JPH0583841A - Digital protective relay unit - Google Patents

Abstract

PURPOSE:To realize simultaneous inspection of the soundness of current transformer and signal processing system, including the primary windings thereof, by stopping the function of a protective relay based on an output signal from the secondary winding of a second auxiliary current transformer at the time of inspection. CONSTITUTION:A second auxiliary current transformer 25 comprises a second primary winding 25a and a secondary winding 25b and when a residual circuit current Iz flows through the winding 25a, a voltage Vz, i.e., a second primary detection signal, is outputted from the secondary winding 25b connected with a current/voltage converting resistor Rz. When an inspection start signal 22 is not fed to a control signal output section 29, switches 26, 27, 16 closes, opens and closes, respectively, and a relay operating section 15 performs protective relay operation. Consequently, a digital protective relay unit 30 can inspect the soundness of the current transformer 25 and a residual circuit signal processing system 23 simultaneously including the primary winding 25b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective relay for performing a protective relay operation relating to a power system by using not only the quantity of electricity of a three-phase main circuit in the power system but also the residual circuit current in a residual circuit of a main current transformer. A device, a digital protection relay device for performing a protection relay calculation and the like using a computer, in particular,
The present invention relates to an auxiliary current transformer for residual circuit current transformer and a relay device capable of inspecting the soundness of a residual circuit signal processing system as a signal processing system for the signal output from this current transformer and simplifying the inspection device. ..

[0002]

2. Description of the Related Art In the above main circuit, when the three phases are in a balanced state, the above-mentioned residual circuit current is zero, so whether the auxiliary current transformer for residual circuit current transformation and the residual circuit signal processing system are sound or not. It is impossible to easily inspect the relay with a protective relay device that does not have a prescribed inspection device.
The digital protection relay device 1 having the configuration is adopted. Then, in FIG. 3, 2r, 2s, 2t are both attached to the three-phase main circuit 3 consisting of each phase of r, s, t and connected in a star shape. Reference numeral 6 is connected to the current transformers 2r, 2s, 2t such that the respective primary windings 4a, 5a, 6a are connected through the primary winding 7a of the second auxiliary current transformer 7 in the illustrated Y-Y connection. Both are first
The auxiliary current transformers Rr, Rs, Rt are current transformers 4, 5, 6
The primary phase windings 4a, 5a, 6a as the primary windings of the current transformers 4a, 5a, 6a are caused to flow by the secondary phase currents Ir, Is, It generated by the main current transformers 2r, 2s, 2t, respectively. The currents generated in the respective secondary windings 4b, 5b, 6b of 5, 6 are the voltages Vr, V as the first primary detection signals, respectively.
s and Vt are both current / voltage conversion resistors and R
z is the residual current Iz flowing through the second primary winding 7a as the primary winding of the current transformer 7 connected in series to the residual circuit of the main current transformers 2r, 2s, 2t. It is a current-voltage conversion resistor that changes the current generated in the secondary winding 7b into the voltage Vz as the second primary detection signal.

Fr, Fs, Ft and Fz are voltages Vr and V
Main circuit 3 as a target frequency component for each of s, Vt, and Vz
Is a analog filter that extracts a voltage component having a frequency component substantially equal to the rated frequency f of the switch, and 8 is a switch 9 that opens and closes the circuit according to the input control signal 21c.
The current source 10 is configured to flow the inspection current Ia through the tertiary winding 7c of the current transformer 7 via the
An A / D conversion unit is composed of a multiplexer 11 that repeats the operation of sequentially outputting each output voltage of Fz one by one, and an AD converter 12 that converts the output voltage of the multiplexer 11 into a digital signal, and 13 is output from the AD converter 12. Signal waveform shaping processing is performed on the digital voltage signal corresponding to the first primary detection signal Vr, Vs, Vt, which is a signal corresponding to each of the secondary phase currents Ir, Is, It. Next detection signals 13r, 13s, 13t
And a second secondary detection signal 13z corresponding to the residual circuit current Iz, which is a signal corresponding to the second primary detection signal Vz.

Reference numeral 14 is a signal processing section comprising filters Fr, Fs, Ft, Fz, an AD conversion section 10 and a waveform shaping section 13, and 15 is a third circuit opening / closing circuit according to an input third control signal 21a. Switch 16 and detection signals 13r, 1
Both 3s and 13t are directly input and the detection signal 13
z is input via switch 16 and signals 13r, 13
s, 13t, 13z is used to perform a protection relay operation, and at least one trip signal 17 depending on the operation result.
A relay operation unit including an operation unit main body 17 that outputs a, and 18 receives a second secondary detection signal 13z, and a fourth control signal 21 while the signal 13z is being input.
When b is input, an effective value calculation operation for calculating the effective value Sz of the signal 13z is performed in the effective value calculation unit 19, and then the calculated result is compared with a predetermined reference value K1 and the comparison result is obtained. This is a residual circuit current monitoring unit in which the comparison calculation unit 20 performs the comparison calculation operation for outputting the inspection signal 20a. And then
Here, the signal 20a indicates that Sz ≧ K1 and the arithmetic unit 20
Is a binary signal that exhibits a value of "0" when Sz <K1 and the operation unit 20 determines that Sz <K1 has a value of "1". When the inspection start signal 22 is input, 21 performs once a series of control signal output operation A1 for outputting or extinguishing the third control signal 21a, the fourth control signal 21b, and the fifth control signal 21c in a predetermined procedure. In the control signal output section, the control signal output operation A1 in this case is performed by the third to fifth control signals 21a,
By 21b and 21c, the switch 9 is closed during the time period during which the switch 16 is open, and is monitored during the time period during which the switch 9 is closed. A signal output operation for operating the switches 9, 16 and the monitoring unit 18 so that the residual circuit current monitoring operation B including the above-described effective value calculation operation and comparison operation in the section 18 starts and ends. is there. Then, the digital protection relay device 1 described above is configured by the respective parts shown in FIG. 3 except the main circuit 3.

[0005]

In the protection relay device 1, each part is constructed as described above, and in addition, when each part of the device 1 is sound and the main circuit 3 is in the three-phase balanced state, the current source is 8 and switch 9 form a current transformer tertiary winding 7c
When the inspection current Ia is applied to the
The current Ia is set so as to satisfy ≧ K1. Therefore, in this relay device 1, when the circuit 3 is in the three-phase balanced state, by inputting the inspection start signal 22 to the control signal output unit 21 and observing the state of the inspection signal 20a,
A current transformer 7 as an auxiliary current transformer for residual circuit current flow, and a residual circuit signal processing system 23 including a portion for performing operation of obtaining a detection signal 13z from the detection signal Vz in the signal processing unit 14 and a resistor Rz. It is clear that it can be easily inspected whether or not is sound, but in this inspection, since the current Ia is made to flow through the winding 7c, there is no abnormality such as disconnection or short circuit of the winding 7a. There is a problem that it cannot be detected depending on the signal 20a. In addition, since the current source 8 and the winding 7c described above are required in this case, the auxiliary current transformation including these two, the switches 9 and 16, the monitoring unit 18, and the control signal output unit 21. There is also a problem that the configuration of the inspection device 24 for the instrument 7 and the signal processing system 23 described above is complicated. An object of the present invention is to allow the residual circuit current Iz to flow through the primary winding 7a when the main circuit 3 is in a balanced state without providing the current source 8 and the winding 7c, and thus a current transformer. 7 and the signal processing system 23 can be collectively checked for soundness without excluding the primary winding 7a, and the structure of an inspection device for performing this check can be simplified. is there.

[0006]

To achieve the above object, according to the present invention, there are provided three main current transformers which are attached to a three-phase main circuit and are commonly connected at one end thereof and connected in a star shape. , Three first auxiliary current transformers provided corresponding to the main current transformers, one end of each primary winding of which is connected to the other end of the main current transformer, and one end of which is the first auxiliary current transformer A second auxiliary current transformer connected to the other end of each primary winding of the current transformer, the other end of which is connected to a common connection point of the main current transformer,
In a digital protection relay device that performs a protection relay operation based on the output signal of each secondary winding of the auxiliary current transformer and the second auxiliary current transformer, one of the three first auxiliary current transformers is inspected at the time of inspection. Is disconnected to perform an inspection operation based on the output signal of the secondary winding of the second auxiliary current transformer, and stop the protection relay operation based on the output signal of the secondary winding of the second auxiliary current transformer. It is characterized by doing. Further, according to the embodiment of the present invention, 1) three main current transformers mounted in a three-phase main circuit and connected in a star shape, and three main current transformers corresponding to each of the main current transformers are provided. A first auxiliary current transformer, a second auxiliary current transformer, a first switch that performs a circuit opening / closing operation according to an input first control signal, and a circuit opening / closing operation according to an input second control signal And a second switch that operates as a primary winding of the first auxiliary current transformer to the main current transformer corresponding to the first auxiliary current transformer for each of the first auxiliary current transformers. First
One end of a primary winding is connected, one end of a second primary winding as a primary winding of the second auxiliary current transformer is connected to a neutral point of the main current transformer, and the second primary winding is connected. The other end of the wire is connected to the other end of the first primary winding of the arbitrary specific auxiliary current transformer as the first auxiliary current transformer via the first switch, and the specific auxiliary current transformer is connected. The first primary winding of each of the two first auxiliary current transformers except the current transformer, and the other end of the first primary winding of the specific auxiliary current transformer is directly connected to the other end of the first primary winding. By connecting to the neutral point via the second switch, each secondary winding of the first auxiliary current transformer flows through the first primary winding corresponding to the secondary winding. The first primary detection signal as an analog signal corresponding to the next phase current is output and the secondary winding of the second auxiliary current transformer is connected to the front side. A relay input section that outputs a second primary detection signal as an analog signal according to the residual circuit current flowing through the second primary winding, and each of the three first primary detection signals for convenience and the second primary detection signal. Signal processing such as target frequency component extraction, AD conversion, and signal waveform shaping is sequentially performed for each of the three, and the corresponding three first secondary detection signals corresponding to each of the secondary phase currents and the residual circuit current are handled. A signal processing unit that outputs the second secondary detection signal and a third switch that opens and closes the circuit according to the input third control signal are provided, and all the first secondary detection signals are directly At least one trip signal that is input and that the second secondary detection signal is input through the third switch, and that performs protection relay calculation using both the secondary detection signals and that corresponds to the calculation result. To output -The arithmetic unit and the second secondary detection signal are input, and when the fourth control signal is input in the state where the second secondary detection signal is input, the effective value of the second secondary detection signal A residual circuit current monitoring unit for performing a residual circuit current monitoring operation including an effective value calculation calculation operation for calculating and a comparison calculation operation for comparing the calculation result with a predetermined reference value and outputting an inspection signal according to the comparison result. And a control signal output section that once performs a series of control signal output operations for outputting or extinguishing the first to fourth control signals in a predetermined procedure when an inspection start signal is input. The operation is such that the second switch is in a closed state during a time zone in the middle of the time zone in which the third switch is open,
And a time in the middle of the time period in which the first switch is in the open state during a time period in the middle of the time period in which the second switch is in the closed state A signal that causes the first to third switches and the residual circuit current monitoring unit to operate according to the first to fourth control signals so that the residual circuit current monitoring operation starts and ends during the band. The digital protection relay device is configured to perform an output operation, and 2) in the relay device described in 1) above, the inspection start signal is digital so that it is a signal periodically input to the control signal output unit. 3) In the relay device according to any one of 1) or 2) above, the first and second primary detection signals are both first and second auxiliary current transformers. Electric currents transformed by each of Constituting the digital protective relay device to be a voltage signal obtained by converting the voltage.

[0007]

With the above construction, in any protection relay device, three main current transformers are provided when the three-phase main circuit is in a balanced state by the control signal output operation performed by the control signal output section. Of the secondary auxiliary current of the specific auxiliary current transformer other than the first primary winding of the specific auxiliary current transformer, the total current of the two secondary phase currents flowing through each of the other two primary primary windings. Can be made to flow without significantly affecting the operation of the relay calculation unit, and the magnitude of the second secondary detection signal based on this sum current can be changed by the inspection signal output by the residual circuit current monitoring unit. Since it can be inspected and the current source 8 and the tertiary winding 7c described above are unnecessary in this case, the soundness of the second auxiliary current transformer and the above-mentioned residual circuit signal processing system 23 connected to this current transformer is sound. Check for the exclusion of the secondary primary winding No it can be performed collectively, and configuration of the inspection apparatus for performing this inspection is that the digital protection relay device becomes simple to obtain.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of the structure of an embodiment of the present invention. In this figure, the same parts as those in FIG. Then, in FIG.
5 is a second primary winding 25a as a primary winding and a secondary winding 2
5b and the residual circuit current Iz flows through the winding 25a to output the second primary detection signal as the voltage Vz from the secondary winding 25b to which the current / voltage conversion resistor Rz is connected as shown in the figure. The second auxiliary current transformer corresponding to the above-mentioned current transformer 7, 26 is a first switch that opens and closes the circuit in response to the input first control signal 29a, and 27 is a second input. A second switch that opens and closes the circuit in response to the control signal 29a, and 28 is a main current transformer 2r, 2s, 2t, a first auxiliary current transformer 4, 5, 6, a current transformer 25, a switch 26, and 27 is a relay input section in which resistors 27, Rr, Rs, Rt, and Rz are connected as shown in the figure. 29 is a series of control signal outputs for outputting or extinguishing the first control signal 29a, the second control signal 29b, the third control signal 21a, and the fourth control signal 21b in a predetermined procedure when the inspection start signal 22 is input. This control signal output operation A2 is performed by the control signal output unit corresponding to the control signal output unit 21 that performs the operation A2 once.
2, as shown in FIG. 2, the second switch 27 is in the closed state and the switch 27 is in the closed state during the time period T2 in the middle of the time period T1 in which the third switch 16 is open. Time zone T2
The first switch 26 is in the open state during the time zone T3 in the middle of the period, and the residual circuit current monitoring operation B is started and ended during the time zone T4 in the middle of the time zone T3 in which the switch 26 is in the open state. As described above, the switch 16, 26, 27 and the residual circuit current monitor 18 are operated to output signals 29a, 29b, 21a, 21b. Reference numeral 30 denotes a digital protection relay device including the respective parts shown in FIG. 1 except the main circuit 3.

The relay device 30 is constructed as described above. When the inspection start signal 22 is not input to the control signal output section 29, the switch 26 is closed, the switch 27 is open, and the switch 16 is opened.
Is closed, the relay calculator 15 is in a state in which it can perform a normal protection relay calculation. If the main circuit 3 is in a three-phase balanced state at this time, the secondary phase current Ir is set to I and a is set to a.
= Exp (j2π / 3), Ir = I, Is = a ² I,
Because of the relationship of It = aI, the residual circuit current Iz, which is the sum of Ir, Is, and It, is zero. However, in this case, the signals 29a, 29b, 21 are output from the signal output unit 29.
When the state of the time zone T3 in FIG. 2 appears by outputting a, Iz = Ir + It = (1+
a) · I, the effective value is equal to that of the current Ir and the current Iz having a phase leading by 60 degrees with respect to Ir is the winding 25a.
In this case, if the current transformer 25 and the residual circuit signal processing system 23 described above are both sound, the effective value Sz of the detection signal 13z corresponding to Iz is always Sz ≧ K2 with respect to the reference value K2. The reference value K2 in the comparison calculation 20 is set so that the value of the signal 20a is “0” when Sz ≧ K2, and the value of the signal 20a is “1” when Sz <K2. The arithmetic unit 20 is configured as described above. Then, in the relay device 30, as described above, the monitoring operation B is performed during the time zone T4 in FIG. 2, and at this time, the detection signal 13z is input to the arithmetic unit body 17 of the relay arithmetic unit 15. There is no such thing.

That is, in the relay device 30, by the control signal output operation A2 performed by the signal output unit 29, the main current transformers 2r, 2 when the main circuit 3 is in the three-phase balanced state.
In the winding 25a that forms the residual circuit of s, 2t, the sum current (I
r + It) can be made to flow without significantly affecting the operation of the relay arithmetic unit body 17, and the magnitude of the signal 13z based on this sum current (Ir + It) can be checked by the check signal 20a. Further, in this case, the inspection device 31 corresponding to the above-described inspection device 24 is formed by the switches 26, 27, 16 and the monitoring unit 18 and the signal output unit 29.
Therefore, the relay device 30 checks the soundness of the current transformer 25 and the residual circuit signal processing system 23 together and the primary winding 25.
It is also clear that the inspection device 31 which can be carried out without excluding a and is a relay device having a simpler configuration than the above-mentioned inspection device 24. In the above embodiment, the switches 26 and 27 are connected so that Iz = Ir + It. However, according to the present invention, Iz = Ir + I.
The switches 26 and 27 may be connected so that s or Iz = Is + It. In the above embodiment, the inspection start signal 22 is input to the control signal output unit 29 at an appropriate time. However, according to the present invention, the signal 22
May be periodically input to the signal output unit 29.

[0011]

As described above, according to the present invention, three main current transformers which are attached to a three-phase main circuit and which are commonly connected at one end and are connected in a star shape, and the main current transformer Three first auxiliary current transformers, each of which is provided correspondingly and has one end connected to the other end of the main current transformer, and one primary winding of the first auxiliary current transformer having one end A second auxiliary current transformer connected to the other end of the wire and the other end of which is connected to a common connection point of the main current transformer, the first auxiliary current transformer and the second auxiliary current transformer.
In a digital protection relay device that performs a protection relay operation based on an output signal of each secondary winding of the auxiliary current transformer, at the time of inspection, one of the three first auxiliary current transformers is disconnected and the second auxiliary current transformer is disconnected. The inspection operation is performed based on the output signal of the secondary winding of the auxiliary current transformer, and the protection relay operation based on the output signal of the secondary winding of the second auxiliary current transformer is stopped. Furthermore, according to an embodiment of the present invention, 1)
Three main current transformers attached to a three-phase main circuit and connected in a star shape, three first auxiliary current transformers corresponding to each of the main current transformers, and a second auxiliary current transformer A switch, a first switch for performing a circuit opening / closing operation according to an input first control signal, and a second switch for performing a circuit opening / closing operation according to an input second control signal, and For each auxiliary current transformer, one end of the first primary winding as the primary winding of the first auxiliary current transformer is connected to the main current transformer corresponding to the first auxiliary current transformer, and the second auxiliary current transformer is connected. One end of the second primary winding as the primary winding of the current transformer is connected to the neutral point of the main current transformer, and the other end of the second primary winding serves as an arbitrary first auxiliary current transformer. To the other end of the first primary winding of the specific auxiliary current transformer of the first auxiliary current transformer, and to each of the two first auxiliary current transformers excluding the specific auxiliary current transformer. By directly connecting to each other end of the first primary winding of the first auxiliary winding, and connecting the other end of the first primary winding of the specific auxiliary current transformer to the neutral point via the second switch. Outputting a first primary detection signal as an analog signal corresponding to a secondary phase current flowing through a first primary winding corresponding to the secondary winding from each secondary winding of the first auxiliary current transformer, and second auxiliary A relay input section that outputs a second primary detection signal as an analog signal according to the residual circuit current flowing from the secondary winding of the current transformer to the second primary winding, and three first primary detection signals for convenience And the second primary detection signal, target frequency component extraction, AD conversion, and signal waveform shaping are sequentially performed, and three first secondary detection signals corresponding to each of the secondary phase currents are provided. Outputting a second secondary detection signal corresponding to the residual circuit current And No. processing unit,
A third switch that opens and closes the circuit according to a third control signal that is input is provided, all the first secondary detection signals are directly input, and the second secondary detection signal is the third switch. A relay operation section that is input via the above-mentioned secondary detection signal and performs a protection relay operation using the two secondary detection signals to output at least one trip signal according to the operation result; and a second secondary detection signal, When the fourth control signal is input while the second secondary detection signal is input, the effective value calculation operation for calculating the effective value of the second secondary detection signal and the operation result are set to a predetermined reference value. And a residual circuit current monitoring unit that performs a residual circuit current monitoring operation including a comparison calculation operation that outputs an inspection signal corresponding to the comparison result, and a first to fourth control signals when the inspection start signal is input. Is output or disappears according to the specified procedure. And a series of control signal output operation is carried out once the control signal output unit that, the control signal output operation,
2nd during the time zone in the middle of the 3rd switch opening
A time period in which the first switch is in the open state and the first switch is in the open state during a time period in the middle of the time period in which the switch is in the closed state and the second switch is in the closed state. The first to third switches and the residual circuit current monitoring unit are operated by the first to fourth control signals so that the residual circuit current monitoring operation starts and ends during the time period in the middle of the band. The digital protection relay device is configured to perform a signal output operation, and 2) in the relay device according to the above item 1), the inspection start signal is a signal periodically input to the control signal output unit. A digital protection relay device, and 3) the relay device according to any one of 1) or 2) above, wherein the first and second primary detection signals are both first and second auxiliary current transformers. The current transformed by each of the And configure the digital protective relay device to be a voltage signal obtained by conversion into.

For this reason, with the above configuration, in any of the protection relay devices, the control signal output operation performed by the control signal output section causes the three main circuits to operate when the three-phase main circuit is in a balanced state. Two secondary phase currents that conveniently flow through each of the other two first primary windings of the auxiliary current transformer except the first primary winding in the second primary winding that constitutes the residual circuit of the current transformer Of the second secondary detection signal based on the sum current can be output from the residual circuit current monitoring unit. It can be inspected by an inspection signal, and in this case, the above-mentioned current source 8 and tertiary winding 7c
Is unnecessary, the soundness of the second auxiliary current transformer and the above-mentioned signal processing system 23 connected to the current transformer can be collectively checked without excluding the second primary winding. And, a digitel protection relay device in which the configuration of the inspection device for performing this inspection is simplified can be obtained. Therefore, the present invention has the effect of improving the reliability in terms of the self-inspection function and the number of parts as compared with the conventional device. is there.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of the configuration of an embodiment of the present invention.

FIG. 2 is an operation mode explanatory diagram of a main part in the embodiment shown in FIG.

FIG. 3 is an explanatory diagram of a configuration of a conventional digital protection relay device.

[Explanation of symbols]

 2r main current transformer 2s main current transformer 2t main current transformer 3 three-phase main circuit 4 first auxiliary current transformer 4a first primary winding 4b secondary winding 5 first auxiliary current transformer (specific auxiliary current transformer 5a 1st primary winding 5b secondary winding 6 1st auxiliary current transformer 6a 1st primary winding 6b secondary winding 13r 1st secondary detection signal 13s 1st secondary detection signal 13t 1st secondary Detection signal 13z Second secondary detection signal 14 Signal processor 15 Relay calculator 16 Third switch 17a Trip signal 18 Residual circuit current monitor 20a Inspection signal 21a Third control signal 21b Fourth control signal 22 Inspection start signal 25th 2 Auxiliary current transformer 25a Second primary winding 25b Secondary winding 26 First switch 27 Second switch 28 Relay input section 29 Control signal output section 29a First control signal 29b Second control signal 30 Digital protection relay device B residual Circuit current monitoring operation Ir secondary phase current Is secondary phase current It secondary phase current Iz residual circuit current Vr first primary detection signal Vs first primary detection signal Vt first primary detection signal Vz second primary detection signal

Claims (4)

[Claims] 1. Three main current transformers attached to a three-phase main circuit, one ends of which are commonly connected to each other and connected in a star shape, and primary windings respectively provided corresponding to the main current transformers. Of three first auxiliary current transformers each having one end connected to the other end of the main current transformer, and one end connected to the other end of each primary winding of the first auxiliary current transformer and the other end A second auxiliary current transformer connected to a common connection point of the main current transformer, and protection based on output signals of respective secondary windings of the first auxiliary current transformer and the second auxiliary current transformer In a digital protection relay device that performs a relay operation, one of the three first auxiliary current transformers is used for inspection.
The pieces are separated to perform an inspection operation based on the output signal of the secondary winding of the second auxiliary current transformer, and a protection relay operation based on the output signal of the secondary winding of the second auxiliary current transformer. Digital protection relay device characterized by stopping. 2. Three main current transformers mounted in a three-phase main circuit and connected in a star shape, and three first auxiliary current transformers corresponding to each of the main current transformers. A second auxiliary current transformer, a first switch that performs a circuit opening / closing operation according to an input first control signal, and a second switch that performs a circuit opening / closing operation according to an input second control signal. One end of a first primary winding as a primary winding of the first auxiliary current transformer is provided for each of the first auxiliary current transformers, and the main current transformer corresponding to the first auxiliary current transformer has one end thereof. One end of a second primary winding as a primary winding of the second auxiliary current transformer is connected to a neutral point of the main current transformer, and the other end of the second primary winding is arbitrary And a second auxiliary current transformer as one of the first auxiliary current transformers connected to the other end of the first primary winding via the first switch and Directly connected to each of the other ends of the first primary windings of each of the two first auxiliary current transformers excluding the specific auxiliary current transformer, and of the first primary winding of the specific auxiliary current transformer. The other end of each of the secondary windings of the first auxiliary current transformer is connected to the neutral point via the second switch, so that the first primary winding corresponding to the secondary winding. An analog signal corresponding to a residual circuit current flowing from the secondary winding of the second auxiliary current transformer through the second primary winding while outputting a first primary detection signal as an analog signal corresponding to a secondary phase current flowing through Second as a signal
A relay input section for outputting a primary detection signal; and each of the three first primary detection signals and the second
Target frequency component extraction for each primary detection signal, A
Each signal processing such as D conversion and signal waveform shaping is sequentially performed, and three convenient first secondary detection signals corresponding to each of the secondary phase currents and second secondary detection signals corresponding to the residual circuit currents are generated. A signal processing unit for outputting and a third switch for performing a circuit opening / closing operation according to a third control signal that is input are provided, all the first secondary detection signals are directly input, and the second secondary detection signal is input. A next detection signal is input through the third switch, and a relay operation unit that performs a protection relay operation using both the secondary detection signals and outputs at least one trip signal according to the operation result; An effective value for calculating the effective value of the second secondary detection signal when the second control signal is input while the second secondary detection signal is being input and the second secondary detection signal is being input. Calculate calculation operation and the result of this calculation to a predetermined reference value A residual circuit current monitoring unit that performs a residual circuit current monitoring operation including a comparison calculation operation that outputs a check signal corresponding to the comparison result, and the first to fourth control signals when an inspection start signal is input. And a control signal output section that performs a series of control signal output operations for outputting or disappearing in a predetermined procedure once, wherein the control signal output operation is a time in the middle of the time period in which the third switch is open. The second switch is in the closed state during the band, and the first switch is in the open state during a time period in the middle of the time period in which the second switch is in the closed state, and the first switch The first to third switches and the residual circuit current monitoring unit are configured so that the residual circuit current monitoring operation starts and ends during a time period in the middle of the time period in which the switch is in the open state. Operate by the first to fourth control signals Digital protection relay device which is a signal output operation. 3. The digital protective relay device according to claim 2, wherein the inspection start signal is a signal periodically input to the control signal output section. 4. The relay device according to claim 2 or 3, wherein both the first and second primary detection signals are first.
And a digital protection relay device, which is a voltage signal obtained by converting a current transformed by each of the second auxiliary current transformer into a voltage.