JPH0832127B2 - Protective relay - Google Patents

Description

The present invention relates to a protective relay device used in a power system to which overcurrent protection is applied.

[Conventional technology]

FIG. 3 is a schematic configuration diagram showing a conventional protective relay device. In the figure, 1 is a power source, 2 is a power receiving transformer, 3 is a protective relay device, 4 is a bus bar, and 5 and 6 are other power systems. 7 is a circuit breaker (hereinafter abbreviated as CB) provided on the power supply side of the bus bar 4, and 8, 9 and 10 are CBs provided on the load side of the bus bar 4, 11, 12 is a CB provided on the connecting lines 5 and 6, 13
Is a time-delay type overcurrent relay (hereinafter abbreviated as OCT) as a first low speed operation relay, 14,15,16 is a normal overcurrent relay (hereinafter abbreviated as OC) as a first high speed operation relay, 17
Is an OCT as a second low speed relay, and 18 is an OC as a second high speed relay.

Further, 19 is a power source of another electric power system, 20 is a power receiving transformer, 21 is a bus bar, 22, 23, 24 are CB, and 25 is a bus line of another substation or a substation 26 for users. Although illustration of OC, OCT, etc. is omitted for the power system on the side of the power source 19, it is assumed that protection equivalent to that of the power system on the side of the power source 1 is made.

By the way, the power system on the side of the power source 1 and the power system on the side of the power source 19 are in a state of being connected by the connecting lines 5 and 6 and the bus 25. This makes it possible to supply power from the other power system in the event of an accident in one of the power systems, making it impossible to supply power from that power system. This is to allow it.

Next, the operation will be described. For example, when an accident such as a short circuit occurs at point A in FIG. 3, OC14 and OCT13,17 and OCT (not shown) related to CB22,23 are started. But,
Operating time is different between OC and OCT, OC14 operates faster, so only CB8 is actually tripped,
No other CB will trip.

[Problems to be solved by the invention]

Since the conventional protective relay device is configured as described above, it has the following problems.

That is, if there is a short circuit or other accident at point B in FIG. 3, the operating speeds of the OCT for CB7, 11, 22, and 23 are the same, so not only CB7 but also CB23 that should not be tripped. I was tripped and could not improve the reliability of grid operation. In particular, the voltage near the busbars 4 and 21 is high, and even if an attempt is made to protect the busbar with sufficient reliability, it is difficult to achieve it from the viewpoint of cost and balance with protection of other parts. It was

The present invention has been made to solve the above problems, and an object of the present invention is to obtain a protective relay device that trips CBs only at necessary points to sufficiently secure the reliability of system operation. And

[Means for solving problems]

The protective relay device according to the present invention attaches a directional relay to a predetermined CB, detects the direction of the accident occurrence point, and based on the conditions related to this direction, all CBs at an intermediate speed between OC and OCT. An operation command circuit for outputting an operation signal is provided.

[Action]

The output signal of the operation command circuit according to the present invention is issued after the occurrence of an accident and after the lapse of an intermediate time between the operation times of OC and OCT. Only the CB trips based on the operation of
When an accident occurs on the load side of the CB provided with OCT, all CBs provided with OCT trip based on the output signal of the operation command circuit.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 27 is a directional relay (hereinafter abbreviated as DS) 28,2
The protective relay device includes 9,30 and an operation command circuit 31.

When an accident occurs, the DSs 28, 29, 30 detect whether the accident occurrence point is "inward direction" or "outward direction" for each. The direction of the inward direction and the outward direction is determined by the direction of the CT attached to each DS. For example, for DS28 and 29, the inward direction is the load side of the CT mounting position (CT mounting in Fig. 1). In the DS30, the inner direction is the power supply side of the CT mounting position (upward direction from the CT mounting position in FIG. 1). And these DS28,2
9,30 is based on the input from each CT, IN output terminal, O
Send an output signal to one of the UT output terminals.

FIG. 2 is a circuit diagram showing the internal configuration of the operation command circuit. In the figure, 32, 33, and 34 are AND circuits that take the AND of any two internal direction signals of DS28, 29, and 30, 35 is an OR circuit that takes either OR, 36 is a timer circuit, 37 is AN
OR that takes the OR of the outputs from D circuits 32, 33, 34 and timer circuit 36
A circuit, 38 is an OR circuit that takes the OR of the external direction signal of any of DS28, 29, 30 and 39 is the output of the OR circuit 37 and the output of the OR circuit 38 (L signal) and the AND, and CB7 , 8,9,
This is an AND circuit that outputs operation command signals to 10, 11, and 12. Then, the operation command circuit 31 determines the speed (time) from the occurrence of the accident until the AND circuit 39 outputs the operation command signal as OC14,1.
It is set to be slower than the operating speed (time) of 5,16,18 and faster than OCT17.

Next, the operation will be described. Similar to the case of FIG. 3,
Considering the case where there is an accident at point A, DS28, 29, 30 all output an internal direction signal (actually, almost no current flows to the DS31 side and no internal direction signal is output, but DS28 , 29
Since the AND is established, the result does not change), and since there is no one that is outputting the external direction output signal, the AND circuit 39
The condition of is satisfied and the operation command signal is output to CB7-12.
However, since the operating speed of OC is faster, OC14 operates first and trips CB8, which returns the grid current to the normal state. Therefore, the operation command signal from the operation command circuit 31 is canceled, and only CB8 among CB7 to 12 is tripped, as in the case of FIG.

Next, if there is an accident at point B,
Similar to the case of the accident at the point, the condition of the AND circuit 39 is satisfied, and the operation command signal is output to CB7 to 12, but this time OCT
Due to the slow operation speed of 17, all of CB7-12 are tripped. And, of course, the CB22 and CB23 on the power supply 19 side are not tripped.

When an accident occurs at point C on the other power system side, the DS29 outputs an external direction signal.
The condition of the D circuit 39 is not satisfied, and the operation command circuit 31 does not output the operation command signal.

If CB11,12 are open, AND circuits 32,33,
Although 34 does not function, if the DS 28 outputs the internal direction signal, the timer circuit 36 is started and after a predetermined time, CB7 to 10 are tripped. The predetermined time in this case can be considered to be almost the same as the OCT operation time.

In the above embodiment, the operation command circuit 31 of DS28, 29, 30 is used.
Output of the AND circuit 34
The DS28, 29, 30 may be prioritized by removing the.

Further, in the above embodiment, the connection lines 5 and 6, the load-side bus bar
Although the case where both 25 are provided has been described, the case where only one of them is provided may be provided.

〔The invention's effect〕

As described above, according to the present invention, an operation command circuit that trips all circuit breakers unless the high-speed relays trip the circuit breakers when each direction relay detects that an accident has occurred inward In addition, if a high-speed operation relay and the operation command circuit do not trip the circuit breaker in the event of an accident, the circuit breaker provided on the connection line will trip. You can trip only the circuit breakers where you need them without tripping unnecessary circuit breakers, and because there is no need for timed coordination between the circuit breakers on the power supply side of the bus and the circuit breakers of the connecting lines, If an accident occurs, the circuit breaker can be tripped quickly.

[Brief description of drawings]

1 is a schematic configuration diagram showing a protective relay device according to an embodiment of the present invention, FIG. 2 is a schematic configuration diagram showing an operation command circuit used in FIG. 1, and FIG. 3 is a conventional protective relay device. It is a schematic block diagram which shows an electric equipment. 4 is a bus bar, 5 and 6 are connection lines, 7 to 12 are CBs (circuit breakers), 14 to 1
6, 18 are OC (overcurrent relays), 17 are OCT (timed overcurrent relays), 27 are protective relays, 28-30 are DS (direction relays), and 31 is an operation command circuit. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A circuit breaker provided on a load side and a power supply side of a bus bar and a connection line connecting to another power system, and a circuit breaker provided on the load side of the bus bar when an accident occurs on the load side. When a high-speed relay that trips, a directional relay that is provided on the power supply side of the busbar and the connection line and that detects the direction of the accident occurrence point, and that each of the directional relays detects an accident in the internal direction If the high-speed operation relay does not trip the circuit breaker, the operation command circuit that trips all the circuit breakers, and if an accident occurs, the high-speed operation relay and the operation command circuit must trip the circuit breaker. A protective relay device comprising a low-speed operation relay that trips a circuit breaker provided in the connection line.