Control system and management method

Abstract

To determine disconnection of a primary coil with high accuracy while maintaining high reliability.SOLUTION: The control system 23 includes an instrument transformer 30 including a primary coil 31 including a first input-end X1 and a second input-end X2 to which electric power is supplied from the electric power system 10, and a secondary coil 32 including a first output-end Y1 and a second output-end Y2, a first detection antenna 41 that detects an electric field generated at the first input-end X1 in a non-contact manner, and a second detection antenna 42 that detects an electric field generated at the second input-end X2 in a non-contact manner. The voltage detection circuit 50 specifies the first voltage X1 between the first input-end X2 and the second input-end V1 from the detection results by the first detection antenna 41 and the second detection antenna 42, and generates the detection signal D corresponding to the first voltage V1, and the control unit 60 determines the presence or absence of disconnection in the primary coil 31 according to the second voltage Y1 between the first output-end Y2 and the second output-end V2 and the detection signal D.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a technique for detecting a disconnection in a potential transformer used to control the supply / cutoff of power from a power system to power equipment. [Background technology]

[0002] Techniques for controlling the supply / cutoff of power from a power system to power equipment such as a transformer have been proposed. For example, Patent Document 1 discloses a digital relay with a redundant configuration that controls a circuit breaker in response to a logical product from two MPUs. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-207637 Summary of the Invention [Problem to be solved by the invention]

[0004] The voltage supplied from the power grid is converted to a lower voltage by a potential transformer, and the circuit breaker is controlled by analyzing the converted voltage.Even when power is being supplied normally from the power grid, a break in the primary coil of the potential transformer may be detected as an abnormality, resulting in the circuit breaker being unnecessarily controlled to the cut-off state.

[0005] By analyzing the current flowing through the primary coil of a potential transformer, it is possible to detect a primary coil breakage independently of the power supply status of the power grid. However, a resistive element for current detection must be installed in parallel with the primary coil. The influence of the resistive element causes the voltage of the primary coil to fluctuate, which can reduce the accuracy of detecting power grid abnormalities. Furthermore, if the resistive element is damaged or fails, the high-voltage parts of the potential transformer may short-circuit each other, resulting in reduced reliability.

[0006] In consideration of the above circumstances, one aspect of the present disclosure aims to determine whether a primary coil is open with high accuracy while maintaining high reliability. [Means for solving the problem]

[0007] In order to solve the above problems, a control system according to one embodiment of the present disclosure includes a potential transformer including a primary coil having a first input terminal and a second input terminal to which power is supplied from a power grid, and a secondary coil having a first output terminal and a second output terminal; a first detection unit that non-contactly detects an electric field generated at the first input terminal; a second detection unit that non-contactly detects an electric field generated at the second input terminal; a voltage detection unit that identifies a first voltage between the first input terminal and the second input terminal from the detection results by the first detection unit and the second detection unit and generates a detection signal according to the first voltage; and a first state determination unit that determines whether or not there is an open circuit in the primary coil according to the second voltage between the first output terminal and the second output terminal and the detection signal.

[0008] A management method according to one embodiment of the present disclosure is a method for managing a power system including an instrument transformer including a primary coil having a first input terminal and a second input terminal to which power is supplied from a power grid, and a secondary coil having a first output terminal and a second output terminal, and includes contactlessly detecting an electric field generated at the first input terminal, contactlessly detecting an electric field generated at the second input terminal, determining a first voltage between the first input terminal and the second input terminal from the detection results by the first detection unit and the second detection unit, and generating a detection signal according to the first voltage, and determining whether or not there is an open circuit in the primary coil according to the detection signal and a second voltage between the first output terminal and the second output terminal. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a block diagram illustrating a configuration of a power system according to a first embodiment. [Figure 2] FIG. 2 is a block diagram illustrating a configuration of a voltage detection circuit. [Figure 3]FIG. 2 is a block diagram illustrating a functional configuration of a control unit. [Figure 4] FIG. 4 is an explanatory diagram of the operation of a state determination unit. [Figure 5] 10 is a flowchart illustrating a specific procedure of a management process. [Figure 6] FIG. 10 is a block diagram illustrating the configuration of Comparative Example 1. [Figure 7] FIG. 10 is a block diagram illustrating the configuration of a power system according to a second embodiment. [Figure 8] FIG. 10 is a block diagram illustrating the configuration of Comparative Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The following description of an embodiment of the present disclosure will be given with reference to the accompanying drawings. Note that the embodiment described below is an exemplary embodiment that may be envisioned when implementing the present disclosure. Therefore, the scope of the present disclosure is not limited to the embodiment exemplified below.

[0011] A: First embodiment 1 is a block diagram illustrating the configuration of a power system 100 according to a first embodiment. The power system 100 is a system that realizes various functions using power (three-phase AC power) supplied from a power grid 10 via a distribution line 11. The power grid 10 is, for example, a distribution system or a transmission system for supplying power generated by a power generation facility (not shown) such as a thermal power plant or a nuclear power plant to consumers such as business facilities or ordinary homes.

[0012] The power system 100 includes a power facility 21, a circuit breaker 22, and a control system 23. The power facility 21 is a power receiving facility that operates using AC power supplied from the power grid 10 via a distribution line 11. Examples of the power facility 21 include a substation facility that converts AC power, or a power transmission facility that transmits AC power to other facilities.

[0013] The circuit breaker 22 is installed between the power system 10 and the power equipment 21. The circuit breaker 22 is a switch that switches between supplying and cutting off power from the power system 10 to the power equipment 21. That is, the circuit breaker 22 is controlled to either a conductive state in which power is supplied from the power system 10 to the power equipment 21, or a cut-off state in which the supply of power to the power equipment 21 is cut off.

[0014] The control system 23 is a computer system that controls the circuit breaker 22. Specifically, the control system 23 controls the circuit breaker 22 to either a conductive state or a cut-off state depending on the state of the power system 10. Specifically, the control system 23 controls the circuit breaker 22 to the cut-off state when an abnormality occurs in the power system 10, and maintains the circuit breaker 22 in the conductive state when the power system 10 is normal. As can be understood from the above explanation, the control system 23 functions as a protective relay that protects the power equipment 21 from an abnormality in the power system 10.

[0015] 1, the control system 23 includes a voltage transformer 30, a voltage detection sensor 40, a voltage detection circuit 50, a control unit 60, and an operation control circuit 70. The control system 23 may be realized by a single device, or may be realized by multiple devices configured separately from each other. For example, one or more of the voltage transformer 30, the voltage detection sensor 40, the voltage detection circuit 50, and the operation control circuit 70 may be configured as separate devices external to the control system 23.

[0016] The potential transformer 30 is a transformer that converts the high voltage supplied from the power grid 10 into a low voltage that can be processed by the control unit 60. Specifically, the potential transformer 30 is a transformer including a primary coil 31 and a secondary coil 32. The primary coil 31 is a coil including a first input terminal X1 and a second input terminal X2. Power is supplied to the primary coil 31 of the potential transformer 30 from the power grid 10. For example, a U-phase current is supplied to the first input terminal X1 from the power grid 10, and a V-phase current is supplied to the second input terminal X2 from the power grid 10. On the other hand, the secondary coil 32 is a coil including a first output terminal Y1 and a second output terminal Y2. The potential transformer 30 converts the voltage between the first input terminal X1 and the second input terminal X2 into a voltage that can be processed by the control unit 60 and outputs the voltage between the first output terminal Y1 and the second output terminal Y2.

[0017] The voltage detection sensor 40 is a sensor that detects an electric field near the first input terminal X1 and the second input terminal X2. The voltage detection sensor 40 of the first embodiment includes a first detection antenna 41 and a second detection antenna 42. The first detection antenna 41 is installed near the first input terminal X1 with a gap therebetween. The second detection antenna 42 is installed near the second input terminal X2 with a gap therebetween. The first detection antenna 41 and the second detection antenna 42 are installed at a distance from each other. The first detection antenna 41 and the second detection antenna 42 are configured, for example, by conductive patterns formed on a wiring board on which the voltage transformer 30 is mounted.

[0018] The first detection antenna 41 detects the electric field generated at the first input port X1 in a non-contact manner. Specifically, the first detection antenna 41 outputs an observation signal P1 having a signal level corresponding to the electric field generated at the first input port X1. The second detection antenna 42 detects the electric field generated at the second input port X2 in a non-contact manner. The second antenna outputs an observation signal P2 having a signal level corresponding to the electric field generated at the second input port X2. Note that the first detection antenna 41 is an example of a "first detection unit," and the second detection antenna 42 is an example of a "second detection unit."

[0019] The voltage detection circuit 50 is an electric circuit that determines the voltage between the first input terminal X1 and the second input terminal X2 (hereinafter referred to as "first voltage V1") from the detection results obtained by the first detection antenna 41 and the second detection antenna 42, and generates a detection signal D corresponding to the first voltage V1. FIG. 2 is a block diagram illustrating the configuration of the voltage detection circuit 50. As illustrated in FIG. 2, the voltage detection circuit 50 of the first embodiment includes a voltage determination unit 51 and a voltage comparison unit 52.

[0020] The voltage identifier 51 identifies the first voltage V1 from the observation signal P1 generated by the first detection antenna 41 and the observation signal P2 generated by the second detection antenna 42. For example, the voltage identifier 51 identifies the first voltage V1 from the difference between the observation signal P1 and the observation signal P2.

[0021] The voltage comparison unit 52 is a comparator that compares the first voltage V1 identified by the voltage identification unit 51 with a predetermined first threshold T1. Specifically, the voltage comparison unit 52 generates a detection signal D according to the comparison result between the first voltage V1 and the first threshold T1 (i.e., the magnitude relationship between the two). The detection signal D in the first embodiment is a binary signal that represents the comparison result by the voltage comparison unit 52. Specifically, the voltage comparison unit 52 outputs a high-level (H) detection signal D when the first voltage V1 exceeds the first threshold T1, and outputs a low-level (L) detection signal D when the first voltage V1 is below the first threshold T1. Note that the level of the detection signal D may be either high or low when the first voltage V1 and the first threshold T1 are equal.

[0022] The voltage detection circuit 50 may include a filter that reduces noise from the observation signals P1 and P2, and an amplifier that amplifies the detection signal D. The detection signal D generated by the voltage detection circuit 50 is supplied to the control unit 60 in FIG. 1.

[0023] The control unit 60 determines whether or not there is an abnormality in the power system 10 and whether or not there is an open circuit in the primary coil 31 of the potential transformer 30. The control unit 60 of the first embodiment includes an A / D converter 61A, a control device 62A, a storage device 63, and a display device 64.

[0024] The input terminals of the A / D converter 61A are connected to the first output terminal Y1 and the second output terminal Y2 of the secondary coil 32 of the potential transformer 30. The A / D converter 61A generates digital data representing the voltage between the first output terminal Y1 and the second output terminal Y2 (hereinafter referred to as the "second voltage V2"). The second voltage V2 is a voltage that is sufficiently lower than the voltage supplied to the potential transformer 30 from the power system 10. That is, the turns ratio of the primary coil 31 and the secondary coil 32 in the potential transformer 30 is selected so that the second voltage V2 is a low voltage that can be processed by the control unit 60.

[0025] The control device 62A is composed of one or more processors that control each element of the control unit 60. Specifically, the control device 62A is composed of one or more types of processors, such as a CPU (Central Processing Unit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), or an ASIC (Application Specific Integrated Circuit).

[0026] The storage device 63 is one or more memories that store programs executed by the control device 62 A and data used by the control device 62 A. The storage device 63 is configured by a known recording medium such as a semiconductor recording medium.

[0027] The display device 64 displays an image under the control of the control device 62A. Specifically, for example, a liquid crystal display panel is exemplified as the display device 64. The display device 64 of the first embodiment displays, for example, whether or not there is an abnormality in the power system 10 and whether or not there is a break in the primary coil 31.

[0028] Fig. 3 is a block diagram illustrating an example of the functional configuration of the control unit 60. As illustrated in Fig. 3, the control device 62A executes a program stored in the storage device 63 to realize a plurality of functions (a state determination unit 621, a state notification unit 622).

[0029] The state determination unit 621 determines whether or not there is an abnormality in the power system 10 and whether or not there is a break in the primary coil 31, based on the second voltage V2 between the first output terminal Y1 and the second output terminal Y2 and the detection signal D generated by the voltage detection circuit 50. The state determination unit 621 is an example of a "first state determination unit."

[0030] 4 is an explanatory diagram of the operation of the state determination unit 621. When an abnormality occurs in the power grid 10, it is assumed that the first voltage V1 between the first input terminal X1 and the second input terminal X2 will be lower than the appropriate value. That is, when an abnormality occurs in the power grid 10, the first voltage V1 will fall below the first threshold value T1, and as a result, the detection signal D will be set to a low level. Therefore, as illustrated as State 2 in FIG. 4, when the detection signal D is at a low level (i.e., when the first voltage V1 is lower than the first threshold value T1), the state determination unit 621 determines that an abnormality has occurred in the power grid 10.

[0031] On the other hand, when the first voltage V1 exceeds the first threshold value T1, the power supply from the power grid 10 is in a normal state. The first voltage V1 exceeds the first threshold value T1 when the potential transformer 30 is in a normal state (when no open circuit has occurred in the primary coil 31) or when an open circuit has occurred in the primary coil 31 of the potential transformer 30.

[0032] When the potential transformer 30 is in a normal state, the second voltage V2 of the secondary coil 32 is maintained at a predetermined low voltage above the second threshold T2. On the other hand, when an open circuit occurs in the primary coil 31 of the potential transformer 30, the voltage applied to the primary coil 31 drops to 0 V, and as a result, the second voltage V2 of the secondary coil 32 drops to a voltage (e.g., 0 V) ​​below the second threshold T2.

[0033] Taking the above tendency into consideration, the state determination unit 621 determines that an open circuit has occurred in the primary coil 31 of the potential transformer 30 when the first voltage V1 exceeds the first threshold value T1 and the second voltage V2 is below the second threshold value T2 (for example, when the second voltage V2 is 0 V), as exemplified as State 3 in Fig. 4. As described above, in the first embodiment, it is possible to determine whether or not an abnormality has occurred in the power system 10 and whether or not an open circuit has occurred in the primary coil 31, depending on the first voltage V1 and the second voltage V2.

[0034] On the other hand, as illustrated as State 1 in FIG. 4 , when the first voltage V1 exceeds the first threshold value T1 and the second voltage V2 exceeds the second threshold value T2, the state determination unit 621 determines that the power system 10 is normal and that no open circuit has occurred in the primary coil 31 of the voltage transformer 30. That is, the state determination unit 621 determines that the voltage transformer 30 of the power system 10 is also normal. As described above, in the first embodiment, it can be determined that the power supply by the power system 10 is normal and that no open circuit has occurred in the primary coil 31, based on the first voltage V1 and the second voltage V2. Note that the result of the determination by the state determination unit 621 when the first voltage V1 is equal to the first threshold value T1 or when the second voltage V2 is equal to the second threshold value T2 is arbitrary.

[0035] 3 notifies the user of the determination result by the state determination unit 621. Specifically, the state notification unit 622 displays an image (e.g., a character string) indicating the determination result by the state determination unit 621 on the display device 64. For example, the state notification unit 622 notifies the user by displaying an image on the display device 64 that the power system 10 and the potential transformer 30 are normal (state 1), that an abnormality has occurred in the power system 10 (state 2), or that an abnormality has occurred in the potential transformer 30 (state 3).

[0036] The operation control circuit 70 in FIG. 1 controls the circuit breaker 22 between the power system 10 and the power equipment 21. That is, the operation control circuit 70 outputs a tripping signal Q to the circuit breaker 22 to control the circuit breaker 22 to the cut-off state (i.e., trip) in accordance with the determination result by the state determination unit 621. Specifically, when the state determination unit 621 determines that an abnormality has occurred in the power system 10, the operation control circuit 70 transmits the tripping signal Q to the circuit breaker 22 to control the circuit breaker 22 to the cut-off state. Therefore, when an abnormality has occurred in the power system 10, the circuit breaker 22 transitions to the cut-off state, and as a result, the supply of power from the power system 10 to the power equipment 21 is cut off.

[0037] On the other hand, if the power system 10 is in a normal state, there is no need to cut off the supply of power to the power equipment 21 even if an open circuit occurs in the primary coil 31 of the potential transformer 30. Therefore, if the state determination unit 621 determines that an open circuit has occurred in the primary coil 31, or if the state determination unit 621 determines that the power system 10 is normal and that an open circuit has not occurred in the primary coil 31, the operation control circuit 70 does not send a cutoff signal Q to the circuit breaker 22. In other words, the operation control circuit 70 maintains the circuit breaker 22 in a conductive state.

[0038] FIG. 5 is a flowchart illustrating the procedure of an operation (hereinafter referred to as "management processing") executed by the control system 23. For example, the management processing is started in response to an interrupt that occurs at a predetermined interval. The management processing illustrated below is an example of a "management method."

[0039] When the management process is started, the control device 62A acquires data representing the second voltage V2 between the first output terminal Y1 and the second output terminal Y2 from the A / D converter 61A (S1). The control device 62A (state determination unit 621) determines whether the second voltage V2 is lower than the second threshold value T2 (S2). That is, the control device 62A determines whether or not there is an open circuit in the primary coil 31 of the potential transformer 30.

[0040] If the second voltage V2 exceeds the second threshold T2 (S2: NO), this means that both the power system 10 and the voltage transformer 30 are normal (state 1 in FIG. 4). Therefore, the control device 62A (state notification unit 622) notifies the user by displaying on the display device 64 that no abnormality has occurred in the power system 10 or the voltage transformer 30 (S3).

[0041] On the other hand, if the second voltage V2 is lower than the second threshold value T2, this indicates that an abnormality has occurred in the power grid 10 or that a disconnection has occurred in the primary coil 31. If the second voltage V2 is lower than the second threshold value T2 (S2: YES), the control device 62A acquires the detection signal D generated by the voltage detection circuit 50 (S4). Note that, in parallel with the management process by the control device 62A, the voltage detection circuit 50 generates the detection signal D from the observation signal P1 supplied from the first detection antenna 41 and the observation signal P2 supplied from the second detection antenna 42.

[0042] The control device 62A (state determination unit 621) determines whether or not the detection signal D is at a low level (S5). That is, the control device 62A determines whether or not there is an abnormality in the power system 10 depending on whether or not the first voltage V1 between the first input terminal X1 and the second input terminal X2 is lower than the first threshold T1.

[0043] If the second voltage V2 falls below the second threshold T2 (S2: YES) and the detection signal D is at a low level (S5: YES), this means that an abnormality has occurred in the power system 10 (state 2 in FIG. 4). Therefore, the control device 62A (state notification unit 622) notifies the user of the abnormality in the power system 10 by displaying a warning image on the display device 64 (S6). Then, the operation control circuit 70 outputs a trip signal Q to the circuit breaker 22 (S7). Upon receiving the trip signal Q, the circuit breaker 22 transitions to the trip state. That is, the supply of power from the power system 10 to the power equipment 21 is cut off.

[0044] On the other hand, if the second voltage V2 is lower than the second threshold T2 (S2: YES) and the detection signal D is at a high level (S5: NO), this means that an open circuit has occurred in the primary coil 31 of the potential transformer 30 (state 3 in FIG. 4). Therefore, the control device 62A (state notification unit 622) notifies the user of the open circuit in the primary coil 31 by displaying a warning image on the display device 64 (S8). As described above, in the first embodiment, the open circuit in the primary coil 31 is notified to the user, so that the user of the control system 23 can recognize the need to replace or repair the potential transformer 30. The specific steps of the management process are as described above.

[0045] Incidentally, as a configuration for detecting the presence or absence of a disconnection in the primary coil 31 of the voltage transformer 30, a configuration (hereinafter referred to as "Comparative Example 1") for detecting a current flowing in a path between the first input terminal X1 and the second input terminal X2 (hereinafter referred to as "voltage detection path 35") may also be considered, as exemplified in Fig. 6. In the voltage detection path 35, a high-impedance resistive element 36 is disposed in parallel with the primary coil 31.

[0046] However, in Comparative Example 1, the voltage of the primary coil 31 fluctuates due to the influence of the resistive element 36. Therefore, the accuracy of determining whether or not there is an abnormality in the power system 10 according to the first voltage V1 between the first input terminal X1 and the second input terminal X2 may decrease. Furthermore, if the resistive element 36 is damaged or malfunctions, the first input terminal X1 and the second input terminal X2 of the potential transformer 30 may be short-circuited to each other. The short-circuit between the first input terminal X1 and the second input terminal X2 causes a large current to flow between them, which may damage the control system 23.

[0047] In contrast to Comparative Example 1, in the first embodiment, the presence or absence of an open circuit in the primary coil 31 of the voltage transformer 30 is determined based on the result of contactless detection of the electric field at the first input terminal X1 by the first detection antenna 41 (observation signal P1) and the result of contactless detection of the electric field at the second input terminal X2 by the second detection antenna 42 (observation signal P2). Therefore, compared to Comparative Example 1 in which the presence or absence of an open circuit is determined using the voltage detection path 35 between the first input terminal X1 and the second input terminal X2, fluctuations in the voltage of the primary coil 31 in the voltage transformer 30 can be suppressed. As a result of suppressing voltage fluctuations in the primary coil 31, the first embodiment can determine the presence or absence of an abnormality in the power system 10 with higher accuracy than Comparative Example 1. Furthermore, according to the first embodiment, it is not necessary to install the resistive element 36 between the first input terminal X1 and the second input terminal X2, and therefore, the occurrence of a malfunction due to damage to the resistive element 36 can be suppressed. As described above, according to the first embodiment, compared to Comparative Example 1, it is possible to determine the disconnection of the primary coil 31 with high accuracy while maintaining high reliability.

[0048] Furthermore, in the first embodiment, when it is determined that a break has occurred in the primary coil 31 (state 3) or when it is determined that the power system 10 and the primary coil 31 are normal (state 1), the circuit breaker 22 is maintained in the conductive state, and when it is determined that an abnormality has occurred in the power system 10 (state 2), the circuit breaker 22 is controlled to the cut-off state. Therefore, compared to a configuration in which the circuit breaker 22 is controlled to the cut-off state even when a break has occurred in the primary coil 31, it is possible to reduce the possibility that the supply of power from the power system 10 to the power equipment 21 will be unnecessarily cut off.

[0049] B: Second embodiment A second embodiment of the present disclosure will be described. Note that, for elements in the following exemplary aspects that have the same functions as those in the first embodiment, the same reference numerals as those in the first embodiment will be used, and detailed descriptions of each will be omitted as appropriate.

[0050] 7 is a block diagram illustrating the configuration of a power system 100 in the second embodiment. In the second embodiment, the configurations and operations of the control unit 60 and the operation control circuit 70 differ from those in the first embodiment. The configurations and operations of the other elements in the power system 100 (the potential transformer 30, the voltage detection sensor 40, and the voltage detection circuit 50) are the same as those in the first embodiment.

[0051] 7, the control unit 60 of the second embodiment includes an A / D converter 61B and a control device 62B in addition to the same elements as those of the first embodiment (A / D converter 61A, control device 62A, storage device 63, and display device 64). The A / D converter 61A and the A / D converter 61B are installed in parallel. In the second embodiment, the instrument transformer 30, the voltage detection sensor 40, and the voltage detection circuit 50 are shared by the control device 62A and the control device 62B.

[0052] Similar to the A / D converter 61A, the input terminals of the A / D converter 61B are connected to the first output terminal Y1 and the second output terminal Y2 of the secondary coil 32 of the potential transformer 30. The A / D converter 61B generates digital data representing a second voltage V2 between the first output terminal Y1 and the second output terminal Y2.

[0053] The control device 62B is composed of one or more processors that control each element of the control unit 60. Specifically, the control device 62B is composed of one or more types of processors, such as a CPU, DSP, FPGA, or ASIC. The control device 62A and the control device 62B share a storage device 63 and a display device 64. However, the storage device 63 dedicated to the control device 62A and the storage device 63 dedicated to the control device 62B may be installed separately.

[0054] The control device 62B executes a program stored in the storage device 63, thereby functioning as a state determination unit 621 and a state notification unit 622, similar to the control device 62A of the first embodiment. The operations of the state determination unit 621 and the state notification unit 622 realized by the control device 62B are similar to those of the first embodiment. That is, the state determination unit 621 of the control device 62B determines whether or not there is an open circuit in the primary coil 31 of the potential transformer 30, based on the second voltage V2 between the first output terminal Y1 and the second output terminal Y2 and the detection signal D. As described above, in the second embodiment, determination of the states of the power system 10 and the primary coil 31 is duplicated. The state determination unit 621 realized by the control device 62B is an example of a "second state determination unit."

[0055] The operation control circuit 70 of the second embodiment controls the circuit breaker 22 in accordance with the results of determinations made by both the control device 62A and the control device 62B. Specifically, the operation control circuit 70 controls the circuit breaker 22 to the cutoff state when both the state determination unit 621 of the control device 62A and the state determination unit 621 of the control device 62B determine that an abnormality has occurred in the power system 10. In other words, if only one of the state determination unit 621 of the control device 62A and the state determination unit 621 of the control device 62B determines that an abnormality has occurred in the power system 10, a cutoff signal Q is not output to the circuit breaker 22. For example, the operation control circuit 70 outputs the logical AND of the determination result of the state determination unit 621 of the control device 62A and the determination result of the state determination unit 621 of the control device 62B as the cutoff signal Q to the circuit breaker 22.

[0056] The second embodiment also achieves the same effects as the first embodiment. Furthermore, in the second embodiment, when the determination results of both the state determination unit 621 of the control device 62A and the state determination unit 621 of the control device 62B match, the circuit breaker 22 is controlled to the cut-off state. That is, for example, when only one of the control device 62A and the control device 62B erroneously determines an abnormality in the power system 10 for some reason, the circuit breaker 22 is maintained in the conductive state. Therefore, high reliability can be achieved in the control of the circuit breaker 22.

[0057] Incidentally, as a configuration for doubling the determination of the state of the power system 10 and the primary coil 31, for example, a configuration in which the instrument transformer 30, the voltage detector sensor 40, and the voltage detection circuit 50 are individually installed in each of the control devices 62A and 62B (hereinafter referred to as "Comparative Example 2") can be envisioned, as illustrated in Fig. 8. However, Comparative Example 2 has the problems of the configuration of the control system 23 becoming complicated and the size of the control system 23 becoming larger.

[0058] In contrast to Comparative Example 2, in the second embodiment, the instrument transformer 30, the voltage detection sensor 40, and the voltage detection circuit 50 are shared by the control devices 62A and 62B. Therefore, the second embodiment has the advantage that the configuration of the control system 23 is simplified and the scale of the control system 23 can be reduced compared to Comparative Example 2.

[0059] C: Modified Example Specific modified embodiments that can be added to each of the embodiments exemplified above are exemplified below. Two or more embodiments arbitrarily selected from the following examples may be appropriately combined within the scope of not being mutually contradictory.

[0060] (1) In the above-described embodiments, the detection signal D is exemplified as a binary signal representing the result of comparison between the first voltage V1 and the first threshold T1. However, the form of the detection signal D is not limited to the above examples. For example, the voltage detection circuit 50 may generate the detection signal D representing the first voltage V1 between the first input terminal X1 and the second input terminal X2. That is, the voltage comparison unit 52 in the above-described embodiments may be omitted. In an embodiment in which the detection signal D represents the first voltage V1, the control device 62A and the control device 62B compare the first voltage V1 represented by the detection signal D with the first threshold T1. That is, the voltage comparison unit 52 in the above-described embodiments is realized by the control device 62A and the control device 62B.

[0061] In each of the above-described embodiments, a binary signal corresponding to the comparison result between the first voltage V1 and the first threshold T1 is supplied to the control unit 60 as the detection signal D. Therefore, compared to the embodiment in which the detection signal D representing the first voltage V1 is supplied to the control unit 60, the processing load on the control unit 60 (control devices 62A and 62B) can be reduced.

[0062] (2) In the above-described embodiments, the determination result by the status determination unit 621 is notified to the user by displaying an image on the display device 64. However, the configuration and method by which the status notification unit 622 notifies the user of the determination result are not limited to the above examples. For example, the status notification unit 622 may notify the user of the determination result by the status determination unit 621 by playing back a sound. Furthermore, the status notification unit 622 may notify the user of the determination result by the status determination unit 621 by transmitting the determination result by the status determination unit 621 to an information device such as a smartphone used by the user. As illustrated above, the display device 64 in the above-described embodiments is an example of a notification device that notifies the user of the determination result by the information determination unit.

[0063] (3) As described above, the functions of the control system 23 according to each of the above embodiments are realized by cooperation between one or more processors constituting the control device 62A or 62B and a program stored in the storage device 63. The programs exemplified above can be provided in a form stored on a computer-readable recording medium and installed on a computer. The recording medium is, for example, a non-transitory recording medium, such as an optical recording medium (optical disk) such as a CD-ROM, but also includes any known type of recording medium, such as a semiconductor recording medium or a magnetic recording medium. Note that a non-transitory recording medium includes any recording medium other than a transitory, propagating signal, and does not exclude volatile recording media. Furthermore, in a configuration in which a distribution device distributes a program via a communication network, the recording medium storing the program in the distribution device corresponds to the non-transitory recording medium described above.

[0064] (4) The term "nth" (n is a natural number) in this application is used only as a formal and convenient label to distinguish each element in the description and does not have any substantive meaning. Therefore, there is no room for restrictive interpretation of the position or order of each element based on the term "nth."

[0065] D: Notes From the above-described exemplary embodiments, the following configurations can be understood, for example.

[0066] A control system according to one aspect (Aspect 1) of the present disclosure includes a potential transformer including a primary coil having a first input terminal and a second input terminal to which power is supplied from a power grid, and a secondary coil having a first output terminal and a second output terminal, a first detection unit that non-contactly detects an electric field generated at the first input terminal, a second detection unit that non-contactly detects an electric field generated at the second input terminal, a voltage detection unit that identifies a first voltage between the first input terminal and the second input terminal from detection results by the first detection unit and the second detection unit and generates a detection signal corresponding to the first voltage, and a first state determination unit that determines whether or not there is an open circuit in the primary coil based on a second voltage between the first output terminal and the second output terminal and the detection signal. In the above aspect, the presence or absence of an open circuit in the primary coil is determined based on a result of the first detection unit's non-contact detection of the electric field at the first input terminal and a result of the second detection unit's non-contact detection of the electric field at the second input terminal. Therefore, compared to a configuration in which the presence or absence of a wire break is determined based on the results of detecting a current flowing between the first input terminal and the second input terminal via a path separate from the primary coil, for example, it is possible to determine with high accuracy whether a wire break is present in the primary coil while maintaining high reliability.

[0067] In a specific example (Aspect 2) of Aspect 1, the voltage detection unit includes a voltage determination unit that determines the first voltage and a voltage comparison unit that compares the first voltage with a first threshold, and the detection signal is a binary signal that represents a comparison result by the voltage comparison unit. In the above aspect, a binary signal that corresponds to a result of comparing the first voltage with the first threshold is generated as the detection signal. Therefore, the processing load on the first state determination unit is reduced compared to a configuration in which a detection signal representing the first voltage is supplied to the first state determination unit.

[0068] In a specific example (Aspect 3) of Aspect 1 or Aspect 2, the first state determination unit determines that an abnormality has occurred in the power grid when the first voltage is lower than the first threshold, and determines that an open circuit has occurred in the primary coil when the first voltage is higher than the first threshold and the second voltage is lower than a second threshold. In the above aspect, it is possible to determine whether an abnormality has occurred in the power grid and whether an open circuit has occurred in the primary coil according to the first voltage and the second voltage.

[0069] In a specific example (Aspect 4) of Aspect 3, the first state determination unit determines that the power grid is normal and that no open circuit has occurred in the primary coil when the first voltage exceeds the first threshold value and the second voltage exceeds the second threshold value. In the above aspect, it can be determined that the power grid is normal and that no open circuit has occurred in the primary coil, depending on the first voltage and the second voltage.

[0070] In a specific example (Aspect 5) of Aspect 4, the power supply system further includes an operation control unit that controls a circuit breaker between the power system and the power equipment, and the operation control unit maintains the circuit breaker in a conductive state when the first state determination unit determines that an open circuit has occurred in the primary coil and when the first state determination unit determines that the power system is normal and that no open circuit has occurred in the primary coil, and controls the circuit breaker to a cutoff state when the first state determination unit determines that an abnormality has occurred in the power system. In the above aspect, the circuit breaker is maintained in a conductive state when it is determined that an open circuit has occurred in the primary coil or when it is determined that the power system and the primary coil are normal, and the circuit breaker is controlled to a cutoff state when it is determined that an abnormality has occurred in the power system. Therefore, compared to a configuration in which the circuit breaker is controlled to a cutoff state even when an open circuit has occurred in the primary coil, the possibility of unnecessary cutoff of the power supply from the power system to the power equipment can be reduced.

[0071] In a specific example (Aspect 6) of Aspect 5, a second state determination unit is further provided that determines whether or not there is an open circuit in the primary coil according to the second voltage and the detection signal, and the operation control unit controls the circuit breaker to the cut-off state when both the first state determination unit and the second state determination unit determine that an abnormality has occurred in the power grid. In the above aspect, the circuit breaker is controlled to the cut-off state when the determination results of both the first state determination unit and the second state determination unit match. Therefore, high reliability can be achieved in the control of the circuit breaker.

[0072] In a specific example (Aspect 7) of any one of Aspects 3 to 6, the control system further includes a status notification unit that notifies the user of a disconnection in the primary coil when the status determination unit determines that the primary coil has been disconnected. In the above aspects, the disconnection in the primary coil is notified. Therefore, the user of the control system can recognize the need to replace or repair the instrument transformer.

[0073] A management method according to one aspect (aspect 8) of the present disclosure is a method for managing a power system including an instrument transformer having a primary coil including a first input terminal and a second input terminal to which power is supplied from a power grid, and a secondary coil including a first output terminal and a second output terminal, and includes contactlessly detecting an electric field generated at the first input terminal using a first detection unit, contactlessly detecting an electric field generated at the second input terminal using a second detection unit, determining a first voltage between the first input terminal and the second input terminal from the detection results by the first detection unit and the second detection unit, and generating a detection signal corresponding to the first voltage, and determining whether or not there is an open circuit in the primary coil based on the second voltage between the first output terminal and the second output terminal and the detection signal. [Explanation of symbols]

[0074] 100...power system, 10...power system, 21...power equipment, 22...circuit breaker, 23...control system, 30...instrument transformer, 31...primary coil, 32...secondary coil, 35...voltage detection path, 36...resistance element, 40...voltage detection sensor, 41...first detection antenna, 42...second detection antenna, 50...voltage detection circuit, 51...voltage identification section, 52...voltage comparison section, 60...control unit, 61A, 61B...A / D converter, 62A, 62B...control device, 621...status determination section, 622...status notification section, 63...storage device, 64...display device, 70...operation control circuit.

Claims

1. a potential transformer including a primary coil having a first input end and a second input end to which power is supplied from a power grid, and a secondary coil having a first output end and a second output end; a first detection unit that detects an electric field generated at the first input terminal in a non-contact manner; a second detection unit that detects an electric field generated at the second input terminal in a non-contact manner; a voltage detection unit that identifies a first voltage between the first input terminal and the second input terminal from detection results by the first detection unit and the second detection unit, and generates a detection signal corresponding to the first voltage; a first state determination unit that determines whether or not there is a break in the primary coil according to a second voltage between the first output terminal and the second output terminal and the detection signal; A control system comprising:

2. The voltage detection unit a voltage specifying unit that specifies the first voltage; a voltage comparison unit that compares the first voltage with a first threshold value; The detection signal is a binary signal that represents the comparison result by the voltage comparator. The control system of claim 1.

3. The first state determination unit determining that an abnormality has occurred in the power grid when the first voltage is lower than the first threshold; When the first voltage exceeds the first threshold value and the second voltage falls below the second threshold value, it is determined that an open circuit has occurred in the primary coil. The control system of claim 2.

4. The first state determination unit When the first voltage exceeds the first threshold value and the second voltage exceeds the second threshold value, it is determined that the power system is normal and that no open circuit has occurred in the primary coil. The control system of claim 3.

5. An operation control unit that controls a circuit breaker between the power system and the power equipment, The operation control unit maintaining the circuit breaker in a conductive state when the first state determination unit determines that an open circuit has occurred in the primary coil and when the first state determination unit determines that the power system is normal and that no open circuit has occurred in the primary coil; When the first state determination unit determines that an abnormality has occurred in the power system, the circuit breaker is controlled to an interrupted state. The control system of claim 4.

6. a second state determination unit that determines whether or not there is a break in the primary coil according to the second voltage and the detection signal; The operation control unit controls the circuit breaker to an interrupted state when both the first state determination unit and the second state determination unit determine that an abnormality has occurred in the power grid. The control system of claim 5.

7. a state notification unit that notifies the user of a break in the primary coil when the first state determination unit determines that the break in the primary coil has occurred; 7. The control system of claim 3, further comprising:

8. A method for managing a power system including a potential transformer including a primary coil having a first input terminal and a second input terminal to which power is supplied from a power grid, and a secondary coil having a first output terminal and a second output terminal, the method comprising: detecting an electric field generated at the first input terminal in a non-contact manner using a first detection unit; detecting an electric field generated at the second input terminal in a non-contact manner using a second detection unit; determining a first voltage between the first input terminal and the second input terminal from detection results by the first detection unit and the second detection unit, and generating a detection signal according to the first voltage; determining whether or not there is an open circuit in the primary coil according to a second voltage between the first output terminal and the second output terminal and the detection signal; A management method implemented by a computer system including:

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