JP2022172806A - Protective relay device - Google Patents

Abstract

To provide a protective relay device that does not require adjustment of output timing, etc., does not use switching contacts (c-contacts), has the same level of reliability as those of conventional devices with a simpler contact configuration, and enables slimmer hardware.SOLUTION: A protective relay device equips each internal circuit with an automatic monitoring function which detects abnormality of each internal circuit. Output circuit units 5A and 5B of the protective relay device include a first series circuit formed by a normally open contact 6Ab of an internal circuit of an A system and a first normally open contact 4Ba1 of an internal circuit of a B system, a second series circuit by the normally open contact 6Ab of the internal circuit of the A system and a normally closed contact 4Ba2 of the automatic monitoring function of the B system, and a third series circuit by a normally closed contact 4Aa of the automatic monitoring function of the system A and a second normally open contact 6Bb of the internal circuit of the system B. In a normal condition in which a circuit breaker is interrupted by forming one or more series circuits, no fault has occurred in the circuit breaker, and the automatic monitoring function has not detected an abnormality in the internal circuit, all normally open contacts are open.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to measures for improving the reliability of a protection relay device having a redundant configuration.

Protective relay devices are used to detect an accident that has occurred in a power system and immediately output a trip command to the circuit breaker to open the circuit breaker and minimize the effects of this abnormality.

In order to improve reliability, protection relay devices have conventionally used a configuration in which the internal circuits are duplicated, so that even if a failure occurs in one device, a trip command can be output to the other device. By making it a circuit, it prevents erroneous non-operation (not operating when it should be operating). In addition, by duplicating the internal circuit and connecting each circuit breaker control output contact in series, a configuration is used to prevent malfunction (operating when it should not operate).

The protective relay device further has an automatic monitoring function for monitoring its own state, and judges that the device is abnormal when an abnormality continues for a certain period of time or longer in each internal circuit. In this case, since the circuit breaker control output contact cannot be controlled, control of the circuit breaker control output contact is disabled in order to prevent malfunction.

Considering the case where the device malfunctions in such internal circuits, a configuration has been proposed in which a bypass control contact (which operates when the device malfunctions) is connected in parallel to the circuit breaker control output contact.

Due to the above, even if one of the duplicated internal circuits fails, the trip command will not be output due to the bypass circuit. It has a switching circuit configuration.

Patent Literature 1 is known as a protection relay device having such a configuration. In Patent Document 1, the internal circuit is duplicated as described above, the bypass control contact is connected in parallel to the circuit breaker control output contact of each output circuit, and the parallel circuits are connected in series and duplicated. there is In addition, if each internal circuit is unlucky enough to have an internal abnormality, etc., both bypass control contacts will be closed, and current will flow through the bypass control contacts, causing the circuit breaker to trip. It has means for adjusting the output timing of the bypass command so as not to occur.

Patent No. 5426412

In Patent Document 1, a D flip-flop to which a bypass command and a sampling clock are given is applied as output timing adjustment means so that both bypass control contacts are not closed at the same time. A command is output to the bypass control normally open contact (a contact) with a delay of one clock with respect to the normally closed contact (b contact).

Due to the above, even if the duplicated internal circuits fail at the same time, the trip output will not be erroneously output via the bypass control contact. Since the time at which the control contact operates is delayed by one clock, there is a possibility that fault removal will also be delayed by one clock.

In addition, since the operating time varies for each contact, if the variation is for one clock, as a result, each bypass control contact is closed and the circuit breaker is tripped.

In order to prevent such operation delays and malfunctions, for example, instead of using the bypass control normally open contact and the bypass control normally closed contact, a changeover contact (c contact) is used. It is not affected and normal operation is possible.

However, in the case of a configuration using a switching contact (c-contact), the contact configuration becomes complicated, and there are problems of an extra cost increase and an increase in mounting space.

The present invention has been proposed to solve the above problems. It does not require adjustment of the output timing, etc., does not use a switching contact (c contact), and has the same reliability as the conventional one with a simpler contact structure. It is also an object of the present invention to provide a protection relay device capable of slimming down hardware.

In view of the above, in the present invention, there is provided a "protection relay device including a duplicated internal circuit that gives a break command to a circuit breaker when an accident is detected in a power circuit, wherein the protection relay device detects an abnormality in each internal circuit. An automatic monitoring function is provided for each internal circuit, and the output part of the protection relay device is a first series circuit with the normally open contact of the internal circuit of system A and the first normally open contact of the internal circuit of system B. a second series circuit of the normally open contact of the internal circuit of system A and the normally closed contact of the automatic monitoring function of system B; and a third series circuit with a normally open contact, the circuit breaker is interrupted by the formation of one or more series circuits, no accident has occurred in the power circuit, and the automatic monitoring function detects abnormalities in the internal circuit A protective relay device characterized in that all of the normally open contacts and the normally open contacts are in an open state in a normal state in which the is not detected.

With the circuit configuration of the present invention, the same reliability and hardware as the configuration in which the parallel circuits of the circuit breaker control output contacts and the bypass control contacts, which are the trip circuits in the case of the conventional duplex configuration, are serially duplexed and connected. It is possible to have a slim circuit configuration with less .

Furthermore, unlike conventional systems, in the event of an internal abnormality or the like, both bypass control contacts are closed, current flows through the bypass control contacts, and the circuit breaker is tripped. Thus, there is no need to adjust the output timing, and the countermeasure can be taken only by the contact configuration.

The figure which shows the block structural example of the protection relay apparatus with which the internal circuit was made into the duplication structure. The figure which shows the structure of the trip circuit of the protection relay apparatus based on the Example of this invention. FIG. 4 is a diagram for explaining processing when an A-system internal circuit malfunctions; FIG. 4 is a diagram for explaining processing when an A-system internal circuit malfunctions;

Examples of the present invention will be described below.

FIG. 1 is a diagram showing a block configuration example of a protection relay device in which an internal circuit has a redundant configuration.

The protection relay device 100 of FIG. 1 is duplicated with an internal circuit 100A and an internal circuit 100B. Since it is necessary to distinguish between the internal circuits 100A and 100B, one internal circuit 100A is called the A system, and the other internal circuit 100B is called the B system. Since the A system and the B system have the same function, only the configuration of the A system will be described here.

This protection relay device 100 comprises an input converter 1A, an analog filter 2A, an A/D converter 3A, a CPU section 4A, an output circuit section 5A, and an automatic monitoring function 6A.

The input converter 1A is insulated from the VT (Voltage Transformer) and CT (Current Transformer) of the electric power system and electric power equipment, and converts voltage values and current values into analog/digital converters. It is equipped with an auxiliary VT and an auxiliary CT for converting to a higher level. The input conversion section is isolated from the main VT (Voltage Transformer) and main CT (Current Transformer) of the power system and power equipment, and the voltage value and current value are sent to the analog/digital conversion section. Equipped with auxiliary VT, CT for conversion to suitable levels. The input conversion section is isolated from the main VT (Voltage Transformer) and main CT (Current Transformer) of the power system and power equipment, and the voltage value and current value are sent to the analog/digital conversion section. Equipped with auxiliary VT, CT for conversion to suitable levels.

The analog filter 2A is implemented to remove unnecessary frequency components that cause aliasing errors contained in the input voltage and current signals.

The A/D converter 3A samples an output voltage or current analog signal and converts it into a digital quantity.

The CPU section 4A performs protection calculation using the digital value converted by the A/D converter 3A and determines whether an accident has occurred in the system. When it is determined that an accident has occurred in the power system, a control command is output from the CPU section 4A to the circuit breaker control contact of the output circuit section 5A.

The output circuit section 5A is composed of a plurality of contacts that open and close in accordance with a control command from the CPU section 4A, and gives a trip command to the circuit breaker. In the illustrated example, the output circuit section has a dual system configuration of 5A and 5B, but it may be configured with a single system. When the output circuit section is configured as a dual system of 5A and 5B, it is preferable to provide a logical sum output for circuit breaker operation when the condition of either output circuit section is satisfied.

The automatic monitoring function 6A constantly monitors the state of the internal circuit, and when an abnormality occurs, outputs a control command to the bypass control contact of the output circuit section 5A, and the output of the internal circuit that is highly likely to give an erroneous output. Prevents an externally output circuit breaker from being erroneously opened.

FIG. 2 shows the configuration of the trip circuit of the protection relay device according to the embodiment of the present invention. Since the trip circuits are formed to have the same circuit configuration in both the output circuit sections 5A and 5B, the A-system output circuit section 5A will be described here. Both of the output circuit sections 5A and 5B are provided with circuit breaker control contacts 4Aa and 4Ba operated by commands from the CPU sections 4A and 4B and bypass control contacts 6Aa and 6Ba operated by commands from the automatic monitoring function 6A. I have. As one of the circuit breaker control contacts 4Aa and 4Ba, 4Ba has two sets of contacts 4Ba1 and 4Ba2 in this example.

The trip circuits in the output circuit sections 5A and 5B of FIG. 2 have the following logic circuit configuration. Here, between the positive and negative control power supplies (not shown), a first switch is provided by a circuit breaker control contact 4Aa operated by a command from the A system CPU unit 4A and a circuit breaker control contact 4Ba1 operated by a command from the B system CPU unit 4B. A series circuit is formed, and when a first series circuit is formed, a trip command is issued, and the trip command excites an auxiliary relay (not shown) to trip the circuit breaker. Generally, this auxiliary relay is connected in series with these series circuits between positive and negative control power sources (not shown) to trip the circuit breaker.

Here, the circuit breaker control contact 4Aa and the circuit breaker control contact 4Ba are normally open contacts (contact a) that are closed when an accident in the equipment to be protected is detected in the CPU units 4A and 4B. With this first series circuit, when both of the double internal circuits detect an accident in the device to be protected, a tripping operation for breaking is executed. The devices to be protected are transmission lines, transformers, busbars, generators, and other power devices in the power system, and are self-removal by opening circuit breakers when an accident is detected.

In addition, the trip circuits in the output circuit units 5A and 5B of FIG. A second series circuit is formed by 4Ba2, and the formation of the second series circuit is regarded as a trip command. It should be noted that the second series circuit can be said to be a first auxiliary circuit for tripping the circuit breaker when there is an abnormality in the A-system internal circuit. A third series circuit is formed between the positive and negative control power sources by the circuit breaker control contact 4Aa from the A system CPU unit 4A and the bypass control contact 6Bb from the B system automatic monitoring function 6B. is formed, a trip command is issued, and the trip command excites an auxiliary relay (not shown) to trip the circuit breaker. The third series circuit can be said to be a second auxiliary circuit for tripping the circuit breaker when an abnormality occurs in the B-system internal circuit.

Here, the bypass control contacts 6Ab and 6Bb from the automatic monitoring functions 6A and 6B are normally closed contacts (b contacts) that operate according to commands from the automatic monitoring functions 6A and 6B. When there is no abnormality in the internal circuits of the A system and B system monitored by each, the output is always given, and the bypass control contacts 6Ab and 6Bb are placed in the normal state where there is no abnormality in the internal circuit and are opened. operating. This is because a power failure occurs and current is not applied to the contact coils of the bypass control contacts 6Ab and 6Bb. When normally open contacts are used as the bypass control contacts 6Ab and 6Bb, current is not applied to the contact coils when there is a power failure, so the contacts are open and the bypass circuit functions even if there is a device failure (power failure). This is because the trip command cannot be output.

As a result, in the circuit of FIG. 2, no accident has occurred in the device to be protected and no abnormality has been detected in the internal circuits of the A and B systems monitored by the automatic monitoring functions 6A and 6B, respectively. Under normal conditions, all contacts 4Aa, 4Ba (4Ba1, 4Ba2), 6Ab, 6Bb are open.

The two arrows in FIG. 2 indicate that an accident has occurred in the equipment to be protected, two sets of internal circuits have detected the accident, and the internal circuits of the A and B systems monitored by the automatic monitoring functions 6A and 6B are abnormal. is not detected, a first series circuit is formed and current flows between the positive and negative control power supplies (not shown), that is, a circuit breaker trip command is output.

FIG. 3 is a diagram for explaining the processing when an A-system internal circuit malfunctions. In the trip circuit of FIG. 2, it shows the circuit configuration when the system A automatic monitoring function 6A detects an abnormality in the system A internal circuit, and the state when an accident occurs in the protected equipment in this state. . In this state, the reliability of the contact 4Aa is lowered due to an abnormality in the A-system internal circuit, and the open/close state of the contact 4Aa is unreliable.

At this time, the automatic monitoring function 6A detects an abnormality in the A-system internal circuit and closes the normally closed contact 6Ab of the automatic monitoring function 6A which has been open. In the first series circuit, even if 4Aa is closed due to a device failure in the internal circuit 4A, the contact 4Aa in the B-system internal circuit is correctly open. This means that the circuit breaker will not be operated. In addition, when an accident occurs in the equipment to be controlled and the circuit breaker should be opened, the contact 4Ba and the bypass control contact 6Ab of the B system, whose internal circuit is normal in the second series circuit, will This means that the interrupting operation by the heavy system is executable. Three arrows in FIG. 2 represent that a second series circuit is formed and current flows between positive and negative control power sources (not shown), that is, a circuit breaker trip command is output.

FIG. 4 is a diagram for explaining processing when an internal circuit of system B is abnormal. In the trip circuit of FIG. 2, it shows the circuit configuration when the system B automatic monitoring function 6B detects an abnormality in the system B internal circuit, and the state when an accident occurs in the equipment to be protected in this state. . In this state, the reliability of the contact 4Ba (4Ba1, 4Ba2) is lowered due to an abnormality in the B-system internal circuit, and the open/closed state is unreliable.

At this time, the automatic monitoring function 6B detects an abnormality in the internal circuit of the B system and closes the normally closed contact 6Bb of the automatic monitoring function 6B which has been open. In the first series circuit, even if 4Ba1 is closed due to a device malfunction in the internal circuit 4B, the contact 4Aa of the A-system internal circuit is correctly open. This means that the circuit breaker will not be operated. Also, in the second series circuit, even if 4Ba2 is closed due to a device failure in the internal circuit 4B, the contact 6Aa of the A-system automatic monitoring function 6A is correctly open, so the second series circuit cannot be formed. This means that the circuit breaker will not be operated without In addition, when an accident occurs in the equipment to be controlled and the circuit breaker should be opened, the contact 4Aa and the bypass control contact 6Bb of the system A, whose internal circuit is normal in the third series circuit, will This means that the interrupting operation by the heavy system is executable. Three arrows in FIG. 2 represent that a third series circuit is formed and current flows between positive and negative control power sources (not shown), that is, a circuit breaker trip command is output.

The bypass circuit using the normally closed contacts 6Ab and 6Bb of the automatic monitoring functions 6A and 6B is bypassed only by the AND of the normally closed contacts 6Ab and 6Bb that operate when the internal circuit fails and the normally open contacts 4Aa and 4Ba that operate normally. Since the circuit functions and the contact configuration enables a trip command in one system, there is no need to consider the function to lock the bypass circuit of the normal system or the variation in contact operation time. Even in the case of the contact configuration, unnecessary operations such as mistripping do not occur.

100: Protective relay devices 100A, 100B: Internal circuits 1A, 1B of the protective relay device: Input converters 2A, 2B: Analog filters 3A, 3B: A/D converters 4A, 4B: CPU
5A, 5B: DO circuits 6A, 6B: automatic monitoring function 4Aa, 4Ba: normally open contacts of internal circuit 6Ab, 6Bb: normally closed contacts of automatic monitoring function

Claims (3)

A protective relay device including a duplicated internal circuit that gives a break command to a circuit breaker when an accident is detected in a power circuit,
The protection relay device has an automatic monitoring function for detecting an abnormality in each internal circuit for each of the internal circuits,
The output part of the protective relay device includes a first series circuit formed by a normally open contact of the internal circuit of the A system and a first normally open contact of the internal circuit of the B system, the normally open contact of the internal circuit of the A system, and the B A second series circuit with a normally closed contact of the automatic monitoring function of the system, and a third series circuit with a normally closed contact of the automatic monitoring function of the A system and a second normally open contact of the internal circuit of the B system, interrupting the circuit breaker by forming one or more series circuits;
All of the normally open contacts and normally open contacts are open in a normal state in which no accident has occurred in the power circuit and the automatic monitoring function has not detected an abnormality in the internal circuit. protection relay device. A protection relay device according to claim 1,
The automatic monitoring function opens the first normally open contact and the second normally open contact when an abnormality in the internal circuit is not detected, and opens the first normally open contact when an abnormality in the internal circuit is detected. A protection relay device, wherein the second normally open contact is closed. A protection relay device according to claim 1 or claim 2,
A protection relay device, wherein the series circuit is connected in series with an auxiliary relay between control power sources, and the circuit breaker is operated by the excitation of the auxiliary relay.

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