JPH08336230A - Digital protective relay - Google Patents

Abstract

PURPOSE: To obtain a digital protective relay in which the function of relay operating sections can be checked individually by commanding a test input means to output a test signal when a switching is made to a state for testing a desired relay element and interrupting the signal line from desired relay element to a trip signal output means. CONSTITUTION: An input mode selection circuit 4 for switching the data input to each relay operating section 2a-2c between an input converting section 1 and a test section 6 is inserted between the input converting section 1 and the relay operating section 2a-2c. When an element selecting section 7 at the test section 6 is switched to test mode in order to switch the input state of a desired relay operating section 2a among the plurality of relay operating sections 2a-2c, a switch 4a is turned to the test section 6 side by a control signal from the element selecting section 7 thus bringing about a test mode. At the same time, the element selecting section 7 opens the working contact 5a for the relay operating section 2a thus blocking delivery of an abnormal signal to the outside.

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 for disconnecting a faulty part from a system when a fault occurs in a power facility and a power system installed in an electric station.

[0002]

2. Description of the Related Art Generally, electromagnetic relays such as induction disc type and induction cylindrical type have been used for a long time as structures of protection relays, and analog static type using an electronic circuit. Furthermore, various types of systems have been realized up to the digital type in which input voltage and current are digitally encoded and processed, but in recent years, the digital type has become the mainstream due to the demand for higher performance and higher functionality. Is coming.

FIG. 4 is a diagram showing the structure of a conventional general digital protection relay device.

In the figure, reference numeral 40 is a conventional digital protection relay device. This digital protection relay device 4
0 is the input conversion unit 41, the relay calculation units 42a to 42d,
The sequence operation unit 43 and the like are included. An AND circuit 43a and an OR circuit 43 are provided in the sequence operation unit 43.
Logic circuits such as b and 43c are provided in a complicated combination.

In the case of this digital protection relay device 40, the quantity of electricity that is normally input to the input converter 1 from the instrument transformer 45 of a certain power system is converted by the input converter 1 from an analog signal to a digital signal. It Then, the converted amount of electricity is individually processed by each of the relay computing units 42a to 42d provided in the power system. Here, the calculation result is the individual relay calculation unit 42a.
When the range value set in advance to 42d is out of the range, a signal indicating an abnormality is output as a digital signal, and this output signal is output to the AND circuits 43a and O in the sequence operation unit 43.
Logic sequence processing is performed by the R circuits 43b, 43c and the like, and the processing results are output as various trip signals for disconnecting each power equipment and power equipment installed in the power system from the system.

By the way, the digital protection relay device 40
When the digital protection relay device 40 is actually used, that is, when the digital protection relay device 40 continues to protect some device or equipment, when it is desired to check the operation of a relay element in the protection relay device 40, for example, After changing the condition settings of the relay operation unit 42a and the like, in order to actually confirm the operating characteristics, the input source, that is, the amount of electricity of a certain condition must be input from the input conversion unit 41 side in a form conforming to reality. I have to.

However, normally, the input converter 41 is connected in parallel with a plurality of relay calculators 42a to 42d.

Therefore, for example, if a certain amount of electricity is input to the input conversion unit 41, it will affect relay operation units other than the one to be confirmed, so that a desired relay operation unit can be maintained while protection is being continued. It is impossible to confirm only the operating characteristics.

Therefore, conventionally, the operation is continued without confirming the operating characteristics of the relay after changing the set value, or
Alternatively, it is necessary to temporarily stop the protection function of the entire digital protection relay device 40 and then confirm the desired operating characteristics. For example, in the case of a power plant, it is preferable to stop the protection function one by one in terms of system operation. Absent. Further, the sequence operation unit 4 of the digital protection relay device 40
When OR circuits 43b and 43c are provided in 3,
That is, in the case of a configuration in which a trip signal is output when any one of the relay calculation units 42b, 42c, and 42d operates, only the relay calculation unit that first operates with the electric quantity input from the input conversion unit 41 Since the trip signal is output at the timing of, it is not possible to confirm whether or not the other relay calculation units actually operated.

Therefore, in order to confirm the operating point of each relay operation section, it is necessary to modify the internal wiring and the like in a simulated manner, and in some cases, a simulated modification of the peripheral equipment may occur and the tester It was supposed to increase the burden on the.

[0011]

As described above, in the above-mentioned conventional digital protection relay device, since a plurality of relay calculation units are connected in parallel to the input conversion unit, individual relays are continuously protected. There is a problem that the operation of the arithmetic unit cannot be checked.

Further, the sequence operation unit takes in information on the operation contacts of the plurality of relay operation units and complicates a plurality of logics such as an AND circuit and an OR circuit,
Since a trip signal is output to the circuit breaker, when performing a test by inputting a simulation for each circuit breaker, there is a risk that the trip signal will be erroneously output even to the circuit that should not be operated. In a large plant in
Depending on the driving condition, it may cause a serious problem.

The present invention has been made in order to solve such a problem, and while the protection of the system is being continued, it is possible to confirm the operation of each of the plurality of relay arithmetic units including the sequence arithmetic unit, and It is an object of the present invention to provide a digital protection relay device capable of surely and safely performing the operation check of (1) without erroneously operating the other.

[0014]

In order to solve the above-mentioned problems, the digital protection relay device according to claim 1 comprises:
A plurality of relay elements that operate when the electricity amount of the power system is out of a predetermined range and output a signal indicating an abnormality, and based on the signals output from each of the relay elements, perform logic sequence processing, and the power system And a trip signal output means for outputting a trip signal to equipment installed in the relay element, the test signal simulating the electric quantity instead of the electric quantity at the time of a test, the test signal being arranged before the plurality of relay elements. By a test input means for inputting to, a desired relay element among the plurality of relay elements, an operation state selection means for switching from an operation state that normally protects the power system to a test state, and the operation state selection means. When the test state is switched to test the desired relay element, the test input means is instructed to output a test signal, and And from the relay element includes a blocking means for blocking the signal line to the trip signal output means.

According to another aspect of the digital protection relay device of the present invention, an input conversion unit for converting the electric quantity of the electric power system into digital data and a value of the digital data arranged in the electric power system and converted by the input conversion unit. , A plurality of relay elements that operate when outputting from a predetermined range to output a signal indicating an abnormality, and based on the signals output from each of the relay elements, perform logic sequence processing, and the equipment installed in the power system A sequence operation unit that outputs a trip signal to the input conversion unit, and an input mode selector that is arranged between the input conversion unit and the plurality of relay elements and switches the signal input to each relay element from the input conversion unit to the other. A circuit, an output line arranged between the plurality of relay elements and the sequence operation unit, and an output line from each of the relay elements to the sequence operation unit. A relay operation contact breaking circuit for disconnecting and connecting, and an element selecting unit for switching an operation state of a desired relay element among the plurality of relay elements from an operation state normally protecting the power system to a testable state. ,
When the operation state is switched to a test state for testing a desired relay element by the element selection unit, a test signal for testing the desired relay element is generated, and the input mode selection circuit and the relay are generated. A test unit for controlling the operation contact breaking circuit to cut off the output line from the desired relay element and for instructing the input mode selection circuit to input the test signal to the desired relay element. ing.

Further, in the digital protection relay device according to the third aspect of the present invention, an input conversion unit for converting the electric quantity of the power system into digital data and a value of the digital data arranged in the power system and converted by the input conversion unit. , A plurality of relay elements that operate when outputting from a predetermined range to output a signal indicating an abnormality, and based on the signals output from each of the relay elements, perform logic sequence processing, and the equipment installed in the power system To a sequence operation unit that outputs a trip signal to the relay operation contact circuit that disconnects and connects each signal output line from the plurality of relay elements to the sequence operation unit, and a desired relay element among the plurality of relay elements Test the relay operating contact circuit to shut off the signal output line from the desired relay element. It is provided with the door unit.

According to another aspect of the digital protection relay device of the present invention, an input conversion unit for converting the electric quantity of the electric power system into digital data and a value of the digital data arranged in the electric power system and converted by the input conversion unit. , A plurality of relay elements that operate when outputting from a predetermined range to output a signal indicating an abnormality, and based on the signals output from each of the relay elements, perform logic sequence processing, and the equipment installed in the power system A sequence operation unit that outputs a trip signal to a relay operation contact circuit that disconnects and connects the output line from the sequence operation unit, and a relay operation when testing a desired relay element among the plurality of relay elements. A sequence calculation output cutoff function unit for controlling the contact circuit and cutting off a desired output line in advance is provided.

[0018]

According to the first aspect of the present invention, when a desired relay element is tested, the operating state is switched to the test state by the operating state selecting means, and the test input means arranged before the plurality of relay elements, A test signal simulating the amount of electricity is input to the relay element. When the desired relay element is operated by the test signal, a signal indicating an abnormality is output from the relay element to the trip signal output means,
At this time, since the signal line to the trip signal output means is cut off by the breaking means, the trip signal output means does not output the trip signal as a result of the test operation of a certain relay element.

According to the second aspect of the invention, in order to confirm the operation of the desired relay element, when the relay element is selected by the element selection unit and switched to the test state, the input mode selection circuit is controlled. The signal line from the input converter to the relay element is disconnected, the output line from the desired relay element is blocked, and the test signal is input to the relay element from the disconnected input mode selection circuit.

Now, when the desired relay element operates,
A signal indicating an abnormality is output from the relay element to the sequence operation unit, but at this time, since the signal line to the sequence operation unit is interrupted by the relay operation contact interruption circuit arranged between the relay element and the sequence operation unit, A trip signal is not output as a result of a test operation of a relay element. As a result, even when the digital protection relay device continues to protect the power system, it is possible to confirm the operation of the desired relay element without affecting others.

Further, in testing the desired relay element among the plurality of relay elements, when the test mode of the test section is selected, the signal output line from the desired relay element is cut off. Therefore, the result of the test operation of the desired relay element is not output to the sequence calculation unit, and the operation check of the desired relay element can be performed reliably, safely and selectively without affecting the others.

Further, in the invention according to claim 4, when the desired relay element among the plurality of relay elements is tested, the desired output line from the sequence operation part is cut off, and the sequence operation output, that is, the trip signal is generated. Since it is invalidated, it is possible to prevent unnecessary operation of objects other than the target operation end at the time of testing.

As a result of the above, even when the protection of the power system is continued,
The operation check for each of the plurality of relay elements can be performed while including the sequence operation unit. In addition, the operation confirmation of each of the relay elements and the sequence operation unit described above can be performed reliably and safely without causing other malfunctions.

[0024]

Embodiments of the present invention will now be described in detail with reference to the drawings.

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

In the figure, reference numeral 1 denotes an input conversion unit, which converts the amount of electric power (analog signal) input from, for example, a transformer 45 for an instrument provided in an electric power system in a power plant into a digital signal. Reference numerals 2a to 2c are relay operation units as relay elements, which are provided at different points in the power system and which indicate an abnormality when the value of the digital signal input from the input conversion unit 1 is out of a predetermined range. Is output. For example, the relay computing unit 2a and the like are provided at a point on the primary side such as a generator, which is a facility of the power system, and operate with current. The relay calculation unit 2b and the like are provided at the secondary side point of the generator and operate with current. The relay calculation unit 2c is the same as that of the above generator.
It is a so-called 87 relay that operates based on the current value from the secondary side and the secondary side and the voltage from another converter. Reference numeral 3 denotes a sequence operation unit, which is incorporated with a logic circuit such as an AND circuit and an OR circuit incorporated therein, and outputs a trip signal based on the signal output from each of the relay operation units 2a to 2c. Reference numeral 4 denotes an input mode selection circuit, which is provided between the input conversion unit 1 and the relay calculation units 2a to 2c and is used to input data to the relay calculation units 2a to 2c among the input conversion unit 1 or the test unit 6. The role of switching to either one of. For example, the relay element is switched to either the normal mode or the test mode. Reference numeral 5 denotes a relay operation contact breaking circuit, which is provided between the relay operation units 2a to 2c and the sequence operation unit 3 and is controlled by the test unit 6 to have internal relay operation contacts 5a.
.About.5c are opened, and the outputs from the relay computing units 2a to 2c are cut off so as not to be output to the sequence computing unit 3. 6 is a test section. This test section 6
When the simulated relay element in the test section is selected, the element selection section 7 that controls the input mode selection circuit 4 and the relay operation contact breaking circuit 5 according to the selection content, and the input signal (input Signal conversion section 8 for converting the analog amount into a digital value for each element.
a to 8c, the level operation unit 9 that changes (increases or decreases) the input amount of each test signal according to the operation content and outputs the operation amount, and the operation performed when the level operation unit 9 is operated by the element selection unit 7. It is composed of switches 10a to 10c for transmitting a test signal to each of the signal converters 8a to 8c according to the contents.

Next, the operation of the digital protection relay device of the first embodiment will be described.

In this digital protection relay device, when testing a desired relay among the plurality of relay computing units 2a to 2c, such as the relay computing unit 2a, first, the input state of the relay computing unit 2a is switched to the test mode. For,
When a switch (not shown) in the element selection section 7 of the test section 6 is switched to the test mode position, the input mode selection circuit 4 is controlled by the control signal from the element selection section 7 and the internal switch 4a is moved to the test section 6 side. Switch to test mode. At this time, the other relay calculation units 2b and 2c are
The normal mode remains and the normal protection operation state continues.

At the same time, the element selecting section 7 controls the relay operation contact cutoff circuit 5 to open the operation contact 5a corresponding to the relay operation section 2a to cut off the output of the signal indicating the abnormality to the outside.

Then, the examiner may select, for example, the signal converter 8a.
Select a conversion element such as, and select the level operation unit 9 in the test unit 6.
Is operated to change the type or level of the test signal, the changed test signal is input from the level operation unit 9 to the input mode selection circuit 4 through the signal conversion unit 8a.

In the input mode selection circuit 4, the switch 4a
Only the switch to the test side, this switch 4a
The test signal is input to the relay calculation unit 2a through the relay calculation unit 2a, and the relay calculation unit 2a operates accordingly. A signal indicating an abnormality is output from the relay operation unit 2a by this operation, but this signal is not output to the subsequent circuits, that is, the sequence operation unit 3 and the like because the operation contact 5a has already been opened.

Whether or not the relay operation unit 2a has operated can be confirmed by checking an operation memory (not shown) in the relay operation unit 2a. The test signal output from the test unit 6 is a signal simulating the input conversion unit 1 that is an input of the selected relay element. In the test unit 6, the analog filter circuit in the input conversion unit 1 is included. The various conversion circuits described above are replaced with certain constants to output signals equivalent to those of the input conversion unit 1.

As described above, according to the digital protection relay device of the first embodiment, the digital protection relay device allows the equipment (generator) in a certain system to have a plurality of relay operation units 2a-2.
Even during the protection operation in c, the input mode selection circuit 4 and the relay operation contact breaking circuit 5 are provided in the preceding stage, and while controlling these from the test unit 6, the desired relay operation unit 2a is controlled.
Since the test signal is input only to the relay operation result signal and the relay operation result signal is not output, only the relay operation unit 2a is tested without affecting the other relay operation units 2b and 2c and the sequence operation unit 3. can do.

In this embodiment, the test section 6 is provided with the three signal converting sections 8a to 8c, but the types of the test signals are different from each other, and the signal converting sections 8a to 8c are the relay calculating sections 2a. 2c does not correspond one-to-one to 2c, but if one relay computing section has a plurality of input terminals, a test signal for the relay computing section may be output from a plurality of signal converting sections.

Next, a digital protection relay device according to a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a diagram showing the configuration of a digital protection relay device according to a second embodiment of the present invention. The same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

As shown in the figure, the digital protection relay device of the second embodiment includes a relay operation contact circuit 20 for disconnecting / connecting a signal output line between each of the relay operation units 2a to 2c and the sequence operation unit 3. , A test section 21 for controlling the operation of the relay operation contact circuit 20.

The test section 21 has a mode selection section 22 having operation modes such as a normal mode and a test mode, and among the operation modes of the mode selection section 22, a relay element (relay calculation sections 2a to 2c) desired by a tester. ) Is selected, the relay operation contact circuit 20 is instructed to interrupt the signal output lines from all the relay calculation units 2a to 2c and connect only one desired output line. And an element selection unit 23.

The relay operation contact circuit 20 is a normally-closed switch 20a that temporarily shuts off the output lines of all the relay calculation units 2a to 2c (relay elements) when the test mode is selected.
20c, 20e and normally open switches 20b, 20d, 20 for connecting the output lines of only the desired relay elements after disconnection
f is connected in parallel with each other.

In the digital protection relay device of the second embodiment, when each of the relay computing units 2a to 2c is individually tested, a tester operates an operation panel (not shown) of the testing unit 21 to perform relaying, for example. When the test mode of the arithmetic unit 2a or the like is selected, the mode selection unit 22 is set to the test mode, and the element selection unit 23 causes the relay operation contact circuit 2 to operate.
0 is controlled and normally closed switches 20a, 20c, 20e
Is opened, and the output lines in the subsequent stages of all relay elements are cut off.

Then, only the selected relay element, that is, only the output line from the relay computing section 2a is connected by the normally open switch 20b.

By changing the input of the input conversion section 1 in this state, the operation of only the relay calculation section 2a can be confirmed.

As described above, according to the digital protection relay device of the second embodiment, the relay operation contact circuit 20 includes the normally closed switches 20a, 20c and 20e and the normally open switch 20b.
20d and 20f are connected in parallel to each other to form a so-called B contact, and when the tester switches the operation mode to the test mode and selects the desired relay operation unit 2a,
The element selection unit 23 controls the relay operation contact circuit 20 to temporarily cut off all output lines, and then a desired relay element, that is, only the output line from the relay operation unit 2a is connected to the two-step operation procedure. Therefore, the operation check for each relay element including the sequence processing can be surely performed without error.

Next, a digital protection relay device according to a third embodiment of the present invention will be described with reference to FIG. FIG. 3 is a diagram showing the configuration of a digital protection relay device according to a third embodiment of the present invention. The same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, reference numeral 30 denotes a sequence operation output cutoff circuit, which cuts off a plurality of outputs from the sequence operation unit 3 respectively.
have c. Reference numeral 31 denotes a sequence operation output selection function unit, which is used for the sequence operation output cutoff circuit 3 in the test mode
It controls 0. a, b, and c are sequence outputs, that is, trip signals.

In the case of the digital protection relay device of the third embodiment, the trip signal to be cut off can be designated by instructing the sequence operation output selection function unit 31 before selecting the test mode.

For example, when the sequence operation output selection function unit 31 is instructed to invalidate the sequence output a, the sequence operation output selection function unit 31 causes the sequence operation output cutoff circuit 30 to cut off the signal corresponding to the sequence output a. The part 31a is controlled to cut off the signal line.

When a test mode for a certain relay operation unit is selected, a test signal is input to that relay operation unit to operate the relay operation unit, and its output signal is input to the sequence operation unit 3.

Since various logic circuits are complicatedly combined in the sequence operation unit 3, the tester does not know what trip signal is output. However, after the sequence operation is performed here, each Even if the trip signal is output to the equipment, the output line that should not be output is blocked by the blocking unit 31a, so that the trip signal is not erroneously output to the output line.

That is, when testing a desired relay element, the output signal can be invalidated at the final stage where the trip signal is output.

As described above, according to the digital protection relay device of the third embodiment, the sequence operation output selection function part 31
Since the final trip signal from the sequence operation unit 3 can be individually cut off in advance by instructing to, the trip signal is erroneously sent to other than the target operation end when confirming the operation of a relay operation unit. It can be prevented from being output. For example, when testing individual relays installed in various systems in a power plant or the like, it is possible to prevent an unnecessary trip operation from occurring in equipment installed in an unexpected place.

[0051]

As described above, according to the first aspect of the invention, at the time of the test, the test signal simulating the electric quantity of the power system is input to the relay element, and the signal line from the relay element is cut off. Therefore, even when the digital protection relay device is in operation, that is, while the power system is continuously protected, it is possible to confirm the operation of the desired relay element without affecting the other.

According to the second aspect of the present invention, during the test, after the output line from the desired relay element is cut off, a test signal simulating the electric quantity of the power system is input to the relay element, Therefore, the trip signal is not output as a result of the test operation of the relay element. As a result, even when the digital protection relay device continues to protect the power system, it is possible to confirm the operation of the desired relay element without affecting others.

Furthermore, according to the third aspect of the present invention, the desired output line from the sequence operation unit can be cut off in advance before the test, so that it is erroneously excluded from the test target in each power device test, for example, each circuit breaker test. The trip signal will not be output to the circuit breaker.

According to the invention described in claim 4, when a desired relay element among a plurality of relay elements is tested,
Since the desired output line from the sequence operation unit is cut off and the sequence operation output, that is, the trip signal is invalidated, it is possible to prevent unnecessary operation of anything other than the target operation end during the test.

As a result, the operation confirmation for each of the plurality of relay operation units can be performed including the sequence operation unit even while the protection of the system is continued. In addition, the operation confirmation of each of the above-mentioned parts can be performed reliably and safely without causing the other parts to malfunction.

[Brief description of drawings]

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

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

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

FIG. 4 is a diagram showing a configuration of a conventional digital protection relay device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Input conversion part, 2a-2c ... Relay operation part, 3 ... Sequence operation part, 4 ... Input mode selection circuit, 5 ... Relay operation contact interruption circuit, 6, 21 ... Test part, 9 ... Level operation part, 7, 23 ... Element selection section, 10a-10c ... Switch, 8a-8c ... Signal conversion section, 20 ... Relay operation contact circuit, 22 ... Mode selection section, 30 ... Sequence operation output cutoff circuit, 31 ... Sequence operation output selection function section.

Claims (4)

[Claims] 1. A plurality of relay elements that operate when a quantity of electricity in a power system is out of a predetermined range and output a signal indicating an abnormality, and a logic sequence process based on the signals output from each of the relay elements. And a trip signal output means for outputting a trip signal to the equipment installed in the electric power system, and a test signal that is arranged in front of the plurality of relay elements and simulates the electric quantity instead of the electric quantity at the time of test. Test input means for inputting a signal to the relay element, a desired relay element among the plurality of relay elements, an operating state selecting means for switching from an operating state that normally protects the power system to a test state, and Instructing the test input means to output a test signal when the operating state selection means switches to a test state for testing the desired relay element. With a digital protective relay device, characterized in that from the desired relay elements; and a blocking means for blocking the signal line to the trip signal output means. 2. An input conversion unit for converting the electric quantity of the electric power system into digital data; and an input conversion unit arranged in the electric power system, which operates when the value of the digital data converted by the input conversion unit is out of a predetermined range. A plurality of relay elements that output a signal indicating an abnormality, based on the signals output from each of the relay elements, performs a logic sequence process, a sequence operation unit that outputs a trip signal to the equipment installed in the power system, and An input mode selection circuit disposed between the input conversion unit and the plurality of relay elements, and switching a signal input to each relay element from the input conversion unit to another input mode selection circuit; A relay operation contact breaking circuit which is arranged between the sequence operation units and which interrupts and connects the output line from each of the relay elements to the sequence operation unit. An element selection unit that switches an operation state of a desired relay element among the plurality of relay elements from an operation state in which the power system is normally protected to a testable state, and an operation state is desired by the element selection unit. When switching to a test state for testing the relay element of, while generating a test signal for testing the desired relay element, and controlling the input mode selection circuit and the relay operation contact breaking circuit, A digital protection relay device, comprising: a test unit that cuts off an output line from a desired relay element and instructs the input mode selection circuit to input the test signal to the desired relay element. . 3. An input conversion unit for converting the electric quantity of the electric power system into digital data; an input conversion unit arranged in the electric power system and operated when the value of the digital data converted by the input conversion unit is out of a predetermined range. A plurality of relay elements that output a signal indicating an abnormality, based on the signals output from each of the relay elements, performs a logic sequence process, a sequence operation unit that outputs a trip signal to the equipment installed in the power system, and A relay operation contact circuit for disconnecting and connecting each signal output line from the plurality of relay elements to the sequence operation unit, and a relay operation contact circuit when testing a desired relay element among the plurality of relay elements And a test unit for cutting off the signal output line from the desired relay element. Protection relay equipment. 4. An input conversion unit for converting the electric quantity of the electric power system into digital data, and an operation performed when the value of the digital data converted by the input conversion unit arranged in the electric power system is out of a predetermined range. A plurality of relay elements that output a signal indicating an abnormality, based on the signals output from each of the relay elements, performs a logic sequence process, a sequence operation unit that outputs a trip signal to the equipment installed in the power system, and , A relay operation contact circuit that disconnects and connects the output line from the sequence operation unit, and a relay operation contact circuit that controls the relay operation contact circuit when testing a desired relay element among the plurality of relay elements, and outputs a desired output in advance. A digital protection relay device comprising: a sequence calculation output cutoff function unit for cutting off a line.