Power system real-time closed-loop test method and system constructed based on cascading failure recording file

Abstract

The invention provides an electric power system real-time closed-loop test method and system based on cascading failure recording file construction, and belongs to the technical field of electric power system real-time closed-loop test. In order to solve the technical problems of low communication efficiency and low test efficiency in a novel electric power system secondary protection field remote closed-loop test, a control host carries out loading analysis on an original wave recording file in a remote COMTRADE format received through a wireless network to obtain time domain characteristic information of a waveform, and sends the time domain characteristic information to a wireless network; original waveform time domain feature information is stored as a recording file of a time frequency matrix and then sent to a playback device, the playback device performs electrical quantity information data playback based on an original waveform, and on one hand, playback waveform data is recorded by an acquisition channel and used for analyzing whether the data output by playback is consistent with the original recording file or not; on the other hand, transmitting to a protection device for fault simulation test; the method is applied to the real-time closed-loop test of the power system.

Description

Technical Field

[0001] This invention provides a method and system for real-time closed-loop testing of power systems based on cascading fault waveform files, belonging to the field of real-time closed-loop testing technology for power systems. Background Technology

[0002] With the gradual adjustment of the energy structure and the proposal of dual-carbon goals, power grid construction is also gradually developing towards the direction of large-scale integration of new energy sources and high penetration of power electronic equipment. With the rapid construction of ultra-high voltage AC / DC projects and the large-scale integration of photovoltaic, wind power, and energy storage, the complexity of the power system has increased, the uncertainty has intensified, and the vulnerability has increased. The new power grid exhibits new characteristics such as bidirectional power flow, controlled short-circuit current, and voltage support from distributed power sources, which also requires relevant power testing methods to keep up with the development level and direction of the new power system.

[0003] For example, as the proportion of new energy sources such as wind power and photovoltaic power in the power system increases, their volatility and intermittency make cascading faults more complex. For instance, if new energy sources disconnect from the grid, voltage collapse will cause traditional generating units to trip. It is necessary to construct corresponding cascading fault information to complete fault testing and maintenance. The constructed cascading fault waveform file contains actual fault data after new energy sources are connected to the grid, such as wind power converter disconnection signals and photovoltaic inverter low voltage ride-through response signals. Real-time closed-loop testing based on this file data can verify the system's ability to withstand cascading faults after new energy sources are connected to the grid, providing a safety guarantee for the increase in the penetration rate of new energy sources.

[0004] However, current traditional testing methods are difficult to cover the coupled interlocking scenarios of new energy-traditional units-loads. At the same time, the low communication efficiency and low testing efficiency faced in the remote closed-loop testing of secondary protection in new power systems will make it difficult to transmit and play back the waveform recording files of interlocking faults, and thus make it impossible to realize remote closed-loop testing of the power grid. Summary of the Invention

[0005] To address the technical problems existing in the background art, the present invention adopts the following technical solution: a real-time closed-loop testing method for power systems based on cascading fault waveform files, comprising the following testing steps:

[0006] Step 1: The control host loads and parses the raw waveform recording file in COMTRADE format received via the wireless network to obtain the time-domain characteristic information of the waveform, including the effective values. Peak Amplitude Sudden Change Frequency variation Phase change distortion rate Rise time Falling edge time Duration The electrical characteristics of the original waveform are stored as a time-frequency matrix waveform recording file and then sent to the playback device. The expression of the time-frequency matrix is:

[0007] ;

[0008] Step 2: The playback device plays back electrical quantity information data based on the original waveform. The played-back waveform data is recorded by the acquisition channel to analyze whether the playback output data is consistent with the original waveform file. On the other hand, it is transmitted to the protection device for fault simulation test.

[0009] Step 3: Perform initial authentication and verification on the replayed waveform data:

[0010] After recording the replayed waveform data, the control host extracts the time-domain feature information of the acquired waveform to form a time-domain matrix P. The time-domain matrix P is then compared with the original waveform information time-domain matrix F for similarity. The formula for calculating the similarity S is as follows:

[0011] ;

[0012] Where M is the number of rows in the time-domain matrix and N is the number of columns in the time-domain matrix; The original waveform time-domain matrix, To acquire the waveform time-domain matrix;

[0013] Step 4: The control host compares the status of the trip output of the protection device with the consistency of the playback test discrimination logic library to realize the authentication discrimination of the waveform playback output closure test;

[0014] Step 5: Based on the dual authentication results of Step 3 and Step 4, complete the real-time closed-loop test and discrimination of the power system.

[0015] Step 2 involves constructing zero-crossing directional clipping and splicing waveforms to perform fault simulation testing. The specific method is as follows:

[0016] Define the start time of the A-phase voltage waveform received by the playback device as t0, the first zero-crossing point of the waveform as t1, and the second zero-crossing point as t2. Then the waveform corresponding to t2-t1 is a complete cycle M.

[0017] At time t1 of phase A voltage, tm÷(t2-t1) cycles are superimposed forward to ensure that the reclosing charging of various protection test faults is completed and various alarm signals disappear stably;

[0018] Similarly, for other phase voltages and all phase currents, the waveform files corresponding to t2-t1 are superimposed based on time t1;

[0019] For continuous playback of multiple waveform files, the last waveform of the previous waveform file that rises above zero is recorded as t3, and the first waveform of the next waveform file that rises above zero is recorded as t4. The waveforms are superimposed with tn÷(t2-t1) cycles, where tn is an integer second, satisfying tn=t4-t3.

[0020] In step 1, the control host specifically uses multiple channels to transmit multiple waveform files in parallel to the playback device. The method is as follows:

[0021] The server has n waveform recording files that need to be remotely transmitted and synchronously played back via a wireless network. One control host controls n playback devices simultaneously. The control host is the client and the playback devices are the server.

[0022] First, the control host establishes n TCP-based communication links in parallel to ensure normal communication between the control host and the playback device;

[0023] Secondly, establish n waveform file transmission channels based on broadcast messages, and transmit different waveform recording files to n playback devices simultaneously via broadcast messages;

[0024] Finally, the playback device parses and edits the received n waveform files, splicing them together to achieve rapid transmission and continuous playback of the waveform files.

[0025] The test system used to implement the real-time closed-loop test method for power systems based on cascading fault waveform files includes a control host, a playback device, and protection devices, wherein:

[0026] The control host and the playback device establish an interactive channel through a wireless network, and the control host transmits the relevant waveform recording files to the playback device through the wireless channel.

[0027] After parsing the waveform recording file, the playback device outputs analog signals such as voltage and current, as well as switch signals of the position of disconnectors and circuit breakers in real time, and performs output signal acquisition and self-test simultaneously to determine whether the output analog signals and switch position signals are distorted.

[0028] The playback device outputs analog and digital signals to the protection device. The protection device analyzes the acquired analog and digital signals, triggers the corresponding protection action logic, and drives the action digital signal to change position. The playback device collects the change information of the protection device's action digital signal and generates a short message to feed back to the control host. The control host completes the closed-loop automatic test of the protection device based on the electrical quantity characteristic signals of the obtained waveform file and the received protection device switch position signals.

[0029] The advantages of this invention compared to the prior art are as follows: This invention provides a real-time closed-loop test scheme for power systems based on cascading fault waveform recording files. It constructs the transmission of cascading fault waveform recording files through wireless remote control, and performs remote closed-loop testing on the secondary protection field of new power systems. It adopts a waveform playback and switch feedback method to construct a closed-loop test method based on waveform files, which solves the problems of low communication efficiency and low testing efficiency faced in remote closed-loop testing of secondary protection fields of new power systems, and ensures the safety and reliability of the operation of new power systems. Attached Figure Description

[0030] The present invention will be further described below with reference to the accompanying drawings:

[0031] Figure 1 This is a schematic diagram of the structure of the real-time closed-loop test system for power systems of the present invention;

[0032] Figure 2 This is a flowchart of the closed-loop testing method based on waveform online dual authentication of the present invention;

[0033] Figure 3 This is a schematic diagram illustrating the waveform editing and splicing principle based on absolute time scale of the present invention.

[0034] Figure 4 This is a schematic diagram illustrating the principle of parallel transmission of waveform files according to the present invention. Detailed Implementation

[0035] like Figures 1 to 4 As shown, this invention provides a real-time closed-loop testing method and system for power systems based on cascading fault waveform files. The method mainly constructs cascading fault waveform files based on waveform playback and switch quantity feedback, which are used for remote operation and maintenance testing of secondary protection in new power systems. This solves the technical problems of low communication efficiency and low test quality faced in remote closed-loop testing of secondary protection in new power systems.

[0036] To achieve the above objectives, this invention provides a real-time closed-loop testing system consisting of a control host and a playback device. The control host and playback device establish an interactive channel via a wireless network. The control host transmits relevant waveform recordings to the playback device via the wireless channel. After parsing the waveform recordings, the playback device outputs analog signals such as voltage and current, as well as switch signals such as the positions of disconnectors and circuit breakers, in real time. Simultaneously, it performs output signal acquisition and self-testing to determine whether the output analog and switch signals are distorted. Simultaneously, the playback device outputs the analog and switch signals to a protection device. The protection device analyzes the acquired analog and switch signals, triggers the protection action logic of the relevant protection function, and drives the action switch signal to change position. The playback device acquires the change information of the protection device's action switch signal and feeds it back to the control host via a short message. The control host completes the closed-loop automatic test of the protection device based on the electrical characteristic signals of the obtained waveform file and the received change information of the protection device's action switch signal.

[0037] Based on the above testing system, the present invention also provides a real-time closed-loop testing method consisting of a control host and a playback device, specifically including the following steps:

[0038] Step 1: Load and parse the raw waveform recording file in COMTRADE format received wirelessly to obtain the time-domain characteristic information of the waveform, including but not limited to the effective value. Peak Amplitude Sudden Change Frequency variation Phase change distortion rate Rise time Falling edge time Duration Based on electrical characteristics, the relevant original waveform time-domain feature information is stored as a time-frequency matrix, expressed as:

[0039] ;

[0040] The number of rows M represents time information, and the number of columns N=9.

[0041] Step 2: Play back electrical quantity information data based on the original waveform. The played-back waveform data is recorded by the acquisition channel to facilitate analysis of whether the playback output data is consistent with the original waveform file; on the other hand, the playback waveform signal is transmitted to the protection device to perform relevant fault simulation.

[0042] Step 3: After recording the playback information, extract the time-domain feature information of the acquired waveform to form a time-domain matrix P. Compare the time-domain matrix P with the original waveform information's time-domain matrix F to achieve the first authentication and discrimination of the waveform playback data. The formula for calculating the similarity S between time-domain matrices P and F is:

[0043] ;

[0044] Where M is the number of rows in the time-domain matrix and N is the number of columns in the time-domain matrix;

[0045] The original waveform time-domain matrix, To acquire the waveform time-domain matrix;

[0046] Step 4: By collecting the change information of the action switch of the protection device and comparing it with the playback test discrimination logic library, the discrimination of waveform playback output closure test is realized;

[0047] Step 5: Achieve dual authentication closure test discrimination by combining steps 3 and 4.

[0048] Furthermore, this invention performs fault simulation testing by constructing zero-crossing directional editing and splicing waveforms. The specific method is as follows:

[0049] Taking phase A voltage as an example, the start time of the phase A voltage waveform received by the playback device is recorded as t0, the first zero-crossing point of the waveform is recorded as t1, and the second zero-crossing point is recorded as t2. The waveform corresponding to t2-t1 is a complete cycle M. Considering that the reclosing charging time is approximately 15 seconds and the CT / PT disconnection alarm clearing time is approximately 10 seconds, the phase A voltage at time t1 is extended forward by tm = 16 seconds, i.e., tm ÷ (t2-t1) cycles are superimposed to ensure that the reclosing charging for various protection test fault simulations is completed and various alarm signals stably disappear. Similarly, for other phase voltages and all phase currents, the corresponding t2-t1 waveform files are superimposed based on time t1.

[0050] Similarly, for continuous playback of multiple waveform files, the last waveform of the previous waveform file that rises above zero is recorded as t3, and the first waveform of the next waveform file that rises above zero is recorded as t4. The waveforms are superimposed with tn÷(t2-t1) cycles, where tn is an integer second, tn=t4-t3. Taking multiple reclosing tests as an example, tn can be set to 16s.

[0051] Furthermore, when the control host sends the waveform recording file to the playback device, it adopts a multi-channel, multi-waveform recording file parallel transmission method, specifically including:

[0052] The server has n waveform recording files that need to be remotely transmitted and synchronously played back via a wireless network. A control host controls n playback devices simultaneously. The control host is the client, and the playback devices are the servers. First, the control host establishes n TCP-based communication links in parallel to ensure normal communication between the control host and the playback devices. Second, n waveform file transmission channels based on broadcast messages are established, and different waveform recording files are simultaneously transmitted to the n playback devices via broadcast messages. Finally, the playback devices parse the information and edit and splice the waveforms from the received n waveform recording files to achieve fast transmission and continuous playback of waveform files.

[0053] For example, taking a control host + 2 playback devices + 3 waveform files as an example, the waveform file has 30 channels. Among them, waveform recording channels 1-10 are the playback channel information corresponding to playback device 1, and waveform recording channels 2-20 are the playback channel information corresponding to playback device 2. The control host establishes 2 parallel interactive channels based on TCP and 3 waveform file transmission channels based on broadcast messages. Waveform file 1, waveform file 2, and waveform file 3 are transmitted to playback device 1 and playback device 2 simultaneously through parallel transmission. Playback device 1 performs waveform editing and splicing on the three waveform files 1-10, and playback device 2 performs waveform editing and splicing on the three waveform files 2-20. Finally, under clock synchronization, the control host remotely controls playback device 1 and playback device 2 through TCP commands to achieve synchronous waveform playback output.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A real-time closed-loop testing method for power systems based on cascading fault waveform files, characterized in that: The test steps include the following: Step 1: The control host loads and parses the raw waveform recording file in COMTRADE format received via the wireless network to obtain the time-domain characteristic information of the waveform, including the effective values. Peak Amplitude Sudden Change Frequency variation Phase change distortion rate Rise time Falling edge time Duration The electrical characteristics of the original waveform are stored as a time-frequency matrix waveform recording file and then sent to the playback device. The expression of the time-frequency matrix is: ； Step 2: The playback device plays back electrical quantity information data based on the original waveform. The played-back waveform data is recorded by the acquisition channel to analyze whether the playback output data is consistent with the original waveform file. On the other hand, it is transmitted to the protection device for fault simulation test. Step 3: Perform initial authentication and verification on the replayed waveform data: After recording the replayed waveform data, the control host extracts the time-domain feature information of the acquired waveform to form a time-domain matrix P. The time-domain matrix P is then compared with the original waveform information time-domain matrix F for similarity. The formula for calculating the similarity S is as follows: ； Where M is the number of rows in the time-domain matrix and N is the number of columns in the time-domain matrix; The original waveform time-domain matrix, To acquire the waveform time-domain matrix; Step 4: The control host compares the status of the trip output of the protection device with the consistency of the playback test discrimination logic library to realize the authentication discrimination of the waveform playback output closure test; Step 5: Based on the dual authentication results of Step 3 and Step 4, complete the real-time closed-loop test and discrimination of the power system.

2. The real-time closed-loop testing method for power systems based on cascading fault waveform files as described in claim 1, characterized in that: Step 2 involves constructing zero-crossing directional clipping and splicing waveforms to perform fault simulation testing. The specific method is as follows: Define the start time of the A-phase voltage waveform received by the playback device as t0, the first zero-crossing point of the waveform as t1, and the second zero-crossing point as t2. Then the waveform corresponding to t2-t1 is a complete cycle M. At time t1 of phase A voltage, tm÷(t2-t1) cycles are superimposed forward to ensure that the reclosing charging of various protection test faults is completed and various alarm signals disappear stably; Similarly, for other phase voltages and all phase currents, the waveform files corresponding to t2-t1 are superimposed based on time t1; For continuous playback of multiple waveform files, the last waveform of the previous waveform file that rises above zero is recorded as t3, and the first waveform of the next waveform file that rises above zero is recorded as t4. The waveforms are superimposed with tn÷(t2-t1) cycles, where tn is an integer second, satisfying tn=t4-t3.

3. The real-time closed-loop testing method for power systems based on cascading fault waveform files as described in claim 2, characterized in that: In step 1, the control host specifically uses multiple channels to transmit multiple waveform files in parallel to the playback device. The method is as follows: The server has n waveform recording files that need to be remotely transmitted and synchronously played back via a wireless network. One control host controls n playback devices simultaneously. The control host is the client and the playback devices are the server. First, the control host establishes n TCP-based communication links in parallel to ensure normal communication between the control host and the playback device; Secondly, establish n waveform file transmission channels based on broadcast messages, and transmit different waveform recording files to n playback devices simultaneously via broadcast messages; Finally, the playback device parses and edits the received n waveform files, splicing them together to achieve rapid transmission and continuous playback of the waveform files.

4. The test system used to implement the real-time closed-loop test method for power systems based on cascading fault waveform files as described in claim 1, characterized in that: Includes a control host, playback device, and protection device, among which: The control host and the playback device establish an interactive channel through a wireless network, and the control host transmits the relevant waveform recording files to the playback device through the wireless channel. After parsing the waveform recording file, the playback device outputs analog signals such as voltage and current, as well as switch signals of the position of disconnectors and circuit breakers in real time, and performs output signal acquisition and self-test simultaneously to determine whether the output analog signals and switch position signals are distorted. The playback device outputs analog and digital signals to the protection device. The protection device analyzes the acquired analog and digital signals, triggers the corresponding protection action logic, and drives the action digital signal to change position. The playback device collects the change information of the protection device's action digital signal and generates a short message to feed back to the control host. The control host completes the closed-loop automatic test of the protection device based on the electrical quantity characteristic signals of the obtained waveform file and the received protection device switch position signals.

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