JP3243295B2 - Protective relay - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective relay device for switching the order of load interruption when an abnormality occurs in a system frequency due to occurrence of an accident in a power system.

[0002]

2. Description of the Related Art When an accident occurs in an electric power system, an abnormality in the system frequency is predicted. FIG. 3 is a block diagram of a conventional protection relay device that detects such an abnormality in the system frequency. The operation will be described below with reference to FIG.

The protection relay 1 inputs a bus voltage v to frequency detection relays 11A and 11B to detect the frequency of the system. One frequency detection relay 11A operates when the frequency of the system drops to f1 or less, and does not operate when the frequency is f1 or more. The operation output of the frequency detection relay 11A is input to a timer 12A of the next stage, and is output for a predetermined time t1.
The operation is performed after the elapse of seconds, and the output T1 becomes 1.

On the other hand, the frequency detection relay 11B operates when the frequency of the system falls below f2, and
In the above case, no operation is performed. This frequency detection relay 11
The operation output of B is input to the next-stage timer 12B, and after a lapse of a predetermined time t2 seconds, the output becomes T2 = 1. here,
There is a relationship of system frequency f1> system frequency f2.

[0005] By the way, in order to determine the target to be cut off, a negative
Connection information between load or generator and power system bus (with circuit breaker and
Or status information of the disconnector, etc.). In the illustrated example, the determination is made based on the breaker contact information CB1, CB2, CB3, and CB4. That is, if any one of the circuit breakers CB1 and CB2 is turned on, the output L1 of the OR circuit 13A becomes L1 = 1. This condition and the output T1 = 1 of the timer 12A are input to the AND circuit 14A at the next stage. Similarly, circuit breakers CB3, C
If any of B4 enters, the output L of the OR circuit 13B
2 = 1, which is input to the next-stage AND circuit 14B.
The AND condition with the output T2 = 1 of the timer 12B is satisfied, and the shutoff 2 = 1 is output from the AND circuit 14B, and the shutoff command is output. Circuit breakers CB1, CB2 or CB3, C corresponding to the objects to be interrupted according to the command of interruption 1 or interruption 2
B4 is tripped and opened.

The above operation is shown in a time chart of FIG. That is, when the normal frequency f0 of the power system drops from f0 to f1 to f2 due to a system fault, the frequency detection relay 11A operates at f1 or less. This operation detects the continuation of the fixed time t1 by the next-stage timer 12A. At this time, if any of the circuit breakers CB1 and CB2 is ON, the timer 12A
The AND condition with the operation output of (1) is satisfied, a cutoff 1 command is output, and the circuit breakers CB1 and CB2 are tripped and opened from entering.

Further, when the frequency falls below f2,
The frequency detection relay 11B operates. This operation detects the continuation of the predetermined time t2 by the next-stage timer 12B. At this time, if any of the circuit breakers CB3 and CB4 is ON, the timer 1
AND condition between the operating output of the 2B is outputted blocked 2 command is satisfied, the circuit breaker CB3, CB4 is tripped in this
The connected load is shut off. As a result, the system frequency is restored to f0 in a normal state before the occurrence of the system accident. Conversely, the frequency
If the number increases, increase the operating frequency above the rated frequency.
This frequency relay operates using the set frequency relay.
If this happens, trip the circuit breaker in the same way and shut off the generator.
You.

[0008]

As described above, the conventional method has a negative effect according to the frequency fluctuation (decrease / increase) level.
This is an order cutoff method in which the load and generator are fixed. Therefore the load corresponding to the cut-off in the frequency variation is small level, the generator can not effect is obtained by blocking and no further corresponds to blocking a large level of the next frequency variable load, also blocked by blocking generator There is a problem that the effect is low and the system frequency is not restored to the original value.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problem, and an object of the present invention is to provide a protection relay device having a function of switching the order of interruption using the result of judging the presence or absence of an interruption target. is there.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method of connecting a power system to a power system via a switch when the system frequency is abnormal due to the occurrence of a power system accident or when the abnormality is predicted. Of multiple loads or generators
Among them, in a protective relay for recovering the frequency abnormality by tripping a load or a generator having a size commensurate with the recovery of the frequency abnormality, a plurality of protection relays installed to detect a system frequency in the power system and having different operating frequencies. and pieces of the frequency detection relay, the load or generator with plural kinds of combination state between the power system more connection information input to the plurality of connection information each other about the existence of a connection between the bus
Create and output a logic signal for each combination state
Decoder, negative not connected to the power system bus
Ago always frequency change of a lower level state except a load or generator to perform the ordering interruption of the load or the generator
The output signal of the decoder and the plurality of frequency detection
And a cutoff order switching unit comprising a logic circuit for combining the output signal of the array with the output signal of the array .

[0011]

According to the protective relay device of the present invention, blocking rank switching unit with using a blocking target determination results than breaker on / off the load that can be blocked by the first frequency fluctuation level, the generator, following frequency variation level The frequency that can be interrupted by a load or a generator , such as a generator
This enables the load and circuit breaker to be cut off in order from the time when the fluctuation level is small.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a protection relay device 1 according to one embodiment of the present invention. In FIG. 1, the same parts as those in FIG. 3 are denoted by the same reference numerals. A structural feature is that a cutoff order switching unit 15 that switches the order of cutoff using the result of determination of a cutoff target is provided.
It comprises circuits 152A, 152B, 152C, 152D and OR circuits 153A, 153B. The other configuration is the same as that of the conventional example, and therefore the same portions will be described with the same reference numerals. Next, the operation of the present embodiment will be described.

The contact information of the circuit breakers CB1, CB2, CB3, CB4 is input to the OR circuits 13A, 13B, and if any of the circuit breakers is turned on, the output L of the OR circuits 13A, 13B.
1, L2 = 1 is input to the cutoff order switching unit 15 of the next stage. The cutoff order switching unit 15 switches the cutoff order based on the decoding of the L1 and L2 signals and the decoding result.

First, an object to be interrupted is decoded by the decoder 151 from the L1 and L2 signals. FIG. 2A is a truth table of the decoder 151. That is, the combination (0, 1, 2, 3) of the two signals L1 and L2 is decoded, and when the combination is 0, Y0
= 1, Y1 = 1 for combination 1, Y2 = 1 for combination 2,
In the case of combination 3, Y3 = 1 is output.

The next-stage AND circuits 152A, 152B, 1
52C and 152D perform the next operation in response to a signal from the preceding circuit. The AND circuit 152A satisfies the AND condition with the timer 12A operation signal T1 = 1 and the output signal Y1 = 1 of the decoder 151, and the output signal is output to the next-stage OR circuit 1
53A is input and a cutoff 1 command is output. The AND circuit 152B satisfies the condition when the timer 12A operation signal T1 = 1 and the output signal Y2 = 1 of the decoder 151, and the output signal is input to the OR circuit 153B at the next stage and the cutoff 2 command is output. The AND circuit 152C satisfies the condition when the timer 12A operation signal T1 = 1 and the output signal Y3 = 1 from the decoder 151, and the output signal is input to the OR circuit 153A at the next stage and the cutoff 1 command is output. The AND circuit 152D satisfies the condition when the timer 12B operation signal T2 = 1 and the output signal Y3 = 1 from the decoder 151.
53B, and the cutoff 2 command is output.

That is, in the combination of the output signals L1 and L2 from the OR circuits 13A and 13B, if only the signal L2 is present, the cutoff order is increased by one and the cutoff condition is switched from the timer 12B to the timer 12A. FIG.
(B) shows a list of shutoff targets and the corresponding timers. Signal L
1 or only L2, the timer 12A corresponds to the combination. When the signals L1 and L2 are all present, the signal L1 is the timer 12A and the signal L2 is the timer 1A.
2B is applicable. By increasing the order of interruption in this way, the objects to be interrupted in order interruption do not drop out, and it is possible to prevent a reduction in control effect.

[0018]

As described above, according to the present invention, change frequency in the conventional
The blocking target load dealing fixed in accordance with the dynamic level were sequence interrupted, but blocking order by decrypting the determination result of <br/> blocking target existence by the connection information of the switch according to the present invention Since the order of the objects to be interrupted can be switched (forwarded) in descending order, the load can be interrupted even when the frequency fluctuation level is small. That is, a protection relay device having an extremely excellent control effect can be provided by switching the load interrupting order and interrupting the load.

[Brief description of the drawings]

FIG. 1 is a block diagram of a protection relay device according to an embodiment of the present invention.

FIG. 2A is a truth table of a decoder, and FIG.
Is a list of objects to be shut down and the corresponding timer.

FIG. 3 is a block diagram of a conventional protection relay device.

FIG. 4 is a time chart of the conventional protective relay device of FIG. 3;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Protective relay device, 11A, 11B ... Frequency detection relay, 12A, 12B ... Timer, 15 ... Shutdown order switching part,
CB1 to CB4 ... circuit breakers.

Claims (1)

(57) [Claims] When a system frequency is abnormal due to the occurrence of an accident in a power system or when the abnormality is predicted, a plurality of loads or generators connected to the power system via a switch.
Among them, in a protective relay that recovers the frequency abnormality by pulling off a load or a generator of a size commensurate with the recovery of the frequency abnormality, is installed to detect a system frequency in the power system,
A plurality of frequency detection relays having different operating frequencies; and a connection between the load or the generator and the power system bus .
Enter multiple connection information about the presence or absence of this multiple connection
In addition to creating multiple combinations of information,
A decoder that outputs a logic signal for each combination state,
Load or generator not connected to the power system bus
Output of the decoder such that the load or the generator is always shut off from the state where the frequency change level is small except for
Signals and output signals of the plurality of frequency detection relays;
And a cut-off order switching unit comprising a logic circuit combining the following .