JP7766570B2 - Digital protective relay and its test system and test method - Google Patents

Description

This disclosure relates to a digital protective relay and its test system and test method.

Some digital protective relays have a data output section for an oscilloscope recording device (such as an electromagnetic oscillograph or digital data recorder) for use in operational tests (see, for example, Japanese Patent Application Laid-Open No. 8-98388 (Patent Document 1)). During an operational test, a test current or test voltage is input into the digital protective relay to operate it, and the calculation process within the protective relay and the digital output signal are recorded on the oscilloscope recording device. Based on the waveform data recorded on the oscilloscope recording device, it is determined whether the protective relay is operating properly.

In addition, some digital protective relays are equipped with Internet Protocol communication means and web server functionality. This makes it possible to operate and view internal information about the digital protective relay, such as setting values, from a maintenance personal computer equipped with a browser (see, for example, Japanese Patent Application Laid-Open No. 2001-333549 (Patent Document 2)).

Japanese Patent Application Publication No. 8-98388 Japanese Patent Application Laid-Open No. 2001-333549

With the above digital protection relay configuration, operational test settings, such as the type of signal output from the data output section for the oscilloscope recorder, can be easily performed while checking the screen of the maintenance computer.

However, in order to perform an operational test and check the results, an oscilloscope recorder capable of recording multiple high-speed signals must be used. Unlike maintenance computers, oscilloscope recorders do not have the functionality to display the type of input signal for each channel, and so they cannot be said to have excellent usability. Furthermore, in order to check the results of an operational test, it is necessary to output the waveform data recorded on the oscilloscope recorder, which requires time and effort to check.

This disclosure was made in consideration of the above-mentioned problems, and one of its objectives is to provide a function that allows for more efficient performance testing of a digital protective relay equipped with a data output unit for an oscilloscope recorder and an interface for connecting to a maintenance computer.

In one embodiment, the digital protective relay comprises an analog-to-digital converter, a protective relay calculation unit, a signal status table, an oscilloscope output processor, and a web-application program interface (API) server. The analog-to-digital converter receives a signal representing an electrical quantity acquired from the power system during normal operation and a test signal during an operational test, and digitally converts the input signal representing the electrical quantity and the test signal. The protective relay calculation unit performs various protective relay calculations on the digitally converted signal representing the electrical quantity and the test signal. The signal status table stores, while constantly updating, the on/off states or numerical values of the input signals, intermediate signals during calculation, and output signals of the protective relay calculation unit for various protective relay calculations performed on the digitally converted test signals during an operational test. The oscilloscope output processor reads the on/off states or numerical values of multiple signals selected by the user from the signal status table from the signal status table every first period and outputs them to an oscilloscope recorder. In response to a request from an external maintenance computer, the WEB-API server reads the on/off states or numerical values of the selected signals from the signal status table every second period, which is longer than the first period, and transmits the read values to the maintenance computer.

In the above embodiment, the oscilloscope output processing unit reads the on/off states or numerical values of the selected multiple signals from the signal status table every first period and outputs them to the oscilloscope recording device, and the WEB-API server reads the on/off states or numerical values of the selected multiple signals from the signal status table every second period and sends them to the maintenance computer, allowing for more efficient performance testing than conventional methods.

FIG. 1 is a block diagram showing an example of a hardware configuration of a test system for a digital protection relay. FIG. 2 is a block diagram illustrating an example of a hardware configuration of a maintenance PC. FIG. 2 is a block diagram showing an example of the functional configuration of the digital protection relay, the maintenance PC, and the oscilloscope recording device shown in FIG. 1 . 10 is a flowchart showing the operation of the HMI tool during an operation test of the digital protective relay. FIG. 10 is a diagram showing an example of an oscilloscope setting/test start screen displayed on the display unit of the maintenance PC by the HMI tool. FIG. 10 is a diagram showing an example of an editing screen for an oscilloscope output pattern displayed on a display unit of a maintenance PC by an HMI tool. FIG. 10 is a diagram showing an example of an oscilloscope setting/test start screen display during an operation test of a digital protection relay. 10 is a flowchart showing the operation of the HMI tool during an operation test of a digital protection relay in the test system of embodiment 2. FIG. 10 is a diagram showing another example of the display of the oscilloscope setting/test start screen during an operation test of a digital protection relay. 1 is a flowchart illustrating a method for testing a digital protection relay. FIG. 6 is a simplified diagram of the display area of the output signal list in FIG. 5 . FIG. 2 is a diagram for explaining input to the learning device. FIG. 10 is a diagram illustrating the configuration of a learning device for rearranging selection signals. FIG. 10 is a diagram illustrating learning in a model generation unit. 10 is a flowchart relating to a learning process of the learning device. FIG. 1 is a diagram illustrating the configuration of an inference device for determining the optimal order of selection signals. 10 is a flowchart relating to an inference process of the inference device.

Each embodiment will be described in detail below with reference to the drawings. Note that identical or corresponding parts will be given the same reference symbols and their descriptions will not be repeated.

Embodiment 1.
[Example of hardware configuration of test system 8]
Fig. 1 is a block diagram showing an example of the hardware configuration of a test system 8 for a digital protective relay 1. As shown in Fig. 1, the test system 8 includes the digital protective relay 1, a maintenance personal computer (PC) 2, a test signal input device 3, and an oscilloscope recorder 4. The oscilloscope recorder 4 is an electromagnetic oscillograph or a digital data recorder, etc., and records a plurality of input high-speed digital signals.

The digital protection relay 1 comprises an input conversion unit 10, an A/D (Analog-to-Digital) conversion unit 20, an arithmetic processing unit 30, and an I/O (Input and Output) unit 40. These components will be explained in order below.

The input conversion unit 10 is used to receive the high voltage and high current of the electrical equipment at the power station via an instrument voltage transformer (VT) and an instrument current transformer (CT), respectively. The input conversion unit 10 includes input converters 11_1, 11_2, 11_3, ... (collectively referred to as input converters 11) for each input channel to adjust the signal levels of the input signals IN1, IN2, IN3, ... of the multiple input channels. The input converters are, for example, auxiliary transformers.

During an operational test, each input channel of the input conversion unit 10 is connected to the test signal input device 3. The test signal input device 3 is equipped with multiple current sources and multiple voltage sources, and during an operational test, it inputs a test current or test voltage (hereinafter collectively referred to as a test signal) to each input channel of the digital protection relay 1. In one embodiment, the test current and test voltage output from the test signal input device 3 and the timing at which the test current and test voltage are output are controlled by the maintenance PC 2.

The A/D conversion unit 20 includes analog filters 21_1, 21_2, 21_3, ... (collectively referred to as analog filters 21) provided for each input channel, a multiplexer 22, and an A/D converter 23. Furthermore, a sample-and-hold circuit may be provided after the analog filter 21 and before the multiplexer 22 for each input channel.

The analog filter 21 prevents aliasing during A/D conversion by passing low-frequency components, including the fundamental components, of the input signals IN1, IN2, IN3, etc. The multiplexer 22 sequentially takes in the multi-channel input signals and inputs them as a single signal to the A/D converter 23. The A/D converter 23 converts the input signal into a digital value.

The arithmetic processing unit 30 is based on a microcomputer including a CPU (Central Processing Unit) 31, RAM (Random Access Memory) 32, ROM (Read Only Memory) 33, and bus 34. Alternatively, at least a portion of the arithmetic processing unit 30 may be composed of at least one of a PLD (Programmable Logic Device) such as an FPGA (Field Programmable Gate Array) or a dedicated integrated circuit such as an ASIC (Application Specific Integrated Circuit).

The CPU 31 controls the digital protection relay 1 and performs various protection relay calculations using the time-series digital data output from the A/D converter 23. The RAM 32 and ROM 33 are used as work memory for the CPU 31. The ROM 33 is configured as an electrically rewritable non-volatile memory such as an EEPROM (Electrically Erasable Programmable Read-Only Memory) or flash memory. The ROM 33 stores operating programs, various data, etc.

The I/O unit 40 includes a LAN (Local Area Network) interface (I/F) 41, an oscilloscope output interface (I/F) 42, multiple digital output circuits (D/O) 43, and multiple digital input circuits (D/I) 44.

The LAN interface 41 connects to the maintenance PC 2 via Internet Protocol communication. The oscilloscope output interface 42 is connected to the oscilloscope recorder 4, and outputs multiple digital signals selected by the user in parallel and at high speed to the oscilloscope recorder 4. The digital output circuit 43 outputs digital signals to power equipment (circuit breakers, switches, etc.) external to the digital protective relay 1. The digital input circuit 44 receives digital signals from power equipment external to the digital protective relay 1.

[Example of hardware configuration of maintenance PC]
Fig. 2 is a block diagram showing an example of the hardware configuration of the maintenance PC 2. As shown in Fig. 2, the maintenance PC 2 includes a CPU 50, a RAM 51, a ROM 52, a display unit 53, an input unit 54, a LAN interface (I/F) 55, and a bus 56 connecting these components.

The CPU 50 executes an HMI (Human Machine Interface) tool (reference numeral 70 in Figure 3), which is a program for performing maintenance, management, testing, etc. of the digital protection relay 1. RAM 51 and ROM 52 are used as work memory for the CPU 50. ROM 52 is configured as electrically rewritable non-volatile memory such as EEPROM or flash memory. ROM 52 stores programs executed by the CPU 50 and various data. The display unit 53 is a display for displaying information to the user. The input unit 54 is a user interface, such as a keyboard and mouse, for accepting input from the user. The LAN interface 55 is connected to the digital protection relay 1 and test signal input device 3 via Internet Protocol communication.

[Functional configuration of test system 8]
FIG. 3 is a block diagram showing an example of the functional configuration of the digital protection relay 1, the maintenance PC 2, and the oscilloscope recorder 4 shown in FIG.

As shown in FIG. 3, the digital protection relay 1 includes the input conversion unit 10, A/D conversion unit 20, LAN interface 41, and oscilloscope output interface 42 described in FIG. 1, as well as a protection relay calculation unit 60, a signal status table 61, an oscilloscope output processing unit 62, a WEB-API (Application Programming Interface) server 63, an oscilloscope output pattern storage area 64, and a selected signal storage area 65. The protection relay calculation unit 60, oscilloscope output processing unit 62, and WEB-API server 63 may be realized by the CPU 31 in FIG. 1 executing a program, or at least a portion of them may be realized by a PLD or ASIC. The signal status table 61, oscilloscope output pattern storage area 64, and selected signal storage area 65 are realized by the RAM 32 and ROM 33 in FIG. 1.

Specifically, during an operational test of the digital protective relay 1, the protective relay calculation unit 60 performs various protective relay calculations on the test signal 66 A/D converted by the A/D conversion unit 20.

The signal state table 61 stores and updates the state or numerical value (on/off state for binary signals, numerical value for numerical signals) of input signals, intermediate signals during the operation, and output signals for various protective relay calculations. The update cycle of the signal state table 61 is shorter than the output cycle to the oscilloscope recorder 4. The on/off state or numerical value of each signal stored in the signal state table 61 can be accessed by specifying a cell address (also simply referred to as an address). The number of signals stored in the signal state table 61 may be, for example, 1,000 or more. Note that either the on state (also referred to as an active state) or the off state (also referred to as an inactive state) of a binary signal corresponds to a high level of the signal, and the other corresponds to a low level of the signal.

The oscilloscope output processing unit 62 extracts the state or numerical value of a signal selected by the user (hereinafter referred to as the selected signal) from the states or numerical values of over 1,000 signals stored in the signal state table 61, and outputs this periodically (for example, every few milliseconds) to the oscilloscope recorder 4 via the oscilloscope output interface 42. The number of signals that can be output to the oscilloscope recorder 4 is limited by the data processing speed, and is, for example, around 32.

The WEB-API server 63 responds to requests from the maintenance PC 2 by communicating with the maintenance PC 2 via the LAN interface 41. For example, it becomes possible to check and change setting values from the maintenance PC 2. Furthermore, during an operational test of the digital protection relay 1, the maintenance PC 2 periodically retrieves the signal status or numerical values stored in the signal status table 61 via the WEB-API server 63 (for example, every few hundred milliseconds).

The oscilloscope output pattern storage area 64 is a memory area for storing combinations of signals (i.e., oscilloscope output patterns) selected for output to the oscilloscope recorder 4. That is, the oscilloscope output pattern storage area 64 stores identifiers for multiple oscilloscope output patterns and addresses in the signal state table 61 corresponding to the multiple signals selected for each oscilloscope output pattern. By predefining multiple oscilloscope output patterns, the signal selection process when conducting an operational test can be simplified.

The selected signal storage area 65 is a memory area for storing the identifier of the oscilloscope output pattern that is actually output to the oscilloscope recorder 4 and the address in the signal status table 61 that corresponds to the signal selected as that oscilloscope output pattern. During an operational test of the digital protection relay 1, the data at the address specified by the selected signal storage area 65 from the data of the many signals stored in the signal status table 61 is output to the oscilloscope output processing unit 62.

The HMI tool 70 running on the maintenance PC 2 displays a menu on the display unit 53 of the maintenance PC 2, executes the menu selected by the user, and accepts input from the user. The HMI tool 70 also communicates with the WEB-API server 63 of the digital protection relay 1 to read and rewrite various settings of the digital protection relay 1 in accordance with user requests.

In addition, during an operational test of the digital protection relay 1, the HMI tool 70 reads the state or numerical value of the selected signal (on/off state for binary signals, numerical value for numerical signals) from the signal state table 61 at regular intervals (for example, every few hundred milliseconds) via the WEB-API server 63 and displays it on the display unit 53.

The oscilloscope recording device 4 includes a recording unit 75, an output unit 76, and a simple display unit 77. The recording unit 75 is a memory for recording multiple time series data output from the digital protection relay 1 via the oscilloscope output interface 42. The output unit 76 outputs the time series data recorded in the recording unit 75 to a printer or display. The simple display unit 77 displays the on/off state of binary signals currently being output from the digital protection relay 1. The simple display unit 77 includes, for example, a number of light-emitting diodes corresponding to the number of signals.

HMI Tool Functionality for Testing Digital Protection Relays
4 is a flowchart showing the operation of the HMI tool 70 during an operation test of the digital protective relay 1. The function of the HMI tool 70 for the operation test of the digital protective relay 1 will be described in detail below.

When the HMI tool 70 is started, in step S10 of Figure 4, the HMI tool 70 displays a menu on the display unit 53. This menu displays items such as checking and changing various setting values and controlling operational tests, which can be selected by the user.

When the user selects control of the operation test of the digital protection relay 1 (YES in step S20), the HMI tool 70 displays the "Oscilloscope Settings/Test Start" screen on the display unit 53 of the maintenance PC 2 (step S30).

Figure 5 shows an example of an oscilloscope setting/test start screen 80 displayed on the display unit 53 of the maintenance PC 2 by the HMI tool 70. The oscilloscope setting/test start screen 80 includes an area 82 that displays the oscilloscope output pattern name, an oscilloscope output pattern selection area 81, an area 84 that displays a list of output signals corresponding to the selected oscilloscope output pattern, a number 83 indicating the display order of the output signals, an oscilloscope edit button 85, a test start button 86, and an end button 87.

When the HMI tool 70 displays the oscilloscope setting/test start screen 80, it requests the WEB-API server 63 to send the address information of all selected signals stored in the selected signal storage area 65 to the HMI tool 70. The HMI tool 70 converts the address information of the selected signals into signal names and displays them in the output signal list display area 84. For example, in the case of Figure 5, the 32 signal names set as the No. 3 oscilloscope output pattern selected by the selection unit 81 (i.e., "▽▽▽ test") are displayed in the output signal list display area 84.

The order in which signal names are displayed in the output signal list display area 84 follows the order of the data stored in the oscilloscope output pattern storage area 64 and the selected signal storage area 65. Alternatively, an identifier representing the display order (for example, number 83 representing the display order in Figure 5) may be stored in the oscilloscope output pattern storage area 64 and the selected signal storage area 65, and the signal names may be displayed in the order according to this identifier.

In addition, the ROM 52 of the maintenance PC 2 pre-stores a data table showing the correspondence between the signal names of all signals stored in the signal status table 61 of the digital protection relay 1 and the addresses in the signal status table 61. The HMI tool 70 converts signal names and addresses based on this data table.

When the user changes the oscilloscope output pattern by operating the oscilloscope output pattern selection section 81 in Figure 5, the HMI tool 70 requests the WEB-API server 63 to change the identification number of the oscilloscope output pattern stored in the selected signal storage area 65 and the address information of the corresponding selected signal. Once the WEB-API server 63 has completed changing the contents of the selected signal storage area 65, it sends the address information of all selected signals newly stored in the selected signal storage area 65 to the HMI tool 70. The HMI tool 70 converts the address information of the selected signals into signal names and displays them in the output signal list display area 84.

When the user selects the oscilloscope edit button 85 (YES in step S40 of Figure 4), the HMI tool 70 displays the "Oscilloscope Output Pattern Edit" screen on the display unit 53 of the maintenance PC 2.

Figure 6 shows an example of an oscilloscope output pattern editing screen displayed on the display unit 53 of the maintenance PC 2 by the HMI tool 70. The oscilloscope output pattern editing screen includes an input area 90 for the oscilloscope output pattern name, an input area 91 for keywords for signal search, a display area 93 for the searched signal name, and a display area 97 for the selected signal name.

When entering keywords for signal searches, the user can select "contains," "starts with," or "ends with" using the selection unit 92. When the user enters a keyword in the keyword input area 91, the HMI tool 70 searches the data table for the corresponding signal name and displays it in the display area 93. If there are many searched signal names, the screen can be scrolled by moving the scroll bar knob (slider) 94 up and down to display them.

When the user selects one of the signals displayed in the searched signal name display area 93 and clicks the move button 95, the signal is displayed in the selected signal name display area 97. At this time, the selected signals are displayed in the selected signal name display area 97 in order from top to bottom. When the user selects one of the signals displayed in the selected signal name display area 97 and clicks the move button 96, the signal is removed from the selected signal name display area 97. When the user selects one of the signals displayed in the selected signal name display area 97 and clicks the move button 98, the order in which the signal is displayed (i.e., the number corresponding to the signal) changes up by one. When the user selects one of the signals displayed in the selected signal name display area 97 and clicks the move button 99, the order in which the signal is displayed (i.e., the number corresponding to the signal) changes down by one.

When the user selects the Cancel All button 100, all signals displayed in the selected signal name display area 97 are deselected. As a result, nothing is displayed in the selected signal name display area 97.

When the user selects the automatic sorting button 101, all signals displayed in the selected signal name display area 97 are automatically sorted by the HMI tool 70 into an order that is considered appropriate. Details of this function will be explained in embodiment 3.

When the user clicks the Cancel button 102, the HMI tool 70 ends editing of the oscilloscope output pattern without storing the user-defined information for the oscilloscope output pattern in the RAM 32 and ROM 33 (specifically, the oscilloscope output pattern storage area 64 and the selected signal storage area 65) of the digital protection relay 1. As a result, processing returns to step S30 in Figure 4.

On the other hand, if the user clicks the Save button 103, the HMI tool 70 stores the user-defined information for the oscilloscope output pattern in the RAM 32 and ROM 33 (specifically, the oscilloscope output pattern storage area 64 and the selected signal storage area 65) of the digital protection relay 1, and then ends editing of the oscilloscope output pattern. As a result, processing returns to step S30 in Figure 4.

Next, when the user selects the test start button 86 on the oscilloscope setting/test start screen 80 in Figure 5 (YES in step S60), the test signal input device 3 inputs the test signal 66 to the digital protection relay 1. As a result, the oscilloscope output processing unit 62 outputs data related to the multiple selected signals set as the currently selected oscilloscope output pattern from the signal status table 61 to the oscilloscope recording device 4 via the oscilloscope output interface 42 at regular intervals (referred to as the first period, approximately several milliseconds).

Furthermore, the HMI tool 70 of the maintenance PC 2 requests the WEB-API server 63 to read data related to the selected signals from the signal status table 61 and send it to the maintenance PC 2 at regular intervals (referred to as the second interval, approximately every few hundred milliseconds).

More specifically, the HMI tool 70 converts the signal names of all selected signals displayed in the output signal list display area 84 into the corresponding addresses in the signal status table 61 and sends them to the WEB-API server 63. The WEB-API server 63 accesses the signal status table 61 based on the received addresses, collects the on/off states or numerical values of the signals stored at the corresponding addresses at regular intervals (second intervals), and sends them to the HMI tool 70. Alternatively, the WEB-API server 63 may access the signal status table 61 based on the addresses stored in the selected signal storage area 65, collect the on/off states or numerical values of the signals stored at the corresponding addresses at regular intervals (second intervals), and send them to the HMI tool 70.

Note that the WEB-API server 63 transmits the on/off states or numerical values of all selection signals to the HMI tool 70 during the first transmission during an operational test, but from the second transmission onwards, it may transmit only selection signals whose on/off states or numerical values have changed to the HMI tool 70.

The HMI tool 70 of the maintenance PC 2 displays the binary signal on/off status of the received data related to the multiple selection signals on the display unit 53, corresponding to the signal name (step S70).

The display of the on/off state of the output signal as described above will continue until the oscilloscope output pattern is changed by operating the selection unit 81 on the oscilloscope setting/test start screen 80 in Figure 5, or until a different screen is displayed by selecting the oscilloscope edit button 85 or the end button 87.

Here, the first cycle, during which the selected output signals are read from the signal status table 61 and sent to the oscilloscope recorder 4, is fast, on the order of several milliseconds. In contrast, the second cycle, during which the HMI tool 70 of the maintenance PC 2 retrieves the selected output signals from the signal status table 61 via the WEB-API server 63, is on the order of several hundred milliseconds. Therefore, the on/off states of the binary signals displayed on the display unit 53 of the maintenance PC 2 by the HMI tool 70 do not accurately reflect the state changes of the binary signals. However, when checking the final state of a binary signal, or when checking the state changes of a binary signal that change relatively slowly, on a second-by-second basis, this is easier than checking the content recorded on the oscilloscope recorder 4. Furthermore, unlike the simplified display unit 77 of the oscilloscope recorder 4, the signal names are displayed in association with each other, making it easier for users to confirm the signal names. These features enhance user convenience.

Figure 7 shows an example of the display of the oscilloscope settings/test start screen 80 during an operational test of the digital protection relay 1. As shown in Figure 7, among the signals displayed in the output signal list display area 84, the names of binary signals in the ON state are displayed with a background color 110. Note that the background color 110 is not the only option; the names of binary signals in the ON state and the names of binary signals in the OFF state can be displayed in different ways. This allows the user to easily check the ON/OFF state of binary signals.

When the user selects the End button 87 on the oscilloscope setting/test start screen 80 in Figure 5 (YES in step S80), the HMI tool 70 returns the screen display to the initial screen (step S10).

[Effects of First Embodiment]
According to the test system 8 for the digital protection relay 1 of the first embodiment, during an operation test, the state or value of the signal output from the digital protection relay 1 to the oscilloscope recorder 4 is also output to the maintenance PC 2 via the WEB-API server 63 and the LAN interface 41. The HMI tool 70 of the maintenance PC 2 displays the on/off state of the binary signal acquired from the digital protection relay 1 on the display unit 53 of the maintenance PC 2 in association with the signal name. This allows the user to easily check the on/off state of the binary signal.

Embodiment 2.
In the test system 8 of the second embodiment, when performing an operation test on the digital protection relay 1, the HMI tool 70 of the maintenance PC 2 displays the on/off states of the binary signals in association with the signal names on the display unit 53, and also displays the numerical values of the numeric signals in association with the signal names on the display unit 53. This further improves user convenience.

Figure 8 is a flowchart showing the operation of the HMI tool 70 during an operational test of the digital protection relay 1 in the test system 8 of embodiment 2.

The flowchart in Figure 8 differs from the flowchart in Figure 4 in that step S70 has been changed to step S70A. Specifically, when the user selects the test start button 86 on the oscilloscope setting/test start screen 80 in Figure 5 (YES in step S60), the test signal input device 3 inputs the test signal 66 to the digital protection relay 1. As a result, the oscilloscope output processing unit 62 outputs data representing the multiple selected signals set as the currently selected oscilloscope output pattern from the signal status table 61 to the oscilloscope recording device 4 via the oscilloscope output interface 42 at regular intervals (first intervals). Furthermore, the maintenance PC 2 requests the WEB-API server 63 at regular intervals (second intervals) to read the data representing the multiple selected signals from the signal status table 61 and transmit it to the maintenance PC 2. The HMI tool 70 of the maintenance PC 2 displays the on/off states of the binary signals among the received data for the multiple selection signals on the display unit 53, corresponding to the signal names, and also displays the numerical values of the numeric signals on the display unit 53, corresponding to the signal names (step S70A).

Here, the first period is relatively fast, on the order of several milliseconds, while the second period is relatively slow, on the order of several hundred milliseconds. For this reason, the on/off states of binary signals and the values of numeric signals displayed on the display unit 53 of the maintenance PC 2 by the HMI tool 70 do not accurately reflect the changes in the states and values of the binary signals. However, when checking the final states of binary signals and the final values of numeric signals, or when checking the changes in the states of binary signals and the changes in the values of numeric signals that change relatively slowly, on a second-by-second basis, it is easier to do so than by checking the content recorded on the oscilloscope recorder 4. Furthermore, because the signal states and values are displayed on the display unit 53 in association with the signal names, the user can easily check the signal names. These features further enhance user convenience.

Figure 9 shows another example of the oscilloscope setting/test start screen 80 displayed during an operational test of the digital protection relay 1. The output signal list display area 84 of the oscilloscope setting/test start screen 80 switches every 2 to 3 seconds between a screen displaying signal names as shown in Figure 4 and a screen displaying the on/off states of binary signals and the numerical values of numeric signals as shown in Figure 9, without changing the signal display position. For binary signals, on (ON), off (OFF), and lock (a type of ON) are displayed. Binary signals in the on state are displayed with a background color 110. Note that the background color 110 is not the only option; the binary signal names in the on state and the binary signal names in the off state can be displayed in different ways. For numerical signals, the numerical values are displayed with units and a background color 111 that is different from the binary signal color. This allows the user to easily associate the on/off states of binary signals and numerical signal values in steady state with the signal names.

[Digital protection relay test method]
10 is a flowchart for explaining a method for testing the digital protective relay 1. Hereinafter, the method for testing the digital protective relay described in the first and second embodiments will be summarized with reference to FIG.

In step S100 of Figure 10, first, the test signal input device 3 inputs a test signal 66 to the digital protection relay 1.

In the next step S110, the magnitude of the test signal 66 is adjusted in the input conversion unit 10 of the digital protection relay 1, and the test signal 66 is A/D converted in the A/D conversion unit 20.

In the next step S120, the calculation processing unit 30 performs various protection relay calculations on the A/D converted test signal 66.

In the next step S130, the calculation processing unit 30 stores in the signal status table 61, constantly updating the on/off states or numerical values of the input signals, intermediate signals during calculation, and output signals of the calculation processing unit 30 for various protective relay calculations.

In the next step S140, the calculation processing unit 30 reads the on/off states or numerical values of multiple signals selected by the user from the signals stored in the signal state table 61 from the signal state table 61 for each first period and outputs them to the oscilloscope recorder 4.

In the next step S150, the calculation processing unit 30 functions as a WEB-API server 63, and in response to a request from the maintenance computer 2, reads the on/off states or numerical values of the selected multiple signals from the signal status table 61 for each second period (>first period) and transmits them to the maintenance computer 2.

In the next step S160, the maintenance computer 2 displays the on/off states or numerical values of the selected signals received from the digital protection relay 1 on the display (display unit 53) in association with the signal names of the selected signals.

[Effects of the Second Embodiment]
According to the test system 8 for the digital protective relay 1 of the second embodiment, during an operation test, the signals output from the digital protective relay 1 to the oscilloscope recorder 4 are also output to the maintenance PC 2 via the WEB-API server 63 and the LAN interface 41. The HMI tool 70 of the maintenance PC 2 displays the on/off states of the binary signals among the signals output from the digital protective relay 1 on the display unit 53 of the maintenance PC 2 in association with the signal names, and also displays the values of the numeric signals in association with the signal names on the display unit 53 of the maintenance PC 2. This allows the user to easily check the on/off states of the binary signals and the values of the numeric signals.

Embodiment 3.
In the third embodiment, the operation of the HMI tool 70 when the automatic sorting button 101 is selected on the oscilloscope output pattern editing screen of FIG. 6 will be described.

The order in which signals are displayed as oscilloscope output patterns requires the know-how of experienced testers and designers/developers to ensure that the signals are easy to check. For example, related binary and numeric signals are displayed side by side. Once the purpose of the work is determined, the order in which such signals are displayed will be similar, although there will be some individual differences between testers and designers/developers.

Therefore, the display order of the selected signals set by many experienced testers and designers/developers is used as correct answer data to train the learning device using supervised learning. In this case, the correct answer data is not limited to one, but since they are similar to each other, the output of the trained model is an average of the correct answer data. The trained model obtained in this way is used to automatically sort multiple signals selected by the user. The learning phase and utilization phase will be explained below with reference to the drawings.

[Learning phase]
11 is a simplified diagram of the display area 84 of the output signal list in FIG. 5. For ease of explanation, this embodiment will describe a case where four signals are selected and displayed out of eleven signals from signal A to signal K. In FIG. 11, signal J is displayed in the first display position, signal D is displayed in the second display position, signal A is displayed in the third display position, and signal K is displayed in the fourth display position.

Figure 12 is a diagram explaining the input to the learning device. Referring to Figure 12 (A), the signal selected by the user from signals A to K is assigned a value of 1, and the unselected signal is assigned a value of 0. Therefore, the input in this case is [1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1].

Referring to Figure 12(B), if the four selected signal names are associated with 1, 2, 3, and 4, there are 24 patterns for the order of the four signals, patterns P1 to P24. Therefore, one of these 24 patterns will be the correct data corresponding to the input in Figure 12(A). In the case of Figure 11, the correct data is created by setting the value corresponding to pattern P15 to "1" and the other patterns to "0."

Figure 13 is a configuration diagram of a learning device for rearranging selection signals. As shown in Figure 13, the learning device 120 includes a data acquisition unit 121, a model generation unit 122, and a trained model storage unit 130.

The data acquisition unit 121 acquires, as input 1, information indicating whether or not each signal should be selected, as shown in Figure 12(A). As input 2 (correct answer data), it acquires a pattern indicating the order of the selected signals, as shown in Figure 12(B).

The model generation unit 122 learns the optimal order of selection signals as output based on training data created based on a combination of input 1 and input 2 (correct answer data) output from the data acquisition unit. In other words, it generates a trained model that infers the appropriate order of selection signals as output from input 1 and input 2 (correct answer data) related to the rearrangement of selection signals. Here, the training data is data that associates input 1 and input 2 (correct answer) with each other.

The learning device 120 and the inference device 140, which will be described later, are used to learn the optimal sequence of selection signals, but may be separate devices connected to the maintenance PC 2 of the test system 8 via a network, for example. The learning device 120 and the inference device 140 may also be built into the maintenance PC 2. Furthermore, the learning device 120 and the inference device 140 may reside on a cloud server.

Figure 14 is a diagram explaining learning in the model generation unit. Referring to Figure 14, the model generation unit 122 learns the appropriate order of selection signals using so-called supervised learning, for example, according to a neural network model. Here, supervised learning refers to a technique in which pairs of input and result (label) data are provided to a learning device, which learns the features of the learning data and infers the result from the input.

A neural network consists of an input layer consisting of multiple neurons, an intermediate layer (hidden layer) consisting of multiple neurons, and an output layer consisting of multiple neurons. The intermediate layer may be one layer, or two or more layers.

For example, in a three-layer neural network like the one shown in Figure 14, when multiple inputs are input to the input layer (X1-X3), the values are multiplied by weight W1 (w11-w16) and input to the middle layer (Y1-Y2), and the result is then further multiplied by weight W2 (w21-w26) and output from the output layer (Z1-Z3). This output result changes depending on the values of weights W1 and W2.

In the present disclosure, the neural network learns the output (i.e., the optimal order of selection signals) through so-called supervised learning in accordance with learning data created based on a combination of input 1 and input 2 (correct answer) acquired by data acquisition unit 121. In other words, the neural network learns by inputting input 1 to the input layer and adjusting weights W1 and W2 so that the result output from the output layer approaches input 2 (correct answer).

The model generation unit 122 generates and outputs a trained model 123 by performing the above-described learning. The trained model storage unit 130 stores the trained model 123 output from the model generation unit 122.

Next, the learning process performed by the learning device 120 will be explained using Figure 15. Figure 15 is a flowchart showing the learning process performed by the learning device.

In step S200, the data acquisition unit 121 acquires information indicating whether each signal will be used as input 1, and acquires a pattern indicating the order of the signals selected as input 2 (correct answer). Note that while input 1 and input 2 (correct answer) are acquired simultaneously, it is sufficient that input 1 and input 2 (correct answer) are entered in association with each other, and the data for input 1 and input 2 (correct answer) may be acquired at different times.

In step S210, the model generation unit 122 learns the optimal order of the selection signals as output using so-called supervised learning in accordance with the learning data created based on the combination of input 1 and input 2 (correct answer) acquired by the data acquisition unit 121, and generates a learned model 123.

In step S220, the trained model storage unit 130 stores the trained model 123 generated by the model generation unit 122.

[Utilization phase]
16 is a diagram showing the configuration of an inference device 140 for determining the optimum order of selection signals. Referring to FIG. 16, the inference device 140 includes a data acquisition unit 141 and an inference unit 142.

The data acquisition unit 141 acquires information indicating whether or not each signal is selected as input 1. More specifically, in accordance with embodiments 1 and 2, the data acquisition unit 141 acquires information on multiple selected signals selected by the user to be output to the oscilloscope recorder 4 from the signals to be stored in the signal status table 61.

The inference unit 142 infers as output a pattern representing the optimal order of the selection signals obtained using the trained model 123. That is, by inputting the information acquired by the data acquisition unit 141, i.e., information indicating whether or not each signal will be used, as input 1 to this trained model 123, it is possible to output a pattern representing the optimal order of the selection signals, which is the output inferred from input 1.

For example, as shown in Figure 12, assume that signal A, signal E, signal J, and signal K are selected as selected signals. Compared to the learning data shown in Figures 11 and 12, signal D has changed to signal E. In this case, the trained model 123 outputs pattern P15 as the inference result, and the final order of the selected signals is determined to be the order shown in Figure 16.

In this embodiment, the learned model 123 learned by the model generation unit 122 of the maintenance PC 2 is used to output a pattern representing the optimal order of the selection signals. However, the learned model 123 may be obtained from outside the maintenance PC 2, and a pattern representing the optimal order of the selection signals may be output based on this learned model 123.

Next, using Figure 17, we will explain the process for obtaining a pattern representing the optimal order of selection signals as output using the inference device 140. Figure 17 is a flowchart of the inference process of the inference device 140.

In step S300, the data acquisition unit 141 acquires information indicating whether each signal is to be used as input 1. More specifically, in accordance with embodiments 1 and 2, the data acquisition unit 141 acquires information on multiple selected signals selected by the user to be output to the oscilloscope recorder 4 from the signals to be stored in the signal status table 61.

In step S310, the inference unit 142 inputs the above input 1 into the learned model 123 stored in the learned model storage unit 130, and obtains as output a pattern representing the optimal order of multiple selection signals.

In step S320, the inference unit 142 outputs a pattern representing the optimal order of the multiple selection signals obtained by the trained model 123 to the maintenance PC 2.

In step S330, the HMI tool 70 of the maintenance PC 2 rearranges the signal names displayed in the selected signal name display area 97 on the oscilloscope output pattern editing screen in Figure 6 according to a pattern that represents the optimal order of the multiple selected signals that have been output. This places related signals close to each other, allowing the multiple selected signals to be rearranged in an order that makes it easy to check the test results.

In this embodiment, we have described a case where supervised learning is applied to the learning algorithm used by the model generation unit, but this is not limited to this. In addition to supervised learning, reinforcement learning, unsupervised learning, semi-supervised learning, etc. can also be applied as the learning algorithm.

Furthermore, the learning algorithm used in the model generation unit 122 can be deep learning, which learns to extract features themselves, or machine learning can be performed according to other known methods, such as genetic programming, functional logic programming, or support vector machines.

The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. The scope of this application is indicated by the claims, not the above description, and all modifications within the meaning and scope of the claims are intended to be included.

1 Digital protection relay, 2 Maintenance computer, 3 Test signal input device, 4 Oscilloscope recording device, 8 Test system, 10 Input conversion unit, 11 Input converter, 20 A/D conversion unit, 21 Analog filter, 22 Multiplexer, 23 A/D converter, 30 Processing unit, 31, 50 CPU, 32, 51 RAM, 33, 52 ROM, 34, 56 Bus, 40 I/O unit, 41, 55 LAN interface, 42 Oscilloscope output interface, 43 Digital output circuit, 44 Digital input circuit, 53 Display unit, 54 Input unit, 60 Protection calculation unit, 61 Signal status table, 62 Oscilloscope output processing unit, 63 WEB-API server, 64 Oscilloscope output pattern storage area, 65 Selected signal storage area, 66 Test signal, 70 HMI tool, 75 Recording unit, 76 Output unit, 77 Simple display unit, 80 Oscilloscope setting/test start screen, 120 Learning device, 121, 141 Data acquisition unit, 122 Model generation unit, 123 Trained model, 130 Trained model storage unit, 140 Inference device, 142 Inference unit.

Claims (8)

an analog-to-digital converter that receives a signal representing an amount of electricity acquired from the power grid during normal operation and a test signal during an operation test, and that digitally converts the input signal representing the amount of electricity and the test signal;
a protection relay calculation unit that performs various protection relay calculations on the digitally converted signal representing the electrical quantity and the test signal;
a signal state table that stores, while constantly updating, the on/off states or numerical values of the input signals, intermediate signals during calculation, and output signals of the protection relay calculation unit for the various protection relay calculations performed on the digitally converted test signals during the operation test;
an oscilloscope output processing unit that reads out from the signal state table, for each first period, on/off states or numerical values of a plurality of signals selected by a user from among the signals stored in the signal state table, and outputs the read on/off states or numerical values to an oscilloscope recorder;
a WEB-API (Application Program Interface) server that, in response to a request from an external maintenance computer, reads the on/off states or numerical values of the selected plurality of signals from the signal state table every second period that is longer than the first period and transmits the read information to the maintenance computer. The on/off state or the numerical value of each signal stored in the signal state table can be accessed by specifying the address of the signal state table;
2. The digital protection relay of claim 1, further comprising a first memory area for storing a plurality of addresses of the signal state table corresponding to the selected plurality of signals. The digital protection relay according to claim 2;
an oscilloscope recorder that receives and records the states or values of the selected signals from the oscilloscope output processor for each of the first periods;
a maintenance computer that communicates with the WEB-API server according to an Internet protocol;
the maintenance computer reads out the addresses from the first memory area via the WEB-API server, and displays signal names of the selected signals corresponding to the addresses on a display;
A digital protection relay testing system in which the maintenance computer, during the operational test, displays on the display the on/off states or numerical values of the selected multiple signals read from the signal status table via the WEB-API server, in association with each signal name. The digital protection relay test system of claim 3, wherein the maintenance computer associates the on/off states of the binary signals with their respective signal names by displaying the signal names of the binary signals among the selected plurality of signals on the display in different formats for the on and off states. The digital protection relay test system of claim 3, wherein the maintenance computer associates the on/off states or numerical values of the selected signals with their respective signal names by alternately displaying the signal names of the selected signals and their corresponding on/off states or numerical values in the same position on the display. The maintenance computer further
an acquisition unit that acquires information on a plurality of signals selected by a user from the signals to be stored in the signal status table to be output to the oscilloscope recorder;
an inference unit that infers, from the signal names of the selected plurality of signals, an order of the signal names of the selected plurality of signals when the signal names of the selected plurality of signals are to be displayed on the display, using a trained model for inferring, from the signal names of the selected plurality of signals, an order of the signal names of the selected plurality of signals when the signal names of the selected plurality of signals are to be displayed on the display;
The digital protection relay test system according to any one of claims 3 to 5, wherein the maintenance computer displays the signal names of the selected plurality of signals on the display in the inferred order. The digital protection relay testing system of claim 6, wherein the trained model is generated by supervised learning using an order created by an experienced user as correct answer data. A test method for a digital protective relay, comprising:
inputting a test signal to the digital protection relay;
The digital protection relay performs analog-to-digital conversion of the test signal;
A step in which an arithmetic processing unit of the digital protection relay performs various protection relay operations on the analog/digital converted test signal;
The calculation processing unit stores, in a signal state table while constantly updating, the on/off states or numerical values of the input signals, intermediate signals during calculation, and output signals of the calculation processing unit for the various protective relay calculations;
the calculation processing unit reading out from the signal state table, for each first period, on/off states or numerical values of a plurality of signals selected by a user from among the signals stored in the signal state table, and outputting the read out states or numerical values to an oscilloscope recorder;
the calculation processing unit functions as a WEB-API (Application Program Interface) server, and in response to a request from an external maintenance computer, reads out the on/off states or numerical values of the selected plurality of signals from the signal state table for each second period longer than the first period, and transmits the read out signals to the maintenance computer;
and displaying, by the maintenance computer, on a display, the on/off states or numerical values of the selected plurality of signals received from the digital protection relay in association with the signal names of the selected plurality of signals.