Joint debugging test system, method and device for relay protection device of low-frequency power transmission system

Abstract

The invention provides a joint debugging test system, method and device for a relay protection device of a low-frequency power transmission system, and relates to the technical field of simulation testing, and the system comprises the steps: building a low-frequency AC power transmission simulation system based on a real-time digital simulation platform on a joint debugging test server; the low-frequency alternating-current power transmission simulation system generates a simulation signal according to a preset test item, transmits the simulation signal to the converter control device and the converter protection device through the interface module, and analyzes and verifies an action response result; the converter control device performs a sequential control start-stop test, a steady-state performance test and an operation mode switching test based on the simulation signal; the converter protection device performs a protection function test based on the simulation signal; the protection function test comprises a metallic and transitional resistor short-circuit fault test, a voltage / current transformer disconnection test and a frequency abnormity test, closed-loop joint debugging verification of the low-frequency power transmission relay protection device is realized, protection action and control cooperation are evaluated, and the safety and reliability of the system are improved.

Description

Technical Field

[0001] This application relates to the field of power system simulation and testing technology, and in particular to a joint commissioning test system, method and apparatus for relay protection devices in low-frequency transmission systems. Background Technology

[0002] With the continuous development and widespread application of high-voltage, high-capacity modular multilevel converter (MMC) technology based on fully controlled power electronic devices, a new generation of low-frequency power transmission technology—Flexible Low-Frequency AC Transmission—has emerged, using flexible AC-AC converters as its core component and pulse width modulation (PWM) as its theoretical basis. This technology combines power electronics with traditional AC transmission, enabling flexible conversion and efficient transmission of electrical energy between different frequencies.

[0003] With the continued advancement of flexible and modular trends, the advantages of low-frequency power transmission technology in large-capacity, long-distance power transmission are becoming increasingly apparent: by reducing the transmission frequency, line reactance can be significantly reduced, transmission capacity can be increased, and system losses can be reduced, providing a promising power transmission method for the future "new power system" with a high proportion of clean energy integration and a high proportion of power electronic equipment support. Especially in scenarios such as large-scale grid connection of new energy sources, long-distance transmission, and offshore wind power, flexible low-frequency power transmission technology has significant economic advantages and engineering feasibility.

[0004] In flexible low-frequency AC transmission systems, the Modular Multilevel Matrix Converter (M3C), as the core component for frequency conversion, undertakes the task of energy interaction and control between power frequency and low frequency. AC protection in low-frequency transmission systems mainly includes line protection, transformer protection, and bus protection, and its protection principles involve various forms such as differential current protection, distance protection, and directional elements. However, due to the significant differences between the electrical characteristics of low-frequency systems and traditional power frequency AC systems, their fault current waveforms, transient characteristics, and protection criteria all change, making it difficult to directly apply traditional power frequency protection logic to low-frequency systems.

[0005] Therefore, to ensure the safe and stable operation of low-frequency transmission systems under different fault conditions, it is essential to systematically verify the operating characteristics, coordination relationships, and reliability of relay protection devices. Currently, although flexible low-frequency transmission technology has made some progress in experimental and demonstration projects, there is still no comprehensive method for the joint commissioning and testing of low-frequency transmission relay protection devices. This lack of verification of the effectiveness and adaptability of protection strategies limits the further promotion and practical application of low-frequency transmission projects.

[0006] This section is intended to provide background or context for the embodiments of the invention set forth in the claims. The description herein is not an admission that it is prior art simply because it is included in this section. Summary of the Invention

[0007] To address the problems in the prior art, this application provides a system, method, and apparatus for joint commissioning and testing of relay protection devices in low-frequency power transmission systems, which can solve the problems of complex fault characteristics and lack of empirical verification of relay protection principles in low-frequency power transmission systems.

[0008] In one aspect, the present invention provides a joint commissioning test system for relay protection devices in a low-frequency power transmission system, the system comprising: a joint commissioning test server, a converter control device, and a converter protection device; The joint commissioning test server is based on a real-time digital simulation platform to build a low-frequency AC power transmission simulation system. The low-frequency AC power transmission simulation system is used to generate simulation signals according to preset test items, transmit the simulation signals to the converter control device and the converter protection device through the interface module, and analyze and verify the action response results of the converter control device and the converter protection device. The converter control device is used to perform control function tests based on the simulation signals; the control function tests include sequential start-stop tests, steady-state performance tests, and operating mode switching tests. The converter protection device is used to perform protection function tests based on the simulation signal; the protection function tests include metallic and transient resistance short-circuit fault tests, voltage / current transformer open circuit tests, and frequency anomaly tests.

[0009] Furthermore, the low-frequency AC transmission simulation system includes: a modular multilevel matrix converter, a low-frequency transformer, a power frequency transformer, a low-frequency converter transformer, a power frequency converter transformer, a low-frequency AC circuit breaker, a power frequency AC circuit breaker, a low-frequency transmission line, and a switchyard busbar.

[0010] Furthermore, before conducting control function tests and protection function tests, the joint commissioning test server divides the low-frequency AC transmission simulation system into protection zones according to the substation area. The divided protection zones include the switchyard protection zone, the low-frequency transmission line protection zone, and the frequency converter protection zone. Among them, the frequency converter protection zone includes the low-frequency converter transformer protection zone, the low-frequency bus protection zone, the converter protection zone, the power frequency converter transformer protection zone, and the power frequency bus protection zone; the converter protection zone includes the converter valve protection zone and the valve area power / low-frequency connection line protection zone.

[0011] Furthermore, before conducting control function tests and protection function tests, the joint commissioning test server sets protection fault locations in the low-frequency AC power transmission simulation system; the protection fault locations include the low-frequency bus of the switching station, the low-frequency transmission line, the low-frequency bus of the frequency converter station, the low-frequency converter transformer of the frequency converter station, the low-frequency connection line on the valve side of the frequency converter station, the converter bridge arm of the frequency converter station, the power frequency connection line on the valve side of the frequency converter station, the power frequency converter transformer of the frequency converter station, and the power frequency bus of the frequency converter station.

[0012] Furthermore, it also includes: converter valve control device; The converter valve control device is used to establish a real-time optical communication channel between the converter control device and the low-frequency AC power transmission simulation system during control function tests and protection function tests, so as to complete the execution of trigger commands and feedback of converter valve status.

[0013] In another aspect, the present invention provides a method for joint commissioning and testing of relay protection devices in low-frequency transmission systems, applied to the joint commissioning and testing system for low-frequency transmission system relay protection devices described in any of the above embodiments, the method comprising: Simulation signals are generated according to preset test items, and the simulation signals are transmitted to the converter control device and the converter protection device through the interface module. The converter control device is driven by the simulation signal to conduct control function tests; the control function tests include sequential start-stop tests, steady-state performance tests, and operating mode switching tests. The converter protection device is driven to perform protection function tests based on the simulation signals; the protection function tests include metallic and transient resistance short circuit fault tests, voltage / current transformer open circuit tests, and frequency anomaly tests. The action response results of the converter control device and the converter protection device are analyzed and verified.

[0014] In another aspect, the present invention provides a low-frequency transmission system relay protection device commissioning test apparatus, applicable to the low-frequency transmission system relay protection device commissioning test system described in any of the above embodiments, the apparatus comprising: The simulation signal output unit is used to generate simulation signals according to preset test items, and transmit the simulation signals to the converter control device and the converter protection device through the interface module. The control function test unit is used to drive the converter control device to perform control function tests based on the simulation signals; the control function tests include sequential start-stop tests, steady-state performance tests, and operating mode switching tests. The protection function test unit is used to drive the converter protection device to perform protection function tests based on the simulation signal; the protection function tests include metallic and transient resistance short circuit fault tests, voltage / current transformer open circuit tests, and frequency abnormality tests. The response result verification unit is used to analyze and verify the action response results of the converter control device and the converter protection device.

[0015] To achieve the above objectives, according to another aspect of the present invention, a computer device is also provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the above-described method for joint commissioning test of relay protection devices for low-frequency power transmission systems.

[0016] To achieve the above objectives, according to another aspect of the present invention, a computer-readable storage medium is also provided, on which a computer program / instruction is stored, which, when executed by a processor, implements the steps of the above-described method for joint commissioning and testing of relay protection devices for low-frequency power transmission systems.

[0017] To achieve the above objectives, according to another aspect of the present invention, a computer program product is also provided, comprising a computer program / instruction that, when executed by a processor, implements the steps of the above-described method for joint commissioning and testing of relay protection devices in low-frequency power transmission systems.

[0018] The beneficial effects of this invention are as follows: This application systematically presents methods for setting fault points and fault types within a unified low-frequency transmission system simulation model, and clearly defines the required testing items, elevating the joint commissioning test from fragmented, single-item tests to a systematic and reproducible test scheme. By arranging fault points at typical locations and configuring various short-circuit and abnormal operating conditions, the protection response characteristics of the low-frequency transmission system under different operating states and fault scenarios can be comprehensively examined, enabling targeted verification of the relay protection device's functionality. Through joint commissioning tests, this application can expose weaknesses in relay protection configuration and settings before project commissioning, such as inconsistencies in settings, dead zones, insufficient sensitivity, or overlapping protection, allowing for timely correction and reducing the risks of failure to operate, erroneous operation, and cascading tripping after commissioning. Simultaneously, this application unifies control function tests and protection function tests into the same test methodology framework, achieving coordinated verification between protection devices and between protection and control, ensuring at the system level that faults are correctly identified and isolated without affecting unrelated equipment. This joint commissioning test method can be carried out on a real-time digital simulation platform without relying on the actual power grid and primary equipment. It can perform near-engineering-level simulation verification of complex low-frequency power transmission systems, providing high-safety, high-controllability and high-repeatability technical means for low-frequency power transmission projects in design optimization, factory testing and on-site commissioning, thereby effectively ensuring the safe, stable and reliable operation of low-frequency power transmission systems. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a first structural schematic diagram of the low-frequency power transmission system relay protection device joint commissioning test system provided in an embodiment of the present invention; Figure 2 This is a first structural schematic diagram of the low-frequency power transmission system relay protection device joint commissioning test system provided in an embodiment of the present invention; Figure 3 This is a first structural schematic diagram of the low-frequency power transmission system relay protection device joint commissioning test system provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the basic topology of the modular multilevel matrix converter (M3C) provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the protection zone partitioning of the low-frequency AC power transmission simulation system provided in this embodiment of the invention; Figure 6 This is a schematic diagram of the fault location of the low-frequency AC power transmission simulation system provided in this embodiment of the invention; Figure 7 This is a flowchart illustrating the joint commissioning test method for relay protection devices in low-frequency power transmission systems provided in this embodiment of the invention. Figure 8 This is a schematic block diagram of the structure of the low-frequency power transmission system relay protection device commissioning test device provided in the embodiment of the present invention; Figure 9 This is a schematic diagram of the physical structure of a computer device provided in an embodiment of this application. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0021] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0022] It should be noted that the terms "comprising" and "having" and any variations thereof in the specification, claims and accompanying drawings of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products or devices.

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0024] This invention provides a test system for the joint commissioning of relay protection devices in low-frequency power transmission systems, which is used to perform joint commissioning and functional verification of converter control devices and converter protection devices in low-frequency power transmission systems in a real-time simulation environment.

[0025] The joint commissioning test server serves as the core computing and management platform of the test system. It is used to carry real-time digital simulation software, perform low-frequency power transmission system simulation calculations, generate various simulation signals required for control and protection tests, and collect, record, and analyze the action responses of external converter control devices and converter protection devices.

[0026] Figure 1 This is a first structural schematic diagram of the low-frequency power transmission system relay protection device commissioning test system provided in an embodiment of the present invention, as shown below. Figure 1 As shown, in one embodiment of the present invention, the low-frequency power transmission system relay protection device joint commissioning test system of the present invention includes: joint commissioning test server 1, converter control device 2 and converter protection device 3; The low-frequency AC power transmission simulation system 4 is built on the joint debugging test server 1 based on the real-time digital simulation platform; The low-frequency AC transmission simulation system 4 is used to generate simulation signals according to preset test items, transmit the simulation signals to the converter control device 2 and the converter protection device 3 through the interface module, and analyze and verify the action response results of the converter control device 2 and the converter protection device 3. The converter control device 2 is used to perform control function tests based on the simulation signals; the control function tests include sequential start-stop tests, steady-state performance tests, and operating mode switching tests. The converter protection device 3 is used to perform protection function tests based on the simulation signal; the protection function tests include metallic and transient resistance short-circuit fault tests, voltage / current transformer open circuit tests, and frequency anomaly tests.

[0027] Specifically, the low-frequency AC transmission simulation system 4 is deployed on the joint commissioning test server 1 and runs on a real-time digital simulation platform. This simulation system is used to establish an electrical simulation model of the low-frequency transmission system, and to perform real-time calculations of the voltage, current, and related state quantities of the low-frequency transmission system under different operating states and fault conditions, thereby providing input signals for control function tests and protection function tests.

[0028] In practical implementation, the low-frequency AC transmission simulation system 4 pre-configures various test scenarios and test items through a simulation model. Based on the test item configuration by the user on the joint commissioning test server 1, the low-frequency AC transmission simulation system 4 runs on a real-time digital simulation platform and generates simulated voltage, current, and status signals that match the corresponding test items.

[0029] To enable signal interaction with external devices, the low-frequency AC transmission simulation system 4 is equipped with an interface module. The interface module may include analog output interfaces, digital input / output interfaces, or other interface forms suitable for signal transmission. During real-time simulation calculations, the simulation system outputs simulation signals to the external converter control device 2 and converter protection device 3 through the interface module. Simultaneously, the interface module can also acquire switching action signals or status feedback signals from external devices.

[0030] The converter control device 2 is used to perform control logic operations and execute control strategies for the converter based on the simulation signals provided by the low-frequency AC transmission simulation system 4. In the joint commissioning test system provided by this invention, the converter control device 2 receives simulation voltage, current, and system status signals from the simulation system, processes them as field measurement signals, and thus reproduces the control behavior under real engineering conditions in the test environment.

[0031] During the control function test, the low-frequency AC transmission simulation system 4 generates simulation signals based on preset control test items, including normal start-up and shutdown, steady-state operation, and changes in operating mode. These signals are transmitted to the converter control device 2 via the interface module. The converter control device 2 executes sequential start-up and shutdown logic based on these simulation signals, simulating the entire process of converter control from shutdown to operation and from operation to shutdown. In the steady-state performance test, the converter control device 2 maintains stable operation of the system at the set power or voltage target based on the operating signals provided by the simulation system. In the operating mode switching test, the converter control device 2 switches operating modes based on the changes in operating conditions simulated by the simulation system, such as switching between different power setpoints or different operating modes.

[0032] During the above process, the low-frequency AC power transmission simulation system 4 can record the output results and operation process of the converter control device 2 under different test items, and compare them with the expected control logic or control target to analyze the correctness and stability of the control function.

[0033] The converter protection device 3 is used to protect and isolate faults in the converter and its related electrical equipment. In the joint commissioning test system of this invention, the converter protection device 3 also receives the simulated voltage, current and related status signals output by the low-frequency AC transmission simulation system 4 through the interface module. The low-frequency AC transmission simulation system 4 provides the converter protection device 3 with simulated signals corresponding to the fault conditions in actual operation by setting different fault types and fault conditions during the test.

[0034] During the protection function test phase, the low-frequency AC transmission simulation system 4 generates simulation signals based on preset protection test items, including typical fault conditions such as metallic short-circuit faults, transition resistance short-circuit faults, voltage transformer or current transformer disconnection, and frequency anomalies. The converter protection device 3 performs real-time analysis and judgment on the above signals and performs protection actions such as tripping, blocking, and alarming based on internal protection settings and criteria.

[0035] The low-frequency AC transmission simulation system 4 monitors and records the action time, action type, and whether the action is correct of the converter protection device 3 under the above-mentioned fault conditions, and compares the actual action results with the expected protection behavior to verify the action sensitivity, selectivity, and reliability of the converter protection device 3 under different fault conditions.

[0036] During the control and protection function tests, the low-frequency AC transmission simulation system 4 not only generates and outputs simulation signals, but also analyzes and verifies the action response results of the external converter control device 2 and the converter protection device 3. The simulation system can be configured with corresponding data acquisition and result analysis modules on the joint commissioning test server 1 to uniformly collect control commands, protection action signals, fault records, and other data output by the control and protection devices.

[0037] By comparing the simulated input signals and the response behavior of control and protection devices under different test items, the low-frequency AC transmission simulation system 4 can determine whether the control function test and protection function test meet the expected technical requirements, such as whether sequential start-up and shutdown are correctly completed, whether stable operation is maintained under given steady-state conditions, whether rapid and accurate action is taken when a fault occurs, and whether false tripping or failure to trip is avoided. Based on the above analysis results, the joint commissioning test system can provide a basis for optimizing the relay protection strategy and improving the control logic of the low-frequency transmission system.

[0038] In one embodiment, the low-frequency transmission system relay protection device commissioning test system is implemented using a real-time digital simulation platform (RTDS). A low-frequency AC transmission simulation system 4 (RTDS system) model is built, and with the input / output boards of the real-time digital simulator, a simulation experimental platform for the frequency converter station control protection and valve control system is established, the structure of which is as follows: Figure 2 As shown.

[0039] The RTDS system generates analog outputs (AO) through simulation calculations and simultaneously sends the states of various switching quantities within the simulation model to the actual control and protection devices in the form of digital outputs (DO). The control and protection devices process the analog and switching signals, generate valve control commands and protection action commands, and feed them back to the RTDS system in the form of digital inputs (DI), thus forming a closed loop in the simulation experimental platform. The VBC device used in the experiment is a version designed for the RTDS digital-analog experiment, not the final field version; it serves only as a relay device for signal exchange between the control device and the RTDS system.

[0040] In one embodiment, the low-frequency transmission system relay protection device commissioning test system is as follows: Figure 3 As shown, the low-frequency AC transmission simulation system 4 (RTDS system) includes components such as a multi-functional power electronic transformer, a photovoltaic step-up substation, AC / DC lines, and loads. The GTFPGA module is used to realize communication between the RTDS system and the converter valve control device (VBC). The GTAO module is used to output analog signals, the GTDO module is used to output digital signals, and the GTDI module is used to receive digital input signals. The primary equipment, including the converter primary topology, the industrial / low-frequency converter transformer, the industrial / low-frequency AC circuit breaker, the low-frequency transmission line, and the switchyard busbar, are all modeled and simulated in the real-time digital simulation system (RTDS system).

[0041] The RTDS system outputs analog signals through the GTAO module, which are then sent to the converter protection device 3 and the converter control device 2 after being driven / amplified. The RTDS system outputs digital signals through the GTDO module and receives digital feedback from the protection and control devices through the GTDI module, thus forming a closed loop of control and protection. The GTFPGA module is used to communicate with the converter valve control device VBC via HDLC (High-Level Data Link Control), receive its optical trigger-related signals and convert them into module-level trigger information usable by the simulation system, thereby realizing high-speed linkage between VBC and the RTDS system.

[0042] In one embodiment, the overall method for conducting joint commissioning tests using the low-frequency transmission system relay protection device joint commissioning test system of this application includes: 1) Joint commissioning of low-frequency transmission systems refers to the simultaneous joint testing of system control (mainly converter control at frequency converter stations) and protection. The prerequisite for joint commissioning of low-frequency transmission systems is that each individual device has completed independent testing, passed functional verification, and issued a corresponding test report.

[0043] 2) This test consists of two main parts: protection function testing and control function testing. Protection function verification is the focus of this test plan. Control function testing mainly verifies: normal sequential control operation, switching between different operating modes, and the system's interlocking and unlocking functions, etc. Protection function testing mainly verifies the coordination between the protection devices in various parts of the system, as well as the coordination relationship between protection and control (including fault ride-through function).

[0044] 3) The test needs to be combined with the fault characteristics of the low-frequency transmission system to examine the operation of the protection device under different short-circuit current levels; at the same time, it is necessary to consider different operating conditions of new energy output (such as no-load, half-load, full-load, etc.), as well as different combinations of new energy types and proportions (such as direct drive, doubly fed, or different proportions of photovoltaic); it is also necessary to consider the performance of the system under different operating modes, such as parallel operation of dual valve groups, single valve group shutdown, etc.

[0045] 4) During simulation testing, all protection functions should be activated; when testing backup protection, the main protection function should be deactivated. The protection device should ensure reliable operation for faults within the protection zone and prevent false operation for faults outside the protection zone. After the converter protection system activates, the converter valve should be locked and the corresponding power frequency / low frequency AC switch should be tripped to take the converter valve group and related equipment where the fault occurred out of operation.

[0046] 5) Pre-setting of protection fault points, including metallic faults such as single-phase grounding, phase-to-phase short circuit, two-phase grounding, and three-phase short circuit; for line faults, the situation of grounding through a certain transition resistance should also be considered.

[0047] In one embodiment, the testing of the protection function of a low-frequency transmission system mainly involves verifying the sequential start / stop, interlocking, emergency shutdown, and operation mode switching functions that coordinate with the protection system. This is used to examine the compatibility and reliability of the protection device under typical control conditions. The specific test contents for the control functions are shown in Table 1 below: Table 1

[0048] In the sequential start-up and shutdown test, the sequential start-up process of the system is first verified: starting from the 220kV bus switch on the power frequency side of the frequency converter station, the power frequency side converter transformer, starting resistor, converter valve charging, power frequency side unlocking of converter valve, low frequency side unlocking of converter valve, low frequency bus, low frequency converter transformer, low frequency transmission line, and switch station bus are sequentially connected according to the sequential control logic to complete the system start-up process step by step; then, the relevant equipment is deactivated in the reverse order of the above start-up sequence to complete the sequential shutdown process of the system; on this basis, an emergency shutdown operation is also required under the condition of sequential start-up and normal operation of the system to verify the coordination of control and protection actions and the safe shutdown capability of the system under emergency shutdown conditions.

[0049] In the steady-state performance test, the low-frequency transmission system was first put into operation and connected to the renewable energy power station through sequential system startup. On this basis, the renewable energy output was adjusted in stages: in 50MW increments, the renewable energy output was increased sequentially at predetermined time intervals until the system reached full load. Throughout the process, the system voltage, current, power, and operational stability were recorded to evaluate the steady-state performance of the system and protection and control devices under different load levels. Subsequently, under the condition of full load, the renewable energy output was gradually reduced in 100MW increments at certain time intervals until the output dropped to a lower level. The system operation under each condition was also recorded to analyze the system stability and the coordination performance of protection and control during the output reduction process.

[0050] The operation mode switching test mainly examines the system operation and protection coordination under different operating modes and equipment commissioning / decommissioning conditions. If the operation mode with a sectionalizing switch between the two low-frequency buses F7 and F7' is considered, when a single low-frequency converter transformer is decommissioned, closing the sectionalizing switch between F7 and F7' allows one low-frequency converter transformer to simultaneously drive two sets of converter valves. The system power is evenly distributed between the two valve groups. This condition verifies the coordination of the system and protection when a single low-frequency converter transformer carries two sets of valves. If the sectionalizing switch between the two low-frequency buses F7 and F7' is not considered, when a single low-frequency converter transformer is decommissioned, its corresponding converter valve group is operated by a single low-frequency converter transformer. The power transmission mode is switched to reactive power compensation (STATCOM) mode, which provides reactive power support to the system through the power frequency converter transformer. This is used to examine the system voltage support and protection adaptability after the change of operating mode. In addition, when assuming that a single power frequency converter transformer is out of operation, its corresponding valve group is also switched to reactive power compensation (STATCOM) mode, which provides reactive power support to the low frequency side of the system through the low frequency converter transformer. This operating condition is used to verify the system's low frequency side voltage support capability when the power frequency side equipment is out of operation and the coordination between protection and control during the operation mode switching process.

[0051] In one embodiment, without the relevant stability control device configured, when the system operates at more than 50% of its rated power, if a single low-frequency transmission line or a single converter valve group in the frequency converter station fails to operate, the system will be locked out and shut down due to power surplus. To avoid this factor interfering with the protection action judgment and to better verify the performance of the relay protection device itself, in this scheme, without the stability control device in place, the system operating conditions are limited to less than 50% power or no-load conditions to conduct various fault simulations, thereby verifying the operating characteristics and selectivity of the protection device.

[0052] The protection function tests mainly include: metallic and transient resistance short-circuit faults, voltage / current transformer open-circuit tests, and frequency anomaly tests. Details are shown in Table 2 below. Table 2

[0053] In the metallic and transition resistance short-circuit fault tests, metallic grounding faults within and outside the protection zone were simulated at 18 fault points, including F1 to F12 / F12', according to four pre-set typical fault types. The selectivity and correctness of the protection devices were verified by observing their operation at different fault points and under different fault types. Furthermore, a transient fault was set at the mid-section of a single line at point F3 to simulate the automatic recovery of the line after a short-term fault, verifying whether the line protection could correctly perform the reclosing function. A grounding fault via a 100Ω transition resistor was set at the far end of a single line at point F2 to examine the sensitivity and reliability of the protection under resistance grounding conditions. A grounding fault was set at point F1, simulating a bus tie switch failure, to verify the correctness of the protection operation under bus tie failure conditions, while observing the converter's operating status and the overall system response. In addition, the operating status of the converter under multi-line fault conditions was monitored by simulating dual-line faults at locations F2 to F4. For converter transformers, under full load conditions, different types of fault transition processes are set at the same point outside the grid side and valve side, for example, from single-phase ground fault to two-phase ground fault. The fault transition time is set in the range of 10ms to 300ms to verify the operation process and stability of the protection device when the fault type changes rapidly.

[0054] In the voltage / current transformer disconnection test, a single-phase ground fault is simulated at the aforementioned fault points F1 to F12 / F12', and a voltage transformer (PT) or current transformer (CT) disconnection scenario is superimposed. The operating behavior of the corresponding protection device under the transformer disconnection condition is observed. This test aims to verify whether the protection device can distinguish between primary system faults and transformer abnormalities, and to avoid false tripping or failure to trip due to PT / CT disconnection.

[0055] In the frequency anomaly test, metallic grounding faults were applied at 18 fault points, from F1 to F12 / F12'. The fault process was simulated to detect the low-frequency component of the converter's power frequency side voltage and the frequency component changes of the low-frequency side voltage. The focus was on observing the response of the frequency anomaly protection under the frequency deviation caused by the fault. The sensitivity and reliability of the frequency anomaly protection function were evaluated by recording the protection action sequence, action threshold, and the correspondence between frequency changes and protection responses during the fault duration.

[0056] Through the above series of protection function tests, this solution can comprehensively evaluate the correctness of operation, selectivity and adaptability to system operating conditions of relay protection devices in low-frequency transmission systems under different fault types, fault locations and operating conditions, providing a reliable basis for subsequent protection setting optimization and configuration improvement.

[0057] In one embodiment, the low-frequency AC transmission simulation system 4 includes: a modular multilevel matrix converter, a low-frequency transformer, a power frequency transformer, a low-frequency converter transformer, a power frequency converter transformer, a low-frequency AC circuit breaker, a power frequency AC circuit breaker, a low-frequency transmission line, and a switchyard busbar.

[0058] Specifically, the low-frequency AC transmission simulation system 4 is used to construct an electrical model of the low-frequency transmission system on the real-time digital simulation platform of the joint commissioning test server 1, so as to provide voltage, current and system status simulation signals under real operating conditions for the converter control device 2 and the converter protection device 3. For this purpose, the low-frequency AC transmission simulation system 4 includes: modular multilevel matrix converters, low-frequency transformers, power frequency transformers, low-frequency converter transformers, power frequency converter transformers, low-frequency AC circuit breakers, power frequency AC circuit breakers, low-frequency transmission lines and switchyard busbars, and other primary equipment models.

[0059] In practical implementation, the modular multilevel matrix converter is used to simulate the energy conversion process between the power frequency side and the low frequency side in a low-frequency transmission system. This converter adopts a multi-arm, multi-submodule structure, and the simulation model can reflect the voltage waveform, current distribution, and transient response under fault conditions of the converter under different operating conditions. By modeling the modular multilevel matrix converter, the operating characteristics of the converter in actual engineering can be reproduced on the simulation platform, providing an accurate interface for control function tests and protection function tests.

[0060] By jointly modeling the aforementioned modular multilevel matrix converters, various transformers, AC circuit breakers, transmission lines, and switchyard busbars, the low-frequency AC transmission simulation system 4 can construct a primary electrical model of the low-frequency transmission system on a real-time digital simulation platform that is consistent with the topology and operating characteristics of the actual engineering system. This model provides a unified simulation environment for the converter control device 2 and the converter protection device 3, enabling the joint debugging and verification of the control strategy and protection logic of the low-frequency transmission system without connecting to the real power grid and primary equipment.

[0061] In one embodiment, the modular multilevel matrix converter (M3C) is a voltage source type direct frequency converter consisting of nine bridge arms. These arms connect the three-phase voltages on the power frequency side and the low-frequency side in pairs. Each bridge arm consists of one bridge arm reactor and several full-bridge submodules connected in series. Its topology is as follows: Figure 4 As shown.

[0062] Under conditions of complete structural and parameter symmetry, each bridge arm can be equivalently regarded as a single-phase cascaded inverter, and each bridge arm can be controlled independently. Based on the frequency conversion principle of three-phase synthesis, the output voltage of each phase of the system is obtained by synthesizing the three-phase input voltage through the corresponding bridge arm. A total of 9 bridge arms are required to achieve AC-AC power conversion. The current preliminary design is as follows: each phase bridge arm contains 156 sub-modules, and its modeling adopts the existing MMC module in RTDS. Since the MMC single bridge arm supports a maximum of 128 sub-modules, the number of sub-modules per bridge arm has been equivalently processed in the simulation modeling, setting the number of sub-modules per bridge arm in the model to 78, and correspondingly increasing the voltage of individual sub-modules to ensure that the overall voltage level is consistent with the actual design.

[0063] In one embodiment, low-frequency and power frequency both belong to the AC system. Therefore, in the low-frequency transmission system, both the lines and transformers can adopt the models of conventional AC lines and transformers, where the transformer parameters are shown in Table 3 below. To reduce line losses, the low-frequency transmission lines adopt a double-circuit transmission line configuration; the low-frequency wind turbines of the new energy power plants are modeled using a black-box model encapsulated by the manufacturer's controller.

[0064] Table 3

[0065] In one embodiment, such as Figure 5 As shown, before conducting control function tests and protection function tests, the joint commissioning test server 1 divides the low-frequency AC transmission simulation system 4 into protection zones according to the substation area. The divided protection zones include the switch station protection zone, the low-frequency transmission line protection zone, and the frequency converter station protection zone. Among them, the frequency converter station protection zone includes the low-frequency converter transformer protection zone, the low-frequency bus protection zone, the converter protection zone, the power frequency converter transformer protection zone, and the power frequency bus protection zone. The converter protection zone includes the converter valve protection zone and the valve area power / low-frequency connection line protection zone.

[0066] Specifically, the purpose of low-frequency transmission system protection is to quickly isolate faults when short-circuit faults occur in the system or equipment malfunctions, thereby preventing equipment damage and preventing faults from interfering with the normal operation of other parts of the system. Depending on the different areas of the substation, the protection range can be divided into switchyard protection zone, low-frequency transmission line protection zone, and frequency converter (AC / DC) protection zone.

[0067] Before conducting control function tests and protection function tests, the joint commissioning test server 1 first divides the protection zones of the low-frequency AC transmission simulation system 4. By pre-dividing the protection zones in the simulation system, the protection ranges of different equipment and lines can be clearly defined, providing a clear regional boundary basis for subsequent protection setting configuration, action criterion setting, and protection joint commissioning tests.

[0068] In one embodiment of the present invention, the commissioning test server 1 divides the simulation system into regions based on the topology of the substation and frequency converter in the low-frequency AC power transmission simulation system 4. According to the physical connection relationship between the substation area and the transmission line, the test range of the low-frequency AC power transmission simulation system 4 is divided into three primary protection zones: the switchyard protection zone, the low-frequency transmission line protection zone, and the frequency converter protection zone. The protection devices involved mainly include converter protection, converter transformer protection, line protection, and busbar protection.

[0069] The simulation system includes several protection zones: Switching station protection zone and Variable Frequency (VFD) protection zone. Switching station protection zones encompass the primary equipment within the switching station area of ​​a low-frequency transmission system. VFD protection zones include transformers, circuit breakers, busbars, and interface equipment connected to the power frequency or low-frequency system, all directly connected to the switching station busbar. Low-frequency transmission line protection zones represent the area containing the low-frequency transmission line and its associated equipment. This zone corresponds to the low-frequency transmission line section in actual engineering projects, primarily containing the low-frequency transmission line itself and the switching equipment connected to its ends. Variable Frequency Drive (VFD) station protection zones represent the area containing the primary equipment within the VFD station. This zone corresponds to the VFD station area in actual engineering projects that performs power frequency to low-frequency energy conversion. In the simulation system, this includes various transformers, busbars, and converters associated with the VFD station. To further refine the protection boundaries within the VFD station, the VFD station protection zone is decomposed into multiple secondary protection zones in the simulation system, including: low-frequency converter transformer protection zone, low-frequency busbar protection zone, converter protection zone, power frequency converter transformer protection zone, and power frequency busbar protection zone. Based on the above-mentioned protection zone division, the converter protection zone is further subdivided into converter valve protection zone and valve area / low-frequency connection line protection zone.

[0070] Through the aforementioned hierarchical protection zone division method, the joint commissioning test server 1 established clear protection boundaries for each primary device and its corresponding area in the low-frequency AC transmission simulation system 4. Based on this protection zone division, subsequent control function tests and protection function tests can be configured with test scenarios and test items for different protection zones, facilitating the zonal verification of protection actions in various parts of the switching station, lines, and frequency converter station. This division method not only improves the pertinence and controllability of simulation tests but also facilitates the mapping of protection actions to their respective protection zones when analyzing the action response results of converter control device 2 and converter protection device 3, thereby systematically evaluating the selectivity and coordination of protection devices in various areas of the low-frequency transmission system.

[0071] In one embodiment, since the converter valve's interlocking function is closely related to the control device, the test platform incorporates both the converter's main control device and the valve control device. Therefore, the testing scheme must focus on verifying the converter valve's interlocking function. Given that the converter valve bridge arm in the simulation model uses RTDS built-in modules and has undergone equivalent processing in terms of the number of sub-modules, the self-protection functions of the valve control device modules (such as sub-module overcurrent and overvoltage protection) can be verified by applying corresponding electrical quantities to the valve control device individually.

[0072] In one embodiment, such as Figure 6 As shown, before conducting control function tests and protection function tests, the joint commissioning test server 1 sets protection fault locations in the low-frequency AC power transmission simulation system 4; the protection fault locations include the low-frequency bus of the switch station, the low-frequency transmission line, the low-frequency bus of the frequency converter station, the low-frequency converter transformer of the frequency converter station, the low-frequency connection line on the valve side of the frequency converter station, the converter bridge arm of the frequency converter station, the power frequency connection line on the valve side of the frequency converter station, the power frequency converter transformer of the frequency converter station, and the power frequency bus of the frequency converter station.

[0073] Specifically, before conducting control function tests and protection function tests, the joint commissioning test server 1 first sets up protection fault locations in the low-frequency AC transmission simulation system 4. By pre-defining several typical fault locations, targeted simulations of faults in different areas of the low-frequency transmission system can be performed in the simulation platform, providing a unified fault scenario basis for the testing of the converter protection device 3 and related control logic.

[0074] In one embodiment of the present invention, the joint commissioning test server 1, based on the topology of the low-frequency power transmission system and the frequency converter station, configures multiple representative protection fault locations in the low-frequency AC power transmission simulation system 4. These protection fault locations include: the low-frequency bus of the switching station, the low-frequency transmission line, the low-frequency bus of the frequency converter station, the low-frequency converter transformer of the frequency converter station, the low-frequency connection line on the valve side of the frequency converter station, the converter arm of the frequency converter station, the power frequency connection line on the valve side of the frequency converter station, the power frequency converter transformer of the frequency converter station, and the power frequency bus of the frequency converter station.

[0075] By pre-setting protection fault locations at the aforementioned locations such as the low-frequency busbar of the switching station, low-frequency transmission lines, low-frequency busbar of the frequency converter station, low-frequency converter transformer of the frequency converter station, low-frequency connection line on the valve side of the frequency converter station, converter bridge arm of the frequency converter station, power frequency connection line on the valve side of the frequency converter station, power frequency converter transformer of the frequency converter station, and power frequency busbar of the frequency converter station, the low-frequency AC transmission simulation system 4 can flexibly inject fault conditions from different areas and on different equipment during the test. Based on this, the joint commissioning test server 1 can provide rich and representative fault scenarios for control function tests and protection function tests, enabling the converter control device 2 and converter protection device 3 to undergo comprehensive testing of multiple areas and types of faults during the joint commissioning process. This improves the reference value of the test results for practical engineering applications and enhances the comprehensiveness and reliability of the joint commissioning and verification of relay protection in the low-frequency transmission system.

[0076] In one embodiment, the location of the fault point is shown in Table 4 below: Table 4

[0077] In one embodiment, such as Figure 2 As shown, the low-frequency power transmission system relay protection device commissioning test system also includes: a converter valve control device; The converter valve control device is used to establish a real-time optical communication channel between the converter control device 2 and the low-frequency AC power transmission simulation system 4 during the control function test and protection function test, so as to complete the execution of trigger commands and feedback of the converter valve status.

[0078] Specifically, in the low-frequency transmission system relay protection device joint commissioning test system, in addition to the joint commissioning test server 1, converter control device 2, and converter protection device 3, a converter valve control device is also provided. This converter valve control device is used as a key interface unit between the converter control device 2 and the low-frequency AC transmission simulation system 4 during the control function test and protection function test, to complete the issuance and execution of trigger commands and the feedback of converter valve status information.

[0079] By setting up a converter valve control device between the converter control device 2 and the low-frequency AC transmission simulation system 4, and establishing a real-time optical communication channel during the experiment, this invention can form a highly real-time and highly reliable valve-level control and feedback path in the simulation platform. This path ensures that the trigger commands output by the converter control device 2 can accurately act on the simulated converter valve model, and also enables the operating status of the converter valve to be fed back to the simulation system and the control system in a timely manner, thereby realizing closed-loop verification of the converter control and protection joint commissioning process in the low-frequency transmission system.

[0080] In one embodiment, such as Figure 2 As shown, the low-frequency power transmission system relay protection device commissioning and testing system also includes: a transfer board and an operator workstation; The adapter board is used for signal conversion and level matching between the joint debugging test server 1 (RTDS system) and the external converter control device 2 and protection device. It normalizes the analog and digital outputs from the simulation system before sending them to the device, and reliably transmits the digital and status signals returned from the device back to the simulation system. It serves as the hardware interface platform between the simulation system and the actual device. The operator workstation allows operation and testing personnel to monitor the simulation and protection actions in real time.

[0081] This invention also provides a method for joint commissioning and testing of relay protection devices in low-frequency power transmission systems. By generating simulation signals on a real-time simulation platform, driving the converter control device and the converter protection device to perform control function tests and protection function tests respectively, and performing unified analysis and verification of the action response results of the two, a systematic joint commissioning and comprehensive evaluation of relay protection devices in low-frequency power transmission systems can be achieved.

[0082] Figure 7 This is a flowchart illustrating a method for commissioning and testing relay protection devices in a low-frequency power transmission system according to an embodiment of this application. Figure 7 As shown, the commissioning test method for low-frequency transmission system relay protection devices provided in this application includes: S701: Generate simulation signals according to preset test items, and transmit the simulation signals to the converter control device and the converter protection device through the interface module; Specifically, the joint commissioning test server first generates simulation signals based on preset test items. These preset test items include normal start-stop scenarios, steady-state operation scenarios, and different operating mode switching scenarios for control function testing, as well as various fault scenarios and abnormal operating conditions for protection function testing. These test items are pre-configured within the joint commissioning test server. The low-frequency AC transmission simulation system runs on a real-time digital simulation platform, performing real-time calculations on the primary electrical model of the low-frequency transmission system to obtain voltage, current, and related state variables under different test conditions.

[0083] After generating the simulation signals, the low-frequency AC transmission simulation system transmits the simulation signals to the converter control and protection devices via interface modules. These interface modules can be analog output interfaces, digital output interfaces, or other suitable signal output interfaces, used to convert the simulated voltage, current, and operating status signals into standard signal types that can be received by the converter control and protection devices. Through the connection of the interface modules, the simulation system can continuously provide real-time simulation signals that change over time to external devices during the test, enabling the control and protection devices to obtain input conditions equivalent to field measurements in the test environment.

[0084] S702: Based on the simulation signal, drive the converter control device to perform control function tests; the control function tests include sequential start-stop tests, steady-state performance tests, and operating mode switching tests. Specifically, after the generation and transmission of the simulation signal are completed, the joint debugging test server drives the converter control device to conduct control function tests based on the simulation signal. The converter control device in the joint debugging test system simulates the behavior of the converter control system in actual engineering, and its internal components include sequential start-stop logic, steady-state operation control strategy, and operation mode switching control strategy.

[0085] S703: Drive the converter protection device to perform protection function tests based on the simulation signal; the protection function tests include metallic and transient resistance short circuit fault tests, voltage / current transformer open circuit tests, and frequency anomaly tests. Specifically, the joint commissioning test server also drives the converter protection device to conduct protection function tests based on simulation signals. The converter protection device is used to identify and isolate faults in the converter and its related electrical equipment. In the joint commissioning test, the simulation system provides the protection device with simulated voltage, current and system status signals corresponding to the actual fault conditions by setting different fault scenarios.

[0086] S704: Analyze and verify the action response results of the converter control device and the converter protection device.

[0087] Specifically, the commissioning test server analyzes and verifies the action response results of the converter control device and converter protection device. During the test, the low-frequency AC transmission simulation system on the commissioning test server continuously monitors and records the output signals of the control and protection devices, including control commands, trip signals, interlocking signals, and related status variables.

[0088] By comparing the above-mentioned action response results with the pre-set expected behavior of the test items, the simulation system can determine whether each test meets the established technical requirements. For example, for control function tests, it can verify whether the sequential start-stop process is strictly executed according to the predetermined steps, whether the steady-state performance meets the control accuracy requirements, and whether the switching of operating modes is smooth and reliable; for protection function tests, it can verify whether the protection actions are correct under different faults and abnormal operating conditions, whether the action time meets the sensitivity requirements, and whether there are any false trips or failures to trip.

[0089] Based on the same inventive concept, embodiments of the present invention also provide a low-frequency transmission system relay protection device commissioning test apparatus, which can be used to implement the low-frequency transmission system relay protection device commissioning test method described in the above embodiments, as shown in the following embodiments. Since the principle of the low-frequency transmission system relay protection device commissioning test apparatus in solving the problem is similar to that of the low-frequency transmission system relay protection device commissioning test method, embodiments of the low-frequency transmission system relay protection device commissioning test apparatus can refer to embodiments of the low-frequency transmission system relay protection device commissioning test method, and repeated details will not be elaborated further. As used below, the terms "unit" or "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the apparatus described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0090] Figure 8This is a schematic block diagram of the structure of the low-frequency power transmission system relay protection device commissioning test device provided in the embodiment of the present invention, as shown below. Figure 8 As shown, in one embodiment of the present invention, the low-frequency power transmission system relay protection device commissioning test apparatus of the present invention includes: The simulation signal output unit 801 is used to generate simulation signals according to preset test items, and transmit the simulation signals to the converter control device and the converter protection device through the interface module. The control function test unit 802 is used to drive the converter control device to perform control function tests based on the simulation signals; the control function tests include sequential start-stop tests, steady-state performance tests, and operating mode switching tests. The protection function test unit 803 is used to drive the converter protection device to perform protection function tests based on the simulation signal; the protection function tests include metallic and transient resistance short circuit fault tests, voltage / current transformer open circuit tests, and frequency abnormality tests. The response result verification unit 804 is used to analyze and verify the action response results of the converter control device and the converter protection device.

[0091] The low-frequency transmission system relay protection device commissioning test system, method and device provided in this application realizes the closed-loop verification and commissioning test of low-frequency transmission system relay protection devices in a real-time simulation platform. It can systematically evaluate the correctness, selectivity and coordination with the control system of protection actions, thereby improving the safety and reliability of low-frequency transmission systems.

[0092] Figure 9 This is a schematic diagram of the physical structure of a computer device provided in an embodiment of this application, as shown below. Figure 9As shown, the computer device may include: a processor 901, a communication interface 902, a memory 903, and a communication bus 904. The processor 901, communication interface 902, and memory 903 communicate with each other via the communication bus 904. The processor 901 can call logical instructions in the memory 903 to execute the following methods: generating simulation signals according to preset test items, and transmitting the simulation signals to the converter control device and the converter protection device through the interface module; driving the converter control device to perform control function tests based on the simulation signals; the control function tests include sequential start-stop tests, steady-state performance tests, and operating mode switching tests; driving the converter protection device to perform protection function tests based on the simulation signals; the protection function tests include metallic and transient resistance short-circuit fault tests, voltage / current transformer open-circuit tests, and frequency anomaly tests; and analyzing and verifying the action response results of the converter control device and the converter protection device.

[0093] Furthermore, the logical instructions in the aforementioned memory 903 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, a top-drive control center server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0094] This embodiment discloses a computer program product, which includes a computer program stored on a computer-readable storage medium. The computer program includes program instructions. When the program instructions are executed by a computer, the computer can perform the methods provided in the above-described method embodiments, including, for example: generating simulation signals according to preset test items, and transmitting the simulation signals to the converter control device and the converter protection device through an interface module; driving the converter control device to perform control function tests based on the simulation signals; the control function tests include sequential start-stop tests, steady-state performance tests, and operating mode switching tests; driving the converter protection device to perform protection function tests based on the simulation signals; the protection function tests include metallic and transient resistance short-circuit fault tests, voltage / current transformer open-circuit tests, and frequency anomaly tests; and analyzing and verifying the action response results of the converter control device and the converter protection device.

[0095] This embodiment provides a computer-readable storage medium storing a computer program that causes the computer to execute the methods provided in the above-described method embodiments. For example, the methods include: generating simulation signals based on preset test items and transmitting the simulation signals to the converter control device and the converter protection device via an interface module; driving the converter control device to perform control function tests based on the simulation signals; the control function tests including sequential start-stop tests, steady-state performance tests, and operating mode switching tests; driving the converter protection device to perform protection function tests based on the simulation signals; the protection function tests including metallic and transient resistance short-circuit fault tests, voltage / current transformer open-circuit tests, and frequency anomaly tests; and analyzing and verifying the action response results of the converter control device and the converter protection device.

[0096] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0097] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, produce a machine for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0098] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0099] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0100] In the description of this specification, the references to terms such as "an embodiment," "a specific embodiment," "some embodiments," "for example," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0101] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above descriptions are merely specific embodiments of this application and are not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A low-frequency power transmission system relay protection device joint debugging test system, characterized in that, Comprise: The joint debugging test server, the converter control device and the converter protection device; The low-frequency AC power transmission simulation system is built on the real-time digital simulation platform based on the joint debugging test server; The low-frequency AC power transmission simulation system is used for generating simulation signals according to preset test items, transmitting the simulation signals to the converter control device and the converter protection device through an interface module, and analyzing and verifying the action response results of the converter control device and the converter protection device; The converter control device is used for control function test based on the simulation signals; the control function test includes sequence control start-stop test, steady-state performance test and operation mode switching test; The converter protection device is used for protection function test based on the simulation signals; the protection function test includes metallic and transient resistance short-circuit fault test, voltage / current transformer breakage test and frequency abnormality test.

2. The low-frequency power transmission system relay protection device joint debugging test system according to claim 1, characterized in that, The low-frequency AC power transmission simulation system comprises a modular multilevel matrix converter, a low-frequency transformer, a power frequency transformer, a low-frequency converter transformer, a power frequency converter transformer, a low-frequency AC circuit breaker, a power frequency AC circuit breaker, a low-frequency power transmission line and a switch station bus.

3. The low-frequency power transmission system relay protection device joint debugging test system according to claim 1, characterized in that, Before the control function test and the protection function test, the joint debugging test server divides the low-frequency AC power transmission simulation system according to the substation area; the divided protection area includes a switch station protection area, a low-frequency power transmission line protection area and a frequency conversion station protection area; wherein the frequency conversion station protection area includes a low-frequency converter transformer protection area, a low-frequency bus protection area, a converter protection area, a power frequency converter transformer protection area and a power frequency bus protection area; the converter protection area includes a converter valve protection area and a valve area high / low frequency connection line protection area.

4. The low-frequency power transmission system relay protection device joint debugging test system according to claim 1, characterized in that, Before the control function test and the protection function test, the joint debugging test server sets a protection fault position in the low-frequency AC power transmission simulation system; the protection fault position includes a switch station low-frequency bus, a low-frequency power transmission line, a frequency conversion station low-frequency bus, a frequency conversion station low-frequency converter transformer, a frequency conversion station valve side low-frequency connection line, a frequency conversion station converter bridge arm, a frequency conversion station valve side power frequency connection line, a frequency conversion station power frequency converter transformer and a frequency conversion station power frequency bus.

5. The low-frequency power transmission system relay protection device joint debugging test system according to claim 1, characterized in that, Also include: Converter valve control device; The converter valve control device is used for establishing a real-time optical communication channel between the converter control device and the low-frequency AC power transmission simulation system during the control function test and the protection function test, to complete the execution of the trigger instruction and the feedback of the converter valve state.

6. A method for the combined test of a low-frequency power transmission system relay protection device, applied to the combined test system of the low-frequency power transmission system relay protection device according to any one of claims 1-5, characterized in that, Comprise: According to the preset test items, simulation signals are generated, and the simulation signals are transmitted to the converter control device and the converter protection device through an interface module; Control function test is driven by the converter control device based on the simulation signals; the control function test includes sequence control start-stop test, steady-state performance test and operation mode switching test; Protection function test is driven by the converter protection device based on the simulation signals; the protection function test includes metallic and transient resistance short-circuit fault test, voltage / current transformer breakage test and frequency abnormality test; The action response results of the converter control device and the converter protection device are analyzed and verified.

7. A low-frequency power transmission system relay protection device joint debugging test device applied to the low-frequency power transmission system relay protection device joint debugging test system in any one of claims 1-5, characterized in that, Comprise: The simulation signal output unit is configured to generate a simulation signal according to a preset test item and transmit the simulation signal to the converter control device and the converter protection device through an interface module; The control function test unit is configured to drive the converter control device to perform a control function test based on the simulation signal; the control function test comprises a sequential control start-stop test, a steady-state performance test and an operation mode switching test; The protection function test unit is configured to drive the converter protection device to perform a protection function test based on the simulation signal; the protection function test comprises a metallic and transient resistance short-circuit fault test, a voltage / current transformer disconnection test and a frequency abnormality test; The response result verification unit is configured to analyze and verify the action response results of the converter control device and the converter protection device.

8. A computer device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor executes the computer program to realize the steps of the method of claim 6.

9. A computer readable storage medium having stored thereon computer programs / instructions, characterized in that, The computer program / instruction is executed by the processor to realize the steps of the method of claim 6.

10. A computer program product comprising computer programs / instructions, characterized in that, The computer program / instruction is executed by the processor to realize the steps of the method of claim 6.

Images