between the output terminals uv is 420V.

  In the time domain T2 in the diagram of FIG. 4, an ON signal is transmitted from the control unit 200 (FIG. 2) to the bridging relay (Ry5) 50, and (Ry1, Ry2, Ry3, Ry4, Ry5) = (OFF, OFF , ON, OFF, ON). The resistance value of the current limiting resistor 61 of the present embodiment is the potential in a loop (see the arrow in FIG. 6) from A4 to the series transformer 30 via X2 and B4 and from the series transformer 30 to the input side terminal V. Is set in advance to be 0V everywhere. In this case, the state where the fourth tap (A4) 24 is selected is maintained, and the voltage between the output terminals uv is 420V.

  In the time domain T3 in the diagram of FIG. 4, an OFF signal is transmitted from the control unit 200 (FIG. 2) to the third switching relay (Ry3) 43, and (Ry1, Ry2, Ry3, Ry4, Ry5) = (OFF, OFF, OFF, OFF, ON). In the present embodiment, the time difference from when the control unit 200 transmits an ON signal to the bridging relay (Ry5) 50 to when it transmits an OFF signal to the third switching relay (Ry3) 43 is 200 ms. is there. In this case, the current in the relay circuit 70 flows in the order of A3, X1, B3, B2, X2, and A4 (see arrows in FIG. 7). When the load current is 0 A, the potentials of B2 and B3 are 70V. The 70V is an average potential of the potential 140V of the third tap (A3) 23 and the potential 0V of the fourth tap (A4) 24. On the other hand, in the present embodiment, when the load current is 23.8 A, for example, the resistance values of the current limiting resistors 61 and 62 are set in advance so that the potentials of B2 and B3 are 2V. Therefore, the potential on the output side of the series transformer 30 is approximately 1 V (= 2 V / 3.5) to 20 V (= 70 V / 3.5), and the voltage between the output terminals uv is approximately 421 V to 440 V.

  In the time domain T4 in the diagram of FIG. 4, an ON signal is transmitted from the control unit 200 (FIG. 2) to the fourth switching relay (Ry4) 44, and (Ry1, Ry2, Ry3, Ry4, Ry5) = (OFF, OFF, OFF, ON, ON). In the present embodiment, the time difference from when the control unit 200 transmits an OFF signal to the third switching relay (Ry3) 43 to when the ON signal is transmitted to the fourth switching relay (Ry4) 44 is 100 ms. It is. Further, the resistance value of the current limiting resistor 62 of the present embodiment is set in advance so that current flows mainly from A3 to the series transformer 30 via X1 and B1 (see the arrow in FIG. 8). In this case, the third tap (A3) 23 is selected, and the voltage between the output terminals uv is 460 V (= 420 V + 140 V / 3.5).

  In the time domain T5 in the diagram of FIG. 4, an OFF signal is transmitted from the control unit 200 (FIG. 2) to the bridging relay (Ry5) 50, and (Ry1, Ry2, Ry3, Ry4, Ry5) = (OFF, OFF , OFF, ON, OFF). In the present embodiment, the time difference from when the control unit 200 transmits an ON signal to the fourth switching relay (Ry4) 44 to when it transmits an OFF signal to the bridging relay (Ry5) 50 is 200 ms. is there. Current flows from A3 to the series transformer 30 via X1 and B1 (see arrow in FIG. 9). That is, the state where the fourth tap (A4) 24 is selected is maintained, and the voltage between the output terminals uv is 460V.

<<< Tap switching operation from 460 V to 500 V >>>
An operation in which the control unit 200 switches from the third tap 23 to the second tap 22 in order to switch the voltage between the output terminals uv from 460 V to 500 V will be described.

  In the time domain T1 in the diagram of FIG. 10, (Ry1, Ry2, Ry3, Ry4, Ry5) = (OFF, ON, OFF, ON, OFF). Here, the state of the second switching relay (Ry2) 42 is the same whether the output voltage (460 V) is on or off. Therefore, it is assumed that the state of the second switching relay (Ry2) 42 is on from the relationship with the operation described later.

  In the time domain T2 in the diagram of FIG. 10, an ON signal is transmitted from the control unit 200 to the bridging relay (Ry5) 50, and (Ry1, Ry2, Ry3, Ry4, Ry5) = (OFF, ON, OFF, ON , ON). In this case, the state where the third tap (A3) 23 is selected is maintained, and the voltage between the output terminals uv is 460V.

  In the time domain T3 in the diagram of FIG. 10, an OFF signal is transmitted from the control unit 200 to the fourth switching relay (Ry4) 44, and (Ry1, Ry2, Ry3, Ry4, Ry5) = (OFF, ON, OFF, OFF, ON). In this embodiment, the time difference from when the control unit 200 transmits an ON signal to the bridging relay (Ry5) 50 to when it transmits an OFF signal to the fourth switching relay (Ry4) 44 is 200 ms. is there. The voltage between the output terminals uv can take a value from about 460 V to about 500 V depending on the current flowing through the relay circuit 70.

  In the time domain T4 in the diagram of FIG. 10, an ON signal is transmitted from the control unit 200 to the third switching relay (Ry3) 43, and (Ry1, Ry2, Ry3, Ry4, Ry5) = (OFF, ON, ON, OFF, ON). In the present embodiment, the time difference from when the control unit 200 transmits an OFF signal to the fourth switching relay (Ry4) 44 to when the ON signal is transmitted to the third switching relay (Ry3) 43 is 100 ms. It is. In this case, the second tap (A2) 22 is selected, and the voltage between the output terminals uv is 500 V (= 420 V + 280 V / 3.5).

  In the time domain T5 in the diagram of FIG. 10, an OFF signal is transmitted from the control unit 200 to the bridging relay (Ry5) 50, and (Ry1, Ry2, Ry3, Ry4, Ry5) = (OFF, ON, ON, OFF , OFF). In the present embodiment, the time difference from when the control unit 200 transmits an ON signal to the third switching relay (Ry3) 43 to when it transmits an OFF signal to the bridging relay (Ry5) 50 is 200 ms. is there. The state where the second tap (A2) 22 is selected is maintained, and the voltage between the output terminals uv is 500V.

<<< Tap switching operation from 500 V to 540 V >>>
An operation in which the control unit 200 switches from the second tap 22 to the first tap 21 in order to switch the voltage between the output terminals uv from 500 V to 540 V will be described.

  In the time domain T1 in the diagram of FIG. 11, (Ry1, Ry2, Ry3, Ry4, Ry5) = (ON, ON, ON, OFF, OFF). Here, the output voltage (500 V) is the same regardless of whether the first switching relay (Ry1) 41 is on or off. Therefore, it is assumed that the state of the first switching relay (Ry1) 41 is on from the relationship with the operation described later.

  In the time domain T2 in the diagram of FIG. 11, an ON signal is transmitted from the control unit 200 to the bridging relay (Ry5) 50, and (Ry1, Ry2, Ry3, Ry4, Ry5) = (ON, ON, ON, OFF , ON). In this case, the state where the second tap (A2) 22 is selected is maintained, and the voltage between the output terminals uv is 500V.

  In the time domain T3 in the diagram of FIG. 11, an OFF signal is transmitted from the control unit 200 to the third switching relay (Ry3) 43, and (Ry1, Ry2, Ry3, Ry4, Ry5) = (ON, ON, OFF, OFF, ON). In the present embodiment, the time difference from when the control unit 200 transmits an ON signal to the bridging relay (Ry5) 50 to when it transmits an OFF signal to the third switching relay (Ry3) 43 is 200 ms. is there. The voltage between the output terminals uv can take a value from about 500 V to about 540 V depending on the current flowing through the relay circuit 70.

  In the time domain T4 in the diagram of FIG. 11, an ON signal is transmitted from the control unit 200 to the fourth switching relay (Ry4) 44, and (Ry1, Ry2, Ry3, Ry4, Ry5) = (ON, ON, OFF, ON, ON). In the present embodiment, the time difference from when the control unit 200 transmits an OFF signal to the third switching relay (Ry3) 43 to when the ON signal is transmitted to the fourth switching relay (Ry4) 44 is 100 ms. It is. In this case, the first tap (A1) 21 is selected, and the voltage between the output terminals uv is 540 V (= 420 V + 480 V / 3.5).

  In the time domain T5 in the diagram of FIG. 11, an OFF signal is transmitted from the control unit 200 to the bridging relay (Ry5) 50, and (Ry1, Ry2, Ry3, Ry4, Ry5) = (ON, ON, OFF, ON , OFF). In the present embodiment, the time difference from when the control unit 200 transmits an ON signal to the fourth switching relay (Ry4) 44 to when it transmits an OFF signal to the bridging relay (Ry5) 50 is 200 ms. is there. The state where the first tap (A1) 21 is selected is maintained, and the voltage between the output terminals uv is 540V.

The control unit 200 switches the voltage between the output terminals uv from 540V to 500V from the first tap 21 to the second tap 22, and the control unit 200 switches the voltage between the output terminals uv from 500V to 460V. The operation of switching from the second tap 22 to the third tap 23 and the operation of the control unit 200 switching from the third tap 23 to the fourth tap 24 in order to switch the voltage between the output terminals uv from 460 V to 420 V are described above. This is an operation in the reverse order of the operation of raising the taps 21, 22, 23, and 24.
In the present embodiment, the control unit 200 and an appropriate program that causes the control unit 200 to perform the tap switching operation described above correspond to the control unit.

  Since the voltage adjusting device 10 according to the present embodiment switches the taps 21, 22, 23, and 24 by the switching relays 41, 42, 43, and 44, a mechanically complicated configuration such as a movable contact is not required. As the configuration is simplified, the switching operation of the taps 21, 22, 23, and 24 can be precisely controlled. Further, the bridging relay 50 and the current limiting resistors 61 and 62 make a current limiting bridge between the taps 21, 22, 23 and 24 when the taps 21, 22, 23 and 24 are switched. Thereby, this voltage regulator 10 can regulate the voltage of the said load 120, without interrupting | blocking the load 120, avoiding the short circuit between taps 21, 22, 23, and 24, protecting the adjustment transformer 20. . Further, the control unit 200 precisely controls the switching timing and switching time of the taps 21, 22, 23, and 24. Therefore, the voltage adjustment apparatus 10 of the present embodiment can adjust the voltage quickly (within 500 ms) and sufficiently even with respect to the load 120 with a rapid and large voltage fluctuation, and can be low in cost.

  Moreover, the voltage regulator 10 of this Embodiment is the relay 21 for switching, 21, 22, 23 in the switching initial stage of the tap 21, 22, 23, 24 (time area T1 to T2 of FIG.4, FIG.10 and FIG.11). , 24 while maintaining the state of 24, the bridging relay 50 is changed from the off state to the on state, and the current limiting bridge is formed between the taps 21, 22, 23, 24. Next, after switching the switching relays 41, 42, 43, 44 to a predetermined state to switch the taps 21, 22, 23, 24, for example, the switching end of the taps 21, 22, 23, 24 (FIG. 4). 10 and FIG. 11, the current limiting bridge is released by changing the bridging relay 50 from the on state to the off state in the time regions T4 to T5). Therefore, the voltage regulator 10 of the present embodiment avoids a short circuit between the taps 21, 22, 23, and 24 to protect the regulating transformer 20, and the voltage of the load 120 without interrupting the load 120. Can be adjusted.

  Moreover, the voltage regulator 10 of this Embodiment is equipped with the instrument transformer (PT) 90 and the current transformer (CT) 100. Thereby, if both the voltage (V) and current (I) of the distribution lines S and T are measured, the power factor (cos φ) of the load 120 can be obtained from the phase difference (φ). The voltage drop (VD) of the distribution lines S and T changes according to this power factor (cosφ). Therefore, if the voltage drop (VD) based on this power factor (cosφ) is calculated, the taps 21, 22, 23, and 24 can be effectively selected to compensate for this.

  The above-described embodiments of the present invention are intended to facilitate understanding of the present invention, and are not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and equivalents thereof are also included in the present invention.

  In the above-described embodiment, the current limiting resistors 61 and 62 are used as the current limiting means for limiting the current between the taps 21, 22, 23, and 24. However, the present invention is not limited to this. It may be a flow reactor.

It is a circuit diagram of the voltage regulator of this Embodiment. It is a control block diagram of the voltage regulator of this Embodiment. It is a flowchart for demonstrating the tap selection operation | movement of the voltage regulator of this Embodiment. It is a diagram for demonstrating the operation timing of the switching relay of the voltage regulator of this Embodiment, and the bridging relay. It is a circuit diagram for demonstrating the state of the switching relay and bridge relay in the time domain T1. It is a circuit diagram for demonstrating the state of the switching relay and bridge relay in the time domain T2. It is a circuit diagram for demonstrating the state of the switching relay and bridge relay in the time area | region T3. It is a circuit diagram for demonstrating the state of the switching relay and bridge relay in the time domain T4. It is a circuit diagram for demonstrating the state of the switching relay and bridge relay in the time domain T5. It is another diagram for demonstrating the operation timing of the switching relay of the voltage regulator of this Embodiment, and the bridging relay. It is another diagram for demonstrating the operation | movement timing of the switching relay of the voltage regulator of this Embodiment, and a bridging relay.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Voltage regulator 20 Adjustment transformer 21, 22, 23, 24 Tap 30 Series transformer 41, 42, 43, 44 Switching relay 50 Bridge relay 61, 62 Current limiting resistance 70 Relay circuit 71 1st relay circuit 72 Second relay circuit 90 Instrument transformer 100 Current transformer 110 Control board 120 Load 200 Control unit 210 Timer 220 Memory

Claims (15)

A voltage adjustment device that adjusts the voltage of the distribution line by switching the tap of the transformer connected to the distribution line,
A switching relay in which an on or off state is associated with each tap;
A bridging relay that bridges between the taps by changing from off to on;
Current limiting means for limiting the current flowing between the taps bridged by the bridging relay;
When switching the tap,
While maintaining the switching relay in the on or off state before switching, changing the bridging relay from off to on state, the current limiting bridge between the taps,
While holding the switching relay in the on or off state after switching, the bridging relay of the current limiting bridging means is changed from on to off state to release the current limiting bridging,
Control means;
A voltage regulating device comprising:   The voltage regulator according to claim 1, wherein the current limiting means is a current limiting resistor connected in series with the bridging relay. A voltage measuring device for measuring the voltage of the distribution line, and / or a current measuring device for measuring a current of the distribution line, and
Tap selection means for selecting the tap based on the voltage and / or current respectively measured by the voltage measuring device and / or the current measuring device;
Voltage controller according to claim 1 or 2, further comprising a. The tap selection means is
An operation for calculating a voltage drop at a predetermined point of the distribution line based on the current of the distribution line measured by the current measuring device, and subtracting the voltage drop and the predetermined voltage at the predetermined point from the voltage of the distribution line And
A comparison unit that compares the absolute value of the subtraction value obtained by the calculation unit with a predetermined value;
The voltage regulator according to claim 3 , further comprising: 5. The voltage regulator according to claim 4 , wherein the calculation unit calculates the voltage drop by multiplying a current of the distribution line measured by the current measurement device by an impedance of the distribution line. . The tap selection unit further includes a storage unit that stores data of a cross-sectional area of the distribution line and data of a length to the predetermined point of the distribution line,
The voltage regulator according to claim 5 , wherein the calculation unit calculates an impedance of the distribution line based on the data read from the storage unit. The tap selection unit, when the absolute value of the subtraction value by the comparison unit is determined to be greater than the predetermined value, according to claim 4 to 6, characterized in that selecting the tap elevated or lowered one step The voltage regulator in any one of. The tap selection unit selects the tap that has been increased or decreased by one step when the comparison unit continues to determine that the absolute value of the subtraction value is greater than the predetermined value within a predetermined time. The voltage regulator according to any one of claims 4 to 6 . 9. The voltage regulator according to claim 8 , wherein the predetermined time is approximately 5 seconds to approximately 30 seconds. 10. The voltage regulator according to claim 4, wherein the predetermined value is approximately 20V to approximately 25V. A voltage adjustment method of a voltage adjustment device for adjusting a voltage of the distribution line by switching a tap of a transformer to which the distribution line is connected by a switching relay,
A current-limiting bridging start step for current-limiting bridging between the taps while holding the switching relay associated with each tap in the on or off state in the on or off state before switching;
While maintaining the switching relay in the on or off state after switching, the current limiting bridge releasing step for canceling the current limiting bridge;
A voltage adjusting method for a voltage adjusting apparatus comprising: Prior to the current-limiting bridging start step, a tap selection step of selecting the tap based on the voltage of the distribution line and / or the current of the distribution line,
The voltage adjusting method of the voltage adjusting apparatus according to claim 11 , further comprising: The tap selection step includes:
The voltage drop at a predetermined point of the distribution line is calculated based on the current of the distribution line, and the voltage drop and the predetermined voltage at the predetermined point are subtracted from the voltage of the distribution line, and the absolute value of the subtraction value and the predetermined value Compare with
The voltage adjustment method of the voltage adjustment apparatus of Claim 12 characterized by the above-mentioned. The tap selection step includes:
If it is determined that the absolute value of the subtraction value is greater than the predetermined value, the tap that has increased or decreased by one step is selected.
The voltage adjustment method of the voltage adjustment apparatus of Claim 13 characterized by the above-mentioned. The tap selection step includes:
If the absolute value of the subtraction value is determined to be greater than the predetermined value within a predetermined time, select the tap that has increased or decreased by one step;
The voltage adjustment method of the voltage adjustment apparatus of Claim 13 characterized by the above-mentioned.

Images