A method and system for controlling synchronization output of cross-substation relay protection test based on unified trigger time

Abstract

This invention discloses a method and system for synchronous output control of relay protection testing across substations based on a unified trigger time. The method includes: multi-source fusion time synchronization, dynamic transmission delay calculation and compensation, unified trigger time generation, encrypted distribution of differentiated test parameters, local timing calibration and synchronous output, and multi-dimensional synchronization accuracy verification. This invention generates a future unified trigger time through a master node, and each test terminal independently outputs synchronously based on a local high-precision timer, avoiding the uncertainty of real-time command transmission over the network and achieving microsecond-level time synchronization for cross-substation testing. It is suitable for mixed commissioning and testing scenarios involving equipment from different manufacturers.

Description

Technical Field

[0001] This invention relates to the field of power system relay protection testing technology, and in particular to a synchronous output control method and system for cross-substation relay protection testing based on a unified triggering time. Background Technology

[0002] As power systems develop towards ultra-high voltage, extra-high voltage, and cross-regional intelligent networking, relay protection and automatic safety devices such as line fiber optic differential protection, cross-station regional automatic transfer switches, stability control devices, and cross-station linkage of bus differential protection exhibit operational characteristics of multi-station collaboration, multi-device linkage, and mixed networking of equipment from different manufacturers. To ensure the correctness and reliability of such devices in actual operation, it is necessary to conduct cross-substation relay protection joint commissioning tests before commissioning or during maintenance. High-precision synchronous output from the test terminal is a core prerequisite for the authenticity and validity of the test results. Existing cross-substation relay protection testing technologies mainly suffer from the following problems: (1) The time synchronization method is simple, mostly using satellite time synchronization or network time synchronization, which is easily affected by environmental interference or link jitter. The synchronization accuracy is difficult to stabilize at the microsecond level, and there is a lack of local clock phase-locked mechanism, resulting in large cumulative clock drift error. (2) The transmission delay calculation is a static calculation, which does not take into account the effects of link attenuation and delay fluctuation. The calculation results have large deviations and subsequent compensation is insufficient. (3) The safety margin generated at the triggering time is a fixed value and cannot be dynamically adjusted according to the network environment. It is easy to cause triggering asynchrony due to network jitter and device response delay. (4) The test parameters are uniformly configured, without taking into account the different characteristics of fault electrical quantities in each substation, and cannot truly simulate the on-site fault conditions; (5) The synchronization accuracy verification dimension is singular, only verifying the consistency of timestamps, without considering the synchronization of output amplitude and phase and the coordination of the actions of the device under test, resulting in a one-sided verification result. (6) The data transmission encryption mechanism is simple, mostly using a single algorithm encryption, and lacks two-way device authentication. Data is easily tampered with and stolen, resulting in insufficient communication security.

[0003] Some existing technologies attempt to achieve cross-site test synchronization through satellite time synchronization and real-time control command triggering, but they still rely on real-time commands from the master control node, cannot avoid the uncertainty of network transmission latency, and only support testing of equipment from a single manufacturer, resulting in poor adaptability. Other technologies use mobile terminals to relay control commands to achieve synchronization, but there is a latency superposition problem caused by multiple relay nodes, and the degree of test automation is low, still requiring on-site personnel cooperation, which cannot meet the needs of large-scale cross-site joint debugging and testing. Summary of the Invention

[0004] To address the technical problems existing in the prior art, this invention proposes a synchronous output control method and system for cross-substation relay protection testing based on a unified trigger time. This method achieves microsecond-level time base unification through multi-source fusion time synchronization, precise control of link delay through dynamic delay calculation and compensation, intelligent generation of trigger time through adaptive safety margin, realistic simulation of on-site faults through differentiated parameter configuration, avoidance of network real-time control risks through local independent triggering, and comprehensive evaluation of synchronization accuracy through multi-dimensional verification. This fundamentally solves problems such as poor synchronization, inaccurate test results, low adaptability, and weak security in cross-substation relay protection testing, achieving high-precision, automated, and highly reliable operation of cross-substation testing.

[0005] On the one hand, to achieve the above objectives, the present invention provides a relay protection testing system for substations, comprising: The master control node is deployed in the dispatch center or a designated substation; At least two relay protection test terminals are deployed in different substations and are connected to the main control node. The multi-source fusion timing module is used to provide a unified time reference for the main control node and each of the relay protection test terminals.

[0006] Preferably, the master control node includes: The dynamic delay calculation module is used to perform bidirectional communication with each of the relay protection test terminals to calculate and determine the maximum effective transmission delay of cross-site testing. An adaptive trigger time generation module is used to generate a future unified trigger time based on the maximum effective transmission delay and the dynamic adaptive preset safety margin. The dual-encryption communication module is used to generate a customized test task package containing the unified trigger time and differentiated test parameters, and distribute it to each relay protection test terminal through an encrypted communication channel.

[0007] Preferably, the relay protection test terminal includes: The real-time clock drift calibration unit and the high-precision thermostatic crystal timer are used to perform timed waiting after verifying and extracting the unified trigger time in the customized test task package, and to perform real-time clock drift calibration during the waiting process. The signal generation module is used to independently and synchronously output preset relay protection test quantities when the unified triggering time is reached; The high-precision synchronous acquisition module is used to acquire output status data containing high-precision timestamps and feedback signals from the device under test after synchronously outputting test quantities, and upload them to the master control node.

[0008] On the other hand, to achieve the above objectives, the present invention also provides a method for synchronous output control of cross-substation relay protection testing based on a unified triggering time, comprising: S1. Perform multi-source fusion time synchronization operation on each of the relay protection test terminals to enable all test terminals to obtain a unified system reference time; S2. Based on the bidirectional communication interaction between the main control node and each of the relay protection test terminals, the real-time effective transmission delay of each test terminal is calculated and compensated, and the maximum effective transmission delay of cross-site testing is determined. S3. The master control node generates a future unified triggering time based on the current system reference time, according to the maximum effective transmission delay and the dynamic adaptive preset safety margin. S4. Generate a customized test task package containing the unified trigger time and differentiated test parameters based on the master control node, and distribute it to each relay protection test terminal through an encrypted communication channel; S5. Each of the relay protection test terminals receives and verifies the customized test task package, extracts the unified trigger time, performs timed waiting based on a local high-precision timer, and performs real-time clock drift calibration during the waiting process. When the unified trigger time is reached, the preset relay protection test quantity is output independently and synchronously. S6. After synchronously outputting test quantities, each relay protection test terminal collects output status data containing high-precision timestamps and feedback signals from the device under test and uploads them to the main control node. The main control node performs multi-dimensional verification of the synchronous output accuracy based on the uploaded data.

[0009] Preferably, in S1, performing a multi-source fusion time synchronization operation on each of the relay protection test terminals includes: Based on the multi-source fusion timing module, satellite timing is performed on each of the relay protection test terminals to achieve preliminary time synchronization; It receives air interface time synchronization data, compares it with satellite time synchronization reference time and generates dynamic compensation, and performs secondary calibration on the local system reference time; The local crystal oscillator phase-locked loop is started, and the system reference time after secondary calibration is used as the phase-locked reference to achieve precise phase-locking between the local clock and the reference time.

[0010] Preferably, in step S2, the real-time effective transmission delay of each test terminal is calculated and compensated based on bidirectional communication between the master control node and each of the relay protection test terminals, including: S21. Send a delay probe message with a sending timestamp to the target test terminal based on the master control node; S22. The target test terminal records the receiving timestamp and returns a response message carrying the receiving timestamp, the response sending timestamp, and the link characteristics. S23. The master control node records the response reception timestamp, calculates the basic one-way transmission delay based on the sending timestamp, receiving timestamp, response sending timestamp, and response receiving timestamp, and corrects the basic one-way transmission delay in combination with the link characteristics to obtain the corrected one-way transmission delay. S24. Repeat S21-S23 for several rounds of communication interaction. Calculate the average value and latency fluctuation rate based on the corrected one-way transmission delay. Introduce a latency fluctuation rate correction factor to obtain the real-time effective transmission delay of the test terminal. S25. Traverse all relay protection test terminals and determine the maximum real-time effective transmission delay as the maximum effective transmission delay for cross-site testing.

[0011] Preferably, in S3, the unified triggering time is calculated as follows: T_trigger=T_current+T_max+T_safe; In the formula, T_trigger is the unified trigger time, T_current is the current reference time of the multi-source fusion system, T_max is the maximum effective transmission delay, and T_safe is the dynamic adaptive preset safety margin.

[0012] Preferably, in S4, the encrypted communication channel adopts a device unique identifier two-way authentication and double encryption mechanism, including: The master control node and each relay protection test terminal complete two-way identity authentication based on a pre-stored unique hardware device identifier and establish an encrypted communication connection. The master control node uses a dual encryption algorithm to perform double-layer encryption on the customized test task package, and then distributes it to the corresponding test terminal through a dedicated channel. After receiving the data, the test terminal performs double-layer decryption based on a preset key and uses a dual verification algorithm to verify data integrity. If the verification fails, it sends a retransmission request to the master control node.

[0013] Preferably, in S5, each of the relay protection test terminals has a built-in real-time clock drift calibration unit and a high-precision constant temperature crystal timer. While waiting for the unified trigger time, it periodically compares with the system reference time to calculate the local clock drift. If the local clock drift is detected to exceed a preset threshold, phase and frequency dual calibration is performed.

[0014] Preferably, in S6, the multi-dimensional verification includes: The verification includes at least two of the following: timestamp consistency verification, output synchronization verification, and device action coordination verification; wherein the output synchronization verification includes comparing at least one of the amplitude deviation, phase deviation, and frequency deviation of the output voltage and current signals of each terminal.

[0015] Compared with the prior art, the present invention has the following advantages and technical effects: (1) By using a unified triggering time mechanism, the uncertainty of network latency caused by real-time remote control can be avoided; (2) Each test terminal is independently triggered based on local timing, which improves the synchronization accuracy of cross-site test output; (3) It can achieve millisecond-level synchronous error control, meeting the high time-efficiency test requirements such as line fiber differential protection; (4) It is suitable for various communication environments such as public networks, private networks, and 5G networks, and has good engineering adaptability; (5) It is helpful to accurately assess the sequence of actions and timing characteristics of relay protection devices, and improve the reliability of test results. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the structure of a relay protection test system based on substations according to an embodiment of the present invention; Figure 2 This is a flowchart of a method for synchronous output control of relay protection testing across substations based on a unified triggering time, according to an embodiment of the present invention. Detailed Implementation

[0017] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0018] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0019] This embodiment proposes a relay protection testing system that spans multiple substations, such as... Figure 1 ,include: A master control node is deployed at the dispatch center or a designated substation; At least two relay protection test terminals are deployed in different substations and are connected to the main control node. The multi-source fusion timing module is used to provide a unified time reference for the main control node and each of the relay protection test terminals.

[0020] Furthermore, the master control node includes: The dynamic delay calculation module is used to perform bidirectional communication with each of the relay protection test terminals to calculate and determine the maximum effective transmission delay of cross-site testing. An adaptive trigger time generation module is used to generate a future unified trigger time based on the maximum effective transmission delay and the dynamic adaptive preset safety margin. The dual-encryption communication module is used to generate a customized test task package containing the unified trigger time and differentiated test parameters, and distribute it to each relay protection test terminal through an encrypted communication channel.

[0021] Specifically, the master control node adopts a dual-machine hot standby industrial-grade server, deployed in the scheduling center, and integrates a dynamic latency calculation module, an adaptive trigger time generation module, and a dual-encryption communication module. It supports the visualization configuration of differentiated parameters for each terminal, with a configuration step size ≤0.01A / V, a time accuracy ≤0.1ms, and communicates with each terminal through a 5G hard slicing channel with a latency ≤8ms and a bandwidth ≥200Mbps. The dual-encryption communication module has a built-in hardware unique identifier storage unit, an AES-256+SM4 dual key management unit, and a CRC32+MD5 dual verification unit. The hardware identifier is bound to the physical hardware, and the key update cycle is ≤60 days, realizing two-way device authentication, double-layer data encryption, and dual verification.

[0022] Furthermore, the relay protection test terminal includes: The real-time clock drift calibration unit and the high-precision thermostatic crystal timer are used to perform timed waiting after verifying and extracting the unified trigger time in the customized test task package, and to perform real-time clock drift calibration during the waiting process. The signal generation module is used to independently and synchronously output preset relay protection test quantities when the unified triggering time is reached; The high-precision synchronous acquisition module is used to acquire output status data containing high-precision timestamps and feedback signals from the device under test after synchronously outputting test quantities, and upload them to the master control node.

[0023] Specifically, the relay protection test terminal is deployed in each target substation. It adopts an FPGA + Loongson multi-core processor architecture and integrates a signal generation module, a high-precision synchronous acquisition module (sampling rate ≥ 2MHz), a high-precision isothermal crystal timer (timing accuracy ≤ 0.05ms), and a real-time clock drift calibration unit. It supports the generation of high-precision voltage / current signals from 0 to 1kHz, with amplitude accuracy ≤ 0.05% and phase accuracy ≤ 0.5°.

[0024] Furthermore, the multi-source fusion timing module is integrated into the main control node and each test terminal, including a Beidou / GPS dual-mode timing unit (timing accuracy ≤1μs), a 5G air interface timing unit, and a local temperature-controlled crystal phase-locked loop unit, to achieve three-level time calibration, with time deviation between terminals ≤1μs, providing a high-precision and highly stable time reference for the entire system.

[0025] A synchronous output control method for cross-substation relay protection testing based on a unified triggering time is applied to the aforementioned cross-substation relay protection testing system, such as... Figure 2 ,include: S1. Perform multi-source fusion time synchronization operation on each of the relay protection test terminals to enable all test terminals to obtain a unified system reference time; S2. Based on the bidirectional communication interaction between the main control node and each of the relay protection test terminals, the real-time effective transmission delay of each test terminal is calculated and compensated, and the maximum effective transmission delay of cross-site testing is determined. S3. The master control node generates a future unified triggering time based on the current system reference time, according to the maximum effective transmission delay and the dynamic adaptive preset safety margin. S4. Generate a customized test task package containing the unified trigger time and differentiated test parameters based on the master control node, and distribute it to each relay protection test terminal through an encrypted communication channel; S5. Local timing calibration and synchronous output: Each relay protection test terminal receives and verifies the customized test task package, extracts the unified trigger time, performs timing wait based on a local high-precision timer, and performs real-time clock drift calibration during the waiting process. When the unified trigger time is reached, the preset relay protection test quantity is output independently and synchronously. S6. After synchronously outputting test quantities, each relay protection test terminal collects output status data containing high-precision timestamps and feedback signals from the device under test and uploads them to the main control node. The main control node performs multi-dimensional verification of the synchronous output accuracy based on the uploaded data.

[0026] Furthermore, in S1, a multi-source fusion time synchronization operation is performed on each of the aforementioned relay protection test terminals, including: Based on the multi-source fusion timing module, satellite timing is performed on each of the relay protection test terminals to achieve preliminary time synchronization; It receives air interface time synchronization data, compares it with satellite time synchronization reference time and generates dynamic compensation, and performs secondary calibration on the local system reference time; The local crystal oscillator phase-locked loop is started, and the system reference time after secondary calibration is used as the phase-locked reference to achieve precise phase-locking between the local clock and the reference time.

[0027] Specifically, before the multi-source fusion time synchronization test is launched, the time synchronization calibration of each relay protection test terminal is completed through a three-level calibration method of Beidou / GPS dual-mode satellite time synchronization + 5G air interface time synchronization + local crystal oscillator phase lock, so as to achieve microsecond-level time reference unification.

[0028] Each terminal first receives satellite clock signals through its built-in BeiDou / GPS multi-source fusion timing module. The timing accuracy of this module is ≤1μs. It establishes a reference system time and achieves preliminary synchronization. At this time, the time deviation between each terminal is controlled within 10μs. Then, the main control node accesses the 5G standalone (SA) network, receives the high-precision air interface timing data carried in the base station broadcast frame and completes the clock information parsing, extracts the air interface timing standard time, compares it with the satellite timing reference time at the microsecond level point by point, accurately calculates the real-time deviation value between the two through the time difference calculation algorithm, generates dynamic compensation amount and performs secondary calibration on the local system reference time. After calibration, the time deviation between each terminal is controlled within 3μs. Finally, the local high-precision isothermal crystal phase-locked loop is started, and the system reference time after secondary calibration is used as the phase-locked reference to achieve precise phase-locking between the local clock and the reference time, suppress the temperature drift and random drift of the crystal oscillator, and ultimately ensure that the system reference time deviation of all test terminals does not exceed 1μs, laying a high-precision and highly stable time reference for subsequent synchronous triggering.

[0029] Furthermore, 5G standalone (SA) hard slicing technology allocates dedicated independent channels for test data transmission, completely isolating them from public network services. Communication latency is controlled within 8ms, channel bandwidth is ≥200Mbps, and packet loss rate is ≤0.005%, ensuring low-latency, high-reliability, and high-security transmission of latency detection messages, test task packets, and test data.

[0030] Further, in step S2, based on the bidirectional communication interaction between the master control node and each of the relay protection test terminals, the real-time effective transmission delay of each test terminal is calculated and compensated, including: S21. Send a delay probe message with a sending timestamp to the target test terminal based on the master control node; S22. The target test terminal records the receiving timestamp and returns a response message carrying the receiving timestamp, the response sending timestamp, and the link characteristics. S23. The master control node records the response reception timestamp, calculates the basic one-way transmission delay based on the sending timestamp, receiving timestamp, response sending timestamp, and response receiving timestamp, and corrects the basic one-way transmission delay in combination with the link characteristics to obtain the corrected one-way transmission delay. S24. Repeat S21-S23 for several rounds of communication interaction. Calculate the average value and latency fluctuation rate based on the corrected one-way transmission delay. Introduce a latency fluctuation rate correction factor to obtain the real-time effective transmission delay of the test terminal. S25. Traverse all relay protection test terminals and determine the maximum real-time effective transmission delay as the maximum effective transmission delay for cross-site testing.

[0031] Specifically, the main control node for dynamic transmission delay calculation and compensation conducts at least eight rounds of bidirectional communication with each relay protection test terminal. By combining link attenuation characteristics and delay volatility, accurate calculation and compensation of transmission delay are achieved, and the maximum effective transmission delay for cross-site testing is determined.

[0032] The master control node sends a delay probe message to the target test terminal, carrying a 1μs-level transmission timestamp T1 and a link feature identifier. T1 is generated based on the multi-source fusion system reference time of the master control node. After receiving the message, the target terminal records a 1μs-level receiving timestamp T2 and immediately returns a response message carrying T2, a 1μs-level response sending timestamp T3, and the terminal receiving link attenuation coefficient. T2 and T3 are generated based on the terminal's multi-source fusion system reference time. After receiving the response message, the master control node records a 1μs-level response reception timestamp T4. First, it calculates the round-trip time RTT using the formula RTT=T4-T1. Then, it calculates the basic one-way transmission delay t using the formula t=[(T4-T1)-(T3-T2)] / 2. The basic one-way transmission delay is then corrected by combining the link attenuation coefficient and feature identifier to obtain the corrected one-way transmission delay t'. Repeat the above interaction at least 8 times, calculate the average value of the one-way transmission delay and the delay volatility after multiple rounds of correction, introduce the delay volatility correction factor k (k≥1.05, the larger the delay volatility, the larger the value of k), and obtain the real-time effective transmission delay t''=t'×k of the terminal, with a calculation error ≤0.05ms; Iterate through all test terminals and determine the maximum real-time effective transmission delay as the maximum effective transmission delay T_max for cross-site testing.

[0033] Furthermore, in S3, the unified triggering time generation master node uses the current multi-source fusion system reference time T_current as the benchmark, superimposes the maximum effective transmission delay T_max and the dynamic adaptive preset safety margin T_safe, and generates the future unified triggering time T_trigger through the formula T_trigger=T_current+T_max+T_safe.

[0034] The dynamic adaptive preset safety margin T_safe is used to compensate for network jitter (≤5ms), device response delay (≤0.5ms), clock drift cumulative error (≤0.3ms), and sudden interference in the transmission link. Its value is 15%-35% of the maximum effective transmission delay, and the minimum value is not less than 1.5ms. At the same time, T_safe is dynamically adjusted according to the network jitter variance σ. When σ≤1ms, T_safe is 15%-20%; when 1ms<σ≤3ms, T_safe is 20%-30%; when σ>3ms, T_safe is 30%-35%, ensuring that all test terminals can complete the reception, parsing, caching, and preparation of test parameters before the trigger time.

[0035] Furthermore, in S4, the encrypted communication channel employs a device unique identifier two-way authentication and double encryption mechanism, including: The master control node and each relay protection test terminal complete two-way identity authentication based on a pre-stored unique hardware device identifier and establish an encrypted communication connection. The master control node uses a dual encryption algorithm to perform double-layer encryption on the customized test task package, and then distributes it to the corresponding test terminal through a dedicated channel. After receiving the data, the test terminal performs double-layer decryption based on a preset key and uses a dual verification algorithm to verify data integrity. If the verification fails, it sends a retransmission request to the master control node.

[0036] Specifically, the encrypted distribution of differentiated test parameters to the master control node configures differentiated test parameters for each substation test terminal through a visual configuration module, generates customized test task packages, and distributes them to each terminal through a dedicated 5G hard slice channel with unique device identifiers, two-way authentication, double encryption, and double verification.

[0037] Users can visualize and configure differentiated test parameters for each terminal through the test task configuration module of the master control node, including fault type (intra-zone / extra-zone fault, instantaneous / permanent fault), fault phase current / voltage amplitude / phase / frequency, fault duration, voltage drop ratio, zero-sequence / negative-sequence component configuration, harmonic component configuration, etc. The parameter configuration step size is ≤0.01A / V, and the time configuration accuracy is ≤0.1ms, which truly simulates the differences in electrical quantity characteristics of each station when there is a cross-station fault. The master control node generates customized test task packages for each terminal, including a unified trigger time T_trigger, differentiated test parameters, and exclusive test logic. It completes two-way identity authentication with each terminal based on the unique hardware identifier and establishes an exclusive HTTPS encrypted communication connection. The customized test task package is encrypted with AES-256 algorithm + SM4 national cryptographic algorithm, and then distributed to the corresponding terminal through a dedicated 5G hard slice channel (bandwidth ≥ 200Mbps, packet loss rate ≤ 0.005%). After receiving the data, the terminal performs double-layer decryption based on the preset dual keys and verifies the data integrity using the CRC32+MD5 dual verification algorithm. The verification pass rate is ≥99.99%. If the verification fails, an encrypted retransmission request is initiated (retransmission times ≤3 times). After the verification is successful, the relevant parameters are stored and the terminal enters the test preparation state.

[0038] Furthermore, in S5, each of the relay protection test terminals has a built-in real-time clock drift calibration unit and a high-precision temperature-controlled crystal timer. While waiting for the unified trigger time, it periodically compares with the system reference time to calculate the local clock drift. If the local clock drift exceeds a preset threshold, it performs phase and frequency dual calibration.

[0039] Specifically, the local timing calibration and synchronous output of each relay protection test terminal is based on a high-precision constant temperature crystal oscillator timer and real-time clock drift calibration to achieve timing waiting. When the unified trigger time is reached, the terminal independently and synchronously outputs differentiated test quantities without relying on the real-time control commands of the main control node.

[0040] Each terminal adopts a domestic FPGA and Loongson multi-core processor architecture. After extracting the unified trigger time T_trigger and differentiated test parameters from the customized test task package, a high-precision isothermal crystal timer with a timing accuracy of ≤0.05ms is started, and a countdown wait is performed based on T_trigger. During the waiting process, the terminal's built-in real-time clock drift calibration unit compares the clock drift with the reference time of the multi-source fusion system every 50ms. It calculates the local clock drift using a phase difference calculation algorithm. If the drift exceeds 0.05ms, it immediately performs phase and frequency dual calibration on the local clock to suppress the cumulative clock drift error. When the unified trigger time T_trigger is reached, each terminal independently and synchronously outputs preset differentiated relay protection test quantities. The terminal supports the generation of high-precision voltage / current signals from 0-1kHz, with amplitude accuracy ≤0.05% and sampling rate ≥2MHz. It can accurately generate fault electrical quantity signals such as fault current, voltage drop, and zero-sequence / negative-sequence components. The output time deviation of each terminal is ≤±1ms.

[0041] Furthermore, in S6, the multi-dimensional verification includes: The verification includes at least two of the following: timestamp consistency verification, output synchronization verification, and device action coordination verification; wherein the output synchronization verification includes comparing at least one of the amplitude deviation, phase deviation, and frequency deviation of the output voltage and current signals of each terminal.

[0042] Specifically, after verifying the synchronous output test quantities of each terminal in multiple dimensions, multi-dimensional test data is collected and uploaded to the master control node with a 1μs-level high-precision timestamp. The master control node performs a comprehensive verification of the synchronous output accuracy from three dimensions: timestamp consistency, output synchronization, and device action coordination, and generates a synchronization analysis report.

[0043] Each terminal collects its own output status data (amplitude, phase, and frequency of voltage / current), feedback signals from the relay protection device under test (action start signal, action output signal, and action return signal), and local trigger timing data in real time through a high-precision synchronous acquisition module (sampling rate ≥ 2MHz). All data carries a 1μs-level timestamp and supports local caching (caching capacity ≥ 100G) and incremental synchronization with the cloud. After the data is uploaded to the master control node through the dedicated 5G hard slicing channel, the master control node starts the multi-dimensional precision analysis module and completes the following in sequence: ① Timestamp consistency verification, comparing the deviation of the trigger timestamps of each terminal, with a deviation threshold of ≤±1ms; ② Output synchronization verification, comparing the amplitude deviation (≤0.05%), phase deviation (≤0.5°), and frequency deviation (≤0.01Hz) of the output signals of each terminal; ③ Device action coordination verification, comparing the coordination of the action start time, action exit time, and action return time of each device under test, with an action time difference of ≤2ms. The master control node determines whether the synchronization output accuracy meets the standard based on the verification results. If any dimension fails the verification, a deviation analysis report is automatically generated to locate the cause of the deviation (such as clock drift, transmission delay, device response delay, etc.). If all dimensions pass the verification, a synchronization analysis report and a complete test result report are generated to achieve closed-loop management of test data.

[0044] To more clearly illustrate the technical solution of the present invention, specific embodiments are provided below for description: The method described in this invention is based on a cross-substation relay protection testing system. This system includes an industrial-grade redundant master control node, at least two domestically produced relay protection testing terminals, a 5G SA hard-slicing communication network, and a multi-source fusion timing module. The specific configurations of each part are as follows: The master control node includes: The dynamic delay calculation module is used to perform bidirectional communication with each of the relay protection test terminals to calculate and determine the maximum effective transmission delay of cross-site testing. An adaptive trigger time generation module is used to generate a future unified trigger time based on the maximum effective transmission delay and the dynamic adaptive preset safety margin. The dual-encryption communication module is used to generate a customized test task package containing the unified trigger time and differentiated test parameters, and distribute it to each relay protection test terminal through an encrypted communication channel.

[0045] Specifically, the master control node adopts a dual-machine hot standby industrial-grade server, deployed in the scheduling center, and integrates a dynamic latency calculation module, an adaptive trigger time generation module, and a dual-encryption communication module. It supports the visualization configuration of differentiated parameters for each terminal, with a configuration step size ≤0.01A / V, a time accuracy ≤0.1ms, and communicates with each terminal through a 5G hard slicing channel with a latency ≤8ms and a bandwidth ≥200Mbps. The dual-encryption communication module has a built-in hardware unique identifier storage unit, an AES-256+SM4 dual key management unit, and a CRC32+MD5 dual verification unit. The hardware identifier is bound to the physical hardware, and the key update cycle is ≤60 days, realizing two-way device authentication, double-layer data encryption, and dual verification.

[0046] The 5G SA hard slicing communication network adopts the 5G standalone networking mode, which allocates dedicated independent channels through hard slicing technology, isolating it from the public network. The communication latency is ≤8ms, the packet loss rate is ≤0.005%, and the bandwidth is ≥200Mbps, ensuring low latency and high reliability transmission of test data.

[0047] The relay protection test terminal includes: The real-time clock drift calibration unit and the high-precision thermostatic crystal timer are used to perform timed waiting after verifying and extracting the unified trigger time in the customized test task package, and to perform real-time clock drift calibration during the waiting process. The signal generation module is used to independently and synchronously output preset relay protection test quantities when the unified triggering time is reached; The high-precision synchronous acquisition module is used to acquire output status data containing high-precision timestamps and feedback signals from the device under test after synchronously outputting test quantities, and upload them to the master control node.

[0048] Specifically, the relay protection test terminal is deployed in each target substation. It adopts an FPGA + Loongson multi-core processor architecture and integrates a signal generation module, a high-precision synchronous acquisition module (sampling rate ≥ 2MHz), a high-precision isothermal crystal timer (timing accuracy ≤ 0.05ms), and a real-time clock drift calibration unit. It supports the generation of high-precision voltage / current signals from 0 to 1kHz, with amplitude accuracy ≤ 0.05% and phase accuracy ≤ 0.5°.

[0049] The multi-source fusion timing module is integrated into the main control node and each test terminal. It includes a Beidou / GPS dual-mode timing unit (timing accuracy ≤1μs), a 5G air interface timing unit, and a local temperature-controlled crystal phase-locked loop unit, realizing three-level time calibration. The time deviation between terminals is ≤1μs, providing a high-precision and highly stable time reference for the entire system.

[0050] This embodiment takes the dual-end joint commissioning test of the fiber optic differential protection of substation M (configured with fiber optic differential protection from manufacturer A) and substation N (configured with fiber optic differential protection from manufacturer B) as an example. Two domestically produced relay protection test terminals are used to implement the synchronous output control method of this invention. The specific steps are as follows: 1. System initialization and multi-source fusion time synchronization: S1. Start the industrial-grade redundant master control node of the dispatch center and the two relay protection test terminals deployed in substations M and N respectively. Each device sequentially completes hardware redundancy detection, communication link detection, software program detection, and core module function accuracy detection. After all self-test items are normal, it enters the working state. S2. Each device starts the multi-source fusion timing module, receives satellite clock signals through the Beidou / GPS dual-mode timing unit, and achieves preliminary time synchronization. The time difference between the two terminals is ≤8μs. S3. Two terminals access the 5GSA hard slice network through the 5G communication module, receive the air interface timing data of the base station, compare it with the satellite timing time and perform secondary calibration. After calibration, the terminal time deviation is ≤2μs. S4. The two terminals start the local temperature-controlled crystal phase-locked loop and accurately lock phase with the time reference after secondary calibration. Finally, the reference time deviation between the two terminal systems is ≤0.8μs. S5. After the master control node completes its own multi-source fusion time synchronization, it sends a time synchronization verification request to the two terminals. The terminals return a system reference time with a 1μs-level timestamp. After the master control node confirms that the synchronization accuracy meets the requirements, it proceeds to the next step.

[0051] 2. Dynamic transmission delay calculation and compensation: S1. The master control node sends a delay probe message with T1=1699999999.000000000s (1μs level) and link characteristic identifier to the substation M terminal; S2. Substation M terminal receives the message at T2=1699999999.002800000s and immediately returns a response message carrying T2, T3=1699999999.002900000s and a link attenuation coefficient of 0.98; S3. The master control node receives the response message at T4=1699999999.005750000s, calculates the round-trip time RTT=5.75ms, the basic one-way transmission delay t=[5.75-(0.1)] / 2=2.825ms, and after correction by the attenuation coefficient, t'=2.825×0.98=2.7685ms; S4. Repeat the above steps 10 times to obtain the average delay of M terminal after correction, which is 2.77ms, with a delay fluctuation rate of 0.02. Introduce a correction factor k=1.05, and the real-time effective transmission delay t''=2.77×1.05=2.9085ms; S5. Using the same method, the real-time effective transmission delay of the N terminal in the substation was calculated, and t''=3.892ms was obtained; S6. The master control node determines the maximum effective transmission delay T_max for cross-site testing as 3.892ms, which is rounded down to 3.9ms.

[0052] 3. Unified trigger time generation: S1. The current network jitter variance σ is detected to be 1.2ms. According to the dynamic adaptive rule, T_safe is taken as 25% of T_max, that is, 3.9×25%=0.975ms. Since the minimum value is ≥1.5ms, T_safe is finally set to 1.5ms. S2. The master control node obtains the current reference time of the multi-source fusion system as follows: T_current=1700000000.000000000s; According to the formula T_trigger = T_current + T_max + T_safe; The calculation yields: T_trigger=1700000000.000000000s+3.9ms+1.5ms=1700000000.005400000s.

[0053] 4. Encrypted distribution of differentiated test parameters: S1. Users configure differentiated test parameters for the two terminals through the master control node configuration module: Substation M terminal (A manufacturer protection): Instantaneous fault in phase A zone, fault phase current 5.0A (phase 0°), zero sequence current 0.5A, fault phase voltage drops to 30% of rated voltage, fault duration 200ms, frequency 50Hz; Substation N terminal (B manufacturer protection): Instantaneous fault in phase A zone, fault phase current 5.3A (phase 180°), zero sequence current 0.5A, fault phase voltage drops to 30% of rated voltage, fault duration 200ms, frequency 50Hz; All parameters are configured with a step size of 0.01 A / V and a time precision of 0.1 ms. S2. The master node generates a customized task package for the two terminals, which includes a unified trigger time T_trigger, differentiated parameters and exclusive test logic. Based on the unique hardware identifier, it completes two-way identity authentication with the two terminals and establishes an exclusive HTTPS encrypted connection. S3. The master control node uses the AES-256+SM4 algorithm to encrypt the two task packets in two layers, and then distributes them to the M and N terminals through the 5G hard slice channel. S4. After receiving the data, both terminals complete double-layer decryption and perform double verification using CRC32+MD5. Once the verification is successful, the parameters are stored, and the system enters the test preparation state.

[0054] 5. Local timed calibration and synchronous output: S1. Both terminals start a high-precision thermostatic crystal timer and count down based on T_trigger=1700000000.005400000s; S2. During the waiting process, the two terminals compare their time with the reference time of the multi-source fusion system every 50ms. The local clock drift is detected to be ≤0.03ms, and no additional calibration is required. S3. When the T_trigger moment is reached, the two terminals independently and synchronously output preset differentiated test quantities. Terminal M outputs 5.0A / 0° fault current and terminal N outputs 5.3A / 180° fault current. The amplitude accuracy is ≤0.04% and the phase accuracy is ≤0.3°.

[0055] 6. Multi-dimensional synchronization accuracy verification: S1. Two terminals collect their own output status data and feedback signals from the protected device under test. All data carries a 1μs-level timestamp. M terminal trigger timestamp: 1700000000.005400000s, N terminal trigger timestamp: 1700000000.005400800s, timestamp deviation 0.8μs; The output current of terminal M is 5.000A with a phase of 0°, and terminal N is 5.299A with a phase of 180°. The amplitude deviation is 0.02% and the phase deviation is 0°. M terminal A manufacturer's protection action start time is 10ms and output time is 15ms, N terminal B manufacturer's protection action start time is 10.2ms and output time is 15.1ms, with a time difference of 0.2ms; S2. Data is incrementally synchronized to the master control node through the 5G hard slice channel. The master control node completes multi-dimensional verification: timestamp consistency (deviation 0.8μs≤1ms), output synchronization (amplitude deviation 0.02%≤0.05%, phase deviation 0°≤0.5°), and device action coordination (time difference 0.2ms≤2ms). All dimensions have passed the verification. S3. The master control node generates a synchronization analysis report and a complete fiber optic differential protection dual-end joint debugging test report, and the test is completed.

[0056] 7. Extended application of test scenarios: If the method of this embodiment needs to be applied to the automatic transfer switch test of multi-station chain-type power supply section area or the coordinated action test of cross-station stability control device, it is only necessary to reconfigure the differentiated test parameters (such as fault undervoltage bus, automatic transfer switch action sequence, stability control device linkage logic, etc.) for each substation terminal through the configuration module of the main control node, and repeat the above implementation steps to achieve high-precision synchronous output control of multiple terminals without modifying the system hardware or core logic. At the same time, this method supports the mixed commissioning of relay protection devices of different manufacturers and models. It is only necessary to adapt the technical characteristics of each device when configuring the parameters, which has extremely strong adaptability.

[0057] To verify the effectiveness of the method in this embodiment, three typical test scenarios were selected: line fiber optic differential protection (from different manufacturers), regional automatic transfer switch, and remote tripping. Multiple sets of comparative tests were conducted using the method of this invention, the traditional manual coordination method, and the existing satellite time synchronization + real-time command triggering method. The test results are shown in Table 1 below: Table 1 As can be seen from the above test data, the synchronous output deviation of the method of the present invention is much lower than that of traditional methods and existing technologies, the test success rate is increased by more than 20%, the test time of a single group is shortened by about 50%, and the amplitude and phase accuracy are greatly improved. The overall performance is significantly better than that of existing technologies, and it can effectively meet the high precision, automation and high reliability requirements of cross-substation relay protection joint commissioning test.

[0058] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A relay protection testing system for substations, characterized in that, include: The master control node is deployed in the dispatch center or a designated substation; At least two relay protection test terminals are deployed in different substations and are connected to the main control node. The multi-source fusion timing module is used to provide a unified time reference for the main control node and each of the relay protection test terminals.

2. The cross-substation relay protection testing system according to claim 1, characterized in that, The master control node includes: The dynamic delay calculation module is used to perform bidirectional communication with each of the relay protection test terminals to calculate and determine the maximum effective transmission delay of cross-site testing. An adaptive trigger time generation module is used to generate a future unified trigger time based on the maximum effective transmission delay and the dynamic adaptive preset safety margin. The dual-encryption communication module is used to generate a customized test task package containing the unified trigger time and differentiated test parameters, and distribute it to each relay protection test terminal through an encrypted communication channel.

3. The cross-substation relay protection testing system according to claim 2, characterized in that, The relay protection test terminal includes: The clock drift real-time calibration unit and the high-precision temperature-controlled crystal timer are used to perform timed waiting after verifying and extracting the unified trigger time in the customized test task package, and to perform real-time clock drift calibration during the waiting process. The signal generation module is used to independently and synchronously output preset relay protection test quantities when the unified triggering time is reached; The high-precision synchronous acquisition module is used to acquire output status data containing high-precision timestamps and feedback signals from the device under test after synchronously outputting test quantities, and upload them to the master control node.

4. A synchronous output control method for cross-substation relay protection testing based on a unified triggering time, applied to the cross-substation relay protection testing system according to any one of claims 1-3, characterized in that, include: S1. Perform multi-source fusion time synchronization operation on each of the relay protection test terminals to enable all test terminals to obtain a unified system reference time; S2. Based on the bidirectional communication interaction between the main control node and each of the relay protection test terminals, the real-time effective transmission delay of each test terminal is calculated and compensated, and the maximum effective transmission delay of cross-site testing is determined. S3. The master control node generates a future unified triggering time based on the current system reference time, according to the maximum effective transmission delay and the dynamic adaptive preset safety margin. S4. Generate a customized test task package containing the unified trigger time and differentiated test parameters based on the master control node, and distribute it to each relay protection test terminal through an encrypted communication channel; S5. Each of the relay protection test terminals receives and verifies the customized test task package, extracts the unified trigger time, performs timed waiting based on a local high-precision timer, and performs real-time clock drift calibration during the waiting process. When the unified trigger time is reached, the preset relay protection test quantity is output independently and synchronously. S6. After synchronously outputting test quantities, each relay protection test terminal collects output status data containing high-precision timestamps and feedback signals from the device under test and uploads them to the main control node. The main control node performs multi-dimensional verification of the synchronous output accuracy based on the uploaded data.

5. The method for synchronous output control of cross-substation relay protection testing based on a unified triggering time as described in claim 4, characterized in that, In S1, a multi-source fusion time synchronization operation is performed on each of the aforementioned relay protection test terminals, including: Based on the multi-source fusion timing module, satellite timing is performed on each of the relay protection test terminals to achieve preliminary time synchronization; It receives air interface time synchronization data, compares it with satellite time synchronization reference time and generates dynamic compensation, and performs secondary calibration on the local system reference time; The local crystal oscillator phase-locked loop is started, and the system reference time after secondary calibration is used as the phase-locked reference to achieve precise phase-locking between the local clock and the reference time.

6. The method for synchronous output control of cross-substation relay protection testing based on a unified triggering time as described in claim 4, characterized in that, In step S2, based on the bidirectional communication interaction between the master control node and each of the relay protection test terminals, the real-time effective transmission delay of each test terminal is calculated and compensated, including: S21. Send a delay probe message with a sending timestamp to the target test terminal based on the master control node; S22. The target test terminal records the receiving timestamp and returns a response message carrying the receiving timestamp, the response sending timestamp, and the link characteristics. S23. The master control node records the response reception timestamp, calculates the basic one-way transmission delay based on the sending timestamp, receiving timestamp, response sending timestamp, and response receiving timestamp, and corrects the basic one-way transmission delay in combination with the link characteristics to obtain the corrected one-way transmission delay. S24. Repeat S21-S23 for several rounds of communication interaction. Calculate the average value and latency fluctuation rate based on the corrected one-way transmission delay. Introduce a latency fluctuation rate correction factor to obtain the real-time effective transmission delay of the test terminal. S25. Traverse all relay protection test terminals and determine the maximum real-time effective transmission delay as the maximum effective transmission delay for cross-site testing.

7. The method for synchronous output control of cross-substation relay protection testing based on a unified triggering time as described in claim 4, characterized in that, In S3, the unified triggering time is calculated as follows: T_trigger=T_current+T_max+T_safe; In the formula, T_trigger is the unified trigger time, T_current is the current reference time of the multi-source fusion system, T_max is the maximum effective transmission delay, and T_safe is the dynamic adaptive preset safety margin.

8. The method for synchronous output control of cross-substation relay protection testing based on a unified triggering time as described in claim 4, characterized in that, In S4, the encrypted communication channel adopts a device unique identifier two-way authentication and double encryption mechanism, including: The master control node and each relay protection test terminal complete two-way identity authentication based on a pre-stored unique hardware device identifier and establish an encrypted communication connection. The master control node uses a dual encryption algorithm to perform double-layer encryption on the customized test task package, and then distributes it to the corresponding test terminal through a dedicated channel. After receiving the data, the test terminal performs double-layer decryption based on a preset key and uses a dual verification algorithm to verify data integrity. If the verification fails, it sends a retransmission request to the master control node.

9. The method for synchronous output control of cross-substation relay protection testing based on a unified triggering time according to claim 4, characterized in that, In S5, each of the relay protection test terminals has a built-in real-time clock drift calibration unit and a high-precision constant temperature crystal timer. While waiting for the unified trigger time, it periodically compares with the system reference time to calculate the local clock drift. If the local clock drift exceeds the preset threshold, it performs phase and frequency dual calibration.

10. The method for synchronous output control of cross-substation relay protection testing based on a unified triggering time according to claim 4, characterized in that, In S6, the multi-dimensional verification includes: The verification includes at least two of the following: timestamp consistency verification, output synchronization verification, and device action coordination verification; wherein the output synchronization verification includes comparing at least one of the amplitude deviation, phase deviation, and frequency deviation of the output voltage and current signals of each terminal.

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