JP2002335623A - Digital protective relay - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of the occurrence of duplex A/B both-system voltage relay elements becoming unable to be used, if a PT side fuse melts down, since voltages are inputted to the both-system voltage relay elements from the same PT side. SOLUTION: A digital protective relay which detects faults of power system facilities and performs protection and is composed of multiple system, is provided with a plurality of instrument transformers (VT) 2a, 2b which receive quantities of electricity from the same power system as inputs and are branched and installed, input conversion portions 31-1, 32-1 for level-converting individual quantities of electricity from the instrument transformers, and relay computation means 31-4, 32-4 for relay-computing by using the quantities of electricity from the individual input conversion portions in respective systems.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital protection relay device which outputs a trip command when a fault occurs in a power system or a power system installed in an electric substation and disconnects a faulty portion from the system. .

[0002]

2. Description of the Related Art In general, a digital protection relay device inputs an electric quantity from an electric power system from instrument transformers VT and CT installed in an electric power system and relays whether or not the input electric quantity is out of a predetermined range. It is detected by arithmetic processing and the result is output to the outside of the device. FIG. 5 is a diagram showing a configuration of a conventional general digital protection relay device.

The amount of electricity taken from the generator system 1 is stepped down by an instrument transformer 2a and an instrument transformer 2b.
The signals are input to the system relay device 31 and the II system relay device 32. Further, the electric quantity input from the instrument transformer 2a is converted into the I-system relay input conversion unit 31-1 and the II-system relay input conversion unit 3
2-1 and the electric quantity input from the instrument transformer 2b is converted into the I-system relay input conversion units 31-2 and II.
The level is converted by the system relay input conversion unit 32-2.

Further, the magnitudes of the electric quantities output from the I-system relay input converter 31-1 and the I-system relay input converter 31-2 are compared, and the operation is performed when the difference between the magnitudes exceeds a specified value. The magnitudes of the electric quantities output from the I-system voltage comparison relay 31-3 and the II-system relay input conversion unit 32-1 and the II-system relay input conversion unit 32-2 are compared, and the difference between the magnitudes is equal to or greater than a specified value. , There may be a case where there is a II-system voltage comparison relay 32-3 that operates.

In order to detect an abnormality in the generator system 1,
The I-system relay device 31 has an I-system voltage relay 31-4, and the II-system relay device 32 has a II-system voltage relay 32-4.
Also, an I-system voltage relay 31-4 and a II-system voltage relay 32-
4 performs a relay operation on the basis of the amount of electricity taken from the instrument transformer 2a. Each instrument transformer (particularly, the generator VT) is often provided with a VT fuse 33a and a VT fuse 33b.

The I-system voltage relay 31-4 is activated by the failure of the instrument transformer 2a, the I-system relay input converter 31-1, the VT fuse 33a, etc., and the I-system voltage comparison relay 31-3 is activated. When the malfunction of the voltage relay 31-4 is concerned (for example, when the voltage input becomes 0 due to the blow of the VT fuse, when the I-system voltage relay 31-4 is a relay that performs impedance calculation), the I-system voltage relay 31 -4 locks the output to prevent malfunction of the voltage relay.

[0007] Similarly, the II-system voltage relay 32-4 causes the failure of the instrument transformer 2a and the II-system relay input conversion unit 32-1 to cause the II-system voltage relay 32-4 to fail.
When the system voltage comparison relay 32-3 operates, it has a function of locking the output of the II system voltage relay 32-4. In addition, the digital protection relay device is used to prevent malfunction.
A method of tripping when either the system relay or the system II relay operates (OR trip output 34) and a method of tripping when both the system I relay and the system II relay operate for the purpose of preventing malfunction ( AND trip output 3
In many cases, any one of the methods 5) is adopted.

[0008]

However, in the above conventional apparatus, when one of the branch VTs fails,
For example, when the VT fuse 33a is blown, a voltage difference occurs between the I-system relay input conversion unit 31-1 and the I-system relay input conversion unit 31-2. In the case where the system voltage relay is a relay that is liable to malfunction due to the interruption of the voltage input, an erroneous trip occurs if the OR trip method is adopted, so that the output of the I-system voltage relay 31-4 is locked.

Similarly, the II-system relay input conversion unit 32-1
A voltage difference occurs between the II-system relay input conversion unit 32-2,
The system voltage comparison relay 32-3 operates, and the II system voltage relay 3
The outputs of 2-4 are also locked. Therefore, even if an accident involving a voltage change occurs in the generator system 1 in this situation, there is a disadvantage that a trip cannot be detected by a voltage relay (for example, an impedance calculation relay).

When a failure occurs in the I-system relay input conversion unit 31-1, the I-system voltage comparison relay 31-3 operates to lock the output of the I-system voltage relay 31-4. At this time, if an accident involving a voltage change occurs in the generator system 1, the II-system voltage relay 32-4 operates, but the output of the I-system voltage relay 31-4 remains shut off. If adopted, AND trip output 3
5 does not come out (the same can be said even if a failure occurs in the II-system relay input conversion unit 32-1).

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a protection relay device having a multiplexed configuration performs a relay operation by using electric quantities output from different instrumentation transformers in respective systems, thereby achieving reliability. It is an object of the present invention to provide a digital protection relay device capable of improving performance.

[0012]

A digital protection relay device according to a first aspect of the present invention is a digital protection relay device configured by multiplexing, wherein the digital protection relay device is provided with a branch to which an electric quantity from the same power system is input. A plurality of instrument transformers (VT), an input converter for level-converting each electric quantity from the plurality of instrument transformers, and using the electric quantity from each of the input converters in each system. Means for performing a relay operation by

A digital protection relay device according to a second aspect of the present invention is the digital protection relay device according to the first aspect, wherein voltage comparing means for comparing the amounts of electricity between the instrument transformers (VTs) branched from the same power system. And means for interrupting the output of the relay device according to the comparison result.

A digital protection relay device according to a third aspect of the present invention is the digital protection relay device according to the first aspect, further comprising: means for monitoring a failure of the input conversion unit; and means for shutting off the output of the relay device according to the monitoring result. Equipped.

A digital protection relay device according to a fourth aspect of the present invention is the digital protection relay device according to the first aspect, wherein the voltage comparing means compares the amounts of electricity between the instrumentation transformers (VTs) installed branching from the same power system. First means for interrupting a relay output according to the comparison result, means for monitoring a failure of the input conversion unit, and second means for interrupting the output of the relay device according to the monitoring result. With.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a digital protection relay device according to a first embodiment of the present invention. 1, the same functional portions as those in FIG. 5 are denoted by the same reference numerals, and description thereof will be omitted. In the present embodiment, the protection relay device having the multiplex configuration is configured to perform the relay operation using the electric quantities output from the different transformers for the respective systems.

The voltage of the generator system 1 is branched and output to two series of instrument transformers, ie, an instrument transformer 2a and an instrument transformer 2b. And the instrument transformer 2
The output of a is level-converted by the I-system relay input conversion unit 31-1, and the output of the instrument transformer 2b is level-converted by the II-system relay input conversion unit 32-2. In addition, in order to detect a change in the amount of voltage of the generator system 1 and detect an accident, the I-system relay device 31 accommodates an I-system voltage relay 31-4, and the II-system relay device 32 accommodates a II-system voltage relay 32-4. ing.

The I-system voltage relay 31-4 performs a relay operation based on the output of the instrument transformer 2a branched from the generator system 1, and the II-system voltage relay 32-4 operates on the instrument transformer 2b side. The relay operation is performed by the output of. 3
4 is an I-system voltage relay 31-4 or a II-system voltage relay 3
O that operates when any one of relays 2-4 operates
R trip output.

Next, the operation of FIG. 1 will be described. First,
If the VT fuse 33a is blown during the normal operation, the I-system relay device 31 causes a voltage abnormality in the generator system 1 because the electric quantity output from the I-system relay input conversion unit 31-1 becomes 0. Even if an accident occurs, the I-system voltage relay 31-4 does not operate.

On the other hand, the II system relay device 32 detects an accident occurring in the generator system 1 based on the output of the instrument transformer 2b.
The system relay input conversion unit 32-2 performs level conversion, performs a relay operation with the II system voltage relay 32-4, and detects operation.

If the VT fuse 33b is blown during normal operation, the II system relay device 32 responds because the amount of electricity output from the II system relay input conversion unit 32-2 becomes zero. 1 Even if an accident involving abnormal voltage occurs
The II system voltage relay 32-4 does not operate.

On the other hand, the I-system relay device 31 detects an accident that has occurred in the generator system 1 based on the output of the instrument transformer 2a.
The level is converted by the system relay input conversion unit 31-1, and a relay operation is performed by the I system voltage relay 31-4 to detect the operation.
The trip output is OR trip output 3 of I system and II system.
4 so that the generator system 1
Can be detected.

According to this embodiment, even if one of the VT outputs is cut off, it is possible to detect an accident that has occurred in the generator system, thereby improving the reliability of the digital protection relay device.

FIG. 2 is a block diagram of a digital protection relay device according to a second embodiment of the present invention. 2, the same functional portions as those in FIG. 5 are denoted by the same reference numerals, and description thereof will be omitted. In the present embodiment, the malfunction of the voltage relay can be prevented, and an accident can be detected even if an accident occurs in the generator system.

The voltage of the generator system 1 is branched and output to two series of instrument transformers, ie, an instrument transformer 2a and an instrument transformer 2b. And the instrument transformer 2a
Is converted by the I-system relay input converter 31-1 in the case of the I-system relay device 31, and the level is converted by the II-system relay input converter 32-1 in the case of the II-system relay device 32. Similarly, the output of the instrument transformer 2b is I
In the case of the system relay device 31, the I system relay input conversion unit 31-
2, and the level is converted by the II system relay device 32.
The level is converted by the II-system relay input conversion unit 32-2.

Reference numeral 31-5 denotes an I-system voltage comparison relay. The output voltage of the I-system relay input conversion unit 31-1 is more than a certain set value with respect to the output voltage of the I-system relay input conversion unit 31-2. A relay that operates when it drops. Similarly,
Reference numeral 5 denotes an II-system voltage comparison relay, which operates when the output voltage of the II-system relay input conversion unit 32-1 is lower than the output voltage of the II-system relay input conversion unit 32-2 by a certain set value or more. .

In addition, in order to detect a change in the amount of voltage in the generator system 1 to detect an accident, the I-system relay device 31 has an I-system voltage relay 31-4, and the II-system relay device 32 has a II-system voltage relay 32-. 4 are stored. In addition, I system voltage comparison relay 3
When 1-5 operates, the operation of the I-system voltage relay 31-4 is shut off, and when the II-system voltage comparison relay 32-5 operates, the operation of the II-system voltage relay 32-4 is shut off.

That is, the interruption of each voltage relay is performed by opening the contact at the bottom of each voltage relay. Reference numeral 34 denotes an OR trip output that operates when any one of the I-system voltage relay 31-4 and the II-system voltage relay 32-4 detects an operation.

Next, the operation of FIG. 2 will be described. First,
When the VT fuse 33a is blown during the normal operation, the I-system relay device 31 outputs 0 electric energy from the I-system relay input conversion unit 31-1, but the I-system relay input conversion unit 3
Since the rated voltage is output from 1-2, the I-system voltage comparison relay 31-5 operates. The I-system voltage relay 31-5 detects a VT failure of the series to be operated on by the I-system voltage relay 31-4, so the I-system voltage relay 31-5
-4 operation is cut off.

In the II-system relay device 32, although the electric quantity output from the II-system relay input conversion unit 32-1 becomes zero,
Since the rated voltage is output from the II-system relay input conversion unit 32-2, the II-system voltage comparison relay 32-5 operates. Since the II-system voltage comparison relay 32-5 detects a VT failure different from the series to be calculated by the II-system voltage relay 32-4, the operation of the II-system voltage relay 32-4 is not interrupted.

Here, it is assumed that an accident accompanied by an overvoltage abnormality actually occurs in the generator system 1. First, the I-system relay device 31 detects a calculation target VT failure of the I-system voltage relay 31-4 by the I-system voltage comparison relay.
The system voltage relay 31-4 is in a state where the operation output is cut off.

However, the II-system relay device 32 converts the level of an accident occurring in the generator system 1 by the II-system relay input conversion unit 32-2 based on the output of the instrument transformer 2b.
A relay operation is performed by the II system voltage relay 32-4 to detect the operation. Since the trip output is the OR trip output 34 of the I-system and the II-system, even if one of the VT outputs is cut off, an accident occurring in the generator system 1 can be detected.

According to the present embodiment, even if one of the VT outputs is cut off, malfunction of the voltage relay can be prevented, and even if an accident occurs in the generator system, the accident can be detected. The reliability of the digital protection relay device can be improved.

The trip output of the present embodiment has been described by using the OR trip method for preventing malfunction and non-operation. However, the case of the AND trip method for preventing malfunction will be described. First, when the VT fuse 33a is blown during the normal operation, the I-system relay device 31 reduces the electric quantity output from the I-system relay input conversion unit 31-1 to 0, and the I-system voltage relay 31-4 (the same). (When the relay is an impedance relay, etc.) may malfunction.

Therefore, when the I-system voltage comparison relay 31-5 operates, the relay output is immediately switched to the bypass state (tripping is possible only by the II-system side relay operation). Here, it is assumed that an accident involving an overvoltage abnormality actually occurs in the generator system 1. First, the I-system relay device 31 is in a bypass state, while the II-system relay device 32 determines an accident that has occurred in the generator system 1 based on the output of the instrument transformer 2b.
The level is converted by the II-system relay input conversion unit 32-2, the relay operation is performed by the II-system voltage relay 32-4, and the operation is detected. Therefore, even if one of the VT outputs is cut off, an accident occurring in the generator system 1 can be detected.

According to the present embodiment, even if one of the VT outputs is cut off, the malfunction of the voltage relay can be prevented, and even if an accident occurs in the generator system, the accident can be detected, thereby achieving digital protection. The reliability of the relay device can be improved.

FIG. 3 is a block diagram of a digital protection relay device according to a third embodiment of the present invention. 3, the same functional portions as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. In the present embodiment, even if one of the input converters fails, malfunction of the voltage relay can be prevented, and an accident occurring in the generator system can be detected.

FIG. 3 showing the present embodiment is newly added to the configuration of FIG. 1 by an I-system VT input amount monitoring function 31-6 and a II-system VT input amount monitoring function 32-6. is there.
The I-system VT input amount monitoring function 31-6 monitors the output of the I-system relay input conversion unit 31-1 and shuts off the operation output of the I-system voltage relay 31-4 when detecting an abnormality.

Further, the II-system VT input amount monitoring function 32-6 includes:
The output of the II-system relay input conversion unit 32-2 is monitored, and when an abnormality is detected, the operation output of the II-system voltage relay 32-4 is shut off. It is to be noted that the interruption of the voltage relay is performed by opening the contact located at the lower part of each voltage relay as described above.

In this VT input amount monitoring, as an example, if the voltage amount output from the generator system 1 is normal, the sum of the three-phase vector amounts of the R, S, and T phases is always 0. Therefore, it is realized by monitoring that the sum of the vector amounts has exceeded a certain set value. An OR trip output 34 is output when any one of the I-system voltage relay 31-4 and the II-system voltage relay 32-4 operates.

Next, the operation of FIG. 3 will be described. First,
It is assumed that the I-system relay input conversion unit 31-1 breaks down during normal operation. The I-system VT input amount monitoring function 31-6 detects a failure and shuts off the operation of the I-system voltage relay 31-4. Here, it is assumed that an accident involving a voltage abnormality actually occurs in the generator system 1.

First, the operation output of the I-system voltage relay 31-4 is cut off. However, the II-system relay device 32 performs level conversion of the accident that occurred in the generator system 1 based on the output of the instrument transformer 2b, based on the output of the instrument transformer 2b, and converts the accident to the II-system voltage relay 32-4. Performs a relay operation and detects operation.

Next, consider the case where the II-system relay input conversion unit 32-2 fails during normal operation. The II-system VT input amount monitoring function 32-6 detects a failure and shuts off the operation of the II-system voltage relay 32-4. Here, it is assumed that an accident involving a voltage abnormality actually occurs in the generator system 1. First, the II-system voltage relay 32-4 is in a state where the operation output is cut off.

However, the I-system relay device 31 converts the level of an accident occurring in the generator system 1 by the I-system relay input conversion unit 31-1 based on the output of the instrument transformer 2a.
A relay operation is performed by the I-system voltage relay 31-4 to detect the operation. Since the trip output is the OR trip output 34 of the I-system and the II-system, even if one of the input conversion units fails, an accident occurring in the generator system 1 can be detected.

According to this embodiment, even if one of the input converters fails, malfunction of the voltage relay can be prevented, and an accident occurring in the generator system can be detected. Reliability can be improved.

The trip output of the present embodiment has been described by using the OR trip method for preventing malfunction and non-operation. However, the case of the AND trip method for preventing malfunction will be described. First, if the I-system relay input conversion unit 31-1 fails during normal operation, the I-system VT input amount monitoring function 31
-6 detects a failure and shuts off the operation of the I-system voltage relay 31-4.

Further, upon detection of a failure by the I-system VT input amount monitoring function 31-6, the relay output is immediately switched to the bypass state (tripping is possible only by the II-system side relay operation).
Here, it is assumed that an accident involving an overvoltage abnormality actually occurs in the generator system 1. First, the I-system relay device 31
Is in the bypass state, but the II-system relay device 32 converts the level of the accident occurring in the generator system 1 by the II-system relay input conversion unit 32-2 based on the output of the instrument transformer 2b.
The relay operation is performed by the system voltage relay 32-4 to detect the operation. Therefore, even if one of the VT outputs is cut off, an accident occurring in the generator system 1 can be detected.

According to the present embodiment, even if one of the input converters fails, malfunction of the voltage relay can be prevented, and an accident occurring in the generator system can be detected. Reliability can be improved.

FIG. 4 is a block diagram of a digital protection relay device according to a fourth embodiment of the present invention. 4, the same functional portions as those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted. In the present embodiment, even if one of the input converters fails, malfunction of the voltage relay can be prevented, and an accident occurring in the generator system can be detected.

FIG. 4 showing the present embodiment is newly added to the configuration of FIG. 2 in that an I-system VT input amount monitoring function 31-6 and a II-system VT input amount monitoring function 32-32 are added. 6. The I-system VT input amount monitoring function 31-6 monitors the output of the I-system relay input conversion unit 31-1 and shuts off the operation output of the I-system voltage relay 31-4 when detecting an abnormality.
The II-system VT input amount monitoring function 32-6 monitors the output of the II-system relay input conversion unit 32-2, and shuts off the operation output of the II-system voltage relay 32-4 when an abnormality is detected.

In this VT input amount monitoring, as an example, if the voltage amount output from the generator system 1 is normal, the sum of the three-phase vector amounts of the R, S, and T phases is always 0. Therefore, it is realized by monitoring that the sum of the vector amounts has exceeded a certain set value. An OR trip output 34 is output when any one of the I-system voltage relay 31-4 and the II-system voltage relay 32-4 operates.

Next, the operation of FIG. 4 will be described. First,
It is assumed that the I-system relay input conversion unit 31-1 breaks down during normal operation. The I-system VT input amount monitoring function 31-6 detects a failure and shuts off the operation of the I-system voltage relay 31-4. It is assumed that an accident involving a voltage abnormality actually occurs in the generator system 1 in this state.

At this time, the operation output of the I-system voltage relay 31-4 has already been cut off. However, II
The system relay device 32 detects an accident that has occurred in the generator system 1 based on the output of the instrument transformer 2b.
The level is converted in 2-2, the relay operation is performed in the II voltage relay 32-4, and the operation is detected.

Next, consider the case where the II-system relay input conversion unit 32-2 fails during normal operation. The II-system VT input amount monitoring function 32-6 detects a failure and shuts off the operation of the II-system voltage relay 32-4. Here, it is assumed that an accident involving a voltage abnormality actually occurs in the generator system 1. At this time,
The II-system voltage relay 32-4 is in a state where the operation output has already been cut off.

However, the I-system relay device 31 converts the level of an accident occurring in the generator system 1 by the I-system relay input converter 31-1 based on the output of the instrument transformer 2a.
The relay operation is performed by the I-system voltage relay 31-4 to detect the operation. In addition, since the trip output is the OR trip output 34 of the I system and the II system, even if one of the input conversion units fails, an accident occurring in the generator system 1 can be detected.

In this embodiment, in the case of the I-system relay device 31, an I-system VT input amount monitoring function 31-6 for detecting a failure on the instrument transformer 2a side is provided. In this case, a function VT input amount monitoring function 32-6 for detecting the failure of the instrument transformer 2b is provided.

However, in the case of the input on the opposite side, that is, in the case of the I-system relay device 31, an I-system VT input amount alarm function 31-9 for detecting a failure of the instrument transformer 2b is provided.
In the case of the system relay device 32, it is also useful to provide an II system VT input amount alarm function 32-9 for detecting a failure on the instrument transformer 2a side.

This is, for example, the I-system relay input conversion unit 31
-2 fails, the I-system voltage comparison relay 31-3 outputs
Since the voltage input amount comparison with the system relay input conversion unit 31-1 is performed, it is notified to the outside that the operation of the I system voltage comparison relay 31-3 is in an indefinite state (a state of malfunction or malfunction). It will be useful as a function for

According to the present embodiment, even if one of the input converters fails, malfunction of the voltage relay can be prevented, and an accident occurring in the generator system can be detected. Improvement in performance can be achieved.

[0060]

As described above, according to the present invention, the protection relay device of the multiplex configuration is used for performing the relay operation on the electric quantity output from the different instrument transformers in each system. Even if the VT output is cut off, an accident occurring in the generator system can be detected.

[Brief description of the drawings]

FIG. 1 shows a first digital protection relay device according to the present invention.
FIG. 1 is a configuration diagram showing an embodiment.

FIG. 2 shows a second embodiment of the digital protection relay device according to the present invention.
FIG. 1 is a configuration diagram showing an embodiment.

FIG. 3 is a third view of the digital protection relay device according to the present invention.
FIG. 1 is a configuration diagram showing an embodiment.

FIG. 4 shows a fourth embodiment of the digital protection relay device according to the present invention.
FIG. 1 is a configuration diagram showing an embodiment.

FIG. 5 is a configuration diagram of a conventional digital protection relay device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Generator system 2a Instrument transformer (a) 2b Instrument transformer (b) 31 I-system relay device 31-1 I-system relay input converter (a) 31-2 I-system relay input converter (b) 31 -3 I system voltage comparison relay 31-4 I system voltage relay (relay including voltage element) 31-5 I system voltage comparison relay 31-6 I system VT input amount monitoring function 31-9 I system VT input amount alarm function 32 II system relay device 32-1 II system relay input converter (a) 32-2 II system relay input converter (b) 32-3 II system voltage comparison relay 32-4 II system voltage relay 32-5 II system voltage comparison Relay 32-6 II system VT input amount monitoring function 32-9 II system VT input amount alarm function 33a VT fuse (a) 33b VT fuse (b) 34 OR trip output 35 AND trip output

Claims (4)

[Claims] 1. A digital protection relay device comprising a multiplex system for detecting and protecting a failure of a power system equipment, comprising a plurality of branched and installed instruments to which an electric quantity from the same power system is input. A transformer, an input converter for level-converting each electric quantity from the plurality of instrument transformers, and a means for performing a relay operation by using the electric quantity from each of the input converters in each system. A digital protection relay device characterized by the above. 2. The digital protection relay device according to claim 1, wherein voltage comparing means for comparing the amounts of electricity between the instrument transformers installed branching from the same power system,
Means for interrupting the output of the relay device according to the comparison result. 3. The digital protection relay device according to claim 1, wherein: a means for monitoring a failure of the input conversion unit;
Means for interrupting the output of the relay device according to the monitoring result. 4. The digital protection relay device according to claim 1, wherein a voltage comparing means for comparing the quantity of electricity between the meter transformers installed branching from the same power system and a relay device according to the comparison result. First means for interrupting the output of the input device, means for monitoring a failure of the input conversion unit, and second means for interrupting the output of the relay device according to the monitoring result.
And a digital protection relay device comprising: