Protective relay device and protective system

Abstract

To provide a technique that can reduce security risks through proper management in protective relay devices that use leased line communication networks and general-purpose communication networks.SOLUTION: A protective relay device for protecting a power system includes a first communication unit that communicates with an upper-level device via a leased line communication network, a second communication unit that communicates with a terminal device via a general-purpose communication network, a settling information storage unit that stores settling information about the protective relay device received from the upper-level device by the first communication unit, and a communication function control unit that enables or disables the communication function of the second communication unit based on the settling information.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a protective relay device and a protection system.

Background Art

[0002] Conventionally, a protective relay device performs relay operations to detect faults such as ground faults and short circuits, and protects the power system by sending a trip command to a switch (e.g., a circuit breaker). In such a protective relay device, with the advancement of functional performance, in addition to information necessary for system operation such as control information of the switch, the amount of information to be handled, such as operation information, measurement information such as voltage and current, recording information, and numerical information related to other additional functions, has been increasing.

[0003] For example, Japanese Patent Application Laid-Open No. 2003-88001 (Patent Document 1) discloses a power system management system. The power system management system includes a device control device that controls equipment constituting the power system, and a monitoring control device that acquires internal information of the device control device via a Web communication network and monitors the state of the power system from the internal information, and is configured to change the function of the device control device from outside the device control device by a communication method with higher security than the monitoring system via the Web communication network.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the technology according to Patent Document 1, the Web communication network and the dedicated line are used properly according to the information to be handled. However, since the relay panel is always connected to the Web communication network that can be accessed relatively easily by a third party, there is room for improvement from the perspective of security.

[0006] In one aspect of this disclosure, the objective is to provide a technology that can reduce security risks in protective relay devices utilizing dedicated line communication networks and general-purpose communication networks. [Means for solving the problem]

[0007] According to one embodiment, a protective relay device for protecting a power system is provided. The protective relay device comprises a first communication unit that communicates with a higher-level device via a dedicated line communication network, a second communication unit that communicates with a terminal device via a general-purpose communication network, a setting information storage unit that stores setting information about the protective relay device received from the higher-level device by the first communication unit, and a communication function control unit that controls the communication function of the second communication unit to be enabled or disabled based on the setting information.

[0008] A protection system according to another embodiment comprises a protective relay device for protecting a power system, a higher-level device of the protective relay device, and a terminal device. The protective relay device includes a first communication unit that communicates with the higher-level device via a dedicated line communication network, a second communication unit that communicates with the terminal device via a general-purpose communication network, a setting information storage unit that stores setting information about the protective relay device received from the higher-level device by the first communication unit, and a communication function control unit that controls the communication function of the second communication unit to be enabled or disabled based on the setting information. [Effects of the Invention]

[0009] According to this disclosure, security risks can be reduced in protective relay devices that utilize dedicated line communication networks and general-purpose communication networks. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows an example of the overall configuration of a protective relay device. [Figure 2] This figure shows an example of the functional configuration of a protective relay device according to Embodiment 1. [Figure 3] This flowchart shows an example of the processing procedure for a protective relay device according to Embodiment 1. [Figure 4] This figure shows an example of the functional configuration of a protective relay device according to Embodiment 2. [Figure 5] This flowchart shows an example of the processing procedure for a protective relay device according to Embodiment 2. [Figure 6] This figure shows an example of the functional configuration of a protective relay device according to Embodiment 3. [Figure 7] This flowchart shows an example of the processing procedure for a protective relay device according to Embodiment 3. [Modes for carrying out the invention]

[0011] Embodiments of the present disclosure will be described below with reference to the drawings. In the following description, identical parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions of them will not be repeated.

[0012] Embodiment 1. <Overall Structure> Figure 1 shows an example of the overall configuration of the protective relay device 100. Referring to Figure 1, the protective relay device 100 is a digital type protective relay device installed inside an electrical facility such as a power plant or substation. In this embodiment, the protective relay device 100 collects data on electrical quantities (e.g., current, voltage, etc.) related to the transmission lines L that constitute the power system, and has a fault detection function that detects faults in the power system based on the electrical quantity data.

[0013] Inside the substation, protective relay devices 100, instrument current transformers 2, instrument voltage transformers 4, and circuit breakers 6 are installed. The instrument current transformer 2 measures the current flowing through the transmission line L. The instrument voltage transformer 4 measures the voltage generated in the transmission line L. The current data measured by the instrument current transformer 2 and the voltage data measured by the instrument voltage transformer 4 are input to the protective relay device 100.

[0014] The protection relay device 100 executes a relay operation for accident detection using the collected electrical quantity data, and determines whether an accident has occurred in the power grid (here, the transmission line L). When the protection relay device 100 detects an accident in the transmission line L, it outputs an opening command (for example, a trip signal) to the circuit breaker 6. In addition, when only one of the current and voltage is used in the relay operation, the protection relay device 100 may be configured to capture the current or voltage required for the relay operation.

[0015] As a hardware configuration, the protection relay device 100 includes an auxiliary transformer 10, an A / D (Analog to Digital) conversion unit 20, and an arithmetic processing unit 30.

[0016] The auxiliary transformer 10 takes in the electrical quantities from the instrument current transformer 2 and the instrument voltage transformer 4, and converts them into voltage signals suitable for signal processing in the internal circuit and outputs them. The A / D conversion unit 20 takes in the electrical quantity (that is, the analog electrical quantity) output from the auxiliary transformer 10 and converts it into digital data. Specifically, the A / D conversion unit 20 includes filters 21, 23, sample and hold circuits (corresponding to the SH circuits in the figure) 24, 25, a multiplexer 26, and an A / D converter 27.

[0017] The filters 21, 23 are analog filters, and remove high-frequency noise components from the waveform signals of the current and voltage output from the auxiliary transformer 10. The outputs of the filters 21, 23 are respectively input to the sample and hold circuits 24, 25. The sample and hold circuits 24, 25 sample the waveform signals of the current and voltage output from the filters 21, 23 at a predetermined sampling period.

[0018] Based on the timing signal input from the arithmetic processing unit 30, the multiplexer 26 sequentially switches the waveform signals input from the sample-and-hold circuits 24 and 25 in time series and outputs them to the A / D converter 27. The A / D converter 27 converts the waveform signal input from the multiplexer 26 from analog data to digital data. The A / D converter 27 outputs the digitally converted waveform signal to the arithmetic processing unit 30.

[0019] The arithmetic processing unit 30 is mainly composed of a microcomputer. Specifically, the arithmetic processing unit 30 includes a CPU (Central Processing Unit) 32, a ROM (Read Only Memory) 33, a RAM 34, an auxiliary storage device 35, a DO (Digital output) circuit 36, a DI (Digital input) circuit 37, a display 38, an input interface 39, and a communication interface 40. These are connected by a bus 31.

[0020] The CPU 32 controls the protection relay device 100 by reading and executing the program stored in the ROM 33 in advance. The RAM 34 as a volatile memory and the ROM 33 as a non-volatile memory are used as the main memory of the CPU 32. The ROM 33 stores programs and setting values for signal processing.

[0021] The CPU 32 fetches digital data from the A / D conversion unit 20 via the bus 31. The CPU 32 executes a relay operation for accident detection using the fetched digital data according to the program stored in the ROM 33. The CPU 32 determines the presence or absence of an accident based on the results of each relay operation (i.e., detects an accident).

[0022] When the CPU 3 detects an accident, it outputs an open command to the circuit breaker 6 installed in the power system via the DO circuit 36 to disconnect the accident section from the power system.

[0023] The auxiliary storage device 35 is a storage device with a larger capacity than the ROM 33 and stores data such as programs, detected electrical values, and set values. The auxiliary storage device 35 is composed of, for example, a hard disk or flash memory.

[0024] The DI circuit 37 receives, for example, a digital input signal that indicates the opening and closing information of the circuit breaker 6. In addition to the digital input signal from the circuit breaker 6, the DI circuit 37 may also receive a digital input signal indicating the opening and closing information of a disconnector (not shown).

[0025] The display 38 is, for example, a liquid crystal display. The input interface 39 is typically a set of buttons, etc., that accept various operations from the user (e.g., an operator) of the protective relay device 100. The communication interface 40 mediates data transmission between the protective relay device 100 and an external device.

[0026] Furthermore, at least a portion of the protective relay device 100 may be configured using circuits such as FPGA (Field Programmable Gate Array) and ASIC (Application Specific Integrated Circuit). Also, at least a portion of the protective relay device 100 may be configured using analog circuits.

[0027] <Functional Configuration> Figure 2 shows an example of the functional configuration of a protective relay device 100 according to Embodiment 1. Referring to Figure 2, the protective relay device 100 is configured to communicate with a host device 200 and a terminal device 300. The protection system includes the protective relay device 100, the host device 200, and the terminal device 300.

[0028] The protective relay device 100 includes, as its main functional components, an input unit 102, a data storage unit 104, a relay calculation unit 106, a command output unit 108, a first communication unit 110, a setting information storage unit 112, a communication function control unit 114, and a second communication unit 116. Typically, each of these functions is implemented by the calculation processing unit 30 of the protective relay device 100, but may also be implemented by dedicated hardware circuits.

[0029] The input unit 102 receives the amount of electricity from the power system. The amount of electricity acquired by the input unit 102 is sequentially stored in the data storage unit 104.

[0030] The relay calculation unit 106 performs relay calculations (for example, relay calculations for fault detection) based on the set values ​​included in the set information stored in the set information storage unit 112 and the electrical quantities stored in the data storage unit 104, and detects faults in the power system based on the results of the relay calculations. Typically, the relay calculation unit 106 compares a calculated value obtained by a predetermined calculation using the electrical quantities with the set values ​​included in the set information stored in the set information storage unit 112. The relay calculation unit 106 determines that a fault has occurred (i.e., detects a fault) if the result that the calculated value deviates from the range that conforms to the set value occurs a standard number of times consecutively.

[0031] When a fault is detected by the relay calculation unit 106, the command output unit 108 outputs a trip signal to the circuit breaker 6 to trip (i.e., open) the circuit breaker 6.

[0032] The first communication unit 110 communicates with the host device 200 of the protective relay device 100 via the dedicated line communication network 50. The dedicated line communication network 50 is a communication network of power-dedicated lines, which are transmission lines exclusively for power. The first communication unit 110 communicates with the host device 200 via the dedicated line communication network 50 by sending and receiving signals on the power-dedicated line to and from the host device 200.

[0033] The higher-level device 200 is primarily composed of a microcomputer and is a general-purpose computer including, for example, a CPU, memory (e.g., ROM, RAM, hard disk), and a communication interface. The higher-level device 200 transmits various commands to the protective relay device 100. Typically, the higher-level device 200 transmits setting information for the protective relay device 100. The setting information includes function setting information for enabling or disabling the communication function of the second communication unit 116. Furthermore, the setting information may include a plurality of setting values ​​used by the relay calculation unit 106 of the protective relay device 100 for fault detection.

[0034] The setting information storage unit 112 stores the setting information received from the host device 200 by the first communication unit 110. Typically, the first communication unit 110 sequentially writes the setting information to the setting information storage unit 112.

[0035] The communication function control unit 114 controls the communication function of the second communication unit 116 to be enabled or disabled based on the setting information stored in the setting information storage unit 112. Specifically, the communication function control unit 114 determines whether the function setting information included in the setting information indicates the activation of the communication function of the second communication unit 116 (for example, the value of the function setting information is "1") or the deactivation of the communication function (for example, the value of the function setting information is "0"). Then, the communication function control unit 114 enables or disables the communication function of the second communication unit 116 based on the function setting information.

[0036] The second communication unit 116 communicates with the terminal device 300 via the general-purpose communication network 60. The terminal device 300 is a general-purpose computer mainly composed of a microcomputer, including, for example, a CPU, memory, and communication interface. Typically, the general-purpose communication network 60 is composed of an Internet Protocol (IP) communication network. The second communication unit 116 uses an IP communication network-compatible network and communicates data in the form of packet communication.

[0037] The general-purpose communication network 60 (for example, an IP communication network) is a general-purpose communication network, so the costs required for communication equipment and maintenance are relatively low, but it is relatively easy for third parties to access it. Therefore, the general-purpose communication network 60 is less reliable in terms of security than the dedicated line communication network 50, which is a transmission line dedicated to power. For this reason, the second communication unit 116 can communicate with the terminal device 300 only when its communication function is enabled by the communication function control unit 114. In other words, if the communication function of the second communication unit 116 is disabled, the second communication unit 116 cannot communicate with the terminal device 300.

[0038] Thus, the protective relay device 100 according to this embodiment is not constantly connected to the general-purpose communication network 60, but is connected to the general-purpose communication network 60 only when necessary. Specifically, the protective relay device 100 is connected to the general-purpose communication network 60 only when the function setting information received from the host device 200 via the highly secure dedicated line communication network 50 indicates that the communication function of the second communication unit 116 should be "enabled". Therefore, the situations in which the protective relay device 100 is connected to the general-purpose communication network 60 can be limited.

[0039] Typically, the communication function of the second communication unit 116 of the protective relay device 100 is disabled under normal circumstances and is only enabled when necessary. For example, consider a scenario where a worker retrieves data stored in the protective relay device 100 using a terminal device 300. The worker would then request the person in charge of using the higher-level device 200 to send function setting information to the protective relay device 100 to enable the communication function of the second communication unit 116 of the protective relay device 100.

[0040] Then, the worker uses the terminal device 300 to access the protective relay device 100 via the general-purpose communication network 60. For example, the terminal device 300 communicates with the protective relay device 100 using wireless LAN (Local Area Network) communication. As described above, since the communication function of the second communication unit 116 is enabled, the terminal device 300 can communicate with the protective relay device 100 via the general-purpose communication network 60 and acquire data stored in the protective relay device 100 (for example, information such as the amount of electricity stored in the data storage unit 104).

[0041] After the necessary data has been acquired (i.e., after the work is completed), the worker notifies the person in charge of using the host device 200 that the work is finished. The host device 200 then transmits function setting information to the protection relay device 100 to disable the communication function of the second communication unit 116 of the protection relay device 100.

[0042] Furthermore, the higher-level device 200 may transmit function setting information to enable the communication function of the second communication unit 116 to the protective relay device 100, and then, after a specified time has elapsed, transmit function setting information to disable the communication function to the protective relay device 100.

[0043] <Processing Procedure> Figure 3 is a flowchart showing an example of the processing procedure of a protective relay device 100 according to Embodiment 1. Each process shown in Figure 3 is typically performed by the arithmetic processing unit 30 of the protective relay device 100.

[0044] Referring to Figure 3, the protective relay device 100 determines whether or not it has received setting information from the higher-level device 200 via the dedicated line communication network 50 (step S10). If setting information has not been received (NO in step S10), the protective relay device 100 repeats the process in step S10. If setting information has been received (YES in step S10), the protective relay device 100 stores the received setting information in its internal memory (for example, auxiliary storage device 35) (step S12).

[0045] The protective relay device 100 determines whether to enable or disable a communication function (for example, the communication function of the second communication unit 116) that performs communication via the general-purpose communication network 60, based on the function setting information among the setting information (step S14). If the communication function is to be enabled ("enabled" in step S14), the protective relay device 100 enables the communication function (step S16) and terminates the process. If the communication function is to be disabled ("disabled" in step S14), the protective relay device 100 disables the communication function (step S18) and terminates the process.

[0046] <Advantages> According to Embodiment 1, the protective relay device 100 controls the communication function via the general-purpose communication network 60 based on function setting information received via the highly secure dedicated communication network 50. Therefore, the protective relay device 100 is not always connected to the general-purpose communication network 60, but only when necessary. By appropriately managing communication via the general-purpose communication network 60 in this way, security risks in such communication can be reduced. Furthermore, by transmitting function setting information to the protective relay device 100, the communication function via the general-purpose communication network 60 can be remotely controlled, thereby improving convenience.

[0047] Embodiment 2. <Functional Configuration> Figure 4 shows an example of the functional configuration of the protective relay device 100A according to Embodiment 2. The protective relay device 100A corresponds to the protective relay device 100 in Figure 1, but for convenience, it is denoted with the letter "A" to distinguish it from the protective relay device 100 according to Embodiment 1. This is also the case in Embodiment 3.

[0048] Referring to Figure 4, the protective relay device 100A corresponds to the protective relay device 100 with the addition of a monitoring unit 120. Regarding the functional configuration of the protective relay device 100A that is the same as that of the protective relay device 100, a detailed explanation will not be repeated.

[0049] The monitoring unit 120 monitors the contents of the function setting information contained in the setting information storage unit 112. Specifically, the monitoring unit 120 determines whether the contents of the function setting information have been changed. For example, the monitoring unit 120 determines whether the contents of the function setting information have been changed from "communication function enabled" (for example, the value of the function setting information is "1") to "communication function disabled" (for example, the value of the function setting information is "0"). Similarly, the monitoring unit 120 determines whether the contents of the function setting information have been changed from "communication function disabled" to "communication function enabled".

[0050] If the content of the function setting information is changed, the monitoring unit 120 outputs the changed function setting information to the communication function control unit 114. Based on the changed function setting information, the communication function control unit 114 controls whether the communication function of the second communication unit 116 is enabled or disabled. As a result, similar to Embodiment 1, the communication function of the second communication unit 116 is enabled only when necessary.

[0051] Furthermore, as shown in Figure 4, the input unit 102, data storage unit 104, relay calculation unit 106, command output unit 108, first communication unit 110, setting information storage unit 112, and monitoring unit 120 operate on the real-time OS (Operating System) 130. The communication function control unit 114 and the second communication unit 116 operate on the general-purpose OS 140. Thus, in the protective relay device 100A, the functional configuration related to system operation (e.g., protective relay calculation) operates on the real-time OS 130, while the general-purpose functional configuration other than protective relay calculation operates on the general-purpose OS 140.

[0052] While general-purpose operating systems (OS) have advantages over real-time operating systems, such as easier software development and porting, and greater ease of increasing functionality, they often pose potential security risks. Therefore, if a communication unit (for example, the second communication unit 116) running on a general-purpose OS is constantly connected to the general-purpose communication network 60, it carries security risks such as unauthorized access exploiting vulnerabilities in the OS.

[0053] According to the configuration shown in Figure 4, the communication function of the communication unit operating on the general-purpose OS (i.e., the communication function of the second communication unit 116) is disabled when not needed, thereby reducing the risk of unauthorized access.

[0054] <Processing Procedure> Figure 5 is a flowchart showing an example of the processing procedure of the protective relay device 100A according to Embodiment 2.

[0055] Referring to Figure 5, the processes in steps S10 and S12 are the same as those described in Figure 3. The protective relay device 100A determines whether the content of the function setting information included in the setting information has been changed (step S20). If the content of the function setting information has not been changed (NO in step S20), the protective relay device 100A returns to the process in step S10. If the content of the function setting information has been changed (YES in step S20), the protective relay device 100A determines whether to enable or disable the communication function that performs communication via the general-purpose communication network 60 based on the changed function setting information (step S14). The processes in steps S16 and S18 are the same as those described in Figure 3.

[0056] <Advantages> According to Embodiment 2, in addition to the advantages of Embodiment 1, the decision process for enabling or disabling the communication function of the second communication unit 116 is executed only when the content of the function setting information is changed. Therefore, the processing load can be reduced compared to when the decision process is executed regardless of the content of the function setting information. Furthermore, since the communication function of the communication unit operating on a general-purpose OS (i.e., the communication function of the second communication unit 116) is disabled when not needed, the risk of unauthorized access can be reduced while maintaining convenience.

[0057] Embodiment 3. <Functional Configuration> Figure 6 shows an example of the functional configuration of a protective relay device 100B according to Embodiment 3. Referring to Figure 6, the protective relay device 100B is equivalent to replacing the relay calculation unit 106, communication function control unit 114, and second communication unit 116 of Figure 3 with a relay calculation unit 106B, a communication function control unit 114B, and a second communication unit 116B, respectively. A detailed explanation of the functions of the protective relay device 100B that are the same as those of the protective relay device 100 will not be repeated.

[0058] In addition to the functions of the relay calculation unit 106, the relay calculation unit 106B has the following functions. Specifically, when the relay calculation unit 106B detects an accident, it outputs a detection signal to the communication function control unit 114B indicating that an accident has been detected.

[0059] The communication function control unit 114B has the following functions in addition to the functions of the communication function control unit 114. Specifically, when a fault in the power system is detected by the relay calculation unit 106B (i.e., when a detection signal is output), the communication function control unit 114B enables the communication function of the second communication unit 116B. In other words, regardless of the content of the function setting information (for example, even if the function setting information indicates that the communication function of the second communication unit 116B should be disabled), the communication function control unit 114B enables the communication function of the second communication unit 116B when a fault is detected by the relay calculation unit 106.

[0060] When the communication function of the second communication unit 116B is activated due to the detection of an accident, the second communication unit 116B transmits predetermined data to the terminal device 300. For example, the second communication unit 116B reads the amount of electricity taken in by the input unit 102 during a predetermined period before and after the timing of the detection of the accident from the data storage unit 104 and transmits the amount of electricity to the terminal device 300.

[0061] The communication function control unit 114B disables the communication function of the second communication unit 116B after the transmission of data (e.g., electricity amount) to the terminal device 300 by the second communication unit 116B is completed. In addition, if the communication function control unit 114B enables the communication function of the second communication unit 116B due to the detection of an accident, it may disable the communication function of the second communication unit 116B after a predetermined time has elapsed since the communication function was enabled.

[0062] <Processing Procedure> Figure 7 is a flowchart showing an example of the processing procedure of the protective relay device 100B according to Embodiment 3.

[0063] Referring to Figure 7, the protective relay device 100B determines whether or not it has detected a fault in the power system based on the amount of electricity obtained from the power system (step S30). If a fault is detected (YES in step S30), the protective relay device 100B activates the communication function to perform communication via the general-purpose communication network 60 (step S16) and terminates the process. If no fault is detected (NO in step S30), the protective relay device 100B executes the processes in steps S10 to S18. The processes in steps S10 to S18 are the same as those described in Figure 3.

[0064] <Advantages> According to Embodiment 3, in addition to the advantages of Embodiment 1, the communication function of the second communication unit 116 is automatically activated when a power system fault is detected. Therefore, by accessing the protective relay device 100 using the terminal device 300, fault data can be quickly obtained. Furthermore, by automatically disabling the communication function of the second communication unit 116 after obtaining the necessary data, the time of communication via the general-purpose communication network 60 can be minimized, thereby reducing security risks.

[0065] Other embodiments. The configurations illustrated above as embodiments are examples of the configurations of this disclosure, and can be combined with other known technologies, or modified, such as by omitting parts, without departing from the gist of this disclosure. Furthermore, in the embodiments described above, processes and configurations described in other embodiments may be appropriately adopted and implemented.

[0066] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended.

[0067] The various aspects of this disclosure are summarized below as an appendix. (Note 1) A protective relay device for protecting a power system, comprising: a first communication unit that communicates with a higher-level device via a dedicated line communication network; a second communication unit that communicates with a terminal device via a general-purpose communication network; a setting information storage unit that stores setting information about the protective relay device received from the higher-level device by the first communication unit; and a communication function control unit that controls the communication function of the second communication unit to be enabled or disabled based on the setting information.

[0068] (Note 2) The aforementioned general-purpose communication network includes the Internet Protocol communication network, and the protective relay device is as described in Appendix 1.

[0069] (Note 3) The protective relay device as described in Appendix 1 or Appendix 2, wherein the setting information includes function setting information for enabling or disabling the communication function of the second communication unit.

[0070] (Note 4) The protective relay device according to Appendix 3, further comprising a monitoring unit that monitors the contents of the function setting information, wherein when the monitoring unit determines that the contents of the function setting information have been changed, the communication function control unit controls the communication function of the second communication unit to enable or disable based on the changed function setting information.

[0071] (Note 5) A protective relay device according to any one of the appendices 1 to 4, further comprising: an input unit for receiving the amount of electricity from the power system; and a relay calculation unit that performs relay calculations based on the setting information and the amount of electricity, and detects a fault in the power system based on the result of the relay calculations, wherein when a fault in the power system is detected by the relay calculation unit, the communication function control unit enables the communication function of the second communication unit.

[0072] (Note 6) The protective relay device described in Appendix 5, wherein the second communication unit transmits the amount of electricity taken in by the input unit during a specified period before and after the timing at which the accident is detected to the terminal device.

[0073] (Note 7) The communication function control unit disables the communication function of the second communication unit after the second communication unit has finished transmitting the amount of electricity to the terminal device, as described in Appendix 6 of the protective relay device.

[0074] (Note 8) A protection system comprising a protective relay device for protecting a power grid, a higher-level device for the protective relay device, and a terminal device, wherein the protective relay device includes a first communication unit that communicates with the higher-level device via a dedicated line communication network, a second communication unit that communicates with the terminal device via a general-purpose communication network, a setting information storage unit that stores setting information about the protective relay device received from the higher-level device by the first communication unit, and a communication function control unit that controls the communication function of the second communication unit to be enabled or disabled based on the setting information. [Explanation of symbols]

[0075] 2 Instrument current transformer, 4 Instrument voltage transformer, 6 Circuit breaker, 10 Auxiliary transformer, 20 A / D converter, 21, 23 Filter, 24, 25 Sample-and-hold circuit, 26 Multiplexer, 27 A / D converter, 30 Arithmetic processing unit, 31 Bus, 32 CPU, 33 ROM, 34 RAM, 35 Auxiliary storage device, 36 DO circuit, 37 DI circuit, 38 Display, 39 Input interface, 40 Communication interface, 50 Dedicated line communication network, 60 General-purpose communication network, 100, 100A, 100B Protective relay device, 102 Input unit, 104 Data storage unit, 106, 106B Relay calculation unit, 108 Command output unit, 110 First communication unit, 112 Setting information storage unit, 114, 114B Communication function control unit, 116, 116B Second communication unit, 120 Monitoring unit, 130 real-time OS, 140 general-purpose OS, 200 higher-level devices, 300 terminal devices.

Claims

1. A protective relay device for protecting a power system, A first communication unit communicates with a higher-level device via a dedicated communication network, A second communication unit communicates with terminal devices via a general-purpose communication network, A setting information storage unit that stores setting information for the protective relay device received from the higher-level device by the first communication unit, A protective relay device comprising a communication function control unit that controls the communication function of the second communication unit to be enabled or disabled based on the setting information.

2. The protective relay device according to claim 1, wherein the general-purpose communication network includes an Internet Protocol communication network.

3. The protective relay device according to claim 1 or claim 2, wherein the setting information includes function setting information for setting the communication function of the second communication unit to enable or disable.

4. The system further includes a monitoring unit that monitors the contents of the aforementioned function setting information, The protective relay device according to claim 3, wherein if the monitoring unit determines that the contents of the function setting information have been changed, the communication function control unit controls the communication function of the second communication unit to enable or disable based on the changed function setting information.

5. An input unit that takes in the amount of electricity from the aforementioned power system, The system further comprises a relay calculation unit that performs relay calculations based on the setting information and the amount of electricity, and detects faults in the power system based on the results of the relay calculations, The protective relay device according to claim 1 or 2, wherein when the relay calculation unit detects a fault in the power system, the communication function control unit enables the communication function of the second communication unit.

6. The protective relay device according to claim 5, wherein the second communication unit transmits the amount of electricity taken in by the input unit to the terminal device during a specified period before and after the timing at which the accident is detected.

7. The protective relay device according to claim 6, wherein the communication function control unit disables the communication function of the second communication unit after the transmission of the amount of electricity to the terminal device by the second communication unit is completed.

8. A protective relay device for protecting the power system, The above-mentioned protective relay device and a higher-level device, Equipped with terminal equipment, The aforementioned protective relay device, A first communication unit that communicates with the above-level device via a dedicated line communication network, A second communication unit communicates with the terminal device via a general-purpose communication network, A setting information storage unit that stores setting information for the protective relay device received from the higher-level device by the first communication unit, A protection system including a communication function control unit that controls the communication function of the second communication unit to be enabled or disabled based on the setting information.

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