Anomaly detection device and digital protection relay device

Abstract

Power supply anomaly detection and power supply anomaly detection signal line breakage detection are achieved with a compact device configuration. [Solution] The abnormality detection device 10 detects power supply abnormalities in a digital protection relay device 11 that has one or more power supply systems 18. The abnormality detection device 10 includes one or more abnormality detection circuits 20 that detect abnormalities in the power supply systems 18, an A / D conversion unit 29 that converts the analog form abnormality detection signal output from the abnormality detection circuit 20 into a digital form and outputs it, an abnormality detection signal line 17 that electrically connects the abnormality detection circuit 20 and the A / D conversion unit 29 and transmits the analog form abnormality detection signal, and a CPU 31 that makes a determination including an abnormality in the power supply system 18 based on the digital form abnormality detection signal output from the A / D conversion unit 29.

Description

Technical Field

[0001] The present invention relates to an abnormality detection device and a digital protection relay device.

Background Art

[0002] When an abnormal situation such as a short circuit or a ground fault occurs in the power system, the digital protection relay device plays a role of minimizing the impact of the accident by instantaneously disconnecting the location where the abnormality occurred from the power system.

[0003] The applicant of the present application discloses an invention of a digital protection relay device including an input conversion unit that inputs an electrical quantity from a power system, an analog / digital conversion unit that converts an analog quantity output from the input conversion unit into a digital quantity, and an arithmetic processing unit that executes a predetermined protection relay operation using the converted digital quantity. The arithmetic processing unit detects the occurrence of an accident in the power system by executing arithmetic processing that defines the protection relay operation, and protects the power system by operating a circuit breaker (see Patent Document 1).

[0004] High reliability is required for digital protection relay devices. Therefore, the digital protection relay device according to Patent Document 1 has a self-monitoring function that detects abnormalities in the device while continuing the arithmetic processing related to the protection relay operation.

[0005] In the digital protection relay device according to Patent Document 1, analog input related to the power system is input to the protection relay device via an input conversion circuit provided on an input conversion board in order to ensure insulation from the power system and perform appropriate voltage conversion. The input conversion circuit of the protection relay device is a transformer type and does not require a separate power supply.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

[0007] Incidentally, in digital substations, analog inputs related to the power system are received via an input conversion device. The input conversion board in the input conversion device ensures isolation from the power system using isolation amplifier ICs and isolation delta-sigma modulation ICs, while conversion to the appropriate voltage level is achieved by an amplification circuit using operational amplifier ICs.

[0008] In such cases, for example, it is conceivable that the isolated amplifier IC, isolated delta-sigma modulation IC, and operational amplifier IC mounted on the input conversion board may each require a power supply system with a different voltage value. In this case, when detecting abnormalities in the power supply system and detecting disconnections in signal cables, if we add, for example, a first power supply abnormality detection signal line based on the output of a first abnormality detection circuit belonging to the first power supply system, a second power supply abnormality detection signal line based on the output of a second abnormality detection circuit belonging to the second power supply system, and a signal line for detecting disconnections in analog signal cables, then the input conversion board will require wiring space to connect at least three signal lines in total. Moreover, space will also be required to mount connectors for these three signal lines.

[0009] In short, conventional digital protection relay devices require wiring space for power supply anomaly detection signals and analog signal cable disconnection detection signals, as well as mounting space for the same number of connectors, when detecting power supply anomalies or signal cable disconnection anomalies. As a result, the device configuration becomes larger and costs increase, indicating room for improvement.

[0010] The present invention has been made in view of the above circumstances, and aims to provide an abnormality detection device and a digital protective relay device that can detect power supply abnormalities and disconnection abnormalities in power supply abnormality detection signal lines of a digital protective relay device equipped with one or more power supply systems, with a compact device configuration.

[0011] Furthermore, the present invention aims to provide an abnormality detection device that can detect power supply abnormalities and disconnection abnormalities in power supply abnormality detection signal lines of a predetermined device having one or more power supply systems, with a compact device configuration. [Means for solving the problem]

[0012] To solve the aforementioned problems, the abnormality detection device according to the present invention is An anomaly detection device for detecting power supply anomalies in a digital protection relay device equipped with one or more power supply systems, One or more abnormality detection circuits are provided for each power supply system to detect abnormalities in the power supply system, An A / D conversion unit that converts the analog abnormality detection signal output from the abnormality detection circuit into a digital format and outputs it, An abnormality detection signal line electrically connects the abnormality detection circuit and the A / D conversion unit and transmits the analog form abnormality detection signal, The system includes a determination unit that performs a determination including an abnormality in the power supply system based on an abnormality detection signal in digital form output from the A / D conversion unit, One end of the abnormality detection signal line is connected to ground via a first resistor, while the other end of the abnormality detection signal line is connected to a predetermined voltage source via a second resistor. Its most prominent feature is this. [Effects of the Invention]

[0013] According to the present invention, power supply abnormality detection and disconnection abnormality detection of power supply abnormality detection signal lines can be achieved with a compact device configuration in a digital protection relay device equipped with one or more power supply systems. Issues, configurations, and effects other than those mentioned above will be described in detail in the following appropriate method. [Brief explanation of the drawing]

[0014] [Figure 1] This is a block diagram of a digital protection relay device equipped with an abnormality detection device according to an embodiment of the present invention. [Figure 2]This is a diagram for explaining the abnormality detection operation by the abnormality detection device according to an embodiment of the present invention. [Figure 3] In the block configuration diagram of the digital protection relay device shown in FIG. 1, it is an explanatory diagram showing an example where a disconnection abnormality has occurred in the analog signal cable. [Figure 4] This is an operation flowchart diagram showing the flow of power supply abnormality detection processing of a digital protection relay device including an abnormality detection device according to an embodiment of the present invention. [Figure 5] This is an operation flowchart diagram showing the flow of abnormality detection processing for disconnection of an analog signal cable of a digital protection relay device including an abnormality detection device according to an embodiment of the present invention. [Figure 6] This is an operation flowchart diagram showing the flow of power supply abnormality detection processing and abnormality detection processing for disconnection of an analog signal cable of a digital protection relay device including an abnormality detection device according to an embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0015] The abnormality detection device and the digital protection relay device according to an embodiment of the present invention will be described in detail while appropriately referring to the drawings. In the description of the abnormality detection device and the digital protection relay device according to an embodiment of the present invention, components having common functions are denoted by common reference numerals, and redundant descriptions thereof are omitted.

[0016] 〔Schematic Configuration of Digital Protection Relay Device 11〕 First, the schematic configuration of the digital protection relay device 11 provided with the abnormality detection device 10 according to an embodiment of the present invention will be described with reference to FIG. 1. FIG. 1 is a schematic configuration diagram of the digital protection relay device 11 according to an embodiment of the present invention.

[0017] As shown in FIG. 1, a digital protection relay device 11 equipped with an abnormality detection device 10 according to an embodiment of the present invention includes an input conversion board 13, a CPU board 15, and an analog signal cable 17 that is electrically connected so as to bridge between the input conversion board 13 and the CPU board 15.

[0018] The input conversion board 13 is provided with a first connector 16a, an input conversion circuit (VT / CT) 19, a first power supply system 21, a second power supply system 22, a first abnormality detection circuit 23, a second abnormality detection circuit 24, a first connection point 26a, and a pull-down resistor (Rd) 25a, respectively.

[0019] The CPU board 15 is provided with a second connector 16b, a second connection point 26b, a pull-up resistor (Ru) 25b, an analog filter (AF) 27, an A / D conversion unit (A / D) 29, a CPU 31, a work memory (RAM) 33, a non-volatile memory (Flash) 35, and an input / output interface (I / O) 37, respectively.

[0020] The input conversion circuit (VT / CT) 19 belonging to the input conversion board 13 has a function of converting a plurality of voltage and current signals (refer to "analog input" in FIG. 1) sent from a power system (not shown) into analog voltage signals suitable for processing in an analog electronic circuit (e.g., within the range of ±10V).

[0021] The input conversion circuit (VT / CT) 19 is configured to incorporate, for example, ICs such as an isolation amplifier IC, an isolation delta-sigma modulation IC, and an operational amplifier IC (all not shown). The input conversion circuit (VT / CT) 19 realizes insulation for the power sent from the power system using an isolation amplifier IC and an isolation delta-sigma modulation IC (hereinafter collectively referred to as "isolation ICs"), and realizes conversion of the power sent from the power system to an appropriate voltage level using an amplification IC such as an operational amplifier.

[0022] The analog voltage signal output from the input conversion circuit (VT / CT) 19 is sent to the analog filter (AF) 27 belonging to the CPU board 15 via the first connector 16a, the analog signal cable 17, and the second connector 16b, respectively. In the following explanation, the first connector 16a and the second connector 16b may be collectively referred to simply as "connector 16".

[0023] The first power supply system 21 and the second power supply system 22 supply power at predetermined voltage levels to the isolation IC and amplification IC, respectively, which are built into the input conversion circuit (VT / CT) 19. For example, a 5V power supply is supplied from the first power supply system 21, and a 10V power supply is supplied from the second power supply system 22. In the following explanation, the first power supply system 21 and the second power supply system 22 may be collectively referred to simply as "power supply system 18".

[0024] The first anomaly detection circuit 23 is electrically connected to the first power supply system 21 and detects anomalies based on the output voltage of the first power supply system 21. The second anomaly detection circuit 24 is electrically connected to the second power supply system 22 and detects anomalies based on the output voltage of the second power supply system 22. In the following explanation, the first anomaly detection circuit 23 and the second anomaly detection circuit 24 may be collectively referred to simply as the "anomaly detection circuit 20".

[0025] The abnormality detection circuit 20 is configured to output a voltage of approximately 0V when at least one of the first abnormality detection circuit 23 or the second abnormality detection circuit 24 detects an abnormality. The abnormality detection signal related to the abnormality detection circuit 20 is sent to the A / D converter (A / D) 29 via the first connection point 26a, the first connector 16a, the abnormality detection signal line 14a of the analog signal cable 17, the second connector 16b, the second connection point 26b, and the analog filter (AF) 27, respectively.

[0026] The first connector 16a is provided on the input conversion board 13, while the second connector 16b is provided on the CPU board 15. An analog signal cable 17 is provided between the first connector 16a and the second connector 16b, bridging the gap between them. The analog signal line 14b of the analog signal cable 17 transmits the output voltage signals of the multiple input conversion circuits (VT / CT) 19 on the input conversion board 13 and the output voltage signal of the abnormality detection circuit 20 to the analog filter (AF) 27 on the CPU board 15.

[0027] One end of the abnormality detection signal line 14a (the side facing the input conversion board 13) is connected to ground GND via the first connector 16a, the first connection point 26a, and the pull-down resistor (Rd) 25a. On the other hand, the other end of the abnormality detection signal line 14a (the side facing the CPU board 15) is connected to a predetermined voltage source Vcc via the second connector 16b, the second connection point 26b, and the pull-up resistor (Ru) 25b. The predetermined voltage source Vcc is a voltage source that exhibits an appropriate voltage value Vcc. The pull-down resistor (Rd) 25a corresponds to the "first resistor" of the present invention. The pull-up resistor (Ru) 25b corresponds to the "second resistor" of the present invention.

[0028] The analog filter (AF) 27, which belongs to the CPU board 15, performs a predetermined filtering process on the analog voltage signal output from the anomaly detection circuit 20. The analog filter (AF) 27 plays a role in removing aliasing errors that occur during the A / D conversion process in the A / D conversion unit (A / D) 29. The analog voltage signal after filtering by the analog filter (AF) 27 is sent to the A / D conversion unit (A / D) 29.

[0029] The A / D conversion unit (A / D) 29 performs a predetermined A / D conversion process on the analog voltage signal after it has been filtered by the analog filter (AF) 27. The digital voltage signal after the A / D conversion process by the A / D conversion unit (A / D) 29 is sent to the CPU 31.

[0030] The CPU 31 has the function of determining abnormalities in the power supply system 18 and broken connections in the analog signal cable 17, etc., based on the digital voltage signal (abnormality detection signal) after A / D conversion processing, which is the output of the abnormality detection circuit 20, and performing processing according to the determination result. CPU 31 corresponds to the "determination unit" of this invention. The abnormality detection process of CPU 31 will be described in detail later.

[0031] The work memory (RAM) 33 is used when loading programs that perform calculation processing and abnormality detection processing related to the operation of protective relays, and when temporarily storing the digital voltage signal (abnormality detection signal) after A / D conversion processing by the A / D conversion unit 29.

[0032] The non-volatile memory (Flash) 35 stores programs for performing calculations related to the operation of the protective relay, abnormality detection processing, and the like.

[0033] The input / output interface (I / O) 37 is used when transmitting a digital output signal that operates a circuit breaker (not shown) based on a calculation algorithm related to the operation of a protective relay, and when receiving and transmitting a digital input signal that provides feedback that the circuit breaker has operated.

[0034] An abnormality detection device 10 according to an embodiment of the present invention is configured by the cooperation of various components, including a first connector 16a, a first abnormality detection circuit 23 and a second abnormality detection circuit 24, a first connection point 26a, a pull-down resistor (Rd) 25a, a second connector 16b, a second connection point 26b, a pull-up resistor (Ru) 25b, an analog filter (AF) 27, an A / D converter (A / D) 29, a CPU 31, a work memory (RAM) 33, a non-volatile memory (Flash) 35, an input / output interface (I / O) 37, and an analog signal cable 17 that electrically relays the connection between the input conversion board 13 and the CPU board 15.

[0035] [Anomaly detection principle by anomaly detection device 10] Next, the principle of anomaly detection by the anomaly detection device 10 will be explained with reference to Figures 2 and 3. Figure 2 is a diagram illustrating the abnormality detection operation by the abnormality detection device 10 according to an embodiment of the present invention. Figure 3 is an explanatory diagram showing an example in which a disconnection abnormality occurs in the analog signal cable 17 in the block configuration diagram of the digital protection relay device 11 shown in Figure 1. Figure 2 schematically shows, in relation to the abnormality detection signal voltage Vfd, the thresholds that define the normal voltage range Vrange, consisting of a lower threshold and an upper threshold, on the left side of the page, and the design values ​​corresponding to each abnormality detection state on the right side. Note that the abnormal detection signal voltage Vfd is synonymous with the voltage level related to the abnormal detection signal (digital voltage signal) related to the abnormal detection circuit 20.

[0036] As shown in Figure 2, the CPU 31 determines an abnormality in the power supply system 18 and an open circuit abnormality in the analog signal cable 17 based on the voltage level of the digital voltage signal after A / D conversion processing (abnormality detection signal voltage Vfd), which is the output of the abnormality detection circuit 20. In other words, the CPU 31 determines that both the power supply system 18 and the analog signal cable 17 are normal if the value of the abnormality detection signal voltage Vfd exceeds the lower threshold Vth1 that defines the normal voltage range Vrange, and converges to less than the upper threshold Vth2. Furthermore, the CPU 31 determines that the power supply system 18 is abnormal if the value of the abnormality detection signal voltage Vfd is less than or equal to the lower threshold Vth1 that defines the normal voltage range Vrange. Furthermore, the CPU 31 determines that the analog signal cable 17 is broken if the value of the abnormality detection signal voltage Vfd is greater than or equal to the upper threshold Vth2 which defines the normal voltage range Vrange.

[0037] Here, the lower threshold Vth1 and upper threshold Vth2 that define the normal voltage range Vrange are set considering the following circumstances. In other words, in the normal case where neither the power supply system 18 nor the analog signal cable 17 is in an abnormal state, the design value of the abnormality detection signal voltage Vfd (voltage value at the second connection point) is the divided voltage Vdi obtained by dividing a predetermined voltage source (voltage value related to it) Vcc by the first resistor Rd and the second resistor Ru (see Figure 2). Furthermore, in the case where the power supply system 18 is in an abnormal state, the abnormality detection circuit 20 outputs a voltage of approximately 0V, so the design value of the abnormality detection signal voltage Vfd (voltage value at the second connection point) will be less than or equal to the power supply system abnormality detection output voltage VOL_MAX (a voltage approximately equal to 0V) (see Figure 2). Furthermore, in the case where the analog signal cable 17 is in a disconnection abnormal state (including poor contact of the first connector 16a and the second connector 16b) (see Figure 3), the circuit on the CPU board 15 is electrically disconnected from the circuit on the input conversion board 13, so the design value of the abnormality detection signal voltage Vfd (voltage value at the second connection point) becomes a predetermined voltage source (voltage value related to it) Vcc (see Figure 2).

[0038] Therefore, the lower threshold Vth1 that defines the normal voltage range Vrange is set to an appropriate value that is smaller than the divided voltage Vdi and larger than the output voltage VOL_MAX when a power system abnormality is detected, and that has a predetermined margin (that avoids confusion between normal and abnormal conditions) for each of these values. Similarly, the upper threshold Vth2 that defines the normal voltage range Vrange is set to an appropriate value that is greater than the divided voltage Vdi and less than a predetermined voltage source (voltage value related to it) Vcc, and that has a predetermined margin (that avoids confusion between normal and abnormal conditions) for each of these values.

[0039] The lower threshold Vth1 and upper threshold Vth2, which define the normal voltage range Vrange, are stored in the work memory (RAM) 33.

[0040] The CPU 31 performs abnormality detection processing related to abnormality detection of the power supply system 18 and disconnection abnormality detection of the analog signal cable 17 by comparing and determining the relationship between the abnormality detection signal voltage Vfd, which is the voltage level of the digital voltage signal after A / D conversion processing and is the output of the abnormality detection circuit 20, and the lower threshold Vth1 and upper threshold Vth2 stored in the work memory (RAM) 33.

[0041] [Operation of the digital protection relay device 11 equipped with an anomaly detection device 10] Next, the operation of the digital protection relay device 11 equipped with the abnormality detection device 10 will be explained with reference to Figures 4 to 6 as appropriate.

[0042] Figure 4 is a flowchart illustrating the operation of the abnormality detection process related to the power supply system 18 of a digital protection relay device 11 equipped with an abnormality detection device 10 according to an embodiment of the present invention.

[0043] In steps S41 and S42 shown in Figure 4, the CPU 31 of the anomaly detection device 10 acquires the voltage level of the digital voltage signal (anomaly detection signal voltage Vfd) after A / D conversion processing, which is the output of the anomaly detection circuit 20, and the lower limit threshold Vth1 stored in the work memory (RAM) 33, and compares and determines the magnitude relationship between the voltage level of the anomaly detection signal voltage Vfd and the lower limit threshold Vth1.

[0044] If, as a result of the determination in step S42, the voltage level of the abnormality detection signal voltage Vfd exceeds the lower threshold Vth1 (Yes in step S42), the abnormality detection device 10 terminates the abnormality detection process related to the power supply system 18.

[0045] On the other hand, if the result of the determination in step S42 is that the voltage level of the abnormality detection signal voltage Vfd is less than or equal to the lower threshold Vth1 (No. in step S42), the abnormality detection device 10 proceeds to the next step S43.

[0046] In step S43, the CPU 31 of the abnormality detection device 10 determines that the power supply system 18 is abnormal. Subsequently, the abnormality detection device 10 terminates the abnormality detection process related to the power supply system 18.

[0047] Figure 5 is an operation flowchart illustrating the flow of the disconnection abnormality detection process for the analog signal cable 17 of a digital protection relay device 11 equipped with an abnormality detection device 10 according to an embodiment of the present invention.

[0048] In steps S51 and S52 shown in Figure 5, the CPU 31 of the abnormality detection device 10 acquires the voltage level of the digital voltage signal (abnormality detection signal voltage Vfd) after A / D conversion processing, which is the output of the abnormality detection circuit 20, and the upper limit threshold Vth2 stored in the work memory (RAM) 33, and compares and determines the magnitude relationship between the voltage level of the abnormality detection signal voltage Vfd and the upper limit threshold Vth2.

[0049] If, as a result of the determination in step S52, the voltage level of the abnormality detection signal voltage Vfd is less than the upper threshold Vth2 (Yes in step S52), the abnormality detection device 10 terminates the disconnection abnormality detection process for the analog signal cable 17.

[0050] On the other hand, if the result of the determination in step S52 is that the voltage level of the abnormality detection signal voltage Vfd is equal to or greater than the upper threshold Vth2 (No. in step S52), the abnormality detection device 10 proceeds to the next step S53.

[0051] In step S53, the CPU 31 of the abnormality detection device 10 determines that the analog signal cable 17 is broken. Subsequently, the abnormality detection device 10 terminates the breakage abnormality detection process for the analog signal cable 17.

[0052] Figure 6 is an operation flowchart showing the flow of abnormality detection processing related to the power supply system 18 and analog signal cable 17 of a digital protection relay device 11 equipped with an abnormality detection device 10 according to an embodiment of the present invention. The operation flowchart shown in Figure 6 is a combination of the operation flow shown in Figure 4 and the operation flow shown in Figure 5.

[0053] In step S61 shown in Figure 6, the CPU 31 of the anomaly detection device 10 acquires the voltage level of the digital voltage signal (anomaly detection signal voltage Vfd) after A / D conversion processing, which is the output of the anomaly detection circuit 20, and the lower threshold Vth1 and upper threshold Vth2 stored in the work memory (RAM) 33.

[0054] In step S62 (the same process as in step S42), the CPU 31 of the anomaly detection device 10 compares and determines the relationship between the voltage level of the anomaly detection signal voltage Vfd acquired in step S61 and the lower threshold Vth1.

[0055] If, as a result of the determination in step S62, the voltage level of the abnormality detection signal voltage Vfd exceeds the lower threshold Vth1 (Yes in step S62), the abnormality detection device 10 jumps the processing flow to step S64.

[0056] On the other hand, if the result of the determination in step S62 is that the voltage level of the abnormality detection signal voltage Vfd is less than or equal to the lower threshold Vth1 (No. in step S62), the abnormality detection device 10 proceeds to the next step S63.

[0057] In step S63 (the same process as step S43), the CPU 31 in the abnormality detection device 10 determines that the power supply system 18 is abnormal. Subsequently, the abnormality detection device 10 terminates the abnormality detection process related to the power supply system 18.

[0058] In step S64 (the same process as step S52), if the determination in step S62 indicates that the voltage level of the abnormal detection signal voltage Vfd exceeds the lower threshold Vth1 (Yes in step S62), the CPU 31 in the abnormal detection device 10 compares and determines the relative magnitudes of the voltage level of the abnormal detection signal voltage Vfd acquired in step S61 and the upper threshold Vth2.

[0059] If, as a result of the determination in step S64, the voltage level of the abnormality detection signal voltage Vfd is less than the upper threshold Vth2 (Yes in step S52), the abnormality detection device 10 terminates the series of abnormality detection processes.

[0060] On the other hand, if the result of the determination in step S64 is that the voltage level of the abnormality detection signal voltage Vfd is equal to or greater than the upper threshold Vth2 (No. in step S64), the abnormality detection device 10 proceeds to the next step S65.

[0061] In step S65 (the same process as in step S53), the CPU 31 in the abnormality detection device 10 determines that the analog signal cable 17 is disconnected. Subsequently, the abnormality detection device 10 terminates the disconnection detection process for the analog signal cable 17.

[0062] Conventional digital protection relay devices require a separate signal line for detecting power supply system abnormalities, in addition to the signal line for detecting analog signal cable disconnections. Therefore, in cases requiring two types of power supply systems, for example, a total of three dedicated signal lines are needed: the signal line for detecting analog signal cable disconnections plus two separate signal lines for detecting power supply system abnormalities for each of the two power supply systems.

[0063] In contrast, the abnormality detection device 10 provided in the digital protection relay device 11 according to an embodiment of the present invention provides pull-down resistors (Rd: first resistor) 25a and pull-up resistors (Ru: second resistor) 25b on each individual circuit board (first circuit board and second circuit board), and provides a separate abnormality detection signal cable (abnormality detection signal line) 17 to span between these circuit boards (first circuit board and second circuit board), thereby simultaneously detecting power supply abnormalities and signal cable disconnection abnormalities.

[0064] Furthermore, generally, digital signal lines and analog signal lines are separated by connectors. Therefore, in conventional digital protection relay devices (see Patent Document 1), for example, when transmitting the digital signal output of an abnormality detection circuit to the CPU board, it is necessary to provide a connector for digital signals in addition to the connector for analog signals.

[0065] In other words, conventional power supply anomaly detection technology, for example, uses a high level to indicate normal operation and a low level to indicate an anomaly, and transmits this power supply anomaly detection information as a digital signal. Therefore, a separate digital signal line is required for each anomaly detection item. Furthermore, since digital signals are a source of noise, it is necessary to separate the connectors for digital signals and analog signals.

[0066] In contrast, in the abnormality detection device 10 provided in the digital protection relay device 11 according to the embodiment of the present invention, the abnormality detection signal is an analog signal. Therefore, the abnormality detection signal and the output signal (analog signal) of the input conversion circuit (VT / CT) 19 can be output using a common connector 16. As a result, the abnormality detection device 10 in the digital protection relay device 11 according to the embodiment of the present invention does not require the implementation of a connector dedicated to digital signals, thereby reducing the mounting space for the connector and simultaneously reducing component costs.

[0067] In short, according to the abnormality detection device 10 provided in the digital protection relay device 11 according to an embodiment of the present invention, in a device configuration that requires one or more power supply systems for input conversion circuits, as is used in existing digital substations, power supply abnormality detection and detection of disconnection abnormalities in the power supply abnormality detection signal line can be realized with a compact device configuration using a single abnormality detection signal cable (abnormality detection signal line) 17.

[0068] Furthermore, according to the abnormality detection device 10 provided in the digital protection relay device 11 according to an embodiment of the present invention, by comparing and determining the magnitude relationship between the voltage level of the digital voltage signal (abnormality detection signal voltage Vfd) after A / D conversion processing, which is the output of the abnormality detection circuit 20, and the lower threshold Vth1 and upper threshold Vth2 that define the normal voltage range Vrange, it is possible to determine the normal operation of the digital protection relay device 11, an abnormality in the power supply system 18, and an abnormality in the analog signal cable 17, respectively. Thus, an abnormality detection function that is easy to use and highly reliable can be realized.

[0069] Next, a first modified example of this embodiment will be described. In this embodiment, a pull-down resistor (Rd: first resistor) 25a is provided on the input conversion board (first board) 13, while a pull-up resistor (Ru: second resistor) 25b is provided on the CPU board (second board) 15. Furthermore, one side of the pull-down resistor (Rd: first resistor) 25a is connected to ground GND, while one side of the pull-up resistor (Ru) 25b is connected to a predetermined voltage source Vcc. In addition, in the case where the power supply system 18 is in an abnormal state, the abnormality detection circuit 20 outputs a voltage of approximately 0V.

[0070] In contrast, in the first modified example of this embodiment, unlike this embodiment, a pull-up resistor (Ru: second resistor) 25b is provided on the input conversion board (first board) 13, while a pull-down resistor (Rd: first resistor) 25a is provided on the CPU board (second board) 15. Furthermore, one side of the pull-down resistor (Rd: first resistor) 25a is connected to ground GND, while one side of the pull-up resistor (Ru) 25b is connected to a predetermined voltage source Vcc. In addition, in the case where the power supply system 18 is in an abnormal state, the abnormality detection circuit 20 is configured to output a predetermined voltage Vdd.

[0071] In the first modified example of this embodiment, in the normal case where neither the power supply system 18 nor the analog signal cable 17 is in an abnormal state, the design value of the abnormality detection signal voltage Vfd (voltage value at the second connection point) is the divided voltage Vdi obtained by dividing a predetermined voltage source (voltage value related to it) Vcc by the first resistor Rd and the second resistor Ru. Furthermore, in the case where the power supply system 18 is in an abnormal state, the abnormality detection circuit 20 outputs a predetermined voltage Vdd, so the design value of the abnormality detection signal voltage Vfd (voltage value at the second connection point) is the voltage value obtained by adding the predetermined voltage Vdd to the voltage divider voltage Vdi. Furthermore, in the case where the analog signal cable 17 is in a broken state, the circuit on the CPU board 15 is electrically disconnected from the circuit on the input conversion board 13, so the design value of the abnormality detection signal voltage Vfd (voltage value at the second connection point) becomes approximately equal to 0V.

[0072] According to the first modified example of this embodiment, power supply abnormality detection and disconnection abnormality detection of the power supply abnormality detection signal line of a digital protection relay device 11 having one or more power supply systems can be realized with a compact device configuration, similar to this embodiment. However, the first modified example of this embodiment tends to have a more complex circuit configuration compared to this embodiment.

[0073] In this respect, the abnormality detection device 10 provided in the digital protection relay device 11 according to this embodiment has the advantage of simplifying the circuit configuration compared to the first modified example, because an open-drain output type IC can be used as the power supply abnormality detection circuit.

[0074] Next, a second modified example of this embodiment will be described. In this embodiment, the input conversion board 13 can detect an abnormal state if the power supply system 18 enters an abnormal state, but it cannot detect an abnormal state if only some of the multiple circuits belonging to the input conversion circuit (VT / CT) 19 enter an abnormal state. Implementing abnormality detection for all circuits belonging to the input conversion circuit (VT / CT) 19 would increase the circuit size.

[0075] Therefore, in the second modified example of this embodiment, the functions of voltage circuit zero-phase monitoring, current circuit zero-phase monitoring, and phase current balance monitoring, which are normally performed in the digital protection relay device 11, are used in combination. The functions of voltage circuit zero-phase monitoring, current circuit zero-phase monitoring, and phase current balance monitoring are realized by the CPU 31 on the CPU board 15 executing a predetermined monitoring program.

[0076] If only one of the multiple circuits belonging to the input conversion circuit (VT / CT) 19 enters an abnormal state, only one phase of that circuit will show an abnormal value. By detecting such abnormalities using the functions of voltage circuit zero-sequence monitoring, current circuit zero-sequence monitoring, and phase current balance monitoring, abnormality detection can be achieved.

[0077] Therefore, by combining the functions of voltage circuit zero-phase monitoring, current circuit zero-phase monitoring, and phase current balance monitoring (configured in the second modified example) with the configuration of the abnormality detection device 10 according to this embodiment, it is possible to detect abnormalities not only in the power supply system 18 belonging to the input conversion board 13, but also in all components belonging to the input conversion board 13, while suppressing an increase in circuit size.

[0078] Furthermore, by combining the configuration of the abnormality detection device 10 according to this embodiment with the configuration of the second modified example, an abnormality detection device 10 capable of identifying abnormal parts of components belonging to the input conversion board 13 can be realized. In the second modification, an example was given that demonstrated the execution of all three functions: voltage circuit zero-sequence monitoring, current circuit zero-sequence monitoring, and phase current balance monitoring. As a further modification of the second modification, a configuration that performs one or two combinations of these functions may be adopted.

[0079] [Configuration, operation, and effects of the abnormality detection device 10 and digital protection relay device 11 according to the present invention] The anomaly detection device 10 based on the first perspective is, An abnormality detection device 10 for detecting power supply abnormalities in a digital protection relay device 11 equipped with one or more power supply systems 18, One or more abnormality detection circuits 20 are provided for each power supply system 18 to detect abnormalities in the power supply system 18, The A / D conversion unit 29 converts the analog abnormality detection signal output from the abnormality detection circuit 20 into a digital format and outputs it, An abnormality detection signal cable (abnormality detection signal line) 17 electrically connects the abnormality detection circuit 20 and the A / D conversion unit 29 and transmits the analog form abnormality detection signal, The system includes a CPU (determination unit) 31 that performs a determination including an abnormality in the power supply system 18 based on an abnormality detection signal in digital form output from the A / D conversion unit 29, One end of the abnormality detection signal cable (abnormality detection signal line) 17 is connected to ground via a first resistor 25a, while the other end of the abnormality detection signal line 17 is connected to a predetermined voltage source Vcc via a second resistor 25b.

[0080] According to the anomaly detection device 10 based on the first perspective, power supply anomaly detection and disconnection anomaly detection of the power supply anomaly detection signal line of a digital protection relay device 11 equipped with one or more power supply systems 18 can be achieved with a compact device configuration.

[0081] The anomaly detection device 10 based on the second perspective is the anomaly detection device 10 based on the first perspective, The abnormality detection circuit 20 and the A / D conversion unit 29 are mounted on separate circuit boards 13 and 15, respectively. The first resistor 25a and the second resistor 25b are mounted on the respective individual circuit boards 13 and 15. You may adopt this configuration.

[0082] The anomaly detection device 10 based on the third perspective is the anomaly detection device 10 based on the first perspective, The abnormality detection circuit 20 and the A / D conversion unit 29 are mounted on separate circuit boards 13 and 15, respectively. The first resistor 25a is mounted on the first substrate 13, which is common to the abnormality detection circuit 20, while the second resistor 25b is mounted on the second substrate 15, which is common to the A / D conversion unit 29. The abnormality detection signal cable (abnormality detection signal line) 17 is provided so as to span between the first substrate 13 and the second substrate 15. You may adopt this configuration.

[0083] According to the anomaly detection device 10 based on the second and third aspects, similar to the anomaly detection device 10 based on the first aspect, it is possible to detect power supply anomalies in a digital protection relay device 11 equipped with one or more power supply systems 18, and to detect disconnection anomalies in the power supply anomaly detection signal lines, with a compact device configuration.

[0084] The anomaly detection device 10 based on the fourth perspective is an anomaly detection device 10 based on the third perspective, The abnormality detection circuit 20 detects an abnormality based on the output voltage of the power supply system 18 and outputs a voltage of approximately 0V when the abnormality is detected. You may adopt this configuration.

[0085] According to the anomaly detection device 10 based on the fourth perspective, in addition to the effects and benefits of the anomaly detection device 10 based on the third perspective, the initial objective can be achieved using a more specific configuration.

[0086] The anomaly detection device 10 based on the fifth perspective is an anomaly detection device 10 based on the fourth perspective, The CPU (determination unit) 31 determines, based on the voltage level Vfd related to the digital abnormality detection signal output from the A / D conversion unit 29, that there is an abnormality in the power supply system 18 and an abnormality in the abnormality detection signal cable (abnormality detection signal line) 17. You may adopt this configuration.

[0087] According to the anomaly detection device 10 based on the fifth perspective, the initial objective can be achieved using a more specific configuration, similar to the anomaly detection device 10 based on the fourth perspective.

[0088] The anomaly detection device 10 based on the sixth perspective is an anomaly detection device 10 based on the fifth perspective, When the voltage level Vfd related to the abnormality detection signal under normal conditions is set to converge to a predetermined (normal) voltage range Vrange based on the voltage divider voltages generated by the first and second resistors, The CPU (determination unit) 31 is, If the voltage level Vfd related to the abnormality detection signal is less than or equal to the lower threshold Vth1 related to the voltage range Vrange, it is determined that the power supply system 18 is abnormal. If the voltage level Vfd related to the abnormality detection signal is equal to or greater than the upper threshold Vth2 related to the voltage range Vrange, it is determined that the abnormality detection signal cable (abnormality detection signal line) 17 is broken. You may adopt this configuration.

[0089] According to the anomaly detection device 10 based on the sixth perspective, the initial objective can be achieved using a more concrete configuration compared to the anomaly detection device 10 based on the fifth perspective.

[0090] The digital protection relay device 11 based on the seventh perspective is, A digital protection relay device 11 comprising an input conversion board 13 on which an input conversion circuit 19 for receiving analog input of three-phase power from a power grid is implemented, and a CPU board 15 on which a CPU 31 is implemented, One or more abnormality detection circuits 20 are provided for each power supply system 18 to detect abnormalities in the power supply system 18, The A / D conversion unit 29 converts the analog abnormality detection signal output from the abnormality detection circuit 20 into a digital format and outputs it, An abnormality detection signal cable (abnormality detection signal line) 17 electrically connects the abnormality detection circuit 20 and the A / D conversion unit 29 and transmits the analog form abnormality detection signal, The system includes a CPU (determination unit) 31 that determines whether there is an abnormality in the power supply system 18 and whether there is a disconnection abnormality in the abnormality detection cable (abnormality detection signal line) 17, based on the voltage level Vfd related to the digital abnormality detection signal output from the A / D conversion unit 29. One end of the abnormality detection signal cable (abnormality detection signal line) 17 is connected to ground via a first resistor 25a, while the other end of the abnormality detection signal cable (abnormality detection signal line) 17 is connected to a predetermined voltage source Vcc via a second resistor 25b. The first resistor 25a and the abnormality detection circuit 20 are mounted on the input conversion board 13, while the second resistor 25b and the A / D conversion unit 29 are mounted on the CPU board 15. The abnormality detection signal cable (abnormality detection signal line) 17 is provided to span between the input conversion board 13 and the CPU board 15. You may adopt this configuration.

[0091] According to the digital protection relay device 11 based on the seventh perspective, power supply abnormality detection and disconnection abnormality detection of the power supply abnormality detection signal line of the digital protection relay device 11, which has one or more power supply systems 18, can be realized with a compact device configuration.

[0092] The digital protection relay device 11 based on the eighth perspective is a digital protection relay device 11 based on the seventh perspective, The input conversion circuit includes an isolation IC, and uses the isolation IC to provide electrical isolation from the power system. The one or more power supply systems mentioned above supply power to the ICs mounted on the input conversion board, including the isolation IC. You may adopt this configuration.

[0093] According to the digital protection relay device 11 based on the eighth perspective, in addition to the effects and advantages of the digital protection relay device 11 based on the seventh perspective, the initial objective can be achieved using a more specific configuration.

[0094] The digital protection relay device 11 based on the ninth aspect is a digital protection relay device 11 based on the eighth aspect, The aforementioned abnormality detection signal is output from the input conversion board via a connector common to the output of the input conversion circuit. You may adopt this configuration.

[0095] According to the digital protection relay device 11 based on the ninth perspective, the initial objective can be achieved using a more specific configuration, similar to the digital protection relay device 11 based on the eighth perspective.

[0096] A digital protection relay device 11 based on the tenth perspective is a digital protection relay device 11 based on any of the seventh to ninth perspectives, The aforementioned input conversion circuit includes a plurality of circuits, Each of the aforementioned circuits receives three-phase power from the power system. The CPU performs at least one of the following: zero-sequence monitoring of the voltage circuit, zero-sequence monitoring of the current circuit, and monitoring of the balance of each phase current. You may adopt this configuration.

[0097] According to the digital protection relay device 11 based on the tenth perspective, the initial objective can be achieved using a more concrete configuration compared to the digital protection relay device 11 based on any of the seventh to ninth perspectives.

[0098] The anomaly detection device 10 based on the 11th perspective is, An abnormality detection device 10 that detects a power supply abnormality in a predetermined device 11 having one or more power supply systems 18, One or more abnormality detection circuits 20 are provided for each power supply system 18 to detect abnormalities in the power supply system 18, The A / D conversion unit 29 converts the analog abnormality detection signal output from the abnormality detection circuit 20 into a digital format and outputs it, An abnormality detection signal cable (abnormality detection signal line) 17 electrically connects the abnormality detection circuit 20 and the A / D conversion unit 29 and transmits the analog form abnormality detection signal, The system includes a CPU (determination unit) 31 that performs a determination including an abnormality in the power supply system 18 based on an abnormality detection signal in digital form output from the A / D conversion unit 29, One end of the abnormality detection signal cable (abnormality detection signal line) 17 is connected to ground via a first resistor 25a, while the other end of the abnormality detection signal cable (abnormality detection signal line) 17 is connected to a predetermined voltage source Vcc via a second resistor 25b.

[0099] According to the anomaly detection device 10 based on the 11th perspective, power supply anomaly detection and disconnection anomaly detection of power supply anomaly detection signal lines in a predetermined device 11 equipped with one or more power supply systems 18 can be achieved with a compact device configuration.

[0100] [Other Embodiments] The embodiments and modifications described above are examples of the present invention. Therefore, the technical scope of the present invention should not be interpreted as being limited by these descriptions, as the present invention can be implemented in various forms without departing from its gist or its main features.

[0101] Furthermore, it is possible to replace some of the configurations of the embodiments described here with those of other embodiments, and even to add configurations from other embodiments to the configuration of one embodiment. In addition, it is possible to add, delete, or replace some of the configurations of each embodiment with those of other embodiments. Furthermore, the control lines and information lines shown are those deemed necessary for explanatory purposes, and do not necessarily represent all control lines and information lines in the actual product. In reality, it is safe to assume that almost all components are interconnected.

[0102] For example, in the description of the abnormality detection device 10 and the digital protection relay device 11 according to an embodiment of the present invention, the configuration of the abnormality detection device 10 that detects power supply abnormalities in a digital protection relay device 11 having one or more power supply systems was described as an example, but the present invention is not limited to this example. The present invention may also adopt a configuration in which the abnormality detection device 10 that detects power supply abnormalities is provided in a predetermined device having one or more power supply systems.

[0103] Furthermore, in the description of the abnormality detection device 10 and the digital protection relay device 11 according to the embodiment of the present invention, a configuration that performs abnormality detection processing related to disconnections in the power supply system 18 and the analog signal cable 17 was described as an example, but the present invention is not limited to this example. The present invention may also employ a configuration that performs abnormality detection processing only for the power supply system 18. In this case, while the conventional technology requires multiple digital signal lines for abnormality detection, the present invention can perform abnormality detection processing for the power supply system 18 using a single analog signal line.

[0104] Furthermore, in the description of the abnormality detection device 10 and the digital protection relay device 11 according to the embodiment of the present invention, two power supplies with different voltages were given as examples for the power supply for the ICs belonging to the input conversion circuit (VT / CT) 19, but the present invention is not limited to this example. One power supply may be used for the ICs belonging to the input conversion circuit (VT / CT) 19, or more than two power supplies may be used.

[0105] Furthermore, in the description of the abnormality detection device 10 and the digital protection relay device 11 according to the embodiment of the present invention, an example was described in which the abnormality detection signal related to the abnormality detection circuit 20, which is sent from the input conversion board 13 to the CPU board 15 via the abnormality detection signal line 14a of the analog signal cable 17, is input to the A / D conversion unit (A / D) 29 via the analog filter (AF) 27. However, the present invention is not limited to this example. The analog filter (AF) 27 may be omitted, and the abnormality detection signal related to the abnormality detection circuit 20 sent to the CPU board 15 may be directly input to the A / D conversion unit (A / D) 29.

[0106] Finally, some or all of the components, functions, and processing units in the abnormality detection device 10 and the digital protection relay device 11 according to the embodiment of the present invention may be implemented in hardware, for example, by designing them as integrated circuits. Alternatively, the above-mentioned components, functions, and processing units may be implemented in software by having a processor interpret and execute a program that implements each function. Information such as programs, tables, and files that implement each function can be stored in a recording device such as memory, a hard disk, or an SSD (Solid State Drive), or in a recording medium such as an IC card, an SD card, or a DVD (Digital Versatile Disk). [Explanation of Symbols]

[0107] 10 Anomaly detection device 11. Digital protection relay device (specified device) 13. Input conversion board (first board) 14a Anomaly detection signal line 14b Analog signal line 15. CPU board (second board) 16 connectors 17 Analog signal cable 18 Power system 19. Input conversion circuit (VT / CT) 20 Anomaly detection circuit 21 1st power supply system (power supply system) 22 2nd power supply system (power supply system) 23. First Anomaly Detection Circuit (Anomaly Detection Circuit) 24. Second Anomaly Detection Circuit (Anomaly Detection Circuit) 25a pull-down resistor (first resistor) 25b Pull-up resistor (second resistor) 27 Analog Filter (AF) 29 A / D conversion unit (A / D) 31 CPU (judgment section) Vcc: A predetermined voltage source (and its voltage value) Vdi divided voltage Vfd Anomaly detection signal voltage (voltage level related to the anomaly detection signal) Vrange: Normal voltage range (specified voltage range) Vth1 Lower threshold Vth2 Upper Threshold

Claims

1. An abnormality detection device for detecting power supply abnormalities in a digital protection relay device equipped with one or more power supply systems, One or more abnormality detection circuits are provided for each power supply system to detect abnormalities in the power supply system, An A / D conversion unit that converts the analog abnormality detection signal output from the abnormality detection circuit into a digital format and outputs it, An abnormality detection signal line electrically connects the abnormality detection circuit and the A / D conversion unit and transmits the analog form abnormality detection signal, The system includes a determination unit that performs a determination including an abnormality in the power supply system based on an abnormality detection signal in digital form output from the A / D conversion unit, One end of the abnormality detection signal line is connected to ground via a first resistor, while the other end of the abnormality detection signal line is connected to a predetermined voltage source via a second resistor. An anomaly detection device characterized by the following features.

2. An anomaly detection device according to claim 1, The anomaly detection circuit and the A / D conversion unit are each mounted on separate circuit boards. The first resistor and the second resistor are mounted on each of the individual circuit boards. An anomaly detection device characterized by the following features.

3. An anomaly detection device according to claim 1, The anomaly detection circuit and the A / D conversion unit are each mounted on separate circuit boards. The first resistor is mounted on a first board common to the abnormality detection circuit, while the second resistor is mounted on a second board common to the A / D conversion unit. The abnormality detection signal line is provided so as to span between the first substrate and the second substrate. An anomaly detection device characterized by the following features.

4. An anomaly detection device according to claim 3, The abnormality detection circuit detects an abnormality based on the output voltage of the power supply system and outputs a voltage of approximately 0V when the abnormality is detected. An anomaly detection device characterized by the following features.

5. An anomaly detection device according to claim 4, The determination unit determines, based on the voltage level of the digital abnormality detection signal output from the A / D conversion unit, whether there is an abnormality in the power supply system and an abnormality in the disconnection of the abnormality detection signal line. An anomaly detection device characterized by the following features.

6. An anomaly detection device according to claim 5, When the voltage level of the abnormality detection signal under normal conditions is set to converge to a predetermined voltage range based on the voltage divider voltages generated by the first and second resistors, The determination unit, If the voltage level related to the abnormality detection signal is below the lower limit threshold for the predetermined voltage range, a determination is made that the power supply system is abnormal. If the voltage level of the abnormality detection signal is equal to or greater than the upper threshold for the voltage range, it is determined that the abnormality detection signal line is broken. An anomaly detection device characterized by the following features.

7. A digital protection relay device comprising an input conversion board equipped with an input conversion circuit that takes in analog input of three-phase power from a power grid, and a CPU board equipped with a CPU, One or more abnormality detection circuits are provided for each power supply system to detect abnormalities in the said power supply system, An A / D conversion unit that converts the analog abnormality detection signal output from the abnormality detection circuit into a digital format and outputs it, An abnormality detection signal line electrically connects the abnormality detection circuit and the A / D conversion unit and transmits the analog form abnormality detection signal, The system includes a determination unit that determines the abnormal state of the power supply system and the broken state of the abnormal signal line based on the voltage level of the digital abnormality detection signal output from the A / D conversion unit, One side of the abnormality detection signal line is connected to ground via a first resistor, while the other side of the abnormality detection signal line is connected to a predetermined voltage source via a second resistor. The first resistor and the abnormality detection circuit are mounted on the input conversion board, while the second resistor and the A / D conversion unit are mounted on the CPU board. The abnormality detection signal line is provided so as to span between the input conversion board and the CPU board. A digital protection relay device characterized by the following features.

8. A digital protection relay device according to claim 7, The input conversion circuit includes an isolation IC, and uses the isolation IC to provide electrical isolation from the power system. The one or more power supply systems mentioned above supply power to the ICs mounted on the input conversion board, including the isolation IC. A digital protection relay device characterized by the following features.

9. A digital protection relay device according to claim 8, The aforementioned abnormality detection signal is output from the input conversion board via a connector common to the output of the input conversion circuit. A digital protection relay device characterized by the following features.

10. A digital protection relay device according to any one of claims 7 to 9, The aforementioned input conversion circuit includes a plurality of circuits, Each of the aforementioned circuits receives three-phase power from the power system. The CPU performs at least one of the following: zero-sequence monitoring of the voltage circuit, zero-sequence monitoring of the current circuit, and monitoring of the balance of each phase current. A digital protection relay device characterized by the following features.

11. An abnormality detection device for detecting power supply abnormalities in a predetermined device having one or more power supply systems, One or more abnormality detection circuits are provided for each power supply system to detect abnormalities in the power supply system, An A / D conversion unit that converts the analog abnormality detection signal output from the abnormality detection circuit into a digital format and outputs it, An abnormality detection signal line electrically connects the abnormality detection circuit and the A / D conversion unit and transmits the analog form abnormality detection signal, The system includes a determination unit that performs a determination including an abnormality in the power supply system based on an abnormality detection signal in digital form output from the A / D conversion unit, One end of the abnormality detection signal line is connected to ground via a first resistor, while the other end of the abnormality detection signal line is connected to a predetermined voltage source via a second resistor. An anomaly detection device characterized by the following features.

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