JPH0568167B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a ground fault directional relay device, and in particular to the protection operation of each fault directional relay when a plurality of ground fault directional relays are arranged in series on a distribution line. This invention relates to this type of relay device that provides coordination.

Conventional technology A ground fault directional relay detects zero-sequence voltage and zero-sequence current in the event of a ground fault, compares the phases of these voltages and currents, and detects the fault from the power supply side with the zero-sequence current transformer as the boundary. This is a relay that determines the direction of the load side or the load side and performs a protective operation in the event of a ground fault on the load side.

A ground fault directional relay device generally has several ground fault directional relays arranged in series on a distribution line, detects a ground fault in each section, and immediately disconnects the load side of the distribution line where the fault occurred. Perform protective operations that do not affect healthy sections on the power supply side. The conventional protection operation is explained in the fifth section below.
This will be explained using figures.

Figure 5 is a wiring diagram in which multiple ground fault directional relays are installed on the distribution line, 1 is the transformer on the power supply side, 2 is the bridge or disconnector, 3 is the ground fault relay placed on the power supply side,
4, 5, 6, 7 and 8 are wire disconnectors installed on the distribution line on the distribution line side, 9, 10, 11, 12 and 13
Zero-phase current transformers installed on the load side of each shear disconnector 4, 5, 6, 7, and 8, DGR1, DGR2, DGR
3, DGR4 and DGR5 are the zero-phase current transformer 9,
10, 11, 12, and 13, which are arranged in series from the power supply side (upper stage) to the load side (lower stage), and give a shear disconnection command to the shear disconnectors 4 to 8. . 14 is a zero-phase voltage signal generator such as a zero-phase voltage relay, which converts the zero-phase voltage into a pulse-like signal.
Convert to V ₀ and send the signal to ground fault directional relay DGR1
~Apply in parallel to DGR5.

Next, the operation will be explained. Now, for example, zero-phase current transformer 1
When a ground fault occurs at point E on the load side of No. 1, a zero-phase current is generated in each zero-phase current transformer 9 to 11, and a zero-phase voltage signal _V0 is generated from the zero-phase voltage signal generator 14, causing each fault to occur. Input to directional relay. Then, the relays DGR1 to DGR3 on the power supply side of the ground fault are about to operate. In this case, only the earth fault direction relay DGR3 on the power supply side closest to the ground fault operates and disconnects the shattered circuit breaker 6, and each fault direction relay is The operation time is coordinated between DGR1 to DGR5. This coordination of operation time is generally done by taking into account the break time of the ground fault relay, DGR3 to DGR.
1 and sequential operation time 0.2 seconds, 0.5 seconds and 0.8 respectively
For example, earth fault direction relay
DGR3 operates to cut off the cable breaker 6, disconnecting the distribution line below the fault and preventing the upper ground fault directional relays DGR2 and DGR1 from operating.

Problem to be solved by the invention The operating time of the ground fault direction relay 3 on the power supply side is
It may be set to a short time such as 0.5 seconds.
In this case, the ground fault direction relay DGR1~ on the distribution line side
DGR5 must be set to successively shorter times than 0.5 seconds, but due to the inertial characteristics of the earth fault direction relay,
There is a minimum time required for the operation time of the disconnector, etc.
There is a limit to the amount of time that can be saved. Particularly in the case of large-capacity distribution lines, there is a problem in that when a four-stage or five-stage configuration is arranged in series as shown in FIG. 5, it is virtually impossible to coordinate the operating times.

In order to solve this problem, the applicant of the present application previously proposed Japanese Patent Application No. 1983-267906 (hereinafter referred to as "Japanese Patent Application Laid-Open No. 1983-131722"). Although this prior application solved the above-mentioned conventional problems and put it into practical use, a new problem arose during the implementation process. In other words, the invention of the earlier application is
Because precise operation is performed using a combination of extremely short pulses, the distance between substations with ground fault direction relays and the distance between main substations and sub-substations can be several kilometers. It has been found that when the signal line impedance increases, the signal becomes susceptible to phase delays due to signal line impedance and noise such as induction disturbances.

Therefore, the present invention provides a ground fault directional relay device that is not affected by noise even if there is a distance between substations in which the ground fault directional relay is installed in the invention of the previous application, or between a main substation and a sub substation. The purpose is to provide.

Means for Solving the Problems The first means for solving the above problems in the present invention is to provide a circuit for generating a lock selection signal and a lock signal for each fault direction relay, and a circuit for generating a lock selection signal and a lock signal for each fault direction relay. A prohibition signal generation circuit is provided that outputs an output signal and prohibits the generation of a shrunken command signal when input at the same time. A prohibition signal is given to the ground fault directional relay to lock the interruption command of the ground fault directional relay and prevent each fault directional relay from operating. Signal lines connecting substations are connected with optical fiber cables via signal converters to prevent the common signal lines from receiving noise due to induction disturbances, etc.

Furthermore, the second method is to divide the ground fault direction relay into a plurality of blocks and install a separate zero-phase voltage signal generator in each block to prevent noise from being affected by the impedance of the signal line or due to inductive disturbances. did.

Operation When a ground fault occurs, the zero-sequence voltage signal generated by the zero-sequence voltage signal generator is applied as an electric signal to the ground fault direction relay on the main substation side, and the signal is first converted to the sub-substation side. After being converted into an optical signal by the sub-substation, it is transmitted to the sub-substation via an optical fiber cable, and then converted back to an electrical signal by the sub-substation's signal converter and sent to each fault direction relay at the sub-substation. applied.

In addition, when a ground fault occurs on the sub-substation side, the lock signal generated by each fault direction relay above the ground fault point is converted into an optical signal by the signal converter on the sub-substation side. After that, the signal is transmitted to the main substation via the optical fiber cable, converted into an electrical signal again by the signal converter on the main substation, and applied to each fault direction relay on the main substation. Only the ground fault relay on the power supply side closest to the ground fault point operates, and all the ground fault relays on the upper stage are locked. Therefore, no matter how long the distance between the main substation and the sub-substation is, there will be no noise along the way.

In addition, in an embodiment that does not use signal lines or optical fiber cables to avoid the effects of signal delays and noise, the substation is divided into multiple blocks and a zero-phase voltage signal generator is installed in each block. Since the zero-phase voltage signal is applied only to the ground-fault direction relay in each block, if a ground fault occurs somewhere, the ground fault will be detected within the substation of the block where the fault occurred. The ground-fault relay on the power supply side closest to the block operates according to the time coordinates determined between the blocks, and locks the ground-fault relay in the upper stage of the substation within the block to prevent malfunction.

In addition, time coordination is achieved between the blocks by shortening the operating time of the lower stage than that of the upper stage, so that time coordination of the entire distribution line can be achieved. Therefore, even if the distance between the blocks is long and a normal cable line is used between each block, the zero-phase voltage signal and the lock signal are transmitted and received within the short distance blocks, so noise may be picked up on the way and cause malfunction. Never.

Embodiment FIG. 3 is an internal wiring diagram of the ground fault direction relay of the prior application, and the same symbols as in FIG. 5 indicate the same or equivalent parts, and the explanation will be omitted. FIG. 4 shows a time chart for explaining the operation of FIG. 3.

In Fig. 3, Z ₁ and Z ₂ are connection terminals connected to the zero-phase current transformer, and are connected to the ground fault direction relay DGR in Fig. 5.
4 is a terminal connected to the zero-phase current transformer 12. m, n are zero-phase voltage signal terminals connected to signal lines M, N connected to the zero-phase voltage signal generator 14. 20 is a filter, 21 is an amplifier, and 22 is a waveform shaping circuit that shapes the zero-sequence current I ₀ into a rectangular zero-phase current signal. 23 is a level detection circuit which outputs an output signal when the zero-sequence current I ₀ is above a certain level. 24 is a first AND circuit which receives a zero-sequence current signal and outputs an output signal when an AND condition is established and the zero-sequence current is above a certain level. 25 is a second AND circuit, which receives the output signal of the first AND circuit 24 and the zero-phase voltage signal _V0 , and operates only when both signals are input at the same time and when there is no inhibition signal, which will be described later. Issues a shutdown command signal. 26 is a timer, and the second AND circuit 2
5, the relay 27 is energized after _t2 hours, and the shear breaker 7 is disconnected via the relay 27. A lock signal selection circuit 28 is connected to zero-phase voltage signal terminals m and n, and generates a lock selection signal A shown in FIG. This lock selection signal A becomes an on signal after a certain off time ta from the rise of the zero-phase voltage signal _V0 pulse signal. As shown in FIG. 4, the off-time ta is set to be longer in the order of the upper ground fault direction relays DGR1 to DGR5. Reference numeral 29 denotes a prohibition signal generation circuit, which generates a prohibition signal ( It consists of a waveform shaping circuit 31 that outputs the signal C) in FIG. 4, and prohibits output from the second AND circuit 25. 32 is a timer which outputs an output for t ₁ hour and t ₂ hours after the output of the second AND circuit 25 is received. 33 is a lock signal generation circuit which generates a zero-phase voltage signal from zero-phase voltage signal terminals m and n at time t _b set in each fault direction relay after t ₁ hour.
Outputs a lock signal between the _V0 pulses.
As shown in Fig. 4, this lock signal is generated on the signal lines M and N sequentially from the upper ground fault direction relay after a constant time t _b after the pulse signal of the zero-phase voltage signal _V0 . Set. P2, P3, and P4 indicate lock signals issued from each fault direction relay DGR2, DGR3, and DGR4. Note that the B signal in FIG. 4 indicates the signal at point b on the output side of the AND circuit 30.

Further, as shown in FIG. 4, each fault direction relay is set in such a way that the AND condition of the AND circuit 30 is not satisfied with the signal it generates in relation to the lock signal and the lock selection signal.

Next, the operation will be explained.

Now, if a ground fault occurs at point E' on the load side of the zero-phase current transformer 12 in Figure 5, each fault direction relay
The zero-sequence current I ₀ is input to the zero-sequence current input terminals Z ₁ and Z ₂ of DGR1 to DGR4, and the zero-sequence voltage signal V ₀ is input to the zero-sequence voltage input terminals m and n, and the zero-sequence current I ₀ If it is above a certain level, it is output from the first AND circuit 24 to the second AND circuit 25. This second AND circuit 25 determines the phase of the zero-phase current signal and the zero-phase voltage signal, and when the ground fault is on the load side of the zero-phase current transformer, the AND condition of the second AND circuit 25 is established, a shearing command signal is issued, and timers 26 and 32 are energized. On the other hand, zero-phase voltage signal
At the same time when V ₀ is applied to the zero-phase voltage terminals m and n, the lock signal selection circuit 28 generates a lock selection signal A with a set off time t _a as shown in FIG. 4, and generates a prohibition signal. The signal is input to the AND circuit 30 of the circuit 29 .

The zero-phase voltage signal _V0 is also input to this AND circuit 30, but since the lock selection signal A is set so that the AND condition is not satisfied for both signals, no output signal is output. Furthermore, when the AND condition of the second AND circuit is satisfied and a shearing command signal is issued, the timer 32 is also energized, and after t ₁ hour, it outputs for t ₂ hours and the ground fault direction relays DGR2 and DGR are activated.
3. During this time _t2 , lock signals P2, P3, and P4 are generated from the lock signal generation circuit 33 and placed on the common signal lines M and N of the DGR4. Therefore, as shown in FIG. 4, the AND circuit 30 of the ground fault direction relay DGR1 receives the zero-phase voltage signal _V0 , the lock signals P2, P3, P4 from the ground fault direction relays DGR2, DGR3, and DGR4, and the lock selection signal. A is added, and the lock selection signal A and lock signals P2, P
3 and P4, an AND condition is established, and a B signal is generated at point b on the output side.

When the AND condition with the first lock signal P2 is satisfied, a prohibition signal C is generated from the waveform shaping circuit 31, and an output prohibition signal is given to the second AND circuit 25, inhibiting the output of the shunt command signal and causing a ground fault. Locks the output of directional relay DGR1.

Next, the ground fault directional relay DGR2 is activated by the lock selection signal A and the lock signals P3 and P4 when an AND condition is established, and when the AND condition with P3 is established, the prohibition signal generating circuit 29 outputs a signal from the second AND circuit as described above. 2
5 is given a prohibition signal C, and this ground fault direction relay
DGR2 is also locked. Similarly, ground fault directional relay
DGR3 is also locked as described above by forming an AND circuit with lock signal P4. However, the ground fault direction relay
Since the lock selection signal A of the DGR 4 does not meet the AND condition with any of the lock signals, the lock is not applied, and the timer 26 operates when _t2 hours have elapsed since the cut-off command signal was generated. Turn off the disconnect switch 7 and disconnect the faulty distribution line from the power source.

Next, if a ground fault occurs at point E in Figure 5, the ground fault directional relay DGR4 will not generate a disconnection command signal because the fault is on the power supply side, so the lock signal P4 in Figure 4 will be activated. Therefore, the ground fault direction relay DGR3 is not locked, so that the relay DGR3 is operated and the ground fault direction relay DGR3 is operated to disconnect the ground fault breaker 6 _t2 hours after the generation of the shear break command signal.

After _t2 hours have elapsed, the timer 32 prohibits output, so no lock signal is generated, and each fault direction relay that had been locked until then is unlocked and prepared for the next accident.

As explained above, the invention of the prior application performs operation by inserting a lock signal at extremely short intervals between the pulses in accordance with the pulse phase of the zero-phase voltage signal _V0 , so it is possible to prevent ground faults on the power supply side. Even if the operating time of the relay 3 is set short, a multi-stage ground fault direction relay can be installed, but on the other hand, it is susceptible to noise. In other words, when the distance between each fault direction relay or between a main substation and a sub-substation is very long, reaching several kilometers, there may be transmission delays due to the impedance of the signal lines that connect them, or electromagnetic induction or electrostatic induction. etc., and there is a risk that malfunctions may occur. From this point of view, some kind of countermeasure is required when the signal line installation distance becomes long. The present application relates to an invention that takes this measure, and examples of the invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 shows an example in which the distance between the main substation and the sub-substation is very long. In such a case, the signal line connecting the main substation and sub-substation should be an optical fiber cable, and the signal line M on the main substation side,
N and fiber optic cable ok and signal converter 1
5, and the signal lines M, N' on the sub-substation side and the optical fiber cable OK are connected via the signal converter 16, and the zero-phase voltage signal generator 14
_The zero _- phase voltage signal V ₀ from
5 converts the electrical signal into an optical signal and transmits it, and the signal converter 16 converts the optical signal into an electrical signal and sends it to each fault direction relay DGR 4 on the sub-substation side.
Apply to DGR5 and DGR _o .

Also, the ground fault direction relay DGR on this sub-substation side
Lock signals P ₃ to _{P 5} of 4 to DGR _o are signal converter 1.
6, the signal is once converted into an optical signal, and then converted again into an electrical signal by the signal converter 15 on the main substation side, and then applied to the ground fault direction relays DGR1 to DGR3 on the main substation side.
The signal converters 15 and 16 convert electrical signals into optical signals and vice versa using light emitting diodes, photo diodes, and the like. Regarding the protection operation, since the transmission and reception between the main and sub-substations is only performed via the optical fiber cable, the protection operation is performed in exactly the same order as described above.

No matter how long the distance between the main and sub optical fibers is, the optical fiber has no impedance and is not affected by electromagnetic induction or electrostatic induction, so there is no risk of signal delay or malfunction due to noise. Furthermore, since this optical fiber cable is not subject to inductive interference, it can be laid parallel to power transmission lines.

Figure 2 shows another example in which the distance between the main substation and the sub-substation is long, and the main substation and the sub-substation are not affected by signal delay or noise by not using optical cables. The sub-substation is divided into a plurality of blocks (the illustrated embodiment has two main blocks and two sub-blocks), and each block is provided with an individual zero-phase voltage signal generator 14, 14'.

For example, if the operating time of the ground fault relay 3 on the power supply side is set to 0.5 seconds, the ground fault direction relays DGR1 to DGR3 on the main substation side block
timer 26 (see Figure ₃ ) to 0.35 seconds, and earth fault direction relay DGR4 on the sub-substation side.
~Set the time _T2 of the timer 26 of DGR _o to 0.2 seconds. By doing this, time coordination can be achieved between the blocks of the main and sub-substations, and the operations between the blocks are performed in the order described above.

In this embodiment, since each block has an individual zero-sequence voltage signal generator, a signal line between each block is unnecessary, and it is not affected by the delay of the zero-sequence voltage signal or the noise described above.

Effects of the Invention As described above, the present invention uses an electric signal to operate only the ground fault relay on the power supply side closest to the ground fault, and all the ground fault relays on the upper stage are locked. As there is no need to coordinate the operating times of multiple stages of ground fault relays from the lower stage to the upper stage, even if the operating time of the ground fault direction relay on the power supply side is set to 0.5 seconds or less. It is also possible to install multi-stage ground fault directional relays.

Further, no matter how long the distance between the ground fault direction relays or between the main substation and the sub-substation becomes, it has extremely excellent effects such as no signal delay or malfunction due to the influence of noise.

[Brief explanation of the drawing]

Figures 1 and 2 are wiring diagrams of the earth fault directional relay device of the present invention, Figure 3 is an internal wiring diagram of the earth fault directional relay, and Figure 4 is a time diagram for explaining the operation of Figure 3. The chart diagram, FIG. 5, shows a wiring diagram of a conventional ground fault directional relay device. In the figure, DGR ₁ to DGR ₅ and DGR _o are earth fault direction relays, 14 and 14' are zero-phase voltage signal generators, and 1
5 and 16 are signal converters, M and N are signal lines, 20 is a filter, 21 is an amplifier, 22 is a waveform shaping circuit, 23 is a level detection circuit, 24 is a first AND circuit, and 25 is a second AND circuit, 26 and 32 are timers, 28 is a lock signal selection circuit, 29 is a prohibition signal generation circuit, 33 is a lock signal generation circuit, 40
indicates a backup protection circuit, and OK indicates an optical cable.

Claims (1)

[Claims] 1. A plurality of ground fault direction relays are arranged from the upper stage on the power supply side to the lower stage on the load side of the distribution line, and the zero-sequence voltage and zero-sequence current detected from the distribution line are transmitted to each of these fault direction relays. A pulsed zero-sequence voltage signal and a zero-sequence current signal are provided, and the direction of the ground fault is determined by comparing the phases of these two signals. When a ground fault occurs on the load side, a shear break command signal is issued and protective operation is performed. Ground fault directional relays are installed at multiple substations to
The above-mentioned zero-phase voltage signal is applied from one zero-phase voltage generator to the ground-fault direction relays of each of these substations through a common signal line, and each of these fault-direction relays
A pulse-like lock signal is sent to the common signal line between the pulses of the zero-sequence voltage signal for a certain period of time according to the shear break command signal and applied to the other ground fault direction relays, and each fault direction relay is , take the AND condition between this received lock signal and each lock selection signal,
When the AND condition is satisfied, the output of the power cut command signal is prohibited, and furthermore, the common signal line connecting the substations is an optical cable, and both ends of the optical cable and the signal line of the substation are connected. They are connected via a signal converter, and each substation converts electrical signals to optical signals to be sent to other substations, and converts received optical signals into electrical signals. What is claimed is: 1. A ground fault directional relay device, characterized in that the ground fault directional relay is configured to receive signals by 2. A plurality of ground fault direction relays are arranged from the upper stage on the power supply side to the lower stage on the load side of the distribution line, and each of these fault direction relays transmits the zero-sequence voltage and zero-sequence current detected from the distribution line to the pulsed zero-sequence voltage. The direction of the ground fault is determined by comparing the phases of these two signals, and when a ground fault occurs on the load side, a shear rupture command signal is sent to the timer to cause the shear rupture to occur after a certain period of time. A ground-fault directional relay that performs a protective operation by interrupting the relay is divided into multiple blocks from the upper stage on the power supply side to the lower stage on the load side, and the zero-sequence voltage signal is applied to each block. A signal generator is provided, and the generated zero-sequence voltage signal is applied to the ground fault direction relays in each block via a common signal line, and each of these fault direction relays is controlled at a constant level by the above-mentioned shatter-off command signal. A pulse-shaped lock signal is sent to the common signal line of each block between the pulses of the zero-phase voltage signal for a period of time, and applied to the ground fault direction relay in the block, and each fault direction relay receives this received lock signal. and each block selection signal, and when the AND condition is satisfied, the output of the disconnection command signal is prohibited.Furthermore, the operation time of the ground fault direction relay between each block is A ground fault directional relay device characterized in that the relays are set to be shorter in sequence from the upper stage side to the lower stage side to ensure time coordination between blocks.