Extra-high voltage direct current fault processing method and device

Abstract

The invention provides an extra-high voltage direct current fault processing method and device, and the method comprises the steps: employing an electromechanical-electromagnetic simulation and data simulation combined simulation model, and simulating an extra-high voltage direct current fault event; collecting fault information of the DC fault event in real time; according to the fault information, identifying the fault type and position of the high-voltage DC fault event; determining a fault solution according to the fault type and position; the multiple fault solutions are stored in a fault database; monitoring fault information of the extra-high voltage DC power grid in real time; matching the fault solution from the fault database according to the fault information; and processing the extra-high voltage direct current fault corresponding to the real-time fault information according to the fault solving method. According to the method, the functions of simulation, optimization, decision support and the like are integrated, a complete solution system is formed, and the requirements of fault analysis and solution of the extra-high voltage direct current system are comprehensively met.

Description

Technical Field

[0001] The present application relates to the field of ultra-high voltage power grid safety, and in particular to an ultra-high voltage direct current fault processing method and device. Background Art

[0002] In the current UHV DC transmission system, the analysis of fault data mainly relies on the individual experience and subjective judgment of engineers and operators. Although this analysis method has certain practicality, due to the lack of a unified and objective analysis framework, it often leads to analysis errors, which in turn affects the comprehensiveness and accuracy of fault solutions. Especially in the context of the increasing proportion of new energy access, the complexity and uncertainty of the power grid system have further increased, and traditional fault data analysis methods have been unable to meet the needs of modern power grid operation. Summary of the invention

[0003] The purpose of the present application is to overcome the above-mentioned prior art and provide a method and device for handling UHV DC faults.

[0004] The present application provides a method for handling a UHV DC fault, comprising:

[0005] A joint simulation model of electromechanical-electromagnetic simulation and data simulation is used to simulate UHV DC fault events; simulated fault information of simulated UHV DC fault events is collected in real time;

[0006] Identify the fault type and location of the simulated UHV DC fault event according to the simulated fault information;

[0007] Determine a fault solution based on the fault type and location;

[0008] storing a plurality of said fault resolution methods in a fault database;

[0009] Real-time monitoring of UHV DC grid fault information;

[0010] Matching the fault solution method from the fault database according to the real-time fault information;

[0011] The UHV DC fault corresponding to the real-time fault information is processed according to the fault resolution method.

[0012] Optionally, a joint simulation model of electromechanical-electromagnetic simulation and data simulation is used to simulate UHV DC fault events, including:

[0013] Dividing the UHV DC protection area into multiple fault areas, and determining the fault points and fault types of the fault areas;

[0014] Generate the joint simulation model according to the fault area, fault point and fault type;

[0015] A preset fault event is inserted into the joint simulation model to simulate the UHV DC fault event.

[0016] Optionally, inserting a preset fault event into the joint simulation model to simulate the UHV DC fault event further includes:

[0017] Determining simulated fault data for simulating UHV DC fault events;

[0018] The simulated fault data is compared with the historical fault data, and the accuracy and reliability of the simulation model are verified based on the comparison results.

[0019] Optionally, identifying the fault type and location of the simulated UHV DC fault event according to the simulated fault information includes:

[0020] Extracting behavior data and parameter data from the simulated fault information;

[0021] Associating the behavior data with the parameter data to generate an association relationship;

[0022] Determine the fault type according to the association relationship;

[0023] At the same time, data representing the position is extracted from the parameter data.

[0024] Optionally, determining a fault solution according to the fault type and location includes:

[0025] reconfiguring system parameters according to the fault type and location;

[0026] Inputting the system parameters into the joint simulation model to perform data simulation;

[0027] Determining whether the system parameters are configured correctly according to the results of the data simulation;

[0028] If the system parameters are configured correctly, the system parameters are stored;

[0029] If the system parameters are configured incorrectly, reconfigure the system parameters.

[0030] The present application provides a UHV DC fault handling device, comprising:

[0031] A simulation module for simulating UHV DC fault events using a joint simulation model of electromechanical-electromagnetic simulation and data simulation;

[0032] An acquisition module, used to collect simulated fault information of simulated UHV DC fault events in real time;

[0033] an identification module, used to identify the fault type and location of the simulated UHV DC fault event according to the simulated fault information;

[0034] An analysis module, used to determine a fault solution according to the fault type and location;

[0035] A storage module, used for storing a plurality of the fault solutions into a fault database;

[0036] Monitoring module, used to monitor real-time fault information of UHV DC power grid;

[0037] A matching module, used for matching the fault solution method from the fault database according to the real-time fault information;

[0038] A processing module is used to process the UHV DC fault corresponding to the real-time fault information according to the fault resolution method.

[0039] Optionally, the simulation module uses a joint simulation model of electromechanical-electromagnetic simulation and data simulation to simulate UHV DC fault events, including:

[0040] Dividing the UHV DC protection area into multiple fault areas, and determining the fault points and fault types of the fault areas;

[0041] Generate the joint simulation model according to the fault area, fault point and fault type;

[0042] A preset fault event is inserted into the joint simulation model to simulate the UHV DC fault event.

[0043] Optionally, the simulation module inserts a preset fault event into the joint simulation model to simulate the UHV DC fault event, including:

[0044] Determining simulated fault data for simulating UHV DC fault events;

[0045] The simulated fault data is compared with the historical fault data, and the accuracy and reliability of the simulation model are verified based on the comparison results.

[0046] Optionally, the identification module identifies the fault type and location of the simulated UHV DC fault event according to the simulated fault information, including:

[0047] Extracting behavior data and parameter data from the fault information;

[0048] Associating the behavior data with the parameter data to generate an association relationship;

[0049] Determine the fault type according to the association relationship;

[0050] At the same time, data representing the position is extracted from the parameter data.

[0051] Optionally, the analyzing module matches the fault solution from the fault database according to the fault information, including:

[0052] reconfiguring system parameters according to the fault type and location;

[0053] Inputting the system parameters into the joint simulation model to perform data simulation;

[0054] Determining whether the system parameters are configured correctly according to the results of the data simulation;

[0055] If the system parameters are configured correctly, the system parameters are stored;

[0056] If the system parameters are configured incorrectly, reconfigure the system parameters.

[0057] The beneficial effects of this application are:

[0058] The present application provides a method for handling UHV DC faults, including: using a joint simulation model of electromechanical-electromagnetic simulation and data simulation to simulate UHV DC fault events; collecting simulated fault information of simulated UHV DC fault events in real time; identifying the fault type and location of the simulated UHV DC fault events according to the simulated fault information; determining a fault solution method according to the fault type and location; storing multiple fault solutions in a fault database; real-time monitoring of real-time fault information of the UHV DC power grid; matching the fault solution method from the fault database according to the real-time fault information; and processing the UHV DC fault corresponding to the real-time fault information according to the fault solution method. The present application integrates simulation, optimization, decision support and other functions to form a complete solution system, which fully meets the needs of UHV DC system fault analysis and resolution. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 This is a schematic diagram of the UHV DC fault handling process in this application;

[0060] Figure 2 This is a schematic diagram of the fault simulation process in this application;

[0061] Figure 3 This is the first schematic diagram of the fault analysis in this application;

[0062] Figure 4 This is the second schematic diagram of the fault analysis in this application;

[0063] Figure 5 This is the third schematic diagram of the fault analysis in this application;

[0064] Figure 6 This is the fourth schematic diagram of fault analysis in this application. DETAILED DESCRIPTION

[0065] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that various forms of implementing the present disclosure should not be limited by the embodiments set forth herein. On the contrary, the embodiments are provided to more thoroughly understand the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0066] Please refer to Figure 1 As shown, the present application provides a method for handling UHV DC faults, comprising:

[0067] S101. Use a joint simulation model of electromechanical-electromagnetic simulation and data simulation to simulate UHV DC fault events.

[0068] Please refer to Figure 2 As shown, this application adopts a joint simulation combining electromechanical-electromagnetic and data simulation to ensure comprehensive and accurate simulation of various actual fault scenarios. The steps are as follows:

[0069] S201. Divide the UHV DC protection area into multiple fault areas, and determine the fault points and fault types of the fault areas.

[0070] In the UHV DC transmission system, the protection system is designed to cover and protect multiple key areas of the entire transmission link, including: Converter fault area: This area covers the converter itself and its directly connected components, such as converter valves, bridge arms, converter transformer valve-side windings and valve-side connections.

[0071] The fault areas include:

[0072] Pole fault area: This area includes the pole bus area, neutral bus area, DC filter area, DC line area, etc.

[0073] Converter connecting bus fault area: This area involves converter bypass circuit breaker, converter connecting bus, etc.

[0074] Bipolar fault area: including bipolar connection area, grounding pole area, metal return line area, etc.

[0075] Converter transformer fault area: Converter transformer is a key device connecting the AC system and the converter.

[0076] AC filter fault area: AC filters are used to filter out harmonics in AC current and protect AC systems from harmonic pollution.

[0077] The definition of the fault point is the basis for fault location and diagnosis in this application.

[0078] In the UHV DC transmission system, the fault point is located at any node, component or connection of the circuit. Taking the converter fault area as an example, the fault points include: a short circuit or ground fault occurs in a converter valve or bridge arm inside the converter; a phase-to-phase short circuit or ground fault occurs in the valve-side winding or valve-side connection of the converter transformer; an abnormality of the control system causes the converter to fail to work normally, such as pulse loss, control signal error, etc.; the bypass circuit breaker fails during the opening and closing process and cannot properly isolate the fault area;

[0079] In UHV DC transmission systems, common fault types include:

[0080] Short circuit and grounding fault: such as short circuit of converter, grounding fault of pole busbar, etc.

[0081] Overstress failure: including overvoltage, overload, etc. Device damage:

[0082] Such as capacitor damage, conversion switch unable to break arc, etc.

[0083] Other faults: such as power oscillation, abnormal control signal, etc.

[0084] S202: Generate the joint simulation model according to the fault area, fault point and fault type.

[0085] According to the defined fault area, fault point and fault type, the basic framework of the fault physical model is constructed. The model should describe in detail the electrical parameters, physical connections and interactions between each area and each device.

[0086] For different types of faults, their manifestations in the physical model are refined. For example, short-circuit faults are simulated by changing the impedance of related equipment; overvoltage faults are simulated by setting appropriate voltage thresholds and simulating the system response when the voltage exceeds the threshold; device damage introduces the failure model of the faulty component, such as capacitor breakdown, switch refusal, etc.

[0087] S203: inserting a preset fault event into the joint simulation model to simulate the UHV DC fault event.

[0088] The fault event refers to a protection triggering mechanism.

[0089] A protection trigger mechanism is added to the model to simulate the action process of the protection system in actual operation, including setting protection constants (such as current protection constants, voltage protection constants, etc.). When the system status reaches or exceeds these constants, the corresponding protection actions are triggered (such as circuit breaker tripping, filter removal, etc.).

[0090] In addition to protection triggering, abnormal conditions of the control system are also considered, including: loss, mis-transmission, delay of analog control signals, and the impact of the control system's own faults on the system's operating status.

[0091] By setting the control abnormality logic in the model, the stability and reliability of the system under different control strategies are evaluated.

[0092] In order to simulate the situation when a fault occurs in actual operation, trigger buttons or switches are set in the model. These buttons or switches are manually operated and used to simulate the occurrence of faults during the simulation process. For example, a "short circuit fault trigger" button is set. When the button is pressed, a short circuit fault will occur at the corresponding fault point in the model.

[0093] Before simulation, set the test state of the DC system, including: determining the system wiring mode (such as unipolar operation, bipolar operation, etc.), voltage control mode (such as constant voltage control, constant power control, etc.) and other related parameters. The setting of the test state should ensure that the simulation process can reflect the behavioral characteristics of the system under specific conditions.

[0094] Finally, the set fault model is simulated by triggering the simulation system. During the simulation process, the system will simulate the system response process after the fault occurs according to the settings of the fault physical model, automation events and test status.

[0095] Accurately identify and collect various types of data output by the simulation system. These data sources usually include but are not limited to:

[0096] Analog quantity: Physical quantities that change continuously, such as current, voltage, power, etc. Digital quantity: Such as switch status, protection action signal, etc., which are expressed in the form of 0 or 1. Fault-related action quantity information: When a fault occurs in the system, the protection system, control system, etc. will generate a series of action quantity information, such as circuit breaker tripping signal, filter removal signal, etc.

[0097] After the data is collected, it is formatted and coded to ensure consistency and readability.

[0098] When the data is successfully transmitted to the backend system, it is further processed and stored.

[0099] The data background provides interfaces and services for the fault data acquisition module so that it can easily call the required data.

[0100] S102. Collect simulated fault information of simulated UHV DC fault events in real time.

[0101] Before starting fault data collection, the first step is to establish a stable connection with the data background.

[0102] The data backend is specifically responsible for storing and transmitting simulation data from data simulation, which is the key basis for evaluating system performance and conducting fault analysis.

[0103] The simulation data mainly covers the changes in parameters such as current, voltage, power, etc. determined based on the simulation, such as the number of commutation failures and current waveforms.

[0104] In addition to collecting these parameter data, the behavior data of the protection devices is also tracked and monitored in real time. The protection devices in the UHV power grid system are responsible for responding quickly when a fault occurs and taking corresponding protection measures to ensure the safe and stable operation of the system.

[0105] In the monitoring process of the UHV DC transmission system, after completing the collection of key data and monitoring of the control and protection devices, the preset algorithms and rules will be used to detect faults in the system.

[0106] Taking the converter short circuit fault in the converter fault area as an example, check whether specific fault criteria are met, such as:

[0107] Fault judgment criteria: IacY–max(IdH,IdN)>max(Isc_set,k_set*min(IdH,IdN)) and IacD–max(IdH,IdN)>max(Isc_set,k_set*min(IdH,IdN)).

[0108] Here, IacY and IacD represent the AC current of the Y phase and D phase on the converter transformer valve side, respectively, and IdH and IdN represent the positive and negative values ​​of the DC current, respectively.

[0109] Isc_set is the set short-circuit protection starting current threshold (such as 0.5 times the rated current), and k_set is the set proportional coefficient (such as 0.2), which is used to consider the current ratio when avoiding the most serious fault outside the zone.

[0110] If the above criteria are met, the module will perform a series of protection actions, including X-blocking, tripping start failure, locking the converter switch, long-term action blocking, and triggering the recording function to record detailed data when the fault occurs. The fault data analysis module will then preliminarily determine that the fault occurred in the converter fault area and the fault type is a converter short circuit fault.

[0111] S103: Identify the fault type and location of the simulated UHV DC fault event according to the simulated fault information.

[0112] Analyze the data information generated above, including fault area, fault point, fault type, etc., to discover potential problems and abnormal conditions.

[0113] Taking the converter short circuit fault in the converter fault area as an example, the analysis is as follows:

[0114] The short-circuit protection of the Y bridge and D bridge valves of the high-end valve group is activated, and the overcurrent protection stage IV is activated. The protection executes the X-lock and Y-lock of the high-end converter, trips the AC switch, starts failure and locks, and triggers the recording.

[0115] The valve short-circuit protection adopts differential protection with braking characteristics. When a valve short-circuit or other interphase short-circuit fault occurs, the current amplitude on the valve side of the converter transformer is higher than the DC current. When the difference between the maximum value of the valve-side current of the converter transformer and the maximum value of the DC current reaches the protection start setting, the valve short-circuit protection is activated, and the converter is immediately tripped (under the premise of avoiding the measurement error under the condition of short-term overload of the system, the protection start setting Isc_set is generally taken as 0.5 times the rated current). When considering avoiding the most serious fault outside the zone, k_set is taken as 0.2. The protection should act quickly to remove the fault to avoid the third valve from being turned on. The recommended protection action time is 500us.

[0116] The valve group overcurrent protection detects the maximum value among IDCxN, IVY and IVD. The valve group overcurrent protection includes 4 stages, among which the setting of stage I protection is coordinated with the system's two-hour overload capacity, the setting of stage II protection is coordinated with the system's 3s overload capacity, the setting of stage III protection is coordinated with the valve group's bearing capacity, and the setting of stage IV protection is mainly considered as a backup for valve short-circuit protection.

[0117] After a delay of 120 minutes and a width of 100 ms, the I stage protection switches the control system. After a delay of 125 minutes and a width of 100 ms, the power is reduced and forced to be reduced to the rated power, and the wave recording is triggered. After a delay of 3 seconds and a width of 100 ms, the control system is switched. After a delay of 3.5 seconds and a width of 100 ms, the power is reduced and forced to be reduced to the rated power. After a delay of 3.7 seconds and a width of 100 ms, the converter Y is locked, the AC switch is tripped, and the start-up failure is locked, and the wave recording is triggered. After a delay of 600 ms and a width of 100 ms, the converter Y is locked, the AC switch is tripped, and the start-up failure is locked, and the wave recording is triggered. After a delay of 2 ms and a width of 100 ms, the converter Y is locked, the AC switch is tripped, and the start-up failure is locked, and the wave recording is triggered.

[0118] Please refer to Figure 3-4 As shown, Figure 3In the first part of the image: IVY_L1 is the A-phase current on the Y / Y converter transformer valve side, IVY_L2 is the B-phase current on the Y / Y converter transformer valve side, IVY_L3 is the C-phase current on the Y / Y converter transformer valve side, and IDCP is the DC current on the high-voltage side. The second part: IVD_L1 is the A-phase current on the Y / D converter transformer valve side, IVD_L2 is the B-phase current on the Y / D converter transformer valve side, and IVD_L3 is the C-phase current on the Y / D converter transformer valve side. The third part: CPRY is the Y / Y converter transformer valve trigger pulse, and CPRD is the Y / D converter transformer valve trigger pulse. The fourth part: UDL_IN is the pole bus voltage. Figure 4 In the first part: IVY_L1 is the A-phase current on the valve side of the Y / Y converter transformer, IVY_L2 is the B-phase current on the valve side of the Y / Y converter transformer, and IVY_L3 is the C-phase current on the valve side of the Y / Y converter transformer. The second part: IVD_L1 is the A-phase current on the valve side of the Y / D converter transformer, IVD_L2 is the B-phase current on the valve side of the Y / D converter transformer, and IVD_L3 is the C-phase current on the valve side of the Y / D converter transformer. The third part: UDL_IN is the pole bus voltage, and UDN_IN is the pole neutral bus voltage. The fourth part: IDCP is the high-voltage side DC current, IDCN is the low-voltage side DC current, and IDNC is the neutral bus current (valve side).

[0119] According to the waveforms of S1P1CCPA1 and S1P1CCPA2, it can be analyzed that a valve short circuit fault occurs in the high-end converter, the current flowing through the converter valve increases sharply (increases to about 20,000 amperes), the DC current decreases, and there is a differential current between IVY, IVD, IDCN, and IDCP; CPRY=33, Y-bridge valve 1 and valve 6 are turned on, and the corresponding currents of phase A and phase B of the Y-bridge increase; CPRD=3, D-bridge valve 1 and valve 2 are turned on, and the corresponding currents of phase A and phase C of the D-bridge increase. The current flows through IVY_L1, Y-bridge valve 1, D-bridge valve 2, IVD_L3, IVD_L1, D-bridge valve 1, Y-bridge valve 6, and IVY_L2. Due to the short circuit of the high-end valve group on the rectifier side, the DC voltage on the rectifier side drops, the voltage on the rectifier side is lower than that on the inverter side, and the DC current drops to 0. There is a period of time in the waveform of the low-end valve group when the valve group current is 0.

[0120] Please refer to Figure 5-6 As shown in the figure, according to the DC field operation parameters of the rectifier station and inverter station after the fault, it can be analyzed that the high-end valve group of the rectifier station pole 1 is withdrawn, the power is reduced to 2401MW, the DC voltage Udl is reduced to 378kV, and the DC current Id is increased to 6185A. The high-end valve group of the inverter station pole 1 is withdrawn, the power is reduced to 2039MW, the DC voltage Udl is reduced to 340kV, and the DC current Id is increased to 6184A.

[0121] The expected result is that the short-circuit protection of the Y and D bridge valves operates correctly. The actual result is that the short-circuit protection of the Y and D bridge valves operates correctly. The fault area is judged to be the converter fault area, the fault point is the pole I high-end valve group, and the fault type is a short-circuit fault.

[0122] Once a fault is detected, the module will immediately notify the relevant fault handling module so that timely measures can be taken to handle the fault and ensure the safety and stability of the system.

[0123] S104: Determine a fault solution according to the fault type and location.

[0124] The fault resolution module proposes targeted solutions based on the fault data analysis results, including system recovery strategies, equipment processing methods and emergency treatment measures.

[0125] The system recovery strategy is that when the system detects faults such as short circuit and grounding, and disturbance occurs, the system executes a series of protection strategies to isolate the fault, using its rapidity to suppress the development of the accident, maintain the normal and stable operation of the system, and minimize power loss. Only when a serious fault occurs in the system or a permanent fault occurs in the equipment, and the control system reaches the limit of the control range and the DC system cannot restore stability, the DC action will be activated to shut down the DC system and isolate the faulty equipment.

[0126] Taking the converter short circuit fault in the converter fault area as an example, the converter unit isolation strategy is implemented. When a converter fails, the converter unit is locked and isolated, so that the exiting equipment has a clear disconnection point from the operating system and does not affect the operation of healthy equipment. The operation sequence is: close the converter bypass breaker, close the converter bypass disconnector, open the converter connection disconnector, and implement the converter isolation strategy.

[0127] The restart strategy is that when a transient fault occurs in the DC transmission line, the DC line protection is activated, the DC system restart procedure is started, the rectifier trigger angle is quickly increased to 120°~150°, and it is changed to inverter operation, so that the energy stored in the DC system is quickly released to the AC system, and the DC current quickly drops to zero. After the short-circuit point is freed, the rectifier trigger angle is reduced to restore the DC system to normal operation. The number of restarts is pre-set according to system research. At present, the typical logic of UHV DC restart is two original pressure restarts and two original pressure and one voltage reduction mode. In addition, it also includes system recovery strategies such as power reduction, pole balance, reclosing DC circuit breakers, and emergency shutdown.

[0128] The equipment processing method is to find out the specific cause of the fault through the above analysis, such as equipment aging, component damage, external interference, etc. Taking the converter short circuit fault in the converter fault area as an example, when the valve group control firmware has problems or is broken down, the firmware needs to be upgraded or reinstalled. When key components such as capacitors and reactors are damaged, they need to be replaced in time. When the logic control software fails, software patches or updates are required, including reconfiguring protection devices and adjusting control parameters.

[0129] Furthermore, the emergency handling strategy is to shut down the system immediately when a major fault occurs to prevent the fault from expanding, such as bipolar locking. Isolate the faulty part from the normal operating part to ensure the stable operation of the remaining systems. Enable the emergency communication system to keep in touch with all parties to convey and receive information in a timely manner. When encountering a network attack, immediately cut off the network connection and enable the backup system to prevent the attack from spreading.

[0130] According to the real-time grid status and fault conditions, efficient and accurate solutions are proposed, and autonomous inspection plans are formulated to ensure that all system indicators are normal. Regular maintenance strategies are established to timely discover and eliminate hidden dangers. Key components are replaced regularly according to service life and operating conditions. Through efficient and accurate solutions and maintenance strategies, the stable operation of the system and the reliability of power transmission are guaranteed.

[0131] According to the specific situation of the fault, take corresponding fault repair measures, including: valve group firmware repair, replacement of faulty parts, ACCEL logic software repair or configuration adjustment, etc.

[0132] For example: reconfigure system parameters according to the fault type and location; input the system parameters into the joint simulation model to perform data simulation; determine whether the system parameters are correctly configured according to the results of the data simulation; if the system parameters are correctly configured, store the system parameters; if the system parameters are incorrectly configured, reconfigure the system parameters.

[0133] When the fault is repaired, restart and data recovery are performed to ensure that all important data and settings are preserved, helping the system return to normal operation as soon as possible.

[0134] In emergency situations, this also includes the rapid implementation of emergency response strategies.

[0135] The emergency response strategy includes emergency shutdown, safety isolation, emergency communication and temporary repair measures.

[0136] For example, in the event of a network attack, the attacked network connection is immediately cut off and the backup system is activated to ensure the safety of the power grid. If the fault causes bipolar lockout, emergency shutdown of the DC is immediately implemented to prevent the fault from spreading further and worsening.

[0137] The ability to propose efficient and accurate solutions based on real-time grid status and fault conditions. Based on real-time grid data and analysis results, formulate autonomous DC system inspection plans, establish regular maintenance and inspection strategies, and repair faulty components or replace key components.

[0138] These measures are aimed at preventing potential failures from occurring and improving the reliability and stability of the power grid.

[0139] In the context of hybrid power grids, due to the volatility and uncertainty of renewable energy, the power grid will encounter some unique restart problems. In order to solve the new problems after the access of renewable energy, the restart strategy after the access of renewable energy is optimized.

[0140] Immediate Restart strategy:

[0141] When the fault type is minor and can be resolved in a short time, a direct restart strategy is adopted.

[0142] This means that once the fault is resolved, the system will immediately attempt to restart in order to quickly restore normal operation of the grid.

[0143] This strategy is suitable for short-term failures that have little impact on the system, such as temporary failures of certain equipment or communication interruptions.

[0144] Cold Restart strategy:

[0145] In the case of severe faults or when the system needs to be completely cooled and inspected, the Fault Data Analysis module recommends a cold start strategy.

[0146] In this case, the system will be completely shut down, all devices and components will be turned off, and necessary cooling and inspection will be carried out. Then, after a certain waiting time (this time will vary depending on the type and severity of the fault), the system will be restarted.

[0147] The cold start strategy is suitable for faults that have a major impact on the system and require thorough inspection and repair, such as damage to major equipment or system overheating.

[0148] Soft Restart strategy:

[0149] In the case of protecting system equipment, the soft start strategy is a good choice.

[0150] During the restart process, the system will gradually increase the voltage and current instead of reaching the rated value at once, thus avoiding damage to the equipment caused by sudden load shock.

[0151] The soft start strategy is suitable for devices that are sensitive to voltage and current changes, such as transformers, capacitors, etc.

[0152] Fault Location and Isolation Restart Strategy:

[0153] When ensuring that the fault point does not affect the restart process, the fault location and isolation restart strategy is the first choice.

[0154] In this strategy, the fault point is first located and then isolated from the rest of the grid. Then, after isolating the faulty area, the system attempts to restart.

[0155] This strategy prevents the fault from spreading to other areas and improves the success rate of restart. It is suitable for situations where the fault affects the stability of the entire power grid.

[0156] Based on the fault data analysis, the voltage drop value and power transfer situation analysis include but are not limited to the fault type, impact range, fault cause, etc.

[0157] For example, we analyze whether the power transfer after the DC line voltage reduction and restart is normal, and whether the BPS (Breaker Protection System) reclosing works after the valve group is locked. These analyses help us understand the impact of the fault on the system and the system's self-recovery ability after the fault occurs.

[0158] In response to the restart problem after the access of new energy sources in the hybrid power grid, the fault data analysis module will optimize the restart strategy. This includes determining the appropriate restart time, restart sequence, restart power and other parameters to improve the recovery speed and stability of the power grid.

[0159] Furthermore, by continuously optimizing the restart strategy, we can ensure that the power grid can maintain a stable operating state after the access of new energy sources and provide users with reliable power supply.

[0160] S105: Store the plurality of fault resolution methods in a fault database.

[0161] Based on the above content, a fault resolution method is formed and stored in a pre-set fault database for subsequent use.

[0162] S106 monitors the real-time fault information of the UHV DC power grid.

[0163] Start the fault monitoring system of the UHV DC grid, which is integrated into the grid's automation control system or smart grid management platform. Use sensors, measuring instruments and other equipment to collect real-time operating data of each link in the grid, including key parameters such as voltage, current, temperature, and power factor.

[0164] The collected data is analyzed in real time to identify any abnormal conditions or faults by comparing the actual data with the preset normal range or threshold.

[0165] If the data analysis results show an abnormal situation, mark and identify the specific fault type, such as equipment failure, communication failure, energy imbalance, etc. The identified fault information is recorded in detail in the database, including key information such as the time, location, type, and scope of impact of the fault.

[0166] S107 matches the fault solution from the fault database according to the real-time fault information.

[0167] Extract specific fault information from the real-time monitoring system, including key data such as fault type, location, and impact range. Based on the extracted fault information, search the pre-established fault database. The database should contain various fault types and their corresponding solutions.

[0168] By comparing the fault information with the records in the database, the best fault solution that matches the current fault situation is found. The matching process involves comparisons in multiple dimensions, such as fault type, severity, and impact range.

[0169] When multiple solutions are matched, the most appropriate solution is selected according to the actual situation and priority of the current power grid. Then, the implementation steps and required resources of the selected fault solution are prepared to prepare for the next step of fault handling.

[0170] S108 processes the UHV DC fault corresponding to the real-time fault information according to the fault resolution method.

[0171] According to the matched fault solution, specific fault handling measures are implemented, which involve multiple operations such as system recovery, emergency shutdown, safety isolation, communication recovery, and component replacement.

[0172] During the process of troubleshooting, keep real-time monitoring of the grid operation status to ensure the effectiveness and safety of the troubleshooting measures. Once the troubleshooting is complete, conduct a comprehensive inspection of the grid again to confirm that the fault has been completely resolved and the system has resumed normal operation.

[0173] The troubleshooting process, results, and any valuable lessons learned are recorded in the database for future reference and learning. At the same time, the results are fed back to the relevant personnel or system for subsequent maintenance and improvement.

[0174] After the fault is resolved, the recovery of the power grid is evaluated, including the recovery speed, stability, safety, etc., to ensure that the power grid can continue to operate stably.

[0175] To further illustrate the technical solution of the embodiment of the present application, the following program fragments used in the above embodiment are provided:

[0176] import pandas as pd

[0177] #Example fault library data

[0178] fault_library = {

[0179] 'Fault type': ['Abnormal voltage', 'Overload', 'Abnormal current', 'Short circuit', 'Overheat'],

[0180] 'Affected range':['local','whole','local','whole','local'],

[0181] 'Solution':['Restart system','Reduce load','Repair circuit','Replace parts','Reduce load']

[0182] }

[0183] #Convert to DataFrame

[0184] fault_library_df=pd.DataFrame(fault_library)

[0185] def query_fault_solution(fault_type,impact_range):

[0186] #Query the fault database

[0187] matched_fault=fault_library_df[(fault_library_df['fault type']==fault_type)&(fault_library_df['impact range']==impact_range)]

[0188] if len(matched_fault)>0:

[0189] #Match fault type and impact range

[0190] solution = matched_fault['Solution'].iloc[0]

[0191] return solution

[0192] else:

[0193] return "Unable to find a matching solution"

[0194] #Failure occurs

[0195] fault_type = 'Abnormal current'

[0196] impact_range = 'local'

[0197] #Query the fault library and apply the solution

[0198] solution=query_fault_solution(fault_type,impact_range)

[0199] if solution! = "No matching solution found":

[0200] print(f"fault type:{fault_type}")

[0201] print(f"impact range:{impact_range}")

[0202] print(f"Solution:{solution}")

[0203] else:

[0204] print("Unable to find a matching solution")

[0205] Fault library model tuning code:

[0206] #Import necessary libraries

[0207] import pandas as pd

[0208] from sklearn.model_selection import train_test_split

[0209] from sklearn.ensemble import RandomForestClassifier

[0210] from sklearn.metrics import accuracy_score

[0211] #Example fault dataset

[0212] fault_data = {

[0213] 'Fault Type':['Abnormal Voltage','Overload','Abnormal Current','Short Circuit','Overheat','Abnormal Voltage','Short Circuit','Overload','Abnormal Current','Overheat'],

[0214] 'Affected range':['local','whole','local','whole','local','local','whole','whole','local','local'],

[0215] 'Solution':['Restart the system','Reduce the load','Repair the circuit','Replace the component','Reduce the load','Restart the system','Replace the component','Reduce the load','Repair the circuit','Reduce the load']

[0216] }

[0217] #Convert to DataFrame

[0218] fault_df=pd.DataFrame(fault_data)

[0219] #Data preprocessing

[0220] #Convert categorical data to digital encoding

[0221] fault_df['fault type'] = fault_df['fault type'].astype('category').cat.codes

[0222] fault_df['scope of impact'] = fault_df['scope of impact'].astype('category').cat.codes

[0223] fault_df['Solution'] = fault_df['Solution'].astype('category').cat.codes

[0224] #Feature and label splitting

[0225] X = fault_df.drop('Solution',axis=1)

[0226] y = fault_df['Solution']

[0227] # Split the dataset into training and test sets

[0228] X_train,X_test,y_train,y_test=train_test_split(X,y,test_size=0.2,rando m_state=42)

[0229] # Use random forest model for training

[0230] model=RandomForestClassifier()

[0231] model.fit(X_train,y_train)

[0232] #Verify model accuracy and reliability

[0233] y_pred=model.predict(X_test)

[0234] accuracy=accuracy_score(y_test,y_pred)

[0235] print(f"Model accuracy:{accuracy}")

[0236] #Model tuning (based on adjusting model parameters)

[0237] # Output the tuned model

[0238] optimized_model=model

[0239] #Store to fault library

[0240] #Save the optimized model to a file for subsequent use

[0241] print("Optimized model:")

[0242] print(optimized_model)

[0243] The present application provides a UHV DC fault handling device, comprising:

[0244] A simulation module for simulating UHV DC fault events using a joint simulation model of electromechanical-electromagnetic simulation and data simulation;

[0245] An acquisition module, used to collect simulated fault information of simulated UHV DC fault events in real time;

[0246] an identification module, used to identify the fault type and location of the simulated UHV DC fault event according to the simulated fault information;

[0247] An analysis module, used to determine a fault solution according to the fault type and location;

[0248] A storage module, used for storing a plurality of the fault solutions into a fault database;

[0249] Monitoring module, used to monitor real-time fault information of UHV DC power grid;

[0250] A matching module, used for matching the fault solution method from the fault database according to the real-time fault information;

[0251] A processing module is used to process the UHV DC fault corresponding to the real-time fault information according to the fault resolution method.

[0252] Furthermore, the simulation module uses a joint simulation model of electromechanical-electromagnetic simulation and data simulation to simulate UHV DC fault events, including:

[0253] Dividing the UHV DC protection area into multiple fault areas, and determining the fault points and fault types of the fault areas;

[0254] Generate the joint simulation model according to the fault area, fault point and fault type;

[0255] The UHV DC fault event is simulated according to the preset automation event inserted into the joint simulation model.

[0256] Furthermore, after simulating the UHV DC fault event according to the fault simulation model, the simulation module includes:

[0257] Determining fault data for simulating the UHV DC fault event;

[0258] The fault data is compared with historical fault data, and the accuracy and reliability of the simulation model are verified based on the comparison result.

[0259] Further, identifying the fault type and location of the high voltage direct current fault event according to the fault information includes:

[0260] Extracting behavior data and parameter data from the fault information;

[0261] Associating the behavior data with the parameter data to generate an association relationship;

[0262] Determine the fault type according to the association relationship;

[0263] At the same time, data representing the position is extracted from the parameter data.

[0264] Further, the analysis module matches the fault solution from the fault database according to the fault information, including:

[0265] reconfiguring system parameters according to the fault type and location;

[0266] Inputting the system parameters into the joint simulation model to perform data simulation;

[0267] Determining whether the system parameters are configured correctly according to the results of the data simulation;

[0268] If the system parameters are configured correctly, the system parameters are stored;

[0269] If the system parameters are configured incorrectly, reconfigure the system parameters.

[0270] Although the present invention is disclosed as above by the embodiments, it is not intended to limit the protection scope of the present invention. Any changes and modifications made by any technician familiar with the technology without departing from the concept and scope of the present invention should fall within the protection scope of the present invention.

Claims

1. A method for handling UHV DC faults, characterized in that: include: A joint simulation model combining electromechanical-electromagnetic simulation and data simulation is used to simulate UHV DC fault events; Collect simulated fault information of simulated UHV DC fault events in real time; Identify the fault type and location of the simulated UHV DC fault event according to the simulated fault information; Determine a fault solution based on the fault type and location; storing a plurality of said fault resolution methods in a fault database; Real-time monitoring of UHV DC grid fault information; Matching the fault solution method from the fault database according to the real-time fault information; The UHV DC fault corresponding to the real-time fault information is processed according to the fault resolution method.

2. The UHV DC fault handling method according to claim 1, characterized in that: A joint simulation model combining electromechanical-electromagnetic simulation and data simulation is used to simulate UHV DC fault events, including: Dividing the UHV DC protection area into multiple fault areas, and determining the fault points and fault types of the fault areas; Generate the joint simulation model according to the fault area, fault point and fault type; A preset fault event is inserted into the joint simulation model to simulate the UHV DC fault event.

3. The UHV DC fault handling method according to claim 2, characterized in that: Inserting a preset fault event into the joint simulation model to simulate the UHV DC fault event includes: Determining simulated fault data for simulating UHV DC fault events; The simulated fault data is compared with the historical fault data, and the simulation model is verified according to the comparison result.

4. The UHV DC fault handling method according to claim 1, characterized in that: Identifying the fault type and location of the simulated UHV DC fault event according to the simulated fault information includes: Extracting behavior data and parameter data from the simulated fault information; Associating the behavior data with the parameter data to generate an association relationship; Determine the fault type according to the association relationship; Data representing the position is extracted from the parameter data.

5. The UHV DC fault handling method according to claim 1, characterized in that: Determine the fault solution based on the fault type and location, including: reconfiguring system parameters according to the fault type and location; Inputting the system parameters into the joint simulation model to perform data simulation; Determining whether the system parameters are configured correctly according to the results of the data simulation; If the system parameters are configured correctly, the system parameters are stored; If the system parameters are configured incorrectly, reconfigure the system parameters.

6. A UHV DC fault handling device, characterized in that: include: A simulation module for simulating UHV DC fault events using a joint simulation model of electromechanical-electromagnetic simulation and data simulation; An acquisition module, used to collect simulated fault information of simulated UHV DC fault events in real time; an identification module, used to identify the fault type and location of the simulated UHV DC fault event according to the simulated fault information; An analysis module, used to determine a fault solution according to the fault type and location; A storage module, used for storing a plurality of the fault solutions into a fault database; Monitoring module, used to monitor real-time fault information of UHV DC power grid; A matching module, used for matching the fault solution method from the fault database according to the real-time fault information; A processing module is used to process the UHV DC fault corresponding to the real-time fault information according to the fault resolution method.

7. The UHV DC fault handling device according to claim 6, characterized in that: The simulation module uses a joint simulation model of electromechanical-electromagnetic simulation and data simulation to simulate UHV DC fault events, including: Dividing the UHV DC protection area into multiple fault areas, and determining the fault points and fault types of the fault areas; Generate the joint simulation model according to the fault area, fault point and fault type; A preset fault event is inserted into the joint simulation model to simulate the UHV DC fault event.

8. The UHV DC fault handling device according to claim 7, characterized in that: The simulation module inserts a preset fault event into the joint simulation model to simulate the UHV DC fault event, including: Determining simulated fault data for simulating UHV DC fault events; The simulated fault data is compared with the historical fault data, and the accuracy and reliability of the simulation model are verified based on the comparison results.

9. The UHV DC fault handling device according to claim 6, characterized in that: The identification module identifies the fault type and location of the simulated UHV DC fault event according to the simulated fault information, including: Extracting behavior data and parameter data from the fault information; Associating the behavior data with the parameter data to generate an association relationship; Determine the fault type according to the association relationship; At the same time, data representing the position is extracted from the parameter data.

10. The UHV DC fault handling device according to claim 6, characterized in that: The analysis module matches the fault solution from the fault database according to the fault information, including: reconfiguring system parameters according to the fault type and location; Inputting the system parameters into the joint simulation model to perform data simulation; Determining whether the system parameters are configured correctly according to the results of the data simulation; If the system parameters are configured correctly, the system parameters are stored; If the system parameters are configured incorrectly, reconfigure the system parameters.

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