JP3269693B2 - 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 for protecting a power system, and more particularly to a protective relay having means for detecting an abnormality of a circuit breaker control circuit.

[0002]

2. Description of the Related Art A protection relay drives an opening / closing element (an auxiliary relay or a semiconductor switching element is used) by an output from a relay element for detecting a system fault, and energizes a trip coil of a circuit breaker. The circuit breaker is tripped (trip circuit), and after the accident is eliminated, the switching element is driven to energize the closing coil of the circuit breaker and the circuit breaker is closed (closing circuit). May not have a circuit). There is a possibility that this switching element will be activated when it must not be activated due to a defect. Normally, a plurality of switching elements are connected in series, and one element failure does not cause a malfunction immediately, but the function as a protection relay (selecting and shutting down an accident in a protection section,
Or, after the accident is recovered, the power is surely input). In addition, a disconnection failure may occur in the trip coil or closing coil of the circuit breaker or in the connection cable between the protective relay device and the circuit breaker. In this case as well, there is a possibility that tripping is impossible at the time of an accident or that the vehicle cannot be thrown in after accident recovery. FIG. 9 shows an example of a means for solving these problems.
A method has been proposed in which a fault in the trip circuit is detected and an alarm is displayed by a method as shown in (an example of application to a trip circuit, in which an auxiliary relay is used as a switching element). That is, relay element 1 (accident detection element), 2-1 and 2-2
, 2-3 (contacts 3a, 4-1a, 4-2a, 4-3a of auxiliary relays 3,4-1, 4-2, 4-3 driven by the main detection element)
Circuit breaker trip coil (with impedance Ztr)
A detector for obtaining an output for confirming a potential difference between contacts in parallel with each of the auxiliary relays in a trip circuit in which 5-1, 5-2, and 5-3 are connected between PN power supplies 6a and 6b for control equipment. 7,8-1
, 8-2, 8-3 (all internal configurations are the same).

Reference numeral 9 denotes an internal circuit of the detector (in this example, a circuit using a photocoupler), 9a and 9b are potential difference detection terminals, and 9c is 7a, 8-1a, 8-2a, 8- A detector output terminal corresponding to 3a, 10 is a monitoring current limiting resistor having an impedance R, 11 is a photocoupler, 12a and 12b are Vcc and Gnd power supplies for a logic circuit inside the protective relay, 13 is a pull-up resistor, 14 Is a buffer circuit. If a potential difference occurs between the detectors 9a and 9b, the monitoring current suppressed low by the monitoring current limiting resistor 10 flows between the detectors 9a and 9b, and the photocoupler is turned ON. When the potential difference disappears between 9a and 9b, the photocoupler turns off and the output
9c becomes logic 1. In the normal state, since all the contacts are open, there is a potential difference between the detection terminals of all the detectors in parallel with the contacts, a monitoring current flows to all the detectors, and all the detector outputs are logic 0. Has become. Although the trip coil is energized by the detector, the value of R is selected so that the circuit breaker does not operate (R >> Z).
tr).

Next, a plurality of abnormal state patterns will be described. When the contact 3a is closed due to a defect, no potential difference is generated at the potential difference detection terminal of the detector 7, and the output 7a becomes logic 1. Further, when any of the contacts 4-1a, 4-2a, and 4-3a is closed due to a defect, no potential difference occurs between the parallel contacts. For example, when the contact 4-1a is closed due to a defect, since R >> Ztr as described above, the potential difference between the control power supplies 6a and 6b is almost applied to the current limiting resistor 10 in 7a, and the potential difference between 6c and 6b in FIG. Has almost no potential difference. Therefore, outputs 8-1a, 8-2a, 8-
All 3a are logic 1. The same output is obtained when 4-2a or 4-3a fails. Also, trip coil of circuit breaker
5-1, 5-2, 5-3, or disconnection of the connection cable may occur, but since these two states are in the same mode from the viewpoint of the detector, the disconnection of the trip coil will be described below. . When the trip coil 5-1 is disconnected, the monitoring current does not flow to the detector 8-1 of the disconnected phase of the coil, and the output 8-1a becomes logic 1. Trip coil 2
If there is a disconnection in any of up to 8 units, the detectors 8-1, 8-2, 8-
In 3, the output of the detector of the phase in which the coil is disconnected becomes logic 1. Further, when the trip coils are disconnected in all three phases, no monitoring current flows to all the detectors, and all outputs become 1. If any abnormality occurs in the trip circuit as described above,
An output can be obtained from any of the detectors, and the outputs of all the detectors are supplied to a timer 16 (confirming that the output will continue for a certain period of time) via an OR circuit 15. The trip circuit is monitored. It is needless to say that the above-mentioned method is applied to the closing circuit of the protection relay device according to the same principle.

[0005]

In the monitoring system of the circuit breaker control circuit of the protective relay device described above, the object of detecting the abnormality of the switching element can be achieved. or,
When the cable between the protection device and the circuit breaker and the trip coil of the circuit breaker are disconnected, the same abnormality as described above can be detected, but the following inconvenience occurs. For example, if an abnormality of the circuit breaker control circuit is detected for some reason, it is necessary to identify the abnormal part and repair that part. At this time, all of the protective relay, the circuit breaker and the connection cable must be checked, which causes a delay in repair. In addition, when investigating a circuit breaker, it is an essential condition to stop the electric power system, so that the power transmission is greatly hindered.
The present invention has been made in order to solve the above problems, and a circuit abnormality in the protection relay device and an abnormality outside the protection relay device are distinguished and determined, so that quick maintenance can be performed. An object is to provide a protective relay having a circuit breaker control circuit.

[0006]

According to a first aspect of the present invention, there is provided a protective relay device comprising: a switching element for opening and closing a circuit;
A plurality of switching elements having one terminal connected in common are connected in a series circuit, and when the former switching element and the latter switching element are closed at the same time, the tripping coil or closing coil of the circuit breaker is energized. In a protective relay device provided with a switch control circuit, a first means for detecting a voltage level drop between terminals to be connected and opened in parallel with the former switching element and a respective means connected in parallel to each of the latter switching elements. A second means for detecting a voltage level drop between the switching element terminals, a third means for obtaining a logical product of a plurality of outputs of the second means, an output of the first means and an output of the third means. A fourth means for detecting a mismatch, and when the output of the fourth means has continued for a predetermined time,
The circuit breaker control circuit inside the protection relay is determined to be abnormal. According to a second aspect of the present invention, there is provided a protective relay device comprising: a fifth means for obtaining a logically inverted output of the output of the fourth means; and a logical product of each output of the second means and the output of the fifth means. There is provided a sixth means for obtaining, when an interrupter control circuit outside the protective relay device has an abnormality, an abnormal part is specified by an output of the sixth means. The protective relay device according to claim 3 is configured such that a plurality of switching elements for opening and closing a circuit are connected in series,
When all switching elements connected in series are closed at the same time,
In a protective relay having a circuit breaker control circuit configured to energize a tripping coil or a closing coil of a circuit breaker, a voltage level between respective switching element terminals connected in parallel with each switching element connected in series. A first means for detecting a decrease, and a second means for detecting a mismatch between a plurality of outputs of the first means.
Means for determining that the circuit breaker control circuit inside the protection relay device is abnormal when the output of the second means continues for a predetermined time.

First, in the case of a circuit failure inside the protective relay,
If the first contact is defective, only the detector of the defective circuit has a logic 1 and the others have a logic 0. Therefore, the fourth means for detecting a mismatch becomes an output 1 to detect abnormality. Second
In the case of the contact failure described above, the above-described logic is simply reversed, and can be detected by the fourth means. Also, if one trip coil is disconnected as a case of external failure, no current flows to the detector of the disconnected phase, and the output of that phase is logic 1
Becomes When up to two trip coils are disconnected, the output of the detector of the disconnected phase becomes logic 1 as described above.
If all three phases are disconnected, the monitoring current does not flow to all the detectors, and all the outputs become logic 1. This makes it possible to immediately determine whether a failure occurs inside the protection relay device or a failure outside the protection relay device when a circuit breaker control circuit monitoring failure occurs. it can. In the protective relay device according to the second aspect, an abnormal part can be specified by the output of the sixth means.
The protective relay device according to (1) can determine an abnormality of the circuit breaker control circuit.

[0007]

An embodiment will be described below with reference to the drawings. FIG.
FIG. 1 is a configuration diagram of an embodiment of a protection relay device according to the present invention, which is shown as an application example to a trip circuit. In FIG. 1, the same parts as those in FIG. Detector 7,8- due to circuit failure inside protection relay
The patterns of the outputs 7a, 8-1a, 8-2a and 8-3a of 1, 8-2 and 8-3 are the following two types. One is that when the contact 3a is closed due to a fault, the output 7a becomes logic 1 and the outputs 8-1a, 8-2a, 8-3a
Becomes logical 0. The other is that if one of the contacts 4-1a, 4-2a, 4-3a keeps closing due to a fault, the output 7a will be logic 0, but the parallel contacts 4-1a, 4-2a, As described above, the potential difference does not occur in 4-3a, and the outputs 8-1a, 8-2a, and 8-3a all become logic 1. The same applies when 4-2a or 4-3a fails.

As a defect outside the protection relay device, it is conceivable that the trip coils 5-1, 5-2, 5-3 of the circuit breaker or the connection cable is disconnected. Since these two states are in the same mode as viewed from the detector, the disconnection of the trip coil will be described below. When the trip coil 5-1 is disconnected, a monitoring current flows through the detectors 7, 8-2, 8-3, and outputs 7a, 8-2a,
8-3a becomes logic 0, but the detector of the phase where the coil is disconnected
No monitoring current flows through 1 and the output 8-1a becomes logic 1. If up to two trip coils are disconnected,
The output of only the detector of the phase where the inner coil of 8-1, 8-2 and 8-3 is disconnected becomes output 1. When the trip coil is disconnected in all three phases, the monitoring current does not flow to all the detectors and all outputs are 1
Becomes

Here, the contacts 3a and 4-1a, 4-
It is extremely rare that any one of 2a and 4-3a becomes defective (operational state) at the same time, and since this is equivalent to a trip command, it is not considered. As described above, there is a difference in the output state of the detector between the circuit failure inside the protection relay device and the failure outside the protection relay device. FIG. 2 shows a truth table of detector output states for each failure state. Using this,
A circuit failure inside the protection relay device and a failure outside the protection relay device can be distinguished. That is, in FIG. 1, when the circuit inside the protection relay device is defective, the detector output 7a becomes logic 1 and the output
Either 8-1a, 8-2a, and 8-3a are all at logic 0, or when output 7a is at logic 0 and outputs 8-1a, 8-2a, and 8-3a are all at logic 1 Therefore, the AND circuit 17, the XOR circuit 18, and the timer 19 (detect that the operation is continued for a certain period of time)
Circuit failure detection inside the protection relay device.

FIG. 3 is a block diagram of another embodiment, and the same parts as those in FIGS. 1 and 9 are denoted by the same reference numerals and description thereof is omitted. The same applies hereinafter. In this embodiment, a phase in which a disconnection has occurred is detected. That is, as described above, when there is a disconnection failure outside the protection relay, the detectors 8-1 and 8-2 as shown in FIG.
, 8-3 output is logic 1 only for phase detectors with internal disconnection
Becomes Further, since the output of the XOR circuit 18 indicates a defect inside the protection relay device, the signal 20a obtained by inverting the output from the NOT circuit 20 and the signals 8-1a, 8-2a, 8-3a are respectively logically ANDed (AND circuit).
22-1, 22-2, 22-3) and timers 22-1, 22-2, 22-3
(Confirm that it will continue for a certain period of time), and detect the phase in which the disconnection has occurred based on the timer outputs 22-1a, 22-2a, and 22-3a.

FIG. 4 is a configuration diagram of still another embodiment. The present embodiment is an example of application to a CB three-phase batch trip circuit. Here, in the case of a circuit failure inside the protection relay, the detector outputs 6a and 7a have a logic 1 only on the failure side, and have a logic 0 on the healthy side. In the case of a failure outside the protection relay device, both the detector outputs 6a and 7a become logic 1, so that a failure on the protection relay device side can be detected in the same manner as in the above embodiment.

FIG. 5 is a configuration diagram of still another embodiment. In the present embodiment, as in FIG. 1, an abnormality is detected inside the protective relay device, and an AND circuit that takes the logical product of the output of the OR circuit 15 that takes the logical sum of the outputs of all the detectors and the output of the NOT circuit 20
A disconnection failure outside the protection relay device is detected by 23 and a timer 24 (detecting the continuation of a predetermined time). FIG. 6 shows still another embodiment, which is a modified application example of FIG. 4, an AND circuit 25 for detecting an abnormality inside the protection relay device and taking the logical product of the detector outputs 7a and 8a,
A timer 24 (detecting the continuation of a predetermined time) detects a disconnection failure outside the protection relay. FIG. 7 shows another embodiment, which is an example of application to a trip circuit using a semiconductor switching element (a thyristor is used in this example) instead of the auxiliary relay of FIG. The output from the relay element is the switching element drive circuit 25, 26-1, 26-2, 26-3
Are input to the gates 27, 28-1, 28-2, 28-3 of the thyristor through the gate. Also in this example, it is needless to say that a circuit failure inside the protection relay device (malfunction of the thyristor due to thyristor damage or drive circuit failure) and a failure outside the protection relay device can be distinguished in the same manner as described above.

FIG. 8 is a block diagram of still another embodiment, which is a modified application of FIG. In this embodiment, by inputting the output 19 of the timer to the NOT circuit 20, the timers 22-1, 22-2, and 22-3 in FIG. 3 can be omitted. The effect is exactly the same as in FIG. Although the application example to the trip circuit has been described above, it is needless to say that the invention can be applied to the closing circuit in the same manner. In this embodiment, a circuit using a photocoupler is used as a detector. However, the same method can be realized by using an auxiliary relay. However, in this case, the determination circuit comprises a contact sequence.

[0014]

As described above, according to the protective relay device of the first aspect of the present invention, a detector is provided in parallel with a plurality of switching elements used in a circuit breaker control circuit. Since a circuit for performing a logical operation on the output of the detector is added to the monitoring of the control circuit, it is possible to immediately determine whether an abnormality has occurred inside or outside the protective relay. [Claim 2] can identify an abnormal part, and [Claim 3] can detect an abnormality of the circuit breaker control circuit.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a protection relay device having means for monitoring an abnormality of a circuit breaker control circuit according to the present invention.

FIG. 2 is a truth table showing operation states of detectors corresponding to respective failure modes of the circuit of FIG.

FIG. 3 is a configuration diagram showing another embodiment.

FIG. 4 is a configuration diagram showing still another embodiment.

FIG. 5 is a configuration diagram showing another embodiment of the present invention.

FIG. 6 is a configuration diagram showing another embodiment of the present invention.

FIG. 7 is a configuration diagram showing another embodiment of the present invention.

FIG. 8 is a configuration diagram showing another embodiment of the present invention.

FIG. 9 is a configuration diagram of a conventional monitoring method.

[Explanation of symbols]

 1 Protection relay element (accident detection element) 2,2-1, 2-2, 2-3 Protection relay element (main detection element) 3,4,4-1,4-2,4-3 Auxiliary relay coil 3a , 4a, 4-1a, 4-2a, 4-3a Auxiliary relay contacts 5,5-1, 5-2, 5-3 Breaker trip coil 6a, 6b P, N power supply for control equipment 7, 8, 8 -1, 8-2, 8-3 Detector 9 Internal circuit of detector 10 Monitoring current limiting resistor 11 Photocoupler 12a, 12b Power supply for logic circuit inside protection relay 13 Pull up resistor 14 Buffer circuit 15 OR circuit 17 , 21-1, 21-2, 21-3, 23 AND circuit 18 XOR circuit 19, 19-1, 19-2, 22-1, 22-2, 22-3, 24 Timer circuit 20 NOT circuit 25, 26 -1,26-2,26-3 Switching element drive circuit 27,28-1,28-2,28-3 Thyristor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02H 3/08-3/253 H02H 7/00 H02H ⁷ /10-7/20

Claims (3)

(57) [Claims] An open / close element for opening and closing a circuit and a plurality of open / close elements having one terminal connected in common are connected to form a series circuit, and when the former open / close element and the latter open / close element are simultaneously closed. In a protective relay having a circuit breaker control circuit for energizing a tripping coil or a closing coil of a circuit breaker, a first means for detecting a voltage level drop between terminals to be connected and opened in parallel with the former switching element and A second means for connecting in parallel to each of the latter switching elements and detecting a decrease in the voltage level between the respective switching element terminals; a third means for obtaining a plurality of output logical products of the second means; A fourth means for detecting a mismatch between the output of the first means and the output of the third means,
A protection relay device characterized in that when the output of the fourth means continues for a certain period of time, it is determined that the circuit breaker control circuit inside the protection relay device is abnormal. A second means for obtaining a logically inverted output of the output of the fourth means; and a sixth means for obtaining a logical product of each output of the second means and the output of the fifth means. 2. The protection relay device according to claim 1, wherein when a circuit breaker control circuit outside the protection relay device is abnormal, an abnormal part is specified by an output of the sixth means. 3. A circuit breaker configured to connect a plurality of switching elements for opening and closing a circuit in series, and to energize a trip coil or a closing coil of the circuit breaker when all of the series-connected switching elements are closed at the same time. A protection relay device including a switch control circuit, a first means for detecting a voltage level drop between the respective switching element terminals by connecting in parallel with the respective switching elements connected in series, and a plurality of the first means. It has a second means for detecting output mismatch, and when the output of the second means continues for a predetermined time, it is configured to determine that the circuit breaker control circuit inside the protection relay device is abnormal. Protective relay device.