A relay protection automatic calibration method and a relay protection tester

Abstract

The present invention relates to the technical field of relay protection calibration in substations, and more particularly to a method for automatically calibrating relay protection and a relay protection tester. The present invention calibrates the definite-time overcurrent protection and the definite-time ground protection functions of the relay protection device respectively: controls the relay protection tester to output voltage, current, frequency, and phase to simulate the secondary-side fault conditions of the power system, measures the electrical quantities and time parameters of the calibration device through the input interface of the relay protection tester, automatically generates an experimental report in combination with the database background, judges the pass or fail of the calibration items, and controls the operation process of the relay protection calibration. The present invention solves the problems of difficult calibration of relay protection devices and the need for a large amount of manual operations, and achieves the technical effects of replacing traditional manual operations, reducing the labor intensity of technicians, and ensuring the safety of technicians.

Description

Technical Field

[0001] The present invention relates to the technical field of relay protection calibration in substations, and more particularly to a method for automatically calibrating relay protection and a relay protection tester. Background Art

[0002] The AC power distribution system is an important part of the station service power system of a nuclear power plant. Under any working conditions (normal or accident conditions), it provides a safe and reliable AC power supply for the auxiliary equipment of the nuclear power plant and provides an emergency power supply for the equipment related to nuclear safety to ensure the safe operation of the nuclear power plant. There are many devices in the AC power distribution system of the nuclear power plant, with a high degree of standardization, and the commissioning and operation methods have been quite mature.

[0003] A relay protection device is a secondary device that can timely send a warning to the on-duty operator or directly control the circuit breaker to trip to terminate the development of a fault when a power component or the power system itself in the power system fails and endangers the safe operation of the power system. It plays a crucial role in the safe operation of the power system, directly affecting the safety and stable operation of the system. Maintaining the relay protection device, eliminating device abnormalities and fault defects are important tasks for power system maintenance.

[0004] In order to improve the stability of the medium-voltage station service power system equipment and make the unit safety more guaranteed, relay protection staff need to carry out the "protection setting verification" work many times every year. However, problems such as poor operation and maintenance of staff, misoperation, wiring errors, incorrect installation and commissioning, personal safety problems of staff caused by principle and software defects, poor equipment commissioning quality, potential hazards in the operation of the power system, and heavy work tasks make the calibration of relay protection devices a major problem.

[0005] With the rapid development of automation technology, microcomputer protection in the field of relay protection has become the main means in the current relay protection field of the power system and has also laid a solid foundation for the automatic calibration of relay protection devices. However, as a highly automated operation method in a new application field, the automatic calibration system of relay protection devices has not been studied for a long time at home and abroad. Generally speaking, automatic relay protection calibration is an automated device system that involves the integration of multiple fields and disciplines and has a certain degree of specialization.

[0006] There is little research on the automatic verification of relay protection for high- and low-voltage power distribution devices at home and abroad. Currently, there is no mature and highly targeted product applied in the practice of electrical operations. However, developing a relay protection device verification system that can be process-oriented and standardized can not only increase the reliability of the safe operation of the power grid, improve the efficiency and accuracy of equipment verification, but also reduce the workload and human errors of technical personnel, which is of great significance. In the context of this highly automated era, it is an inevitable trend to cooperate with a computer software system to verify relay protection devices. Therefore, it is necessary to design and research an automatic verification system for relay protection in the power system. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a relay protection automatic verification method to solve the problems of difficult verification of relay protection devices and the need for a large amount of manual operation, so as to replace traditional manual operation, reduce the labor intensity of technical workers, and ensure the safety of technical workers.

[0008] The technical solution of the present invention is as follows:

[0009] The relay protection automatic verification method verifies the definite-time overcurrent protection and definite-time ground protection functions of the relay protection device respectively: controls the relay protection tester to output voltage, current, frequency, and phase to simulate the secondary side fault conditions of the power system, measures the electrical quantities and time parameters of the verification device through the input interface of the relay protection tester, automatically generates an experimental report in combination with the database background, and judges the pass or fail of the verification items to control the relay protection verification operation process.

[0010] As a preferred solution: verifying the definite-time overcurrent protection function of the relay protection device includes verifying the current action value of the relay protection device and verifying the action time of the relay protection device, which specifically includes the following steps:

[0011] S1. Simulate the DC power supply through the voltage output of the relay protection tester to supply power to the relay protection device;

[0012] S2. Adjust the three-phase current output of the relay protection tester respectively to confirm that there is no abnormality in the relay sampling;

[0013] S3. Adjust the time setting value of the low-set definite-time overcurrent protection to the minimum;

[0014] S4. Gradually increase the current of phase A, phase B, and phase C of the relay protection tester in turn until the current I of the relay protection device > the action value of the relay protection device, and record the action current value of the relay protection device;

[0015] S5. Set the current I of the relay protection device > the time setting value of the protection;

[0016] S6. Reset the relay protection device and adjust the three-phase output current of the relay protection tester;

[0017] S7. Operate the relay protection tester to start output, and record the action time of the relay protection device;

[0018] S8. Obtain the protection verification value, automatically judge whether the verification item is qualified, and generate an experiment report.

[0019] As an optimal solution: in the step S1, simulate a 110V DC power supply through the voltage output of the relay protection tester.

[0020] As an optimal solution: in the step S2, adjust the three-phase current outputs of the relay protection tester to 0.5A, 0.8A, and 1A respectively.

[0021] As an optimal solution: in the step S5, according to the project requirement setting value, set the current I> protection time setting value of the relay protection device to 6s.

[0022] As an optimal solution: in the step S6, adjust the A-phase current Ia, B-phase current Ib, and C-phase current Ic outputs of the relay protection tester to 1.2 times the I> action value.

[0023] As an optimal solution: verifying the definite-time ground protection function of the relay protection device includes verifying the current action value of the relay protection device and the action time of the relay protection device, and specifically includes the following steps:

[0024] S10. Adjust the high-set definite-time ground protection time setting value to the minimum and the low-set definite-time ground protection time setting value to the maximum to ensure that the tripping type is high-set definite-time ground protection;

[0025] S20. Set the initial value of the output current, and the defined test data object will download the test data to the controllable power supply circuit of the relay protection tester;

[0026] S30. Steppingly increase the corresponding test variables in the test function body, wait to receive the protection tripping signal until the I> action value of the relay protection device, and read and record the relay protection device action current value;

[0027] S40. According to the relay protection device action current value in the step S30, change the test parameters downloaded by the test data object, adjust the three-phase output current of the relay protection tester, and poll whether the relay protection tester receives the tripping signal of the relay protection device;

[0028] When the relay protection device trips, the test result is returned, and the action time of the relay protection device is displayed;

[0029] S50. The test is over. Store and upload the data, generate an experiment report and a verification result according to the calibration item setting sheet. When exiting the main interface window, exit the main loop, destroy the test server, and restore the protection time setting value of the relay protection device according to the setting sheet.

[0030] As a preferred solution: During the test, the data collected by the relay protection tester can be seen through the interactive text box on the main window. The experiment process can be interrupted or the output electrical quantity of the relay protection tester can be adjusted through the corresponding buttons to manually intervene and adjust the experiment process, and finally complete the automatic calibration of the relay protection device.

[0031] A relay protection tester includes a relay protection tester housing, a controllable power supply, a main control platform, and a control terminal. Inside the relay protection tester housing, there are a controllable power supply and a main control platform. The controllable power supply is rigidly connected to the relay protection device under test through voltage and current output terminals, which is used to provide an auxiliary power supply for the relay protection device under test and can simulate the real working state of the relay protection device on the secondary side of the power system. The main control platform exchanges information with the controllable power supply and can receive the trip signal of the relay protection device under test. The main control platform is interconnected with a control terminal that can output the signal of the main control platform and input a control command to the main control platform.

[0032] As a preferred solution: The control terminal includes a touch screen, an external keyboard, an indicator light, and a control switch. The touch screen is set on the relay protection tester housing and is used to display the input current and status of the relay protection device under test. The touch screen is interconnected with the main control chip. The external keyboard is horizontally set on the relay protection tester housing through an external keyboard bracket, and the external keyboard bracket is fixedly set on the fixed bracket. The output end of the external keyboard is connected to the input end of the main control chip. The indicator light is set above the relay protection tester housing and is used to indicate the operation status of the relay protection tester. The output end of the main control chip is connected to the input end of the indicator light. The control switch is set above the relay protection tester housing, and the controlled end of the control switch is connected to the output end of the main control chip. The control switch includes a device main switch and a stop experiment switch.

[0033] As a preferred solution: The main control platform includes a main control chip, a three-phase controllable power supply output circuit, a minimum system part, and an external interface group. The external interface group includes one or several of an Ethernet interface, a USB interface, an AD / DA interface, and an input quantity interface. The main body of the three-phase controllable power supply output circuit is a three-phase bridge inverter circuit. The minimum system part is the peripheral circuit required for the operation and debugging of the main control chip. The minimum system part includes a power supply circuit, a crystal oscillator clock circuit, and a reset circuit.

[0034] As a preferred solution: A custom button group and a main board interface slot are also set above the relay protection tester housing.

[0035] The beneficial effects of the present invention are as follows:

[0036] (1) The present invention discloses a relay protection automatic calibration method and a relay protection tester, which respectively calibrate the definite-time overcurrent protection and definite-time ground protection functions of a relay protection device: control the relay protection tester to output voltage, current, frequency, and phase to simulate the secondary-side fault conditions of a power system, measure the electrical quantities and time parameters of the calibration device through the input interface of the relay protection tester, automatically generate an experiment report in combination with the database background, and judge the qualification of the calibration items, and control the relay protection calibration operation process. The present invention replaces a large number of manual operations in the relay protection calibration during the current AC power distribution system commissioning, realizes the intelligence and automation of the commissioning work, has the advantages of safety, high efficiency, and accuracy, reduces the labor intensity of technical workers, and ensures the safety of technical workers.

[0037] (2) The present invention is a research and application of artificial intelligence and automation technologies in the field of power distribution commissioning. It replaces a large number of manual operations in the relay protection calibration during the current AC power distribution system commissioning, realizes the intelligence and automation of the commissioning work, and has the advantages of safety, high efficiency, and accuracy. The present invention can automatically complete tasks such as power system fault simulation and relay protection device calibration, improve the safety and automation level of on-site operations, eliminate human errors, make timely and scientific calibrations of the state of relay protection devices, reduce the labor intensity of staff, and improve work efficiency. The present invention has strong interdisciplinary comprehensiveness, conforms to the law of technological development, and has considerable foresight and challenges. The present invention is related to the safe operation of power systems and relay protection devices, has a broad application prospect, and has strong economic and social benefits.

[0038] (3) The voltage and current output control of the present invention can simulate ground faults, phase-to-phase faults, open-circuit faults, etc. on the secondary side of a power system, accurately test the operation conditions, return values, and operation times of the overcurrent protection, distance protection, differential protection, zero-sequence protection, etc. states of a relay protection device, and can automatically judge the qualification of the calibration items and upload data to generate a corresponding experiment report, ensuring the stability and controllability of the calibration process, eliminating the influence of human errors, and greatly reducing the work tasks of technical personnel.

[0039] (3) After introducing this process-based calibration software system in the protection calibration, the present invention can effectively reduce the human error problems caused by reasons such as poor operation and maintenance, wiring errors, incorrect installation and commissioning of staff during the calibration process, eliminate human errors, and can make timely and scientific calibrations of the state of relay protection devices, reduce the labor intensity of staff, improve work efficiency, and at the same time ensure the personal safety problems of staff caused by principle and software defects. It ensures the feasibility, stability, generality, and maintainability of engineering applications. Description of the Drawings

[0040] Figure 1 It is a schematic structural diagram of the relay protection tester of the present invention;

[0041] Figure 2 It is the overall structural schematic diagram of the relay protection automatic calibration device of the present invention;

[0042] Figure 3 It is the connection schematic diagram of each device in the relay protection automatic calibration device of the present invention;

[0043] Figure 4 It is the output circuit diagram of the three-phase controllable power supply of the present invention;

[0044] Figure 5 It is the logic block diagram of the main control chip of the present invention;

[0045] Figure 6 It is the schematic diagram of the Ethernet interface of the present invention;

[0046] Figure 7 It is the schematic diagram of the USB interface of the present invention;

[0047] Figure 8 It is the schematic diagram of the AD / DA interface of the present invention;

[0048] Figure 9 It is the main module diagram of the automatic calibration software system of the present invention;

[0049] Figure 10 It is the schematic diagram of the automatic calibration execution flow of the present invention;

[0050] Figure 11 It is the main UI form of the automatic calibration software system of the present invention;

[0051] Figure 12 It is the interface diagram of the third-level interface "Calibration System Control Center" of the automatic calibration software system of the present invention;

[0052] Figure 13 It is the fourth-level interface diagram of the automatic calibration software system of the present invention.

[0053] Among them: 1. Total device switch; 2. Stop experiment switch; 3. Three-phase output terminals; 4. Input quantity interface A; 5. Input quantity interface B; 6. Controllable power supply; 7. External keyboard bracket; 8. External keyboard; 9. Fixed bracket; 10. Touch screen; 11. Custom button group; 12. Motherboard interface slot; 13. Indicator light; 14. Tester housing. Detailed Implementation Manner

[0054] The relay protection automatic verification device and automatic verification software system have the following main functions: voltage and current amplitude, frequency and phase control of the relay protection tester; input action value, return value and action time information collection of the relay protection tester; automatic verification of test results and data upload. Among them, the voltage and current output control can simulate the grounding fault, phase-to-phase fault and line break fault on the secondary side of the power system, and can accurately test the action status, return value and action time of the overcurrent protection, distance protection, differential protection and zero-sequence protection of the relay protection device, and can automatically judge whether the verification items are qualified or not, and upload the data to generate the corresponding experimental report, which ensures the stability and controllability of the verification process, eliminates the influence of human errors, and greatly reduces the work tasks of technicians.

[0055] Relay protection automatic verification device, combined with Figures 1 to 8 As shown, it includes a relay protection tester, an external computer, and experimental connection wires.

[0056] The relay protection tester of the present invention is the main equipment of the automatic verification system. The first function of the relay protection tester is to serve as an external auxiliary power supply during the verification of the relay protection device. It can be manually controlled to output 110V DC or 110V AC voltage to power the relay protection device; its second function is to output A, B, C three-phase current to simulate the actual working state of the secondary relay protection device of the power system.

[0057] The external computer is the main device that interacts with technical personnel during the automated verification of relay protection devices. It is designed in a streamlined and standardized manner in accordance with the standard protection relay verification method in actual projects. It enables staff to complete the verification of specific items of relay protection devices with "one click" and display the test results such as protection action current and action time returned by the relay protection tester in the interactive text box.

[0058] The relay protection device is the equipment to be tested. During the experiment, it is necessary to connect the fault current simulated by the relay protection tester to the current test terminal, and connect the terminal of the trip signal output relay to the fast input contact of the relay protection tester to feed back the trip signal to the relay protection tester. In addition, the display module of the relay protection device can display the current input current, the current relay status, and the type of tripping fault when tripping.

[0059] The relay protection tester includes a relay protection tester housing 14, a controllable power supply 6, a main control platform, and a control terminal.

[0060] A controllable power supply and a main control platform are arranged inside the housing 14 of the relay protection tester.

[0061] The controllable power supply 6 is rigidly connected to the relay protection device under test through voltage and current output terminals, which is used to provide an auxiliary power supply for the relay protection device under test and can simulate the real working state of the relay protection device on the secondary side of the power system.

[0062] Information interaction is carried out between the main control platform and the controllable power supply, and the tripping signal of the relay protection device under test can be received. The main control platform is interconnected with a control terminal that can output the signals of the main control platform and input control instructions to the main control platform.

[0063] The main control platform includes a main control chip, a three-phase controllable power supply output circuit, a minimum system part, and an external interface group.

[0064] The control terminal includes a touch screen 10, an external keyboard 8, an indicator light 13, and a control switch. The touch screen 10 is arranged on the housing of the relay protection tester and is used to display the input current and status of the relay protection device under test. The touch screen 10 is interconnected with the main control chip. The touch screen in the present invention is a 15-inch touch screen. The external keyboard 8 is horizontally arranged on the housing of the relay protection tester through an external keyboard bracket 7, and the external keyboard bracket 7 is fixedly arranged on a fixed bracket 9. The output end of the external keyboard 8 is connected to the input end of the main control chip. The indicator light 13 is arranged above the housing of the relay protection tester and is used to indicate the operating status of the relay protection tester. The output end of the main control chip is connected to the input end of the indicator light 13. The control switch is arranged above the housing of the relay protection tester, and the controlled end of the control switch is connected to the output end of the main control chip. The control switch includes a device main switch 1 and a stop experiment switch 2.

[0065] The main control chip uses a cyclone IV series lightweight FPGA chip EP4CE6F17C8, and its peripheral circuit mainly includes a minimum system part, an external interface group, control and interaction peripherals, etc.

[0066] The external interface group includes an Ethernet interface, a USB interface, an AD / DA interface, and an input quantity interface. The Ethernet interface is responsible for external data exchange and output control, and communication between the controllable power supply and the main control platform is carried out through the Ethernet interface. The USB interface can be externally connected to a keyboard or copy the measured historical data from the internal storage of the main control device. The AD / DA interface is responsible for reading the analog quantity output of the controllable power supply, converting it into a digital quantity, and handing it over to the touch screen for the convenience of operators to read data. The controllable power supply outputs the analog quantity to the main control platform through the AD / DA interface. The input quantity interface is used to input the action value of the input quantity of the relay protection device under test into the main control chip. At the same time, the main control chip adjusts the output of the PWM interface through a closed-loop control logic to ensure the power output accuracy of the relay protection tester. The input quantity interface includes an input quantity interface A4 and an input quantity interface B5.

[0067] The main body of the three-phase controllable power supply output circuit is a three-phase bridge inverter circuit. When simulating the output of three-phase sinusoidal alternating current, its basic working mode is the 180° conduction mode, that is, the conduction angle of each bridge arm is 180°, the upper and lower two bridge arms of the same phase conduct alternately, the conduction angles of each phase start to differ by 120° in sequence, and the trigger pulses of the thyristors in each phase are controlled by the PWM wave output by the internal main control circuit. By controlling the conduction and non-conduction of the bridge arms and the conduction angle, the test voltage is output. A three-phase output terminal 3 is connected to the three-phase controllable power supply output circuit.

[0068] The minimum system part is the peripheral circuit required for the operation and debugging of the main control chip. The minimum system part includes a power supply circuit, a 50M crystal oscillator clock circuit, and a reset circuit.

[0069] Above the relay protection tester housing 14, a custom key group 11 and a main board interface slot 12 are also provided.

[0070] The automatic calibration software system has a high degree of automation, harmonious human-computer interaction, and controls the relay protection tester to automatically complete the relay protection device calibration process. It can process and standardize the management of the relay protection device calibration process. The automatic calibration software system can control the relay protection tester to output voltage, current, frequency, and phase to simulate the secondary side fault conditions of the power system; and can measure electrical quantities and time parameters such as the operating current, operating time, and return value of the calibration device through the input interface of the relay protection tester. Combined with the database background, it automatically generates an experimental report, judges the qualification of the calibration items, and conducts process-based and standardized management of the relay protection calibration operation process, integrating information such as documents, equipment, and data. Combining task distribution, test execution, process analysis, and data upload, it realizes the organic unity and integration of information flow, workflow, and business flow. It has the advantages of safety, high efficiency, and accuracy, can replace traditional manual operations, reduces the labor intensity of technical workers, and ensures the safety of technical workers.

[0071] The flow-based verification algorithm adopted by the present invention fully considers that in the actual working conditions, the protection setting values artificially set by the relay protection device itself are not the true values under the actual operating state of the secondary-side protection system of the power system. The algorithm truly considers the operation process of technicians for actual protection verification. The automatic verification software system is portable and expandable, and can be adjusted and modified in terms of the process according to the equipment and projects to be verified, with universality. The theoretical bases involved include relay protection principles, communication principles, automatic control technologies, etc. The theoretical bases in each field are quite mature. Through the analysis of each step of the verification process, the present invention integrates and applies the theories, ensuring the feasibility, stability, universality and maintainability of engineering applications, and ensuring the standardization, accuracy, authenticity of verification results and verification accuracy of protection verification. The user-friendly human-computer interaction system eliminates the disadvantages of complex and inflexible operation in the traditional verification process; at the same time, it greatly improves the work efficiency of maintenance personnel and reduces human errors.

[0072] The tested relay of the present invention selects SPAJ142C general combined overcurrent and earth fault protection relay. The combined overcurrent and earth fault relay is a secondary relay, which is connected to the current transformer of the feeder to be protected. The three-phase overcurrent element and the non-directional zero-sequence current element continuously measure the current and zero-sequence current of the feeder to be protected. In case of a fault, these elements can start the external automatic reclosing or trip the circuit breaker according to the selected protection mode. When the fault current exceeds the setting value of the overcurrent element, this element starts, and at the same time starts the corresponding time-delay circuit. When the setting action time arrives, an overcurrent protection action trip command is issued. Similarly, when the fault current exceeds the setting value of the instantaneous overcurrent element, this element starts, and at the same time starts the corresponding time-delay circuit. When the setting action time arrives, an instantaneous overcurrent action trip command is issued. The non-directional zero-sequence overcurrent element is based on the same action principle. This element can send a signal, trip the circuit breaker or start the external automatic reclosing according to different selected protection modes.

[0073] In actual working conditions, when the protection setting values set by the relay protection device are not the true values under the actual operating state of the secondary-side protection system of the power system, if the relay protection device cannot be calibrated before it is put into operation or regularly, it will pose a huge hidden danger to the safe operation of the power system or the auxiliary power of the plant. It is very likely that the protection will refuse to operate or malfunction, thus expanding the scope of influence of the power grid / power plant fault and causing serious adverse consequences. After introducing this process-based calibration software system in the protection calibration, it can effectively reduce the human error problems caused by poor operation and maintenance, wiring errors, incorrect installation and commissioning, etc. of the staff during the calibration process, eliminate the human error, and can make timely and scientific calibration of the state of the relay protection device, reduce the labor intensity of the staff, improve the operation efficiency, and at the same time ensure the personal safety of the staff caused by principle and software defects. It ensures the feasibility, stability, generality and maintainability of the engineering application.

[0074] The main functions of the automatic calibration software are written in Python (version 2.7) language, and the UI interface and main functions require the support of components such as the pywin32 module, tkinter module, and time module.

[0075] The software part of the automatic test system consists of four-level interfaces. After the wiring is completed, the operator enters the login interface. After logging in, enter the next-level interface and start to select the type of relay protection device to be tested and the test items, and enter the automatic test subroutine, including test wiring, sampling inspection, low-setting value definite-time overcurrent protection calibration, high-setting value definite-time overcurrent protection calibration, and definite-time earthing protection calibration, etc.

[0076] The software function modules of the automatic calibration software system are as Figure 9 shown, including test server creation and destruction, test point data switching, obtaining the root node of the test result, extracting the test result, automatic timing, uploading the status of switch quantities, etc.; among them, the main function of encapsulating the test data to switch test points is to change the output of the controllable power supply circuit according to the calibration process of the relay protection device, so as to simulate the fault state of the secondary side of the power system and adjust the output of electrical quantities; obtaining the root node of the test result can read the switch quantity information of the current automatic test from the on-board memory, output the assignment of electrical quantities, phase, etc., read the currently output electrical quantities, and perform analysis and processing; extract the test result, and the part of uploading the switch quantity status information can upload the test data read by the server to the database, combine the background information of the database and the time parameters, automatically generate an experimental report, and judge the qualification of the calibration items, and control the relay protection calibration process.

[0077] The main logical process of the program execution is:

[0078] 1. First, import the py files of the above modules and the corresponding dynamic libraries into the development directory;

[0079] 2. Call tkinter to create the host computer main window, and add controls such as buttons representing various functions and interactive text boxes in the main window;

[0080] 3. After the main window is formed, create an ONLLY test server and pass the main window handle into the service; define a test data object for the test data to download the parameters of the relay protection tester;

[0081] 4. Start initializing global variables such as test data, such as configuring the auxiliary DC power supply terminals Uc and Ux for powering on the relay protection device, and initial values of three-phase current variables Ia, Ib, Ic and their frequencies, phases, etc.;

[0082] 5. Before performing the test, pass the defined IP address and port number PORT into the service function to complete the connection with the relay protection tester and prepare to start the test; among them, the controllable power supply circuit of the relay protection tester is connected to the internal main control platform through a single cross network cable via an Ethernet interface, and the TCP / IP transmission control communication protocol is used. Before using the software system to execute the calibration test process, the server creates a subroutine to bind the IP address and PORT (port number) of the external computer to the relay protection tester, connect to the relay protection tester, declare a strLinkInfo variable in the program, and pass the IP address and port number of the relay protection tester device into this variable, call the OTS_LinkDevice(strLinkInfo) function to make the external computer shake hands with the relay protection tester for hardware connection. After the connection is successful, 'Connection successful' is displayed in the software interactive text box and the test can start.

[0083] When the tester presses the 'Start Test' button, the server activates the test program, assigns the initial values to the defined experimental parameters, and starts the test experiment; at this time, the relay protection device is powered on, prepares to start specific test items, and starts the main program loop.

[0084] Wait for the operator to press the test button for the corresponding calibration item to prepare for the test; among them, each test item is divided into two parts. In the overcurrent protection calibration item: 'Overcurrent Protection Calibration - 1' calibrates the current action value of the relay protection device, and 'Overcurrent Protection Calibration - 2' calibrates the action time of the relay protection device; in the calibration item of the definite-time ground protection function: 'Ground Protection Calibration - 1' calibrates the current action value of the relay protection device, and 'Ground Protection Calibration - 2' calibrates the action time of the relay protection device.

[0085] The automatic verification software system of the present invention consists of four levels of interfaces. The interface part is designed and completed through Unity. Each level of interface includes a call to the main event loop to capture actions on the user's computer screen.

[0086] The first-level interface is the main interface of the software platform, which displays the name "Automatic Verification System for Relay Protection Devices" and the LOGO in the lower right corner. By clicking anywhere on the screen, it is possible to jump to the second-level interface "Operator Login Interface". After entering the bound account password, it is possible to enter the control center of the verification system; if the entered account password is incorrect, a pop-up window will prompt that the account password is incorrect, and it will stay on this interface to re-enter.

[0087] Combined with Figure 12 As shown, the third-level interface is the "Control Center of the Verification System", where different verification items can be selected, including "Test Wiring", "Sampling Inspection", "Low Setting (Overcurrent) Definite-Time Overcurrent Protection Verification", "High Setting (Instantaneous) Definite-Time Overcurrent Protection Verification", "Low Setting Definite-Time Earth Fault Protection Verification", "High Setting Definite-Time Earth Fault Protection Verification", etc.; clicking on different modules can enter the fourth-level interface and create the main window of the application program by connecting to the tester; when the program starts running to create the main form, a test server is created through OTS_CreatServer(). This method is used to receive the window handle of the message sent by the test server, so that the window handle parameter of the main form is bound to the server. The operations performed by the user on the main form can be passed to the server class based on this. At the same time, the electrical quantity parameters output by the tester declared in the server class can also be operated on the main form. If an event is detected in the server, the test server will send a message named WM_ONLLYTS_MSG to the window. However, when the application program no longer needs to use the ONLLY test server, the OTS_DestroyServer() method must be called to release the created test server.

[0088] Combined with Figure 13 As shown, after the host is connected to the tester, it enters the fourth-level interface, and specific experimental steps can be started. This interface includes the experimental project name on the left, the experimental form area in the middle, the experimental data status bar on the right, and the operation shortcut buttons in the lower right corner. After entering the fourth-level interface, it is possible to start selecting the test form for the corresponding test item. After selection, the form will be displayed in the central area of the interface. The test results can be seen in the status bar on the right. After the data is transmitted back, data entry can be performed by directly clicking on the table input box, or it can be modified and adjusted manually; when the entry of a project is completed, the form can be saved in the database by clicking the "Entry Button" for historical data preservation, which is convenient for later verification; at the same time, in this interface, the historical entry data in the database can be read and checked by clicking the "History Button".

[0089] After the operation is completed, you can click the "Return Button", and at this time, the system will automatically destroy the test server created at the beginning of the test and exit the test platform simultaneously.

[0090] Relay protection automatic calibration method, combined with Figures 9 to 11 As shown, calibrate the definite-time overcurrent protection and definite-time ground protection functions of the relay protection device respectively.

[0091] Control the relay protection tester to output voltage, current, frequency, and phase to simulate the secondary side fault conditions of the power system. Measure the electrical quantities and time parameters of the calibration device through the input interface of the relay protection tester, automatically generate an experimental report in combination with the database background, and judge the qualification of the calibration items to control the relay protection calibration operation process.

[0092] Taking the I> of the overcurrent relay protection device as an example: The current element of the SPCJ4D29 relay module is designed as single-phase, two-phase, or three-phase overcurrent protection. It contains two overcurrent segments, namely overcurrent protection I> (low-setting overcurrent protection) and instantaneous overcurrent protection I>> (high-setting overcurrent protection). If the current of one or several phases exceeds the setting value of its corresponding protection, the overcurrent protection or instantaneous overcurrent protection will start. When starting, the corresponding protection issues a start signal SS1 or TS1. At the same time, the digital display on the panel starts. If the fault time exceeds the set operating time, the started protection will operate and trip, issuing a TS2 trip signal to trip the circuit breaker.

[0093] Calibrating the definite-time overcurrent protection function of the relay protection device includes calibrating the current operating value of the relay protection device and calibrating the operating time of the relay protection device, including the following steps:

[0094] S1. Simulate a 110V DC power supply through the voltage output of the relay protection tester to supply power to the relay protection device.

[0095] S2. Adjust the three-phase current outputs of the relay protection tester to 0.5A, 0.8A, and 1A respectively to confirm that there is no abnormality in the relay sampling.

[0096] S3. Adjust the time setting value of the low-setting definite-time overcurrent protection to the minimum, and the time setting value of the low-setting definite-time overcurrent protection is 0.05s, to ensure that the I> of the relay protection device operates when the current reaches the setting value.

[0097] S4. Slowly increase the current of phase A of the relay protection tester (in steps of 0.01A) until the operating value of I> of the relay protection device. At this time, record the operating current value of the relay protection device through the input signal inversion of the relay protection tester; similarly, test phases B and C. At this time, obtain the three-phase operating values of the I> protection.

[0098] S5. Set the time setting value of the I> protection of the relay protection device to 6 s according to the fixed value required by the project.

[0099] S6. Reset the relay protection device and adjust the relay protection tester I a , I b , I c The output is 1.2 times the I> operating value.

[0100] S7. Operate the relay protection tester to start outputting, and record the operation time of the relay protection device through the reverse signal of the input quantity of the relay protection tester.

[0101] S8. Obtain the protection verification value, automatically judge whether the verification item is qualified, and generate an experiment report.

[0102] 'Overcurrent protection verification - 1' verifies the current operating value of the relay protection device:

[0103] First, according to the selected relay protection verification item, the server calls the corresponding voltage and current test module, sets the initial value of the output current according to the setting list of the actual verification item, and transfers the test data to the relay protection tester through the defined test data object m_szTestParam;

[0104] Secondly, in the test function body, the corresponding test variable is increased step by step at 0.01 A / s. After waiting until the operating value of the relay protection device is reached, the protection issues a trip signal. After the relay protection tester captures this information through the input contact and returns, the test function exits the loop body after receiving this trip signal, and records the output current amplitude of the current relay protection tester (accurate to 0.01 A). This amplitude may be different from the protection operating value set by the relay protection device itself, but it is the true value under the actual operating state of the secondary protection system of the power system. At this time, the action current value of the corresponding test item is displayed in the system UI interface interaction text box.

[0105] 'Overcurrent protection verification - 2' verifies the operation time of the relay protection device:

[0106] According to the protection operating current value obtained in 'Overcurrent protection verification - 1', change the test parameters transferred by the test data object m_szTestParam to make the relay protection tester output 1.2 times the protection operating current. At this time, the relay protection tester starts timing, and the host computer polls whether the relay protection tester has received the trip signal of the relay protection device. When the relay protection device trips, the timing of the relay protection tester ends, and the test result is returned to the host computer server. At this time, the operation time of the relay protection device of the corresponding test item (accurate to 0.001 s) is displayed in the system UI interface interaction text box;

[0107] Get the test results, end the test, store and upload the data, generate an experiment report according to the calibration item setting sheet, and generate the calibration results; when exiting the main interface window, exit the main loop and destroy the test server.

[0108] The calibration of the definite-time earthing protection function is similar to the calibration principle of the overcurrent protection. Calibrating the definite-time earthing protection function of the relay protection device includes calibrating the current operating value of the relay protection device and calibrating the operating time of the relay protection device.

[0109] 'Earthing protection calibration - 1' calibrates the current operating value of the relay protection device:

[0110] First, adjust the definite-time earthing protection time setting value of the high setting to the minimum and the definite-time earthing protection time setting value of the low setting to the maximum to ensure that the tripping type is the high-setting definite-time earthing protection and eliminate interference factors;

[0111] Secondly, set the initial value of the output current according to the setting sheet of the actual calibration item, and download the test data to the controllable power supply circuit of the relay protection tester by the defined test data object m_szTestParam; at this time, create a protection tripping flag parameter, and increase the corresponding test variable step by step at 0.01A / s in the test function body, wait to receive the protection tripping signal, and wait until the operating value of the relay protection device is reached. After the relay protection device issues a tripping signal, the relay protection tester captures this information through the input contact and returns. After the test function receives this tripping signal, it exits the loop body, and the program actively obtains the information of the test result root node and reads the current operating value. At this time, the system UI interface interaction text box displays the results of the corresponding test items.

[0112] 'Earthing protection calibration - 2' calibrates the operating time of the relay protection device:

[0113] According to the protection operating current value obtained in 'Earthing protection calibration - 1', change the test parameters downloaded by the test data object m_szTestParam to make the relay protection tester output 1.2 times the protection operating current. At this time, the relay protection tester starts automatic timing, and the host computer polls whether the relay protection tester has received the tripping signal of the relay protection device. When the relay protection device trips, the timing of the relay protection tester ends and returns the test results. At this time, the system UI interface interaction text box displays the operating time of the relay protection device (accurate to 0.001s) of the corresponding test item;

[0114] The test ends, store and upload the data, generate an experiment report according to the calibration item setting sheet, and generate the calibration results; when exiting the main interface window, exit the main loop, destroy the test server, and restore the protection time setting value of the relay protection device according to the setting sheet.

[0115] During the test process, the data collected by the relay protection tester can be seen through the interactive text box on the main window. Through the corresponding buttons, the experiment process can be interrupted or the output electrical quantities of the relay protection tester can be adjusted to manually intervene and adjust the experiment process, and finally complete the automatic calibration of the relay protection device.

[0116] Through the above process, the actual action value and action time of the relay protection device can be accurately measured. Communication method between the relay protection tester and the PC: In this invention, the ONLLY-A460 series relay protection tester is used for the relay protection tester, and the TCP / IP transmission control communication protocol is used. The upper computer is programmed based on the Python language, and the UI interface and main functions need to be completed in cooperation with modules such as pywin32 module, tkinter module, and time module. The main logical process is as follows:

[0117] 1. Call tkinter to create the main window of the upper computer, and add controls such as buttons representing various functions and interactive text boxes in the main window;

[0118] 2. After the main window is formed, create an ONLLY test server, pass the handle of the main window into the service, and start initializing the output parameters of the relay protection tester:

[0119] 3. Define a test data object for the test data of transmitting the parameters of the relay protection tester;

[0120] 4. Before executing the test, pass the defined IP address and port number PORT into the service function to complete the connection with the relay protection tester;

[0121] 5. According to the relay protection calibration items, call the relevant test modules, activate the test program, assign values to the defined experiment parameters, and start the test experiment;

[0122] 6. When the test parameters change, re-encapsulate the test data object, switch the test point, and complete the output adjustment of the relay protection tester;

[0123] 7. Wait to obtain the status information of the relay protection tester's input quantity, end the experiment, obtain the current output electrical parameters, and calculate the action time of the relay protection device;

[0124] 8. Store and upload the data, generate an experiment report according to the calibration item setting list, and generate the calibration result.

[0125] During the development process, the data collected by the relay protection tester can be seen through the interactive text box on the main window. Through the corresponding buttons, the experiment process can be interrupted or the output electrical quantities of the relay protection tester can be adjusted to manually intervene and adjust the experiment process, and finally complete the automatic calibration of the relay protection device.

Claims

1. An automatic verification method for relay protection, characterized in that: Verify the definite-time overcurrent protection and definite-time ground protection functions of the relay protection device respectively: Control the relay protection tester to output voltage, current, frequency, and phase to simulate the secondary-side fault conditions of the power system. Measure the electrical quantities and time parameters of the verification device through the input interface of the relay protection tester. Automatically generate an experiment report in combination with the database background, judge whether the verification items are qualified, and control the operation process of the relay protection verification; Verifying the definite-time overcurrent protection function of the relay protection device includes verifying the current action value of the relay protection device and the action time of the relay protection device. Specifically, it includes the following steps: S1. Simulate the DC power supply through the voltage output of the relay protection tester to supply power to the relay protection device; S2. Adjust the three-phase current output of the relay protection tester respectively to confirm that there is no abnormality in the relay sampling; S3. Adjust the time setting value of the low-set definite-time overcurrent protection to the minimum; S4. Gradually increase the current of phase A, phase B, and phase C of the relay protection tester in turn until the current I of the relay protection device > the action value of the relay protection device, and record the action current value of the relay protection device; S5. Set the current I of the relay protection device > the time setting value of the protection; S6. Reset the relay protection device and adjust the three-phase output current of the relay protection tester; S7. Operate the relay protection tester to start outputting and record the action time of the relay protection device; S8. Obtain the protection verification value, automatically judge whether the verification item is qualified, and generate an experiment report; Verifying the definite-time ground protection function of the relay protection device includes verifying the current action value of the relay protection device and the action time of the relay protection device. Specifically, it includes the following steps: S10. Adjust the time setting value of the high-set definite-time ground protection to the minimum and the time setting value of the low-set definite-time ground protection to the maximum to ensure that the tripping type is high-set definite-time ground protection; S20. Set the initial value of the output current, and download the test data to the controllable power supply circuit of the relay protection tester by the defined test data object; S30. Stepwise increase the corresponding test variables in the test function body, wait to receive the protection tripping signal until the I of the relay protection device > the action value of the relay protection device, and read and record the action current value of the relay protection device; S40. According to the action current value of the relay protection device in step S30, change the test parameters downloaded by the test data object, adjust the three-phase output current of the relay protection tester, and poll whether the relay protection tester receives the tripping signal of the relay protection device; When the relay protection device trips, the test result is returned and the action time of the relay protection device is displayed; S50. The test is over, store and upload the data, generate an experiment report according to the verification item setting list, and generate the verification result; when exiting the main interface window, exit the main loop, destroy the test server, and restore the protection time setting value of the relay protection device according to the setting list.

2. The relay protection automatic calibration method according to claim 1, characterized in that: In step S1, simulate a 110V DC power supply through the voltage output of the relay protection tester.

3. The relay protection automatic calibration method according to claim 1, characterized in that: In the step S2, the three-phase current outputs of the relay protection tester are respectively adjusted to 0.5 A, 0.8 A, and 1 A.

4. The relay protection automatic calibration method according to claim 1, characterized in that: In the step S5, according to the setting value required by the project, the time setting value of the current I> protection of the relay protection device is set to 6 s.

5. The relay protection automatic calibration method according to claim 1, characterized in that: During the test process, the data collected by the relay protection tester can be seen through the interactive text box on the main window. The experimental process can be interrupted or the output electrical quantities of the relay protection tester can be adjusted through the corresponding buttons to manually intervene and adjust the experimental process, and finally complete the automatic calibration of the relay protection device.

6. A relay protection tester, comprising a relay protection tester housing, a controllable power supply, a main control platform, and a control terminal, wherein: Using the relay protection automatic calibration method described in any one of claims 1-5, A controllable power supply and a main control platform are arranged inside the relay protection tester housing; The controllable power supply is rigidly connected to the relay protection device to be tested through voltage and current output terminals, and is used to provide an auxiliary power supply for the relay protection device to be tested and can simulate the real working state of the relay protection device on the secondary side of the power system; The main control platform exchanges information with the controllable power supply and can receive the trip signal of the relay protection device to be tested; the main control platform is interconnected with a control terminal for outputting the signal of the main control platform and inputting a control command to the main control platform.

7. The relay protection tester according to claim 6, characterized in that: The control terminal includes a touch screen, an external keyboard, an indicator light, and a control switch; the touch screen is arranged on the relay protection tester housing and is used to display the input current and status of the relay protection device to be tested, and the touch screen is interconnected with the main control chip; the external keyboard is horizontally arranged on the relay protection tester housing through an external keyboard bracket, and the external keyboard bracket is fixedly arranged on the fixed bracket; the output end of the external keyboard is connected to the input end of the main control chip; the indicator light is arranged above the relay protection tester housing and is used to indicate the operating state of the relay protection tester, and the output end of the main control chip is connected to the input end of the indicator light; the control switch is arranged above the relay protection tester housing, and the controlled end of the control switch is connected to the output end of the main control chip; the control switch includes a device main switch and a stop experiment switch.

8. The relay protection tester according to claim 6, characterized in that: The main control platform includes a main control chip, a three-phase controllable power supply output circuit, a minimum system part, and an external interface group; the external interface group includes one or several of an Ethernet interface, a USB interface, an AD / DA interface, and an input quantity interface; the main body of the three-phase controllable power supply output circuit is a three-phase bridge inverter circuit; the minimum system part is the peripheral circuit required for the operation and debugging of the main control chip, and the minimum system part includes a power supply circuit, a crystal oscillator clock circuit, and a reset circuit.

9. The relay protection tester according to claim 6, wherein: A custom button group and a main board interface slot are further arranged above the relay protection tester housing.

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