JPH06311634A - Protective relay - Google Patents

Abstract

PURPOSE:To provide a protective relay in which a time limit can be provided for fault information regardless of a timer coil and a contact thereof even when a trip relay is locked. CONSTITUTION:Even when a lock switch 3a is locked, an operating time signal is delivered from an operating time set switch 1a for undervoltage protective relay regardless of the state of the lock switch 3a. Upon elapse of an operating time based on the operating time signal after detection of voltage drop, a fault signal is delivered from a fault signal output circuit 2a. Since a fault information relay 7a functions to notify the fault, a time limit can be provided for the fault information. On the other hand, the lock switch 3a delivers a lock signal to a trip relay 6 and locks a circuit breaker.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective relay, and more particularly to a protective relay having a lock switch for locking a fault trip contact.

[0002]

2. Description of the Related Art Conventionally, a plurality of protective relays, for example, an overcurrent protective relay that operates by an overcurrent, an overvoltage protective relay that operates by an overvoltage, and an undervoltage protective relay that operates by a voltage drop are combined into one, There is a compound protective relay that operates a common breaker to isolate the fault location when a fault occurs in which any protective relay operates. FIG. 5 is a block diagram of a control unit for a fault trip contact and a fault notification contact in such a conventional protective relay, FIG. 6 is a diagram showing an operation panel of the undervoltage protection relay in this protection relay, and FIG. 7 is this undervoltage It is a circuit diagram of a failure notification circuit of a protective relay.

In FIG. 5, reference numerals 21a, 21b and 21c respectively indicate operating time settings from detection of a failure of the undervoltage protection relay, the overcurrent protection relay and the overvoltage protection relay to the operation of a fault trip contact (not shown). This is an operating time settling switch used, which outputs an operating time signal indicating the operating time, and when set to the "LOCK" position, outputs a lock signal to the AND circuit described later. 22a, 22b, and 22c receive operating signals, which will be described later, respectively.
a failure signal output circuit for outputting a failure signal after the operating time based on the operating time signals output from the terminals b and 21c, 2
4a, 24b, and 24c are AND circuits, 25 is an OR circuit, 26 is a trip relay that controls a fault trip contact that operates a circuit breaker (not shown), and 27a, 27b, and 27.
c is undervoltage protection relay, overcurrent protection relay,
It is a failure report relay for reporting that the overvoltage protection relay has detected a failure.

Further, ka, kb and kc are detection signals, which are an undervoltage protection relay, an overcurrent protection relay, respectively.
Output from the detection circuit (not shown) of the overvoltage protection relay,
Indicates that each protective relay has detected a fault. In FIG. 6, reference numeral 29 is an operating value setting switch for setting the operating voltage of the undervoltage protection relay, and in FIG.
Is a failure notification contact controlled by the failure notification relay 27a of the undervoltage protection relay, 32 is a timer coil for giving a time limit to the failure notification, 33 is a timer coil contact controlled by the timer coil 32, and 31 is a failure notification. It is a buzzer. Although only the undervoltage protection relay is shown here, the overcurrent protection relay and the overvoltage protection relay also have an operation panel and a failure notification circuit similar to those in FIGS. Further, in the protection relay of FIG. 5, the three protection relays are one, but three or more protection relays may be combined.

Next, the operation of such a protective relay will be described. When setting and operating the undervoltage protection relay, the operator of this protection relay sets, for example, the operation value setting switch 29 to 80 (V) and the operation time setting switch 21a to 6 (SEC) on the operation panel as shown in FIG. To do. When the above setting is performed and the voltage of the power system becomes 80 V or less, the undervoltage protection relay judges that it is out of order, and operates 6 seconds after that. This operation will be described with reference to FIG. 5. First, when a failure is detected in the detection circuit of the undervoltage protection relay, the detection signal ka is output.

Next, since the operation time signal of 6 seconds is output from the operation time setting switch 21a, the failure signal output circuit 22a operates 6 times after the detection signal ka is input.
A failure signal is output after a second (here, "H" level). Further, the operation time setting switch 21a does not output a lock signal (“L” level). Since the failure signal output from the failure signal output circuit 22a is "H" level and the output of the operation time settling switch 21a is "L" level, the output of the AND circuit 24a is "H" level. The output of 25 becomes "H" level. Therefore, the trip relay 26 operates to close the faulty trip contact, and the circuit breaker operates to disconnect the faulty part.

When a failure signal is output, the failure notification relay 27a operates, the failure notification contact 30 shown in FIG. 7 is closed, a current flows, and the timer coil 32 is excited. And
After the set time limit, the timer coil contact 33 is closed and a current flows, so that the buzzer 31 sounds and a failure is reported. In this way, the failure location is separated and the failure is notified, but this is the same for other overcurrent protection relays and overvoltage protection relays.

Further, unlike a protection relay which operates a circuit breaker by detecting a short-circuit failure like an overcurrent protection relay, an undervoltage protection relay detects a voltage drop, so that a failure notification is issued without operating the circuit breaker. You may only want to do it. In this case, the operation time setting switch 21a is set to the "LOCK" position. Set the operating time setting switch 21a to "LOC
When set to the “K” position, the operating time settling switch 21a
Outputs a lock signal (“H” level) and does not output an operation time signal. When the detection signal ka is input to the failure signal output circuit 22a without the operation time signal input, the failure signal output circuit 22a outputs the failure signal after the minimum operation time (0.5 seconds in this case) of the operation time settling switch 21a. It is designed to output.

Therefore, when the lock signal is output, the output of the AND circuit 24a is always at "L" level, and the trip relay 26 does not operate. Therefore, the circuit breaker does not operate,
Only the notification of the failure is performed after the timer coil 32 has timed out after the failure signal is output. When the operation time settling switch 21a is in the "LOCK" position, a failure signal is output after the minimum operation time has elapsed since the decrease in the voltage value was detected. Therefore, if the timer coil 32 and the timer coil contact 33 are not provided. Even after the minimum operation time, the buzzer 31 sounds, and even if the voltage value is restored by a circuit breaker other than the circuit breaker controlled by this protective relay, a failure notification is given. Therefore, by providing the timer coil 32 and the timer coil contact 33, a time margin is provided for the failure notification so that the failure notification is not issued in the above cases.

Further, since the operation time is fixed when the operation time settling switch 21a is in the "LOCK" position as described above, the failure notification contact 30 operates according to the set operation time of the operation time settling switch 21a. The self-diagnosis of checking whether this protective relay is working properly cannot be done without operating the circuit breaker.

[0011]

Since the conventional protective relay is constructed as described above, when the trip alarm is locked and the failure notification is timed, the timer coil and the timer coil contact are required and the failure occurs. There was a problem that the notification circuit became complicated. In addition, there is a problem in that the self-diagnosis cannot be performed by checking the operation of the failure notification relay when the trip relay is locked. In order to solve the above problems, an object of the present invention is to provide a protective relay capable of giving a time limit to a failure notification regardless of the timer coil and the timer coil contact even when the trip relay is locked. Also,
An object of the present invention is to provide a protective relay that can perform self-diagnosis by checking the operation of a failure notification relay even when the trip relay is locked.

[0012]

SUMMARY OF THE INVENTION The present invention is used for setting an operating time from the detection of a failure to the operation, and an operating time for outputting an operating time signal indicating the operating time independently of a lock signal. A settling switch, a fault signal output circuit that outputs a fault signal after the operating time based on the operating time signal after a fault is detected, and a lock switch that outputs a lock signal when the trip relay is locked. I have.

A logic which is provided between the lock switch and the trip relay and outputs a lock signal when a self-diagnosis signal indicating that self-diagnosis is being performed is input or when a lock signal is input from the lock switch. It has a sum circuit.

[0014]

According to the present invention, even when the lock switch is set in the locked state, the operation time settling switch outputs an operation time signal regardless of the state of the lock switch, and the operation time signal is based on the operation time signal after a failure is detected. After the operating time, a failure signal is output by the failure signal output circuit, and the failure notification relay operates to report the failure. On the other hand, the trip relay is locked and the breaker is locked by the lock signal output from the lock switch. Further, the logical sum operation of the self-diagnosis signal and the lock signal is performed by the OR circuit, so that the same operation is performed during the self-diagnosis.

[0015]

FIG. 1 is a block diagram of a control unit for a fault trip contact and a fault notification contact in a protective relay showing one embodiment of the present invention, and FIG. 2 is a diagram showing an operation panel of an undervoltage protection relay in the protective relay. FIG. 3 is a circuit diagram of a failure notification circuit of this undervoltage protection relay.

In FIG. 1, 1a, 1b, and 1c are used to set the operating time of the undervoltage protection relay, the overcurrent protection relay, and the overvoltage protection relay, respectively, and the operation of outputting the operation time signal regardless of the lock signal. The time settling switches 2a, 2b, 2c are detection signals ka, kb,
When kc is input, the operation time setting switches 1a, 1b,
Fault signal output circuits 3a, 3a that output a fault signal after the operating time based on the operating time signal output from 1c
b and 3c are lock switches 4a, 4b and 4c, which are provided on the operation panel independently of the operation time settling switches 1a, 1b and 1c and lock the fault trip contacts, 5 are AND circuits, 5 are OR circuits, 6 is a trip relay, 7a, 7
b and 7c are failure notification relays. In FIG. 2, reference numeral 9 is an operating value setting switch, 10 in FIG. 3 is a failure notification contact, and 11 is a buzzer.

Next, the operation of such a protective relay will be described. Set the lock switch 3a of the operation panel shown in FIG. 2 to "UN
When set to “LOCK”, the lock signal is not output from the lock switch 3a (“L” level). And
The failure signal output circuit 2a outputs a failure signal after an operation time indicated by the operation time signal of the operation time settling switch 1a after the detection signal ka is input. Therefore, after the operating time, the trip relay 6 operates to trip the circuit breaker, and the malfunction reporting relay 7a operates to close the malfunction reporting contact 10 and sound the buzzer 11, thereby disconnecting the fault location and reporting the fault. Is done.

Next, set the lock switch 3a on the operation panel to "L".
If it is set to "OCK", a lock signal is output from the lock switch 3a. Therefore, as in the example of FIG.
The output of a is always at "L" level and the breaker does not operate. On the other hand, the operating time settling switch 1a, which is independent of the lock switch 3a, outputs an operating time signal indicating the set operating time unlike the example of FIG. 5, regardless of the state of the lock switch 3a.

Therefore, when the detection signal ka is input from the failure signal output circuit 2a and the failure signal is output after an operating time, the buzzer 11 sounds to notify the failure.
Therefore, even when the lock switch 3a is in the "LOCK" position, the operation time for failure notification can be set by the operation time setting switch 1a, and the failure notification circuit can be simplified as shown in FIG.

FIG. 4 is a block diagram of a control unit for a fault trip contact and a fault notification contact in a protective relay according to another embodiment of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals. . sa, sb, and sc are self-diagnosis signals indicating that the undervoltage protection relay, the overcurrent protection relay, and the overvoltage protection relay are performing self-diagnosis, 8a, 8b, and 8 respectively.
Reference numeral c is a logical sum circuit for calculating the logical sum of the outputs of the lock switches 3a, 3b, 3c and the self-diagnosis signals sa, sb, sc.

The operation of such a protection relay is basically the same as that of the example of FIG. 1, but for self-diagnosis of the undervoltage protection relay, for example, a self-diagnosis signal sa from outside is not shown.
When (here, "H" level) is input to the OR circuit 8a, the lock switch 3a is set to the "LOCK" position, and the fault trip contact is locked.
Therefore, it is possible to perform self-diagnosis of the undervoltage protection relay by checking the operation of the failure notification contact 10 without operating the circuit breaker.

In the examples shown in FIGS. 1 and 4, lock switches are provided in all of the undervoltage protection relay, the overcurrent protection relay, and the overvoltage protection relay. The lock switch can be omitted.

[0023]

According to the present invention, by providing a lock switch which is independent of the operating time setting switch, the operating time for failure notification can be set by the operating time setting switch even when the trip relay is locked. Therefore, the failure notification can be timed without depending on the timer coil and the timer coil contact, and the failure notification circuit can be simplified. Further, even during self-diagnosis, the operation time for failure notification can be set by the operation time setting switch while the trip relay is locked, so that self-diagnosis can be performed by checking the operation of the failure notification relay.

[Brief description of drawings]

FIG. 1 is a block diagram of a control unit for a fault trip contact and a fault notification contact in a protective relay according to an embodiment of the present invention.

FIG. 2 is a view showing an operation panel of an undervoltage protection relay in the protection relay of FIG.

FIG. 3 is a circuit diagram of a failure notification circuit of an undervoltage protection relay.

FIG. 4 is a block diagram of a control unit for a fault trip contact and a fault notification contact in a protective relay according to another embodiment of the present invention.

FIG. 5 is a block diagram of a control unit for a fault trip contact and a fault reporting contact in a conventional protective relay.

FIG. 6 is a view showing an operation panel of an undervoltage protection relay in the protection relay of FIG.

FIG. 7 is a circuit diagram of a failure notification circuit of an undervoltage protection relay.

[Explanation of symbols]

 1a, 1b, 1c Operating time setting switch 2a, 2b, 2c Fault signal output circuit 3a, 3b, 3c Lock switch 4a, 4b, 4c AND circuit 5 Logical sum circuit 6 Trip relay 7a, 7b, 7c Fault notification relay 8a, 8b, 8c OR circuit ka, kb, kc detection signal sa, sb, sc self-diagnosis signal

Claims (2)

[Claims] 1. A trip signal for operating a circuit breaker for disconnecting a fault location and a fault reporting relay for reporting a fault, and operating the trip relay and the fault reporting relay by outputting a fault signal to provide a fault signal and a lock signal. It is used to set the operating time from the detection of a failure to the operation of the protective relay that locks the trip relay by the output of and activates only the failure notification relay.The operating time signal indicating the operating time is used as the lock signal. Irrespective of whether the operation time set-up switch outputs, a failure signal output circuit that outputs a failure signal after an operation time based on the operation time signal after a failure is detected, and the trip relay lock setting when the trip relay is locked. A protective relay having a lock switch for outputting a lock signal. 2. The protective relay according to claim 1, wherein a self-diagnosis signal, which is provided between the lock switch and the trip relay and indicates that self-diagnosis is being performed, is input, or a lock signal is input from the lock switch. A protective relay having an OR circuit for outputting the lock signal when the protective relay is activated.