JPH11264892A - Protection device of power source system in nuclear power plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To limit the isolation range from the system at an electric accident occurrence location to the minimum in a power source system in a nuclear power plant and prevent a human error during testing during the regular plant check. SOLUTION: In a nuclear power plant sending power generated by a generator to a system via a main transformer 4 and capable of supplying a part of generated electricity by a generator 3 to load in the plant via a transformer 2 in the plant, protection relays 10, 14 and 17 detecting electric accident of the generator 3 and relay (a lockout relay) detecting turbine trip or reactor trip are provided and a generator breaker 19 is automatically tripped only by the relay output signal and the generator 3 is isolated from the system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention makes it possible to minimize the influence on the operation of a power plant and the entire system by finely dividing a part isolated from the system due to an electric accident in a nuclear power plant. This is related to the in-plant power supply system logic.

[0002]

2. Description of the Related Art FIG. 11 is a block diagram showing a configuration of an in-house power supply system of a conventional nuclear power plant disclosed in Japanese Patent Application Laid-Open No. 58-66521. In the figure, 1 is a main transformer, 2 is an in-house transformer, 3 is a generator, 4 is a main transformer, 5
Is a generator load switch, 6 is a generator disconnector, 7 is a meta-clamp receiving circuit breaker, 8 is a protection relay for detecting an internal short-circuit accident of the main transformer 1, 9 is an internal short-circuit accident of the internal transformer 2. 10 is a protection relay for detecting an internal short circuit accident of the generator 3; 11 is a protection relay for detecting a short circuit accident in the main transformer 1, the in-house transformer 2, the generator 3 and the connection portion thereof; Is a protection relay that detects a ground fault in the main transformer 1, 13 is a protection relay that detects a ground fault in the in-house transformer 2, 14 is a protection relay that detects a ground fault in the generator 3, and 15 is a main relay. A protection relay for detecting a ground fault at the connection between the generator 1 and the generator 3, a protection relay 16 for detecting an overcurrent of the in-house transformer 2, and a detector 17 for detecting a loss of field of the generator 3 and reverse power. Protection relays, 18 are the extra-high-speed switchgear insteps and the Otomo line

FIG. 12 shows a logic configuration for tripping the main transformer, the generator load switch, and the power receiving circuit breaker.

Next, a description will be given of the operation of protecting the power supply system in the above-mentioned conventional nuclear power plant. During normal operation,
The electric power of the generator 3 is sent to the system via the main transformer 1 and partly sent to the on-site load via the on-site transformer 2. For example, when a short circuit accident occurs in the Since power supply becomes impossible, the protection relays 10 and 11 detect the accident and trip the main transformer breaker 4. Next, the voltage generation of the generator 3 is stopped, and the
Also trip. In this case, power is supplied to the internal load from another route.

[0005] When a short-circuit fault occurs in the main transformer 1 and the local transformer 2, the fault is detected by the protection relays 8 and 11 and the protection relays 9 and 11, respectively. The power supply circuit breaker 7 is tripped and the generator 3
Stop generating voltage. In addition, for other electrical accidents, each accident is detected by each detection protection relay 12-17.
The main transformer breaker 4 and the meta-clamp power receiving breaker 7 are tripped to stop the voltage generation of the generator 3.

In other words, in the event of an electrical accident in the power supply system in the station, the main transformer breaker 4 is tripped for isolation from the system, and the power receiving circuit breaker 7 is tripped for isolation from the load in the station. And a protection system that stops it.

[0007] Turbine trips other than electric accidents,
In the reactor trip, the generator load switch 5 is tripped, and the voltage generation of the generator 3 is stopped. However, the main transformer breaker 4 and the meta-clamp receiving circuit breaker 7 can supply power from the system to the on-site load without tripping. And

[0008]

As described above, when an electrical accident occurs in the power supply system in the power plant, the circuit below the circuit breaker is tripped by tripping the main breaker 4 as described above. Because it is separated from the system,
There was a problem that the function as a power station had to be stopped wherever the accident was, and power to the internal load had to be supplied through another route.

In addition, during the regular inspection, the generator load switch 5 is opened, the generator is stopped, and power is supplied from the system to the on-site load via the main transformer. If it is operated erroneously during the test, it may lead to tripping of the main transformer breaker. Therefore, there is a problem that curing such as wire breakage is required.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and minimizes the isolation range of an in-plant power supply system from a location where an electrical accident occurs, thereby maintaining the function as a power plant, An object of the present invention is to increase the reliability of load power supply continuity. Another object of the present invention is to prevent human errors at the time of a test during a plant periodic inspection.

[0011]

According to the first aspect of the present invention,
In a nuclear power plant that can send the power generated by the generator to the grid via the main transformer and supply a part of the generated power to the on-site load via the on-site transformer, It is equipped with a protection relay that detects, a relay that detects a turbine trip or a reactor trip (lockout relay), and a generator breaker that automatically trips only with those relay output signals to isolate the generator from the system. And

According to the second aspect of the present invention, the electric power generated by the generator can be sent to the system via the main transformer, and a part of the generated electric power can be supplied to the internal load via the internal transformer. A nuclear power plant is provided with a protection relay for detecting an electrical accident of an in-house transformer, and an in-house transformer circuit breaker for automatically tripping only with the relay output signal and isolating the in-house transformer from the system.

According to the third aspect of the present invention, the power generated by the generator can be sent to the system via the main transformer, and a part of the generated power can be supplied to the on-site load via the on-site transformer. At a nuclear power plant, a protection relay that detects an electrical accident in the main transformer, a protection relay that detects an electrical accident in the main circuit of the generator, and a main transformer that automatically trips only with those relay output signals are provided. Features.

According to a fourth aspect of the present invention, there is provided a switch which receives an automatic trip signal of a circuit breaker due to an electrical accident of a generator and disconnects a protection relay, which has become unnecessary due to isolation from a system, from a CT circuit.

According to a fifth aspect of the present invention, there is provided a switch which receives an automatic trip signal of a circuit breaker due to an electrical accident in an in-house transformer and disconnects a protection relay, which has become unnecessary due to isolation from a system, from a CT circuit. .

The invention according to claim 6 is characterized in that the output of the protection relay, which has become unnecessary due to isolation from the system, is blocked by the output of the protection relay for detecting an electrical accident of the generator.

According to a seventh aspect of the present invention, the output of the protection relay which has become unnecessary due to isolation from the system is blocked by the output of the protection relay for detecting an electrical accident of the in-house transformer.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. In FIG.
1 is a main transformer, 2 is an in-house transformer, 3 is a generator, 4 is a main transformer breaker, 6 is a generator breaker, 7 is a meta-kura receiving breaker,
8 is a protection relay for detecting an internal short circuit accident of the main transformer 1,
9 is a protection relay for detecting an internal short-circuit accident of the in-house transformer 2; 10 is a protection relay for detecting an internal short-circuit accident of the generator 3; 11 is a main transformer 1, an in-house transformer 2, a generator 3 and a connection thereof. , A protection relay for detecting a ground fault of the main transformer 1, a protection relay 13 for detecting a ground fault of the in-house transformer 2, and 14 for the generator 3. Protection relay to detect ground fault,
Reference numeral 15 denotes a protection relay for detecting a ground fault at the connection between the main transformer 1, the local transformer 2 and the generator 3, 16 a protective relay for detecting an overcurrent of the local transformer 2, and 17 a field of the generator 3. A group of protection relays for detecting a magnet loss accident or reverse power, etc., 18 is an extra-high-voltage switchyard, a bus line, and 19 is an accident current provided in place of the conventional generator load switch 5 which cannot interrupt an electric accident current. It is a generator circuit breaker that can be shut off.

FIG. 2 shows a main transformer breaker 4 according to the first embodiment.
A logic configuration for tripping the metal circuit breaker 7 and the generator breaker 19 is shown.

Next, the operation of the first embodiment will be described. In the first embodiment, the protection relay 1 for the generator 3
The circuit breakers to be tripped are changed from the main circuit breaker 4 to the generator circuit breaker 19 by the operations 0, 14, and 17 and the power supply circuit breaker 7 is not tripped. Therefore, in the event of an electrical accident of the generator 3, only the generator is isolated from the system, and power can be supplied to the in-plant load as before the accident, so that the reliability of securing the in-plant power source is further improved.

The main transformer 1, the in-house transformer 2, the generator 3, and the general short-circuit protection relay 11 of the connection thereof are provided with a time lag in the relay output.
The main transformer breaker 4 is configured to trip under the condition that there is no output of 0. Therefore, it does not operate at the time of the short-circuit accident of the generator 3, and the short-circuit accident protection can be continued at a place other than the generator.

Embodiment 2 FIG. In the first embodiment, the case where the generator 3 is isolated from the system by the generator circuit breaker 19 in the event of an accident has been described. However, as shown in FIGS. May be configured to trip only when the protection relays 9 and 16 of FIG.

In this way, without stopping the power supply from the generator 3 to the system, which had been performed before the accident,
System stability can be improved. In this case, there is no problem because power can be supplied to the in-house load from another route as before.

The general short circuit protection relay 11 is provided with a time lag as in the first embodiment, and the main transformer breaker is provided on condition that there is no output from the generator short circuit protection relay 10 and the in-house transformer short circuit protection relay 9. 4 was tripped. As a result, it does not operate at the time of the short-circuit accident of the generator 3 and the in-house transformer 2, and the short-circuit accident protection can be continued at a place other than the generator 3 and the in-house transformer 2.

Further, in the regular inspection, the in-house transformer disconnecting device 21 is opened, and the in-house transformer 2 is isolated from the system, so that the in-house transformer alone can be inspected.

Embodiment 3 FIG. In the first embodiment, a case has been described in which the protection relay 11 constitutes a logic that does not operate in the event of a short circuit of the generator 3. However, as shown in FIG. 5, the protection relay 11 is connected to the generator neutral point CT 22. A switch 23 may be provided between them, and the switch 23 may be tripped by an output signal of the protection relay 10 that operates when an internal short circuit accident occurs in the generator 3.

As a result, the logic can be simplified as shown in FIG. 6, and the reliability of the trip ability at the time of an accident can be improved.

Embodiment 4 In the third embodiment, the method of tripping the switch 23 by the output of the protection relay 10 and not operating the protection relay 11 in the event of an internal short circuit of the generator 3 has been described. However, as shown in FIG.
A switch 25 is provided between the internal transformer 1 and the primary transformer CT24 of the station, and the switch is tripped by the output signal of the protection relay 9 which operates when an internal short circuit occurs in the internal transformer.
As shown in (1), the logic can be simplified, and the reliability of the trip ability at the time of an accident can be improved.

Embodiment 5 In the first embodiment, the logic configuration (see FIG. 2) in which the protection relay 11 does not operate when the generator 3 is short-circuited has been described. However, as shown in FIG. 9, the output of the protection relay 10 locks the protection relay 11. A method of blocking the out-relay output may be used, and there is no need to provide a time lag, so that a more reliable trip capability is provided.

Embodiment 6 FIG. In the fifth embodiment, the logic configuration (see FIG. 9) in which the protection relay 11 does not operate in the event of a short circuit of the generator 3 has been described. However, as shown in FIG. Relay 1
Since a method of blocking with the output of the protection relay 9 so as to prevent operation of the protection relay 1 is added, the isolation range due to the failure can be more concretely specified, and a reliable trip capability equal to or higher than that of the second embodiment can be provided.

[0031]

As described above, according to the present invention, the isolation range of the power supply system in the plant due to the location of the electrical accident is minimized, the function as a power plant is maintained, and the reliability of the load supply in the plant is maintained. Can be up.

In particular, according to the first aspect of the present invention, in the event of an electrical accident of the generator, only the generator is isolated from the system and power can be supplied to the in-plant load as before the accident, so that the in-plant power source is secured. This has the effect of improving the reliability of the device.

According to the second aspect of the present invention, by providing an in-house transformer breaker that trips only when a protection relay for the in-house transformer is activated, the power supply from the generator to the system, which was performed before the accident, is provided. It is possible to improve the stability of the system without stopping the power supply.

According to the third aspect of the present invention, the isolation range of the power supply system in the station due to the location of the electrical accident is minimized, and the function as the power station is maintained and the reliability of the load supply in the station is maintained. Can be done.

According to the inventions of claims 4 to 7, the logic for isolating the power supply system in the office from the system at the place where an electric accident occurs can be simplified, and the reliability of the trip ability at the time of an accident can be improved. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an on-site power supply system of a nuclear power plant according to Embodiment 1 of the present invention.

FIG. 2 is a logic configuration diagram for explaining the operation of the first embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of an on-site power supply system of a nuclear power plant according to Embodiment 2 of the present invention.

FIG. 4 is a logic configuration diagram for explaining an operation according to the second embodiment of the present invention;

FIG. 5 is a block diagram showing a configuration of an in-house power supply system of a nuclear power plant according to Embodiment 3 of the present invention.

FIG. 6 is a logic configuration diagram for explaining the operation of the third embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of an in-house power system of a nuclear power plant according to Embodiment 4 of the present invention.

FIG. 8 is a logic configuration diagram for explaining the operation of the fourth embodiment of the present invention.

FIG. 9 is a logic configuration diagram for explaining the operation of the fifth embodiment of the present invention.

FIG. 10 is a logic configuration diagram for explaining the operation of the sixth embodiment of the present invention.

FIG. 11 is a block diagram showing a configuration of an in-house power supply system of a conventional nuclear power plant.

FIG. 12 is a logic configuration diagram for explaining the operation of the conventional device.

[Explanation of symbols]

1 main transformer, 2 station transformers, 3 generators, 4 main transformer breakers, 6 generator circuit breakers, 7 Metakura power receiving circuit breakers,
8 protection relay, 9 protection relay, 10 protection relay,
11 protection relays, 12 protection relays, 13 protection relays, 14 protection relays, 15 protection relays, 16 protection relays, 17 protection relay groups, 18 extra-high-speed switchyards, otomo-bus, 19 generator circuit breakers, 20 internal transformer shutoffs vessel,
21 In-plant transformer disconnector, 22 Generator neutral point CT,
23 switch, 24 station transformer primary side CT, 25 switch.

Claims (7)

[Claims] 1. A nuclear power plant capable of sending power generated by a generator to a system via a main transformer and supplying a part of the generated power to an on-site load via an on-site transformer. A protection relay that detects an electrical accident in the machine, a relay that detects a turbine trip or a reactor trip (lockout relay), and a generator breaker that automatically trips only with those relay output signals to isolate the generator from the system A protection device for a power supply system in a nuclear power plant, comprising: 2. A nuclear power plant capable of sending electric power generated by a generator to a system via a main transformer and supplying a part of the generated electric power to an on-site load via an on-site transformer. Protection of the power supply system in a nuclear power plant, comprising: a protection relay that detects an electrical accident in a transformer, and an in-house transformer circuit breaker that automatically trips only with the relay output signal and isolates the in-house transformer from the system. apparatus. 3. A nuclear power plant capable of transmitting power generated by a generator to a system via a main transformer and supplying a part of the generated power to an on-site load via an on-site transformer. A nuclear power plant comprising a protection relay for detecting an electrical accident in a transformer, a protection relay for detecting an electrical accident in a power generation main circuit, and a main transformer breaker that automatically trips only with the output signal of those relays. Protection device for the power supply system in the plant. 4. A switch for disconnecting a protection relay, which has become unnecessary due to isolation from a system upon receipt of an automatic trip signal of a circuit breaker due to an electrical accident of a generator, from a CT circuit. The protection device for a power supply system in a nuclear power plant according to any one of the above. 5. The switch according to claim 1, further comprising a switch for receiving a signal from an automatic trip of the circuit breaker due to an electrical accident in the station transformer and disconnecting the protection relay, which has become unnecessary due to isolation from the system, from the CT circuit. The protection device for a power supply system in a nuclear power plant according to any one of claims 3 to 7. 6. The protection relay according to claim 1, wherein an output of the protection relay for detecting an electrical accident of the generator blocks an output of the protection relay whose operation becomes unnecessary due to isolation from the system. The protection device for a power supply system in a nuclear power plant according to any one of the preceding claims. 7. An output of a protection relay which has become unnecessary due to isolation from a system, is blocked by an output of a protection relay for detecting an electrical accident of an in-plant transformer. The protection device for a power supply system in a nuclear power plant according to any one of the above.