JPS5846835A - Network relay - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a network relay used as a protector for a network power distribution system.

When an accident or power outage occurs on the primary side of a network protector, a network relay trips the breaker of the protector and disconnects the faulty bank from the network bus, preventing the fault from spreading to the network bus and healthy banks, and recovering from the fault. After that, the breaker is automatically turned on. As described above, network relays are important devices that affect the reliability of network power distribution systems, and are required to have extremely high reliability. Conventionally, in order to improve the reliability of network relays, a method has been adopted in which a check function is added to the network relays, and simulated inputs are periodically input to check that the relays are operating normally. However, because the network relay is inspected online, the output circuit must be locked during the inspection so that the output during the inspection does not actually operate the breaker.For this reason, the breaker must not be operated during the inspection. If an unexpected situation occurs, the relay 41iW will not be able to operate immediately, and the accident may spread to the healthy bank.To prevent this situation, two network relays are used in parallel. A possible method is to operate the breaker using the logical product of the outputs, leave the output of the relay to be inspected in the operating state during inspection, and inspect the relays alternately. If a situation in which the breaker should be operated occurs during inspection of a relay, the other relay normally detects this and outputs a command to operate the breaker.-The output of the relay being inspected becomes operational. , so the logical product of the two outputs becomes active and the breaker can be operated without any time delay.However, it is expensive because it requires the use of two relays.

An object of the present invention is to provide a relatively inexpensive and highly reliable network relay, the gist of which is to detect reverse current or reverse power in a network protector and trip the circuit breaker of the network protector. A reverse power cutoff circuit that sends out a signal, and a condition that detects the voltage difference between the circuit breaker and its phase when the circuit breaker is in an open state, and that reverse 11151E does not flow to the circuit breaker after it is turned on. A differential current feeding circuit that sends out a closing signal for the breaker, detects that the primary side of the network protector is in a charging state, and the network bus is in a non-electrified state, and sends a closing signal for the breaker. The circuit breaker is equipped with a no-voltage closing circuit that sends out voltage, and is constructed by making only the reverse power cutoff circuit a dual system, and the circuit breaker is tripped by the logical product of the trip signals of the two reverse power cutoff circuits. The present invention provides a network relay with the following features.

Hereinafter, four embodiments of the present invention will be explained with reference to FIG. The network relay 1 measures the voltage on the network transformer TR side of the protector breaker OB with a measuring transformer PTl, and measures the voltage across the network busbar with a measuring transformer PT2. The current is detected by each measuring transformer CT, and the trip signal TX of the circuit breaker CB is generated at the time of an accident, and the closing signal C is generated at the time of recovery from the accident.
x, and has two reverse power circuits with exactly the same characteristics [7, disconnection circuit 10.20, and differential power supply circuit 8o].
and a no-voltage closing circuit 40. An accident or power outage occurs on the primary side of the network transformer TR [7. When the wl current flows from the network bus bar toward the network transformer TR, the reverse power breaker IO detects this and turns on the auxiliary relay 11.

Similarly, the reverse power breaker 20 turns on the auxiliary relay 21, and the trip signal output Tx connected in series with the normally open contacts 11 and 21A of each auxiliary relay is turned on. The auxiliary relays 12 and 22 are turned on when the cough circuit is being inspected, and the normally open contacts 12 and 22A are connected in parallel with the normally open contacts 11 and 21 of the auxiliary relays 11 and 21, respectively.

When the accident or power outage is restored and the primary power of the breaker CB is established, IIEFJE at both ends of the breaker CB is detected, and if the network bus is supplying power to the load, the differential power input circuit 80 connects the auxiliary relay 81. is turned on and the network bus is in a no-voltage state, the no-voltage closing circuit 40 turns on the auxiliary relay 41. Auxiliary relay 82:42 is the aS
It is turned on when the auxiliary relay 81. is under inspection.
41 normally open contacts 81A, 41A are auxiliary relays 82.42
Since each of the normally closed contacts 82A and 42A are connected in series, the closing signal output Cx, which is the result of connecting the respective series circuits in parallel, is turned on.

When inspecting the reverse power cutoff circuit 10 or 20, the auxiliary relay 12 or 22 turns on instantly, and after a predetermined time, the auxiliary relay 11 or 21 turns on. 10 An accident occurred in the network system during inspection of 7 and disconnection O.
Consider the fact that R must be cut off from reverse power. Reverse power breaker W&20 detects the current flowing from the network bus to network relay TH, turns on auxiliary relay 21, and closes normally open contact 21. - The reverse force breaker circuit lO can be checked and the breaker C1l can be tripped.

Reverse 1 force 1. Even if a similar accident occurs during inspection of the broken circuit 20, the circuit breaker CB can be tripped in the same way.

On the other hand, if the fault is restored during inspection of the differential power-on circuit 30 or the no-voltage power-on circuit, there will be a delay in the operation of the circuit, but this will hardly cause the accident to occur again.

Even if it were to happen, it can be easily avoided by contacting the substation and not conducting an inspection when the accident is restored and power is transmitted again from the substation.

− As shown in the figure, the differential voltage input circuit 80 and the non-density input circuit r@
4o only needs to be activated during accident recovery, and sufficient reliability can be ensured by checking during the accident, so there is no need to create a dual system.

The present invention operates as described above, and has the following features compared to conventional devices.

υ By making the reverse power cutoff circuit a dual system and inspecting each circuit alternately, it is possible to respond normally even if an accident occurs during inspection.

2) The reverse power cutoff circuit is a dual system, and the trip signal is sent by the AND of each output, reducing the probability of malfunction.
Improved reliability.

8) Only the reverse power cutoff circuit needs to be a dual system, so
It's not that expensive.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention. 10, 20... Reverse power cutoff circuit. 80...Song...Differential voltage input circuit. 40... Song... No-voltage closing circuit. 8flB, 42B--...Song auxiliary relay normally closed contact.

Claims (1)

[Claims] In a spot network power distribution system in which the secondary sides of a plurality of network protectors are connected to a network bus bar and a load is supplied from the network bus bar, a reverse current or reverse power of the network protector is detected, and the A reverse power cutoff circuit that sends out a trip signal for a circuit breaker in a network protector, and when the circuit breaker is in an open state, there is a difference in electric current between the poles of the circuit breaker FEI! l- A differential voltage switching circuit that detects the phase and sends a switching signal for the breaker on the condition that reverse 14E#lE does not flow to the breaker after switching on, and a charging letter on the primary side of the network protector. Yes, and the network bus is non-electronic F
The circuit breaker is equipped with a switching circuit that detects that the breaker is in the E-shaped layer and sends a switching signal for the circuit breaker. A network relay characterized in that the circuit breaker is tripped by logical product of trip signals.