JPS63294211A - Protective relay - Google Patents

Abstract

PURPOSE:To protect an electric system properly by connecting an accident detector and an output relay through a contact when a breaker is reclosed. CONSTITUTION:When a grounding accident X is generated in a feeder F1, the zero-phase voltage V0 of a grounding transformer 9 and the zero-phase I0 of a zero-phase current transformer 5 are input to a zero-phase voltage input transformer 15 and a zero-phase current input transformer 16, and a grounding accident detector 17 detects the accident as the grounding accident of its own circuit. A coordination timer 18 for the grounding accident is operated and a relay coil 19c for an output relay 19 for the grounding accident is excited, and a normally opened contact 19a is closed, a relay coil 20c of an interruption relay 20 is excited, first and second normally opened contacts 20a1, 20a2 are closed, a breaker 3 for the feeder F1 is interrupted and the feeder F1 is detached from a bus 2. A reclosing sequence 22 simultaneously starts timer operation, a relay coil 23c is excited, a normally opened contact 23a is closed and the breaker 3 is reclosed. A reset timer 30 outputs a signal, a relay coil 31c for a relay 31 for shortening a time limit is excited, and normally opened contacts 31a1, 31a2 are both closed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a protective relay device for protecting an electric power system.

[Conventional technology]

Figure 2 is a single-line diagram of the power distribution system shown in the "Relay Handbook" published by Ohmsha Co., Ltd. on April 25, 1970, and Figure 3 is the one-line diagram shown in Figure 2. FIG. 3 is a circuit diagram of a protective relay device.

In FIG. 2, the secondary side of the distribution transformer 1 is connected to a bus 2, which has feeders Fl, P2. F3 is connected.

The feeder F1 is provided with a current transformer 4 and a zero-phase current transformer 5, and their respective outputs are input to an aI relay 6. Further, the protective relay 6 is connected to a reclosing relay 7. The primary side of a grounding transformer 9 is connected to the bus 2, and its secondary output is input to the protective relay 6.

In Fig. 3, each output of the C-phase current input auxiliary transformer 10 to which the a-phase current 3 of the feeder F1 is inputted and the C-phase current input auxiliary transformer 11 to which the C-phase current IC is inputted both detects a short circuit accident. It is input to a circuit 12, and its output is manually inputted to a cooperative timer 13 for short-circuit accidents. The output side of this short-circuit accident coordination timer 13 is the short-circuit accident output relay 1.
4 relay coil 14c.

Zero-sequence voltage of feeder F1 ■. A zero-sequence voltage input transformer 15 and a zero-sequence current I are input. Each output of the zero-phase current input transformer 16 to which is input is input to a ground fault fault detection circuit 17, and its output is input to a ground fault fault coordination timer 18. The output side of the ground fault coordination timer 18 is connected to the relay coil 19c of the ground fault output relay 19. Further, between the control power lines P and P2, there is a circuit in which the normally open contact 14a of the short circuit fault output relay 14 and the normally open contact 19a of the ground fault fault output relay 19 are connected in parallel.
A relay coil 20c of an auxiliary interrupting relay 20 having a first normally open contact 20a1 for interrupting the circuit breaker in this parallel circuit;
A series circuit with a normally closed auxiliary contact 21b that is linked to the breaking operation of the circuit breaker 3 is connected. The circuit breaker 3 is then cut off by closing the first normally open cut-off contact 20a1. In addition, the control power line P1 is connected to the auxiliary disconnection relay 2.
It is connected to the input side of the re-closing sequence 22 via the second normal contact point 20a2 for breaking the circuit breaker, and the output side thereof is connected to the closing auxiliary relay 23 having the normally open contact 23a for closing the circuit breaker.
The relay coil 23c is connected to the relay coil 23c. The circuit breaker is closed by closing the normally open closing contact 23a.

When a ground fault X occurs in the feeder F1 in the power distribution system shown in FIG.

The zero-sequence current I0 of the zero-sequence current transformer 5 is input to the protective relay 6. These zero-sequence voltages■. The zero-sequence current I0 is input to the zero-sequence voltage input transformer 15 and the zero-sequence current input transformer 16 shown in FIG. 3, and the ground fault detection circuit 17 detects it as a ground fault in its own line. And coordination timer 1 for ground fault accident
8 operates, the relay coil 19c of the ground fault output relay 19 is energized, its normally open contact 19a is closed, and the relay coil 20c of the cutoff relay 20 is energized. The second regular contacts 20a, , 20az are both closed, the circuit breaker 3 (see FIG. 2) is disconnected, and the feeder F1 where the ground fault X has occurred is separated from the bus bar 2. Simultaneously with this cut-off operation, the re-closing sequence 22 starts a timing operation, and after a predetermined time period ends, outputs a signal to the relay coil 23c of the closing auxiliary relay 23, and outputs a signal to the relay coil 23c of the closing auxiliary relay 23.
is energized, the normally open contact 23a is closed, and the circuit breaker in the cut-off state is reclosed. At this time, if the ground fault X of the feeder F1 has not been recovered, the protective relay 6 will detect the ground fault again, and the circuit breaker 3 will be activated after the time limit set in the ground fault coordination timer 18 has expired. The cutoff operates again.

[Problem that the invention seeks to solve]

In the above-mentioned conventional protective relay device, the time limit set for the cooperation timer for short circuit and ground fault is set to 30 to 90 cycles in order to cooperate with the protective relay provided in the lower power system. Therefore, when the circuit breaker is reclosed by the reclosing sequence after the circuit breaker performs the circuit breaking operation, the fault current flows again if the fault has not been recovered. This fault current is detected by the protective relay, and the circuit breaker is shut off again after the cooperative timer has expired. Therefore, the fault current continues until the set time limit ends, and there is a problem that the power system cannot be properly protected.

In view of the above-mentioned problems, the present invention has been developed to ensure coordination with the protective relay installed in the lower-level power system, and to instantly shut off the circuit breaker again if the fault has not been recovered when the circuit is reclosed. The purpose is to provide a protective relay device that properly protects the

[Means for solving problems]

The protective relay device according to the present invention connects a parallel circuit of a cooperative timer and a contact between an accident detection circuit and an output relay,
This contact is configured to close when the circuit breaker is reclosed.

[Effect]

A short circuit or ground fault that occurs in the power system is detected by the fault detection circuit. When an accident is detected and the time limit set in the cooperative timer expires, the output relay operates to shut off the circuit breaker. When a predetermined time period has elapsed after the interruption operation, the circuit breaker is reclosed, and when the circuit breaker is reclosed, the contact connected in parallel with the cooperative timer is closed. Therefore, if the fault has not been recovered when the circuit breaker is reclosed, the fault detection circuit will detect the fault again and the circuit breaker will shut off instantly regardless of the time limit set by the cooperative timer.

As a result, no fault current will flow even if the fault has not been recovered when the circuit breaker is reclosed.

〔Example〕

The present invention will be described in detail below with reference to drawings showing embodiments thereof.

FIG. 1 is a block diagram of a protective relay device according to the present invention.

In FIG. 2, for example, the a-phase current input auxiliary transformer 10 to which the a-phase current ■3 of the feeder F1 is input, and the C-phase current ■6
The respective outputs of the C-phase current input auxiliary transformer 11 to which is input are both input to a short-circuit accident detection circuit 12, and the output thereof is input to a short-circuit accident coordination timer 13. The output side of the short-circuit accident coordination timer 13 is the short-circuit accident output relay 1.
4 relay coil 14c. And the output side of the short circuit accident detection circuit 12 and the short circuit accident output relay 14
A normally open contact 3 of a time limit shortening relay 31, which will be described later, is connected between the
1a1 is connected. Zero-sequence voltage V of feeder F1. A zero-sequence voltage input transformer 15 and a zero-sequence current I are input. Each output of the zero-phase current input transformer 16 to which is input is input to a ground fault fault detection circuit 17, and its output is input to a ground fault fault coordination timer 18. The output side of the ground fault coordination timer 18 is connected to the relay coil 19c of the ground fault output relay 19. Ground fault detection circuit 1
The normally open contact 31a2 of the time limit shortening relay 31 is connected between the output side of 7 and the relay coil 19c of the ground fault output relay 19. Between the control power lines PI and PZ, there is a circuit in which the normally open contact 14a of the short-circuit fault output relay 14 and the normally open contact 19a of the ground fault fault output relay 19 are connected in parallel, and this parallel circuit is connected to a circuit breaker for breaking the circuit breaker. First normally open contact 2
Relay coil 2 of the auxiliary interrupting relay 20 having 0a.
0c and a normally open auxiliary contact 21b interlocked with the breaking operation of the circuit breaker 3 are connected in a series circuit. The circuit breaker 3 is then cut off by closing the first normally open cut-off contact 20a. Further, the control power line P is connected to the input side of the re-closing sequence 22 via the second normal contact 20a2 for breaking of the auxiliary breaking relay 20, and the output side thereof is connected to the normally open contact 23a for closing the circuit breaker. Relay coil 23c of auxiliary closing relay 23 and return timer 30 having
is connected to. This return timer 30 outputs a signal during a period of time counting operation for a predetermined time limit, and automatically returns after the time limit ends. The time limit set in the recovery timer 30 is, for example, a time slightly longer than the time from when the relay coil 23c of the closing relay 23 is energized until the circuit breaker 3 performs the re-breaking operation.

The output side of the recovery timer 30 is the time limit reduction relay 3.
It is connected to relay coil 31c of I. Further, the circuit breaker 3 is closed by closing the normally open closing contact 23a of the closing relay 23.

In the power distribution system shown in FIG. 2, for example, when a ground fault X occurs in the feeder F1, the zero-sequence voltage of the grounding transformer 9. and zero-sequence current I of zero-sequence current transformer 5. is input to the protective relay 6. These zero-sequence voltages V. and zero-sequence current■. are not shown in FIG. 1, but include the zero-phase voltage input transformer 15 and the zero-phase current input transformer
, the ground fault detection circuit 17 detects it as a ground fault in its own line. Then, the ground fault coordination timer 18 operates and the relay coil 19 of the ground fault output relay 19 is activated.
c is energized, its normally open contact 19a is closed, and the relay coil 20c of the cutoff relay 20 is energized.
Both the second regular contacts 20a+ and 20a2 are closed, and the circuit breaker 3 (see FIG. 2) of the feeder F1 where the ground fault X occurred is cut off, and the feeder F1 is separated from the bus bar 2.

Simultaneously with this cut-off operation, the re-closing sequence 22 starts a timing operation and outputs a signal to the relay coil 23c of the auxiliary closing relay 23 and the return timer 30 after the time period ends. Therefore, the relay coil 23c is excited, the normally open contact 23a is closed, and the circuit breaker 3 is reclosed. In addition, in parallel with this operation, the recovery timer 30 measures a predetermined time period and outputs a signal, and the relay coil 31 of the time period shortening relay 31
c is excited, and its normally open contacts 31a1 and 31az are both closed. Therefore, when the circuit breaker 3 is reclosed and the fault has not been recovered, the ground fault detection circuit 17 detects the fault again, and the output of the ground fault detection circuit 17 is instantly transferred to the ground fault output relay. 19, the relay coil 19c is energized, the normally open contact 19a is closed, and the relay coil 20c of the cutoff relay 20 is energized.

Therefore, when the circuit breaker 3 detects an unrecovered ground fault, it immediately shuts off again.

Then, after the circuit breaker 3 is cut off again, the reset timer 30 completes the timing operation for a predetermined time period and resets, its output disappears, and the relay coil 31c of the time limit shortening relay 31 is demagnetized, and its normally open contact 3], a+, and 31a- are both opened to prepare for the detection of a new accident.

In this way, the protective relay of the present invention is installed in the lower power system. Interrupts in coordination with the relay,
If the accident has not been recovered when the circuit is reclosed, the power system will be immediately shut off again to properly protect the power system.

In this embodiment, a ground fault accident has been described, but it goes without saying that a similar protective operation is performed in the case of a short circuit accident in an electric power system. Further, although the protective relay device is applied to the power distribution system, it goes without saying that similar effects can be obtained not only in the power distribution system but also when applied to other power systems that perform time-limited coordination.

〔Effect of the invention〕

As described in detail above, according to the present invention, when the circuit breaker is reclosed, the fault detection circuit and the output relay are directly connected through the contacts, so that the fault detection circuit and the output relay are directly connected through the contacts, so that the circuit breaker can be reclosed even when the fault has not recovered. Even if the circuit breaker recloses, it will shut off instantly.

Therefore, no fault current will flow due to the reclosing of the circuit breaker.

In addition, it is possible to maintain cooperation with a protective relay provided in a lower power system using a coordination timer, thereby providing an excellent effect of providing a protective relay device that can appropriately protect the power system.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a protective relay device according to the present invention, Fig. 2 is a block diagram of a protective relay device according to the present invention;
The figure is a single line diagram of a power distribution system, and FIG. 3 is a block diagram of a conventional protective relay device. 10...A phase current input auxiliary transformer 11...C phase current input auxiliary transformer 12...Short circuit accident detection circuit 13...Short circuit accident coordination timer 14...Short circuit accident output relay 15. ...Zero-phase voltage input transformer 16...Zero-phase current input transformer 17...Ground fault detection circuit 18...Ground fault coordination timer 19...Ground fault output relay 20... -Auxiliary relay for cutoff 22...Auxiliary relay for closing sequence 23...Auxiliary relay for closing 30...Timer for return 31...Relay for time reduction 31a+, 31az
...Normally open contact In the drawings, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] 1. An output signal from an accident detection circuit that detects an accident occurring in a power system is given to an output relay via a coordination timer that has a time limit set in order to cooperate with a protective relay in a lower power system. In the protective relay device, the circuit breaker installed in the power system is cut off by the operation of the output relay, and the circuit breaker is then reclosed. A protective relay device characterized in that a parallel circuit of the cooperative timer and a contact is connected therebetween, and the contact is closed when the circuit breaker is reclosed.