JPH0526411B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a ground fault directional relay device, and in particular to the protective operation of each fault directional relay when a plurality of ground fault directional relays are installed in series on a distribution line. The present invention relates to a differential relay device that performs coordination and backup operations.

Conventional technology Ground fault directional relays detect zero-sequence voltage and zero-sequence current in the event of a ground fault, compare the phases of these voltages and currents, and detect whether the fault is connected to the power supply side by a zero-sequence current transformer. This is a relay that determines whether it is the load side or the load side, and performs a protective operation in the event of a ground fault on the load side. Generally, several ground fault relays are installed in series on a power distribution line to detect a ground fault in each section, cut off the load side of the faulty distribution line, and transfer the relay to other intact sections. Protective actions are being taken to avoid any impact.

The conventional protection operation will be explained below with reference to FIG. Figure 8 is a wiring diagram when multiple (three in the figure) ground fault direction relays are installed on the distribution line, where 1 is the transformer on the power supply side, 2 is the disconnector, and 3 is the relay on the power supply side. The set earth fault direction relays are shown, 4, 5, 6 are the wire breakers installed on the distribution line on the distribution line side, 7,
8 and 9 are zero-phase current transformers provided on the load side of each sheath disconnector 4, 5, and 6, and 10, 11, and 12 are ground faults connected to the zero-phase current transformers 7, 8, and 9. The directional relays are installed in series from the power source side (upper stage) to the load side (lower stage), and give a shear disconnection command to the sheath disconnectors 4, 5, and 6. 13 is a zero-phase voltage signal generator such as a zero-phase voltage relay, which converts the zero-phase voltage Vo into a pulse-like signal.
Convert it to Vo′ and send the signal to the earth fault direction relay 10, 1
1 and 12 in parallel. Next, to explain the operation, if a ground fault occurs at point E on the load side of zero-phase current transformer 9, zero-phase current flows to each zero-phase current transformer 7, 8, and 9, and A zero-phase voltage signal is generated from the voltage signal generator 13, and a ground fault direction relay (hereinafter referred to as
(abbreviated as DGR) 10, 11, 12,
An attempt is made to operate each DGR 10, 11, and 12.
In this case, only the lower DGR 12 operates to quickly disconnect the insulation breaker 6, and the operating times are coordinated among each DGR 10, 11, and 12 so as not to affect the distribution line on the power supply side. ing. This coordination of operation time is generally done by taking into consideration the breakage time of the breakers, and generally from DGR12 to DGR11 on the lower stage, and
DGR10 and operation time are 0.2 seconds and 0.5 seconds, respectively.
The DGR 12 is set to 0.8 seconds and becomes longer in sequence, and the DGR 12 operates first to cut off the breaker 6, disconnecting the distribution line in the fault category and preventing the upper DGRs 11 and 10 from operating.

Problems to be solved by the invention Depending on the power supply company, etc., the power supply side
The operating time of DGR3 may be set to 0.5 seconds. In this case, DGR10, 11, 1 on the distribution line side
2 must be set to successively shorter times than 0.5 seconds, but there is a minimum time required for the inertial characteristics of the DGR, the operating time of the breaker, etc., and there is a limit to the time that can be shortened. Particularly in the case of large-capacity distribution lines, there is a problem in that when three or four stages are configured in series, it is virtually impossible to coordinate the operating times.

Means for Solving the Problems The present invention provides zero-phase voltage signals to each DGR1 as in the past.
Instead of applying it in parallel to DGRs 0, 11, and 12, it is applied in series from the lower DGR12 to the upper DGRs 11 and 10, and when the lower DGR operates, this zero-phase voltage signal is supplied to the upper DGR. The upper stage DGR is disabled by locking it so that it does not occur. This eliminates the need to coordinate operating times between each DGR, and moreover, DGRs can be installed in series.
To shorten operating time regardless of the number of DGRs installed.

Embodiment FIG. 1 is an embodiment of the wiring diagram of the present invention, and the same reference numerals as in FIG. 8 indicate the same or equivalent parts, and the explanation thereof will be omitted.

The difference from the conventional method is the way the zero-phase voltage signal Vo' is given. First, the zero-phase voltage signal Vo' output from the zero-phase voltage signal generator 13 is given to the DGR 12 at the lowest stage, and then
12 output lock circuits (described later)
The point is that it is applied sequentially in series with DGRs 11 and 10.

2 and 3 are internal wiring diagrams and time charts for explaining the operation of the DGR 12, respectively, k and l are terminals connected to the zero-phase current transformer 9,
Zero-sequence current Io is input. 20 is a filter, 2
1 is an amplifier, 22 is a waveform shaping circuit, and
4, the zero-sequence current is shaped into a rectangular wave-like zero-sequence current signal Io'. 23 is a level detection circuit which outputs an output signal when the zero-phase current signal Io is above a certain level. 24 is the first AND circuit, which receives the zero-phase current signal.
Io' is input, and an output signal is output when the signal Io' is above a certain level. A second AND circuit 25 receives the output signal of the first AND circuit 24 and the zero-phase voltage signal Vo', and outputs an output signal when both signals are input simultaneously. Reference numeral 26 denotes an output lock circuit for the zero-phase voltage signal Vo', which inputs the zero-phase voltage signal Vo' from the zero-phase voltage input terminals M and N, and sends an output signal from the output terminals m and n to the upper stage DGR 11. 27, 28
are timers, which are started by the output signal of the second AND circuit 25, and the timer 27 sends a signal to the output lock circuit 26 after time _T1 to output the zero-phase voltage signal.
Vo' is locked to prevent output signals from output terminals m and n, and the timer 28 is set at time T ₂
Afterwards, an output signal is output to energize the relay 29 to disconnect the sheath breaker 6 (FIG. 1).

Note that the operating time T ₁ of the timer 27 and the operating time T ₂ of the timer 28 are set to satisfy T ₁ <T ₂ .

Next, the operation will be explained with reference to the time chart shown in FIG.

In FIG. 3, 1 indicates the input signal Vo of the zero-phase voltage signal generator 13, and 2 indicates its output signal Vo'.

Now, in Fig. 1, E on the load side of the zero-phase current transformer 9
If a ground fault occurs at the point, a zero-sequence current Io is applied to the input terminals k and l of each DGR 10, 11, and 12 in Fig. 2, and a zero-sequence voltage signal is applied to the terminals M and N.
Vo′ is respectively input, and if the zero-sequence current Io is above a certain level, it is shaped and the first AND circuit 2
4 to Io' in FIG. 3, and output to the second AND circuit 25. This AND circuit 2
The phase of the zero-sequence current and zero-sequence voltage signals is determined in step 5, and if the ground fault is on the load side of the zero-sequence current transformer, Io' in 4 and Vo in 5 are determined as shown in Figure 3. ' signals match, the operating condition is established, and the AND circuit 25
An output signal of 7 is outputted from and applied to timers 27 and 28. And after time T ₁ , timer 27
operates and sends a signal to the output lock circuit 26 to lock the output of the lock circuit 26. When this output is locked, the time T ₁
After that, the output of zero-phase voltage signal Vo′ from DGR12 is 6
The zero-phase voltage signal Vo' is not applied to the DGRs 11 and 10 in the upper stage. Therefore, the upper
DGR11 and 10 are inactive, and DGR12
Timer 2 after time T ₂ when only is in operating condition
8 operates to disconnect the shingle breaker 6 via the relay 29, disconnecting the power distribution line that has a ground fault.

Next, if a ground fault occurs in the distribution line between zero-phase current transformers 8 and 9, the DGR 12 will not operate because the fault is on the power supply side, and the output block circuit 26 will not operate.
also does not operate, so the zero-phase voltage signal Vo′ is connected to the upper stage DGR.
11, 12, and DGR11 as above
After time _T1, the output of the output lock circuit 26 is locked to stop the transmission of the zero-phase voltage signal Vo' to the upper stage DGR 10, and after time _T2 , the serpentine 5 is cut off.

In this way, each DGR 10, 11, and 12 operates in the event of a ground fault on the load side and disables the DGR on the power supply side, so even if the operating time of DGR 3 on the power supply source is set to 0.5 seconds, each DGR10,1
Since all the operation times of 1 and 12 can be set to 0.3 seconds, there is no need to coordinate the operation times.
Therefore, the number of stages of ground fault directional relays installed on the power distribution line may be as large as possible.

Next, backup protection will be explained.

In the above example, a ground fault occurred at point E on the load side of the zero-phase current transformer 9, and even though the DGR 12 was activated, for some reason the relay 29 did not output a mustard disconnection signal. If a disconnection signal is issued and the disconnector 6 does not disconnect immediately, the next upper stage DGR 11 must be operated after a certain period of time to minimize the influence on the power supply side. Figure 4 shows a DGR11 with such a backup protection function.
12, a backup circuit 30 is provided in parallel with the timer 28 of FIG.
This backup circuit 30 continues to output the zero-phase current signal even after time _T3 , which is longer than time _T2 of the timer 28.
This circuit provides an operating signal to the relay 29 after time T ₃ on the condition that Io' continues to flow, and outputs an output signal only when a ground fault occurs on the load side and the output of the second AND circuit 25 is output. It consists of a backup operation preparation circuit 31 that outputs a backup, a timer 32 that is started by the output signal of the operation preparation circuit 31, and outputs an output signal when this signal is present for a set time T ₃ or more, and a third AND circuit 33. There is. Note that if the timer 32 has the function of the operation preparation circuit 31, the operation preparation circuit 31 may be omitted.

Next, the backup operation will be explained with reference to the time chart shown in FIG. If the insulator breaker 6 does not disconnect immediately even though the DGR 12 is activated, the upper DGRs 11 and 10 will operate as shown in the fifth diagram.
After time _T1 , the zero-phase voltage signal Vo' is locked by the zero-phase voltage output lock circuit 26, and therefore is in an inoperable state. Furthermore, until time _T1 after the occurrence of a ground fault, the zero-phase voltage signal Vo' is applied to the upper stage DGR 11, and the operating conditions are met, so at that time the backup operation preparation circuit 31 outputs an output signal. The timer 32 is started and a signal is sent to the third AND circuit 33 after time _T3 .
At this time, if the breaker 6 is not disconnected and the zero-sequence current is flowing, the zero-sequence current signal Io' is present, so an output signal is output from the AND circuit 33 and the relay 29 is connected. The breaker 5 is then energized and the breaker 5 is energized to provide backup protection. The above backup operation applies to DGR10 as well, as the same conditions apply.
There is a possibility that the DGR 10 will also operate, but since backup protection is required only in very rare abnormal situations, overprotection operation in this case is unavoidable.

Fig. 6 is a wiring diagram of a DGR showing another embodiment equipped with a backup function. In the embodiment of Fig. 4, the backup operation is performed on the condition that a zero-sequence current exists after time _T3 after the occurrence of an accident. On the other hand, as shown in FIG. 7, the embodiment shown in _FIG .
Vo' is restored, and after time T ₃ ' it is confirmed by the zero-sequence voltage signal and zero-sequence current signal that the fault continues, and backup or disconnection is performed. That is, each DGR10, 11, 12
As shown in FIG. 7, the zero-phase voltage output lock circuit 46 blocks the zero-phase voltage signal Vo' for a time _T1 , releases the lock after a predetermined time _T1 , and outputs an output signal again. Upper DGR10,
11 is provided with a backup circuit 40 consisting of a backup operation preparation circuit 41, a timer 42, and a third AND circuit 43 in parallel with the timer 28. Therefore, if the accident continues after time _T2 as shown in FIG. to perform backup protection. In this embodiment, since accidents are reconfirmed, more accurate backup protection can be performed.

Effects of the Invention As described above, the present invention ensures that no matter where a ground fault occurs on a distribution line, only the ground fault direction relay immediately above the ground fault will operate within a predetermined time _T2 . Therefore, there is no need to coordinate the operating times of multiple stages of ground fault relays from the lower stage to the upper stage, so no matter how many stages of ground fault direction relays are installed in series, it is possible to ensure that only the fault location is detected. Can be severed.

Furthermore, since there is no need to coordinate the time between each fault direction relay, even when performing backup operation of multiple stages installed, each fault direction relay can be operated at a time earlier than the operation time of each fault direction relay on the power supply side. Backup operation can be performed at _T3 , and the spread of the accident to the power supply source can be eliminated.

[Brief explanation of drawings]

Fig. 1 is a layout diagram of a ground fault direction relay device showing one embodiment of the present invention, Fig. 2 is a wiring diagram of a ground fault direction relay device which is an embodiment of the present invention, and Fig. 3 is a diagram of a ground fault direction relay device showing an embodiment of the present invention. FIG. 4 is a wiring diagram of a ground fault directional relay which is an embodiment of the present invention and is equipped with a backup/shutdown function. FIG. 5 is a time chart for explaining FIG. 4. Figure 6 is a wiring diagram of another embodiment equipped with backup and disconnection functions, and Figure 7 is
The figure shows a time chart for explaining FIG. 6, and FIG. 8 shows a wiring diagram of a conventional ground fault direction relay device. In the figure, 4, 5, 6 bridges and disconnectors, 7, 8,
9 is a zero-phase current transformer, 3, 10, 11, 12 are earth fault direction relays, 20 is a filter, 21 is an amplification, 22
23 is a waveform shaping circuit, 23 is a level detection circuit, and 24 is a waveform shaping circuit.
is the first AND circuit, 25 is the second AND circuit, 2
6, 46 are zero-phase voltage output lock circuits, 27, 28
is a timer, 29 is a relay, and 30 and 40 are backup circuits.

Claims (1)

[Scope of Claims] 1. A plurality of ground fault direction relays are installed in series from the upper stage on the power supply side to the lower stage on the load side of the distribution line, and a zero-phase voltage signal detected from the distribution line is transmitted to each of these fault direction relays. and a zero-sequence current signal, the direction of the ground fault is determined by comparing the phases of these two signals, and when the operating conditions are met, a protection operation is performed by sending out a signal or disconnection signal. In the relay device, a lock circuit is provided for inputting a zero-sequence voltage signal to each of the plurality of fault-direction relays and locking the output before sending out a break signal, and transmitting the zero-sequence voltage signal to each of the ground-fault direction relays. The ground fault relays are applied in series from the lowest stage to the upper stage through lock circuits, and the ground fault direction relays for which operating conditions have been established are used to connect the upper stage ground fault direction relays before operation. 1. A ground fault directional relay device, characterized in that it locks a zero-phase voltage signal applied to a ground fault direction relay device. 2 A plurality of ground fault direction relays are installed in series 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 receives the zero-sequence voltage signal and zero-sequence current signal detected from the distribution line. In the earth fault direction relay device, the earth fault direction is determined by comparing the phases of these two signals, and when the operating conditions are met, the earth fault direction relay device is configured to transmit a protection operation by sending out a signal of disconnection. A lock circuit is provided for inputting a zero-sequence voltage signal to each of the plurality of fault-direction relays and locking the output before sending out a break signal, and sequentially transmitting the zero-sequence voltage signal from the bottom to the top of the ground-fault direction relays. The zero-sequence voltage is applied in series through a lock circuit, and the zero-sequence voltage is applied to the upper ground fault directional relay before operation by the ground fault directional relay whose operating conditions are satisfied among these ground fault directional relays. The ground fault relay is characterized in that the signal is locked and the locked ground fault direction relay is caused to perform a backup operation at a predetermined time after the operating time of the locked ground fault direction relay, on the condition that the zero-sequence current exists. Folding direction relay device. 3 A plurality of ground fault direction relays are installed in series 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 signal and zero-sequence current signal detected from the distribution line are transmitted to each of these fault direction relays. In the earth fault direction relay device, the earth fault direction is determined by comparing the phases of these two signals, and when the operating conditions are met, the earth fault direction relay device is configured to transmit a protection operation by sending out a signal of disconnection. A lock circuit is provided for inputting a zero-sequence voltage signal to each of the plurality of fault-direction relays and locking the output before sending out a break signal, and sequentially transmitting the zero-sequence voltage signal from the bottom to the top of the ground-fault direction relays. The zero-sequence voltage is applied in series through a lock circuit, and the zero-sequence voltage is applied to the upper ground fault directional relay before operation by the ground fault directional relay whose operating conditions are satisfied among these ground fault directional relays. The signal is locked and the lock is released at a predetermined time after the operating time, so that the locked earth fault direction relay performs a backup operation on the condition that the zero-sequence voltage signal and the zero-sequence current signal are present. A ground fault directional relay device characterized by: