JP2000253558A - Protection system in generation plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a power supply in a plant being supplied from a system having a protection relay working unnecessarily when a generator load switch (GLBS) is open. SOLUTION: This protection system in a generation plant normally supplies power from a generator 3 to a system and a bus in a plant. However, when a GLBS 5 is open by turbine trip or the like, the input line of protection relays 7 and 9-14 related to generator protection is broken by circuit breakers 15-20, thus preventing improper tripping of a main circuit breaker 4, due to unnecessary operation of the protection relays 7 and 9-14, and hence preventing the cut-off of a power supply line from the system to the bus in the plant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protection system for a power plant such as a nuclear power plant, and more particularly to a generator load switch (GLBS, Generato) for opening and closing a generator output.
The present invention relates to a system for protecting a power supply from a power system from being stopped when the switch is in an open state in a plant having a Load Brack Switch.

[0002]

2. Description of the Related Art FIG. 8 is a circuit diagram in a power plant of a conventional nuclear power plant which is currently employed, and shows each equipment, a power supply configuration and a protection system. In the figure, 1
Is a main transformer, 2 is an on-site transformer, 3 is a generator, 4 is a main transformer, 5 is a generator load switch (GLBS), 6 is a generator disconnector, 7 to 14 are protection relays, 7 Is a differential relay for detecting internal short circuit accidents in main / stationary / generators, 8 is a relay for detecting ground faults in the main circuit of the generator, 9 is a differential relay for detecting internal short circuit accidents in the generator, and 10 is a generator Ground fault detection relay, 1
1 is a field loss relay, 12 is a generator overcurrent relay, 13
Is a generator reverse power relay, and 14 is a generator reverse phase relay.

FIG. 9 is a diagram showing a logic configuration of the protection system, and shows a logic configuration for tripping the main breaker 4 and the GLBS 5. Reference numerals 51 to 58 denote lockout relays which are operated by the operations of the protection relays 7 to 14 to operate the generator lockout relay (A) 61 and the generator lockout relay (B) 62. FIG. 10 shows a DC power supply circuit related to a protection relay. In FIG. 10, 21 to 24
Indicates a no-fuse breaker.

Next, the operation will be described. In FIG. 8, during normal operation, the electric power of the generator 3 is sent to the system via the main transformer 1 and also sent to the on-site load via the on-site transformer 2. In this power supply configuration, protection from an electrical accident is performed by the protection relays 7 to 14. If those protection relays operate due to the electrical accident, the main transformer breaker 4 trips and the voltage generation of the generator 3 stops. Doing so leads to a plant trip.

If it is necessary to stop the voltage generation of the generator 3 due to a non-electrical accident such as a turbine trip (during a periodic inspection, etc.), the GLBS 5 is manually tripped to isolate the generator 3 from the system. ing. In this case, since the in-house electric circuit is normal, the in-house load can be fed from the system via the main transformer 1 and the in-house transformer 2. In this state, the only protection relays necessary to protect the electric circuit are the internal short-circuit accident detection ratio differential relay 7 and the power generation main circuit ground fault detection relay 8, but the other protection relays 9 to 14 are also operable. (Operation standby state).

That is, in the current nuclear power plant, the GLBS 5 is required to protect the electric circuit in the plant when the GLBS 5 is tripped (during a turbine trip or during regular inspection, etc.) and when it is not tripped (during normal operation). The protection relay will be different. That is, when the GLBS 5 is tripping, the number of necessary protection relays is reduced.

Referring to the logic configuration of the protection system shown in FIG. 9, all operations of the protection relays 7 to 14 lead to a trip of the main breaker 4 and a turbine trip or GL.
Even if the GLBS 5 trips due to the manual “open” operation of the BS 5, the protection relays 7 to 1 regardless of the trip.
4 is in an operation standby state.

[0008] The DC power supply circuit related to the protection relay includes:
Since the configuration is as shown in FIG. 10, power is supplied to all of the protection relays regardless of whether or not the GLBS 5 trips.

[0009]

In the conventional in-house electrical circuit protection system, even if the GLBS 5 is tripped, the protection relay 9 for the generator 3 is excluded from protection.
Since the operation standby state is continued in the operation standby state, the trip of the main transformer breaker 4 due to the unnecessary operation needs to be prevented. However, conventionally, the power supply for the protection relays 9 to 14 is turned off.
F, no input to the protection relays 9 to 14 was input, and no processing was performed so that no output was output.

The DC power supply for the protection relay is G
Even when the LBS 5 is tripped, the power supply of the protection relays 7 and 8 necessary for circuit protection and the power supply of the protection relays 9 to 14 which do not require circuit protection at the time of trip are combined, so that they can be isolated. There is a problem that it takes time to perform the sorting operation, and that human error cannot be denied in the sorting operation.

The present invention has been made to solve the above-described problem. When the GLBS 5 is tripped, an erroneous trip of the main transformer circuit breaker 4 is performed by unnecessary outputs of the protection relays 9 to 14. It is an object of the present invention to provide an in-house power supply protection system which prevents the in-house power supply from being stopped due to an erroneous trip. It is another object of the present invention to eliminate the above isolation work and prevent human error.

[0012]

(1) A protection system for a power plant according to the present invention includes a switching device for cutting off a generator load from a generator, a generator disconnector, a main transformer, and a main transformer. And supplying power to the system, supplying power for the in-house power supply via the disconnector, and when the opening / closing means is in an open state, the power plant supplies in-house power from the system, and When the means is in an open state, a block means for blocking at least one of an input signal and an output signal of a protection relay related to protection of the generator among protection relays for protecting the power generation plant is provided. This prevents malfunctions of the breaker and prevents power supply from the system from being stopped.

(2) In addition, power is supplied to the system via a switching means for disconnecting the generator load from the generator, a generator disconnector, a main transformer, and a main transformer, and the power is supplied to the system via the disconnector. A power relay for supplying power for the in-plant power source and supplying the in-plant power from the system when the switching device is opened, wherein the protection relay protects the power plant when the switching device is opened. Among them, there is provided a shut-off means for shutting off a power supply to a protection relay related to the protection of the generator, and the cut-off prevents a malfunction of the main transformer, thereby preventing a power supply from being stopped from a system. Things.

(3) In addition, power is supplied to the system via a switching means for disconnecting the generator load from the generator, a generator disconnector, a main transformer, and a main transformer, and the power is supplied to the system via the disconnector. A power plant for supplying power to the in-plant power source and supplying the in-plant power from the system when the opening / closing device is opened, the power plant including the blocking device of (1) and the shut-off device of (2). It is a thing.

(4) In the above (2) or (3), there is provided a notifying means for notifying that the power of the protection relay to be cut off has been cut off in accordance with the shutting operation of the shutting means.

(5) In any one of the above items (1) to (4), when the disconnector for the generator is in the open state, the protection relays for protecting the power plant among the protection relays for protecting the power plant. And a second blocking means for blocking at least one of an input signal and an output signal of the protection relay.

(6) In any one of the above items (1) to (5), when the disconnector for the generator is opened, the protection relays for protecting the power plant among the protection relays for protecting the power plant. And a second shut-off means for shutting off the power supply to the protection relay related to the protection of the generator by the protection relay.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram of a power plant, and the same reference numerals as those in the conventional drawings denote the same or corresponding components, and a description thereof will be omitted. FIG. 2 is a diagram showing a logic configuration of the protection system.

In FIG. 1, reference numeral 15 denotes protection relays 11 to 1
3 is a circuit breaker that blocks the voltage input to the protection relay 10, and 16 is a circuit breaker that blocks the voltage input to the protection relay 10.
Are circuit breakers that block the current input to the protection relay 9;
Reference numeral 9 denotes a circuit breaker that blocks a current input to the protection relays 11 to 14. Reference numeral 20 denotes a circuit breaker that blocks the current input from the generator 3 among the current inputs to the protection relay (a ratio differential relay for detecting a main change, a change, and an internal short-circuit accident of the generator) 7. When the current input from the generator 3 is blocked, the protection relay 7 becomes a ratio differential relay for detecting an internal short-circuit accident for main / stationary protection.

Next, the operation will be described with reference to FIG. G
When the LBS 5 trips or the GLBS 5 is manually "opened", the circuit breakers 15 to 20 are opened, and the protection relays 7, 9 to 14, which do not require protection of the generator 3, cut off the input signal and operate the relay. Not to do.

As described above, the circuit breakers 15 to 20 separate the generator-side input signal of the protection relay 7 from the input signal of the protection relays 9 to 14, so that the protection relays 7, 9 are separated.
Unnecessary signals and erroneous signals which may be input to １４14 can be reliably blocked, and a highly reliable circuit for preventing tripping of the main transformer circuit breaker 4 can be configured. In this case,
Circuit breakers 15 to 20 are trip signals of GLBS5 ("open").
Since a trip is automatically performed in response to a signal contact), a manual isolation operation is not required, so that the operation time can be reduced and the isolation curing can be prevented from being forgotten.

Embodiment 2 FIG. In the first embodiment, the case where the input signals to the protection relays 9 to 14 are cut off by the circuit breakers 15 to 20 to isolate the protection relays 9 to 14 from the in-house electric circuit has been described. GLBS
The unnecessary output signals of the protection relays 9 to 14 are blocked by the trip signal 5 or the manual "open" operation signal of the GLBS 5. That is, the open signal “1” of the GLBS 5 is set to the close signal “0” by the inverter, and the output of each AND circuit is blocked.

As described above, the protection relays 9 to 1
Even if an unnecessary signal is output from the main circuit breaker 4, the main transformer breaker 4 does not trip, resulting in a more reliable protection system. Further, since the outputs of the protection relays 9 to 14 are blocked, the protection relays (relays for detecting a power supply main circuit ground fault) 8
Can be tested.

Embodiment 3 FIG. In the second embodiment, a case has been described in which a logic is configured to block the output signal so that the protection relays 9 to 14 do not operate when the GLBS 5 is tripped using the “open” signal of the GLBS 5. However, as shown in FIG. 4, the protection relays 9 to 9 are generated by inverting the “open” signal of the generator disconnector 6.
Add logic to block 14 operations. When the GLBS 5 and the generator disconnector 6 are set to "open" at the time of regular inspection, etc., and the internal load is supplied from the system, the main change interruption by the output of the protection relays 9 to 14 is ensured even in the open / close test of the GLBS 5. The erroneous trip of the device 4 can be prevented, and a more reliable protection system can be obtained.

That is, during the regular inspection, the generator disconnector 6 is opened.
In some cases, a test for opening and closing the GLBS 5 may be performed in a state where the output signal blocks of the protection relays 9 to 14 are GLB.
If only the "open" condition of S5 is satisfied, the output signal blocks of the protection relays 9 to 14 may be broken during this open / close test. Therefore, this condition can be prevented by adding the "open" condition of the generator disconnecting switch 6.

Embodiment 4 In the second and third embodiments, the “open” condition of the GLBS 5 and the “open” condition of the generator disconnector 6 are described.
Although a protection logic for blocking the output signals of the protection relays 9 to 14 has been added under the condition, the no-fuse breakers 25 and 26 are provided as shown in FIG. 5 instead of the current protection relay DC power supply circuit shown in FIG. , GLBS5 is tripped by the power supply to eliminate the need for operation and to keep the operation in standby mode.

In this manner, only the protection relays 9 to 14 which do not need to be operated are turned off by the no-fuse breakers 25 and 26.
The operation of the protection relays 9 to 14 itself can be eliminated by performing FF. Of course no fuse breaker 2
5, 26 are trip signals (or GLB) of GLBS5.
By tripping with the "open" operation signal of S5),
There is no manual work, unnecessary protection relays can be isolated,
Efficiency can be improved.

Embodiment 5 In the fourth embodiment, the unnecessary protection relay is disconnected from the DC power supply (no fuse breaker 2).
5 and 26), the protection relay 9
Although the case of preventing the erroneous trip of the main transformer circuit breaker 4 due to .about.14 has been described, as shown in FIG. 6 and FIG. , A notification alarm is issued by the operation signal. Unnecessary protection relay power is OFF
At a glance.

Embodiment 6 FIG. The sixth embodiment is obtained by extracting and combining the embodiments from the first to fifth embodiments. Here, the outline of the first to fifth embodiments is as follows. In the first embodiment, when the GLBS 5 is opened, the input of the protection relay related to the generator is blocked.
In addition to the first embodiment, when the GLBS 5 is opened, the output of the relay is blocked. In the third embodiment, in addition to the second embodiment, the output of the relay is blocked when the generator disconnector 6 is opened. Embodiment 4 is different from Embodiment 3 in that GL
When the BS5 is opened, the power of the relay is cut off. In the fifth embodiment, in addition to the fourth embodiment, a power cutoff is notified according to the cutoff of the relay power in the fourth embodiment.

(1) In the sixth embodiment, only the output of the generator-related protection relay of the second embodiment may be blocked, and the protection relay input block of the first embodiment may be omitted.

(2) Further, when the GLBS 5 of the fourth embodiment is opened, only the power supply of the protection relay is cut off, and the protection relay input block of the first embodiment may be omitted.

(3) The protection relay input block of the first embodiment may be omitted by combining the protection relay output block of the second embodiment and the protection relay power supply of the fourth embodiment.

(4) Further, in the above (1) to (3), the protection relay output block by opening the generator disconnector 6 of the third embodiment may be combined.

(5) The protection relay input block of the first embodiment may be combined with the protection relay power cutoff of the fourth embodiment.

(6) In addition, various combinations from the embodiments may be performed.

In the sixth embodiment, when the protection relay input block of the first embodiment is omitted, the protection relay (ratio differential relay for detecting main change, station change, and internal short-circuit accident of generator) 7 The current input of the generator 3 cannot be interrupted, but the main differential and the internal short circuit accident detection ratio differential relay and the generator internal short circuit accident detection ratio differential relay are installed separately. Can be applied when the protection relay configurations are different.

Embodiment 7 In the third embodiment, a case in which the protection relay output is blocked by opening the generator disconnector 6 is added. However, in the seventh embodiment, as the first case, the generator protection-related Block protection relay input. The block target input is the same target as the input line of the first embodiment.
Block by

The second example of the seventh embodiment is that, when the generator disconnector 6 is opened, the protection relays 9 to related to the generator protection are connected.
14 is turned off.

The third example of the seventh embodiment is to combine the input block, the output block, and the power cutoff of the protection relays related to the generator protection by opening the generator disconnector 6, which is optional by the three parties. The two or three are combined.

The fourth example of the seventh embodiment is to add a notification of power interruption due to the interruption of the relay power supply of the fifth embodiment when the power is interrupted in the second or third example. is there.

[0041]

As described above, according to the present invention, when the opening / closing means for shutting off the load on the generator is opened, the input / output of the protection relay related to the generator protection or the power supply is blocked. In addition, it is possible to prevent the in-house power supplied from the system from being stopped due to malfunction of these protection relays.

[Brief description of the drawings]

FIG. 1 is a circuit diagram in a power plant of a nuclear power plant according to Embodiment 1 of the present invention.

FIG. 2 is a logic diagram of a protection system for a nuclear power plant according to Embodiment 1 of the present invention.

FIG. 3 is a logic diagram of a protection system for a nuclear power plant according to Embodiment 2 of the present invention.

FIG. 4 is a logic diagram of a protection system for a nuclear power plant according to Embodiment 3 of the present invention.

FIG. 5 is a circuit diagram of an in-plant power supply of a nuclear power plant according to Embodiment 4 of the present invention.

FIG. 6 is a circuit diagram of an in-house power supply of a nuclear power plant according to Embodiment 5 of the present invention.

FIG. 7 is a logic circuit diagram of a protection system for a nuclear power plant according to Embodiment 5 of the present invention.

FIG. 8 is a circuit diagram in a power plant of a conventional nuclear power plant.

FIG. 9 is a logic circuit diagram of a conventional protection system for a nuclear power plant.

FIG. 10 is a circuit diagram of an in-house power supply of a conventional nuclear power plant.

[Explanation of symbols]

Reference Signs List 1 main transformer 2 in-house transformer 3 generator 4 main transformer breaker 5 generator load switch (GLBS) 6 generator disconnector 7 ratio differential relay for detecting internal short circuit accident of main transformer, substation and generator Protection relay) 8 Generator main circuit ground fault detection relay (Protection relay) 9 Generator internal short circuit fault detection ratio differential relay (Protection relay) 10 Generator generator ground fault detection relay (Protection relay) 11 Field loss relay (Protection relay) 12 Generator overcurrent relay (Protection relay) 13 Generator reverse power relay (Protection relay) 14 Generator reverse phase relay (Protection relay) 21-26
No fuse breaker 51-58 Lockout relay 61, 62 Generator lockout relay

Claims (6)

[Claims] 1. A switching means for disconnecting a generator load from a generator, a disconnector for the generator, a main transformer, and a main transformer
When power is supplied to the system, power is supplied to the in-house power supply via the disconnector, and when the open / close means is in an open state, the power plant supplies in-house power from the system, and the open / close means includes When it is in an open state, it comprises a block means for blocking at least one of an input signal and an output signal of a protection relay related to protection of the generator among the protection relays for protecting the power generation plant, and the main change interruption by the block. A protection system for a power plant, wherein a malfunction of a power unit is prevented and a supply of in-house power from a system is not stopped. 2. A switching means for interrupting a generator load from the generator, a disconnector for the generator, a main transformer, and a main transformer.
When power is supplied to the system, power is supplied to the in-house power supply via the disconnector, and when the open / close means is in an open state, the power plant supplies in-house power from the system, and the open / close means includes When it is opened, the protection relay for protecting the power plant is provided with shut-off means for shutting off the power supply to the protection relay related to the protection of the generator, and the shut-off prevents malfunction of the main transformer. A power plant protection system, characterized in that supply of in-house power from a power system is not stopped. 3. Power is supplied to the system via a switching means for shutting off a generator load from the generator, a generator disconnector, a main transformer, and a main transformer, and an on-site power supply is supplied via the disconnector. When power is supplied to the opening and closing means,
A power plant for supplying in-house power from the system, comprising a block unit according to claim 1 and a shut-off unit according to claim 2. 4. The protection system for a power plant according to claim 2, further comprising a notifying unit for notifying that the power of the protection relay to be cut off has been cut off in response to the shutting off operation of the shutting off unit. And power plant protection system. 5. The protection system for a power plant according to claim 1, wherein when the disconnector for the generator is opened, the protection relay for protecting the power plant is connected to the protection of the generator. A protection system for a power plant, comprising: a second blocking means for blocking at least one of an input signal and an output signal of a protection relay to be performed. 6. The protection system for a power plant according to claim 1, wherein when the disconnector for the generator is opened, the protection relay for protecting the power plant is related to protection of the generator. A protection system for a power plant, comprising: a second shutoff means for shutting off a power supply to a protection relay related to protection of the generator by the protection relay.