A method, device, equipment and medium for locating a short circuit fault of a converter valve area

Abstract

The application provides a converter valve area short-circuit fault positioning method, device, equipment and medium, the method comprises the following steps: dividing the converter valve fault into eight typical valve area short-circuit faults; RTDS simulation analysis, according to the different converter protection action results, dividing into three types of protection actions, giving the typical fault characteristic quantity of the valve difference protection action for positioning the valve area fault and the eight typical valve area short-circuit quick criterion; according to whether the actual converter protection action occurs in the rectifying station or the inverting station, confirming the valve area short-circuit fault occurring station; according to the converter protection action event of the monitoring background, confirming the converter protection action type and the valve area fault converter bridge; calling the built-in fault recording of the DC control protection, analyzing the converter protection action waveform, analyzing the fault characteristics of the current waveform of the valve side of the converter bridge and the outlet current waveform of the DC side, positioning the valve area short-circuit fault point according to the typical fault characteristic quantity of the valve difference protection action and the eight typical valve area short-circuit quick criterion; and has the advantages of fast positioning speed and simple analysis method.

Description

Technical Field

[0001] This invention relates to the field of short-circuit fault analysis technology in the valve area of ​​ultra-high voltage direct current (UHVDC) transmission converters, specifically to a method, device, equipment, and medium for locating short-circuit faults in the valve area of ​​a converter. Background Technology

[0002] With the rapid development of China's economy and the increasing demand for renewable energy consumption, ultra-high voltage direct current (UHVDC) transmission has experienced rapid development in the past decade. UHVDC transmission plays a crucial role in long-distance, large-capacity energy transmission and regional power grid interconnection, gradually building my country's new UHV power grid. The converter valve is the most important component in a DC transmission system, converting AC to DC power through real-time rectification and inversion. The short-circuit fault characteristics, protection configurations, and principles of converter valves differ from those of conventional AC system equipment. Therefore, studying the short-circuit fault characteristics of converter valves and quickly locating the fault point is of great significance.

[0003] In recent years, there has been considerable research and analysis on the characteristics of converter valve short-circuit faults, the action characteristics of valve short-circuit protection, and converter transformer short-circuit analysis. Many scholars have conducted theoretical analyses and practical simulations of valve short-circuit faults at different conduction times and valve zones, further deepening the research on the action characteristics of valve short-circuit protection and optimizing the valve short-circuit protection action equations. However, research and analysis on converter valve short-circuit fault location are relatively scarce. The proposed fault location methods are not very practical for actual valve short-circuit fault analysis engineering, lacking effective and rapid methods for locating valve zone fault points and improving the efficiency of on-site fault location analysis in converter stations. This study proposes a converter fault location method based on two different valve protection action criteria and fault time periods. However, in the latest UHVDC engineering applications, it is impossible to configure both types of valve protection action criteria simultaneously, and the latest protection action criteria have been optimized and improved. Alternatively, some studies have conducted theoretical analyses of converter grounding faults, proposing a fault location and discrimination approach combining electrical characteristics and time delays. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method, device, equipment and medium for locating short-circuit faults in the valve zone of a converter.

[0005] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0006] In a first aspect, the present invention provides a method for locating short-circuit faults in the valve region of a converter, the method comprising:

[0007] Step S1: Based on different fault points in the converter valve area, classify the converter valve faults into typical valve area short-circuit faults.

[0008] Step S2: Simulate and analyze typical valve area short circuit faults. Based on the different converter protection action results, the protection actions are divided into three categories. Typical fault characteristic quantities of valve differential protection actions for locating valve area faults and rapid judgment criteria for typical valve area short circuits are given.

[0009] Step S3: Based on whether the actual converter protection action occurred at the rectifier station or the inverter station, first identify the converter station where the valve zone short circuit fault occurred.

[0010] Step S4: Next, confirm the converter protection action type based on the converter protection action events monitored in the background: valve differential protection action, valve short circuit protection action, commutation failure protection action;

[0011] Step S5: Next, confirm the faulty converter bridge in the valve area based on the converter protection action events monitored in the background.

[0012] Step S6: Retrieve the built-in fault waveform of the DC control and protection system, and use the waveform recording software to analyze the converter protection action waveform, analyze the fault characteristics of the valve side current waveform and the DC side outlet current waveform, and locate the valve area short circuit fault point based on the typical fault characteristic quantities of the valve differential protection action and the typical valve area short circuit fast judgment criteria given by the simulation in S2.

[0013] Optionally, the typical valve area short-circuit faults in step S1 include: phase-to-phase short circuit on the AC side of the converter valve, single-phase grounding short circuit on the AC side of the converter transformer valve, grounding short circuit on the high-voltage side of the converter valve, grounding short circuit on the low-voltage side of the converter valve, grounding short circuit at the midpoint of the converter valve, single-valve short circuit in the converter valve, single-bridge short circuit in the converter valve, and double-bridge short circuit in the converter valve.

[0014] Optionally, step S2 includes: simulating and analyzing typical valve area short-circuit faults, and classifying the converter protection action results into three categories of protection actions, including:

[0015] When a single-phase ground fault occurs on the AC side of the converter valve, a ground fault occurs on the high-voltage side of the converter valve, a ground fault occurs on the low-voltage side of the converter valve, or a ground fault occurs at the midpoint of the converter valve, the valve differential protection will activate regardless of whether the fault occurs on the rectifier side or the inverter side.

[0016] When a single valve short circuit, single bridge short circuit, double bridge short circuit, or phase-to-phase short circuit occurs on the AC side of the converter valve, if it occurs on the rectifier side, the valve short circuit protection will activate; if it occurs on the inverter side, the commutation failure protection is more likely to activate, and the valve short circuit protection may also activate.

[0017] Typical fault characteristics of differential valve protection action in the positioning valve area: increased current on the high-pressure side of the converter valve, decreased current on the low-pressure side of the converter valve, and increased or decreased AC current on the converter transformer side to 0.

[0018] Optionally, the simulation analysis of typical valve area short-circuit faults includes RTDS simulation analysis.

[0019] Optionally, the valve zone fault converter bridge includes: Y-bridge fault, D-bridge fault, or both Y-bridge and D-bridge fault.

[0020] Optionally, typical quick criteria for diagnosing positioning valve area faults include:

[0021] Quick criterion for single-valve short circuit of rectifier-side converter valve 1: When the current waveform of a certain phase rapidly passes through 0 point at its turn-off moment and rapidly increases in the opposite direction of the other current, it can be quickly determined that it is the current waveform of the faulty converter valve.

[0022] Quick criterion for single valve short circuit in rectifier-side converter valve 2: If the fault waveform does not show an increase in current in the other direction, it can be determined that the valve currently being shut off is short-circuited; the surge current is used to determine which two phases of valves are faulty. There are a total of 4 valves in two phases. After excluding the valves that are currently conducting, there are 2 valves left. If the valve that conducts in the next moment and the current does not surge is in the upper or lower half of the bridge arm, it can be determined that the faulty valve is the shut-off valve of the other half of the bridge arm.

[0023] Quick criterion for single valve short circuit in rectifier-side converter valve 3: If there is no increase in current in the other direction, it can be determined that the valve currently being shut off is short-circuited; the surge in current can be used to determine which two phases of valves are faulty. There are a total of 4 valves in two phases. Excluding the valves that are currently conducting, there are two valves left; if the valve that turns on and experiences a surge in current at the next moment is in the upper or lower half of the bridge arm, it can be determined that the faulty valve is the shut-off valve in that half of the bridge arm.

[0024] Based on the analysis of the characteristics of a single-bridge short-circuit fault, it is known that a judgment condition needs to be superimposed: if the next short-circuit current that crosses zero earliest can be turned off, then it is a single-valve short circuit; otherwise, it is a bridge short circuit.

[0025] Quick criterion for short circuit in single bridge rectifier-side converter valve 4: If there is no increase in current in the other direction, it can be determined that the valve currently being shut off is short-circuited; the surge in current can be used to determine which two phases of valves are faulty. There are a total of 4 valves in two phases. Excluding the valves that are currently conducting, there are two valves left; if the valve that turns on and experiences a surge in current at the next moment is in the upper or lower half of the bridge arm, it can be determined that the faulty valve is the shut-off valve in that half of the bridge arm.

[0026] Next, determine whether it is a bridge short circuit: if the earliest zero-crossing short circuit current cannot be turned off, it is a bridge short circuit; otherwise, it is a single valve short circuit.

[0027] 5. Quick criterion for short circuit of double bridge in rectifier-side converter valve: Based on the quick criterion for single bridge in 4, bridge short circuit is judged. If both bridges are found to have bridge short circuit characteristics, it is judged as a double bridge short circuit.

[0028] Quick criterion for phase-to-phase short circuit on the AC side of the rectifier-side converter valve 6: If there is only a two-phase short circuit current, the short circuit current will continue to exist when the converter valve firing angle shifts to 90 degrees and will not be turned off until several cycles later. The short circuit phase can be determined by the distorted large current.

[0029] Inverter-side converter valve single valve short circuit quick judgment criterion 7: If the AC three-phase voltage does not distort, and a normally conducting valve has a three-phase current of 0 after being turned off, it can be judged that the other valve in the same phase bridge arm of the next conducting valve is a short circuit fault valve.

[0030] Rapid Criterion 8 for Short Circuit of Single-Bridge or Double-Bridge Converter Valve on Inverter Side: If the protection trips due to commutation failure, and at the same time the single-bridge bypass is activated and the three-phase AC current on the grid side becomes zero, it can be determined that there is a short circuit fault in the single-bridge or double-bridge converter valve on the inverter side.

[0031] Secondly, the present invention provides a converter valve zone short-circuit fault location device, the device comprising:

[0032] The fault classification module is used to classify converter valve faults into typical valve area short-circuit faults based on different fault points in the converter valve area.

[0033] The criterion generation module is used to simulate and analyze typical valve area short-circuit faults. Based on the different converter protection action results, it is divided into three types of protection actions, and provides typical fault characteristic quantities of valve differential protection actions for locating valve area faults and fast criteria for typical valve area short circuits.

[0034] The first positioning module is used to first identify the converter station where the valve zone short circuit fault occurred, based on whether the actual converter protection action occurred at the rectifier station or the inverter station.

[0035] The second positioning module is used to confirm the type of converter protection action based on the converter protection action events monitored in the background: valve differential protection action, valve short circuit protection action, and commutation failure protection action.

[0036] The third positioning module is used to confirm the faulty converter bridge in the valve area based on the converter protection action events monitored in the background.

[0037] The fourth positioning module is used to retrieve the built-in fault waveform of the DC control and protection system, and use the waveform recording software to analyze the converter protection action waveform, analyze the fault characteristics of the valve side current waveform and the DC side outlet current waveform, and based on the judgment generation module simulation, it generates typical fault characteristic quantities of valve differential protection action and typical valve area short circuit fast judgment criteria to locate the valve area short circuit fault point.

[0038] Optionally, the typical valve area short-circuit faults include: phase-to-phase short circuit on the AC side of the converter valve, single-phase grounding short circuit on the AC side of the converter valve, grounding short circuit on the high-voltage side of the converter valve, grounding short circuit on the low-voltage side of the converter valve, grounding short circuit at the midpoint of the converter valve, single-valve short circuit in the converter valve, single-bridge short circuit in the converter valve, and double-bridge short circuit in the converter valve.

[0039] Thirdly, the present invention provides an electronic device, including a processor and a storage medium;

[0040] The storage medium is used to store instructions;

[0041] The processor is configured to operate according to the instructions to perform the steps according to the method described above.

[0042] Fourthly, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method.

[0043] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0044] This invention provides a method, device, equipment, and medium for locating short-circuit faults in the valve area of ​​a converter. This method is based on the RTDS system fault simulation of an actual UHVDC engineering model in operation. It simulates fault points in different areas of the converter valve on the rectifier and inverter sides, analyzes the fault waveform characteristics generated by fault points in different valve areas, and provides fault characteristic quantities and typical rapid judgment criteria that have been verified by theoretical analysis and actual control and protection simulation waveform recording.

[0045] In practical applications, it is only necessary to analyze the protection action events and actual control and protection fault waveforms, and compare the fault characteristics of the valve area with typical rapid judgment criteria to quickly locate the short circuit fault point in the valve area. It has the advantages of fast location speed, simple analysis method, avoidance of a large number of theoretical formula calculations, and greatly improves the efficiency of on-site fault analysis and handling, and has important engineering application value. Attached Figure Description

[0046] Figure 1 A flowchart of a converter valve zone short-circuit fault location method provided by the present invention;

[0047] Figure 2 This is a schematic diagram of a typical short-circuit fault point in the valve region of a rectifier-side converter, provided in an embodiment of the present invention. Detailed Implementation

[0048] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0049] This invention provides a method for locating short-circuit faults in the valve region of a converter, the method comprising:

[0050] Step S1: Based on different fault points in the converter valve area, the converter valve faults are divided into eight typical valve area short circuit faults.

[0051] Step S2: RTDS (Real Time Digital Simulation System) simulation analysis of eight typical valve area short circuit faults, classifying them into three types of protection actions based on different converter protection action results, and providing typical fault characteristic quantities of valve differential protection actions for locating valve area faults and fast judgment criteria for eight typical valve area short circuits;

[0052] Step S3: Based on whether the actual converter protection action occurred at the rectifier station or the inverter station, first identify the station where the valve zone short circuit fault occurred.

[0053] Step S4: Next, confirm the converter protection action type based on the converter protection action events monitored in the background: valve differential protection action, valve short circuit protection action, commutation failure protection action;

[0054] Step S5, then confirm the faulty converter bridge in the valve area based on the converter protection action events monitored in the background: Y bridge fault, D bridge fault, or both Y bridge and D bridge fault.

[0055] Step S6: Retrieve the built-in fault waveform of the DC control and protection system, and use the waveform recording software to analyze the converter protection action waveform. Analyze the fault characteristics of the valve side current waveform and DC side outlet current waveform of the Y-bridge and D-bridge. Based on the typical fault characteristic quantities of the valve differential protection action and the eight typical valve area short circuit fast judgment criteria given by the simulation in S2, locate the valve area short circuit fault point.

[0056] In the first preferred embodiment of the present invention: the eight typical valve zone short-circuit faults classified in step S1 include: converter valve zone short-circuit faults mainly include AC side short circuit of converter valve, converter valve short circuit, and DC side short circuit of converter valve; as shown in the appendix. Figure 2 As shown, AC side short circuits in converter valves mainly include phase-to-phase short circuits F1 and F2 on the converter transformer valve side and single-phase ground faults F3 and F4 on the converter transformer valve side. DC side short circuits in converter valves mainly include high-voltage side ground faults F5, low-voltage side ground faults F6, and midpoint ground faults F7. Short circuits in converter valves mainly include single-valve short circuits F8, single-bridge short circuits F9, and double-bridge short circuits F10.

[0057] In the second preferred embodiment provided by the present invention: in step S2, RTDS simulation is performed based on an existing UHVDC model, and the attached... Figure 2Simulations were performed on the eight typical fault locations (F1-F12, Y-bridge and D-bridge) for each of the eight faults shown. The simulation results show that when a single-phase ground fault occurs on the AC side of the converter valve (faults at locations F3 and F4) or a short circuit occurs on the DC side of the converter valve (faults at locations F5, F6, and F7), the valve short-circuit protection does not activate regardless of whether the fault occurs on the rectifier side. When the converter valve is short-circuited (faults at locations F8, F9, and F10) or when there is a phase-to-phase short circuit on the AC side of the converter (faults at locations F1 and F2), the valve short-circuit protection activates during rectifier side faults. However, the commutation failure protection has the highest probability of activation during inverter side faults, and the valve short-circuit protection may also activate.

[0058] Based on RTDS system simulation analysis, the typical fault characteristics of valve differential protection are shown in Table 1 below.

[0059] Table 1. Analysis of typical fault characteristics of valve differential action.

[0060]

[0061] Note: IDCP: DC current on the high-pressure side of the converter valve; IDCN: DC current on the low-pressure side of the converter valve; IVY: Y-bridge valve-side current of the converter valve; IVD: D-bridge valve-side current of the converter valve.

[0062] There are differences in the short circuit characteristics of the valve regions of the rectifier and inverter sides of the converter. For a single valve short circuit on the rectifier side, the fault characteristic waveforms are different at different fault times. Through simulation verification using the RTDS system, the fault characteristics of a single valve short circuit can be divided into three different fault times for analysis and summary: Fault time 1 is when the on-state valve causes a short circuit; Fault time 2 is when the off-state valve causes a short circuit, and the short-circuited valve and the commutation valve at the next time are not on the same half-bridge arm; Fault time 3 is when the off-state valve causes a short circuit, and the short-circuited valve and the on-state valve at the next time are on the same half-bridge arm. In summary, there should be six typical characteristic waveforms.

[0063] Compared to the rectifier side, the short-circuit current is much smaller when a valve short circuit occurs on the inverter side. A single valve short circuit on the inverter side exhibits alternating bypassing; in bridge short circuits, double-bridge short circuits, and double-valve short circuits, the corresponding bridges all exhibit permanent bypassing. This is equivalent to an open circuit on the AC side and a short circuit on the DC side. Due to the larger firing angle on the inverter side, these situations do not produce the surge in short-circuit current seen in rectifier-side valve short circuits. Therefore, the inverter-side commutation failure protection is more likely to activate, although in extreme cases, valve short-circuit protection may activate. For a two-phase short circuit on the AC side of the converter valve, the fault waveform is similar to that of the rectifier station. The general analysis principle is: when the short-circuit current flowing through the normal valve changes from positive to negative, it will shut off; however, due to the large amplitude of the short-circuit current, the zero-crossing time will be affected by the two-phase voltage and loop impedance, resulting in a delay compared to the original commutation time.

[0064] When a single valve short circuit occurs in the rectifier-side converter valve, the fault location criterion 1 is as follows: When the current waveform of a certain phase rapidly crosses zero at its turn-off moment and rapidly increases in the other current direction, it can be determined that it is the faulty valve current waveform.

[0065] When a single valve short-circuit fault occurs in the rectifier-side converter valve, and the short-circuited valve is not in the same half of the bridge arm as the commutation valve at the next moment, the rapid fault location criterion 2 is as follows: If the fault waveform does not show an increase in current in the other direction, it can be determined that the valve currently being shut off has short-circuited; the surge current is used to determine which two phases of valves are faulty. There are a total of 4 valves in two phases of a single bridge. Excluding the valves that are currently conducting, there are two valves remaining; if the valve that conducts at the next moment and whose current does not surge is in the upper or lower half of the bridge arm, it can be determined that the faulty valve is the shut-off valve of the other half of the bridge arm.

[0066] When a single-valve short-circuit fault occurs in the rectifier-side converter valve, and the short-circuited valve is in the same half-bridge arm as the valve that will be turned on in the next phase, the rapid fault location criterion 3 is as follows: If there is no increase in current in the other direction, it can be determined that the valve currently being turned off is short-circuited. The surge in current is used to determine which two phases' valves are faulty. There are four valves in two phases of a single-bridge system; excluding the valve currently being turned on, two valves remain. If the valve that will be turned on in the next phase and experiences a surge in current is in the upper or lower half-bridge arm, then the faulty valve is the shut-off valve in that half-bridge arm. Based on the single-bridge short-circuit fault characteristic analysis below, an additional condition needs to be added: if the earliest zero-crossing short-circuit current can turn off the fault, then it is a single-valve short circuit; otherwise, it is a bridge short circuit.

[0067] Quick Criterion 4 for Locating Short-Circuit Faults in Single-Bridge Rectifier-Side Converter Valve: If there is no increase in current in the other direction, it can be determined that the valve currently being shut off is short-circuited. The surge in current is used to determine which two phases of valves are faulty. There are four valves in two phases of a single-bridge system. Excluding the valve currently conducting, two valves remain. If the valve that turns on next and experiences a surge in current is in the upper or lower half of the bridge arm, the faulty valve is the shut-off valve in that half of the bridge arm. Next, determine if it is a bridge short circuit: if the earliest zero-crossing short-circuit current cannot shut it off, it is a bridge short circuit; otherwise, it is a single-valve short circuit.

[0068] Rapid criterion 5 for locating short circuit faults in the rectifier-side converter valve: Based on rapid criterion 4, determine if the bridge is short-circuited. If both bridges show short-circuit characteristics, it is determined to be a short circuit in both bridges.

[0069] Rapid criterion for locating two-phase short-circuit faults on the AC side of the rectifier-side converter valve 6: When there is only two-phase short-circuit current, the short-circuit current continues to exist even when the converter valve firing angle shifts to 90 degrees, and is only turned off after several cycles. The short-circuit phase can be determined by the distorted large current.

[0070] Rapid criterion for locating a single valve short-circuit fault in the inverter side valve area 7: If the three-phase AC voltage is not distorted, and a normally conducting valve experiences a three-phase current of 0 after being turned off, it can be determined that the other valve in the same phase bridge arm of the next conducting valve is the valve with a short-circuit fault.

[0071] Rapid location of short circuit faults in single-bridge or double-bridge inverter side valve area: 8. The commutation failure protection may be activated, and at the same time, the single-bridge bypass is activated and the three-phase AC current on the grid side becomes zero.

[0072] In the third preferred embodiment provided by the present invention: in step S3, based on the converter protection action event in the converter station monitoring background, it is first determined whether the converter protection action is on the rectifier side or the inverter side.

[0073] In the fourth preferred embodiment provided by the present invention: in step S4, the converter protection action type is confirmed according to the converter protection action event in the converter station monitoring background: valve differential protection action, valve short circuit protection action, and commutation failure protection action.

[0074] In the fifth preferred embodiment provided by the present invention: in step S5, based on the converter protection action event in the converter station monitoring background, the valve area fault converter bridge is confirmed: Y bridge fault, D bridge fault, or both Y bridge and D bridge are faulty.

[0075] In the sixth preferred embodiment provided by the present invention: in step S6, the built-in fault waveform of the DC control protection is retrieved, and the waveform recording software is used to analyze the converter protection action waveform. Based on the relationship between the three-phase AC voltage and the converter transformer valve side current in the fault waveform, the conduction sequence of the 12-pulse converter valve is determined, and then the fault characteristics of the Y-bridge and D-bridge valve side current waveform and the fault characteristics of the DC side outlet current change are confirmed. Based on the typical fault characteristic quantities and eight typical fast judgment criteria given by the simulation in S2, the short circuit fault point in the valve area is located.

[0076] Currently, the control and protection procedures for ultra-high voltage (UHV) projects mainly include the Xuji and NARI lines. For determining the converter valve conduction sequence, NARI's DC control and protection fault recording has a dedicated harp pulse waveform. Based on this waveform, the valve currently conducting can be quickly located, thus determining the 12-pulse converter valve conduction sequence. However, Xuji's DC control and protection requires determining the valve conduction sequence based on the converter transformer wiring method and the relationship between AC voltage and valve-side current electrical quantities. Specific confirmation methods are as follows: One method is based on the AC voltage: if phase A is greater than the zero-crossing point of phase C, the rectifier side moves back approximately 20 degrees to find the conduction point of valve Y1; the inverter side moves back approximately 150 degrees to find the conduction point of valve Y1, thus determining the corresponding waveforms for each Y valve. Another method is based on the converter transformer wiring method and the positive current direction: when wiring method 1, the Y-type current at the converter transformer valve side leads the D-type current; when wiring method 11, the D-type current at the converter transformer valve side leads the Y-type current. The test wiring is an 11-point connection. The phase current of phase A is IA-IB, the phase current of phase B is IB-IC, and the phase current of phase C is IC-IA. Valve D leads valve Y by 30 degrees, so the waveform that leads valve Y1 by 30 degrees is valve D1. The positions of each waveform of valve D are determined in sequence.

[0077] The seventh preferred embodiment provided by the present invention is as follows:

[0078] This invention provides a converter valve zone short-circuit fault location device, the device comprising:

[0079] The fault classification module is used to classify converter valve faults into typical valve area short-circuit faults based on different fault points in the converter valve area.

[0080] The criterion generation module is used to simulate and analyze typical valve area short-circuit faults. Based on the different converter protection action results, it is divided into three types of protection actions, and provides typical fault characteristic quantities of valve differential protection actions for locating valve area faults and fast criteria for typical valve area short circuits.

[0081] The first positioning module is used to first identify the converter station where the valve zone short circuit fault occurred, based on whether the actual converter protection action occurred at the rectifier station or the inverter station.

[0082] The second positioning module is used to confirm the type of converter protection action based on the converter protection action events monitored in the background: valve differential protection action, valve short circuit protection action, and commutation failure protection action.

[0083] The third positioning module is used to confirm the faulty converter bridge in the valve area based on the converter protection action events monitored in the background.

[0084] The fourth positioning module is used to retrieve the built-in fault waveform of the DC control and protection system, and use the waveform recording software to analyze the converter protection action waveform, analyze the fault characteristics of the valve side current waveform and the DC side outlet current waveform, and based on the judgment generation module simulation, it generates typical fault characteristic quantities of valve differential protection action and typical valve area short circuit fast judgment criteria to locate the valve area short circuit fault point.

[0085] Optionally, the typical valve area short-circuit faults include: phase-to-phase short circuit on the AC side of the converter valve, single-phase grounding short circuit on the AC side of the converter valve, grounding short circuit on the high-voltage side of the converter valve, grounding short circuit on the low-voltage side of the converter valve, grounding short circuit at the midpoint of the converter valve, single-valve short circuit in the converter valve, single-bridge short circuit in the converter valve, and double-bridge short circuit in the converter valve.

[0086] The eighth preferred embodiment provided by the present invention is as follows:

[0087] Based on the above embodiments,

[0088] This invention provides an electronic device, including a processor and a storage medium;

[0089] The storage medium is used to store instructions;

[0090] The processor is configured to operate according to the instructions to perform the steps according to the method described above.

[0091] The ninth preferred embodiment provided by the present invention is as follows:

[0092] Based on the above embodiments,

[0093] The present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method.

[0094] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0095] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0096] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0097] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0098] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for locating short-circuit faults in the valve section of a converter, characterized in that, The method includes: Step S1: Based on different fault points in the converter valve area, classify the converter valve faults into typical valve area short-circuit faults. Step S2 involves simulating and analyzing typical valve area short-circuit faults. Based on the different converter protection action results, three types of protection actions are classified, and typical fault characteristics of valve differential protection actions for locating valve area faults and rapid judgment criteria for typical valve area short circuits are given. Among them, the simulation analysis of typical valve area short-circuit faults and the classification of converter protection action results into three types of protection actions include: when a single-phase ground fault occurs on the AC side of the converter transformer valve, a ground fault occurs on the high-voltage side of the converter valve, a ground fault occurs on the low-voltage side of the converter valve, or a ground fault occurs at the midpoint of the converter valve, the valve differential protection will operate regardless of whether it occurs on the rectifier side or the inverter side; when a single valve short circuit, a single bridge short circuit, a double bridge short circuit, or a phase-to-phase short circuit occurs on the AC side of the converter valve, if it occurs on the rectifier side, the valve short-circuit protection will operate; if it occurs on the inverter side, the probability of commutation failure protection operation is higher, and the valve short-circuit protection may operate. Step S3: Based on whether the actual converter protection action occurred at the rectifier station or the inverter station, first identify the converter station where the valve zone short circuit fault occurred. Step S4: Next, confirm the converter protection action type based on the converter protection action events monitored in the background: valve differential protection action, valve short circuit protection action, commutation failure protection action; Step S5: Next, confirm the faulty converter bridge in the valve area based on the converter protection action events monitored in the background. Step S6: Retrieve the built-in fault waveform of the DC control and protection system, and use the waveform recording software to analyze the converter protection action waveform, analyze the fault characteristics of the valve side current waveform and the DC side outlet current waveform, and locate the valve area short circuit fault point based on the typical fault characteristic quantities of the valve differential protection action and the typical valve area short circuit fast judgment criteria given by the simulation in S2.

2. The converter valve zone short-circuit fault location method as described in claim 1, characterized in that, Typical valve area short-circuit faults in step S1 include: phase-to-phase short circuit on the AC side of the converter valve, single-phase ground short circuit on the AC side of the converter transformer valve, ground short circuit on the high-voltage side of the converter valve, ground short circuit on the low-voltage side of the converter valve, ground short circuit at the midpoint of the converter valve, single valve short circuit, single bridge short circuit, and double bridge short circuit.

3. The converter valve zone short-circuit fault location method as described in claim 2, characterized in that, Step S2 includes: Typical fault characteristics of differential valve protection action in the positioning valve area: increased current on the high-pressure side of the converter valve, decreased current on the low-pressure side of the converter valve, and increased or decreased AC current on the converter transformer side to 0.

4. The converter valve zone short-circuit fault location method as described in claim 3, characterized in that, The simulation analysis of typical valve area short-circuit faults includes RTDS simulation analysis.

5. The converter valve zone short-circuit fault location method as described in claim 3, characterized in that, The faulty converter bridges in the valve area include: Y-bridge fault, D-bridge fault, and both Y-bridge and D-bridge fault.

6. The converter valve zone short-circuit fault location method as described in claim 5, characterized in that, Typical quick criteria for diagnosing faults in the positioning valve area include: Quick criterion for single-valve short circuit of rectifier-side converter valve 1: When the current waveform of a certain phase rapidly passes through 0 point at its turn-off moment and rapidly increases in the opposite direction of the other current, it can be quickly determined that it is the current waveform of the faulty converter valve. Quick criterion for single valve short circuit in rectifier-side converter valve 2: If the fault waveform does not show an increase in current in the other direction, it can be determined that the valve currently being shut off is short-circuited; the surge current is used to determine which two phases of valves are faulty. There are a total of 4 valves in two phases. After excluding the valves that are currently conducting, there are 2 valves left. If the valve that conducts in the next moment and the current does not surge is in the upper or lower half of the bridge arm, it can be determined that the faulty valve is the shut-off valve of the other half of the bridge arm. Quick criterion for single valve short circuit in rectifier-side converter valve 3: If there is no increase in current in the other direction, it can be determined that the valve currently being shut off is short-circuited; the surge in current can be used to determine which two phases of valves are faulty. There are a total of 4 valves in two phases. Excluding the valves that are currently conducting, there are two valves left; if the valve that turns on and experiences a surge in current at the next moment is in the upper or lower half of the bridge arm, it can be determined that the faulty valve is the shut-off valve in that half of the bridge arm. Based on the analysis of the characteristics of single-bridge short-circuit faults, it is known that a judgment condition needs to be superimposed: if the converter valve whose short-circuit current crosses zero earliest can be shut off, then it is a single-valve short circuit of the converter valve; otherwise, it is a bridge short circuit. Quick criterion for short circuit in single bridge rectifier-side converter valve 4: If there is no increase in current in the other direction, it can be determined that the valve currently being shut off is short-circuited; the surge in current can be used to determine which two phases of valves are faulty. There are a total of 4 valves in two phases. Excluding the valves that are currently conducting, there are two valves left; if the valve that turns on and experiences a surge in current at the next moment is in the upper or lower half of the bridge arm, it can be determined that the faulty valve is the shut-off valve in that half of the bridge arm. Next, determine whether it is a bridge short circuit: if the converter valve whose short circuit current first crosses zero cannot be shut off, it is a bridge short circuit; otherwise, it is a single valve short circuit of the converter valve.

5. Quick criterion for short circuit of double bridge in rectifier-side converter valve: Based on the quick criterion for single bridge in 4, bridge short circuit is judged. If both bridges are found to have bridge short circuit characteristics, it is judged as a double bridge short circuit. Quick criterion for AC-side phase-to-phase short circuit of rectifier-side converter valve 6: If there is only two-phase short circuit current on the valve side, the valve-side short circuit current will continue to exist when the converter valve firing angle shifts to 90 degrees. The converter valve will not be turned off until several cycles later. The phase of AC-side phase-to-phase short circuit can be determined by the large distorted current in the two-phase short circuit current. Inverter-side converter valve single valve short circuit quick judgment criterion 7: If the AC three-phase voltage does not distort, and a normally conducting valve has a three-phase current of 0 after being turned off, it can be judged that the other valve in the same phase bridge arm of the next conducting valve is a short circuit fault valve. Rapid Criterion 8 for Short Circuit of Single-Bridge or Double-Bridge Converter Valve on Inverter Side: If the protection trips due to commutation failure, and at the same time the single-bridge bypass is activated and the three-phase AC current on the grid side becomes zero, it can be determined that there is a short circuit fault in the single-bridge or double-bridge converter valve on the inverter side.

7. A converter valve zone short-circuit fault location device, characterized in that, The device includes: The fault classification module is used to classify converter valve faults into typical valve area short-circuit faults based on different fault points in the converter valve area. The criterion generation module is used to simulate and analyze typical valve area short-circuit faults. Based on different converter protection action results, it classifies protection actions into three categories, providing typical fault characteristics of differential valve protection actions for locating valve area faults and rapid criteria for typical valve area short circuits. Specifically, the simulation analysis of typical valve area short-circuit faults and the classification of converter protection action results into three categories of protection actions include: when a single-phase ground fault occurs on the AC side of the converter transformer valve, a high-voltage side ground fault occurs on the high-voltage side of the converter valve, a low-voltage side ground fault occurs on the low-voltage side of the converter valve, or a midpoint ground fault occurs on the converter valve, the differential valve protection will activate regardless of whether the fault occurs on the rectifier side or the inverter side; when a single valve short circuit, a single-bridge short circuit, a double-bridge short circuit, or a phase-to-phase short circuit occurs on the AC side of the converter valve, if the fault occurs on the rectifier side, the valve short-circuit protection will activate; if the fault occurs on the inverter side, the probability of commutation failure protection activation is higher, and the valve short-circuit protection may activate. The first positioning module is used to first identify the converter station where the valve zone short circuit fault occurred, based on whether the actual converter protection action occurred at the rectifier station or the inverter station. The second positioning module is used to confirm the type of converter protection action based on the converter protection action events monitored in the background: valve differential protection action, valve short circuit protection action, and commutation failure protection action. The third positioning module is used to confirm the faulty converter bridge in the valve area based on the converter protection action events monitored in the background. The fourth positioning module is used to retrieve the built-in fault waveform of the DC control and protection system, and use the waveform recording software to analyze the converter protection action waveform, analyze the fault characteristics of the valve side current waveform and the DC side outlet current waveform, and based on the judgment generation module simulation, it generates typical fault characteristic quantities of valve differential protection action and typical valve area short circuit fast judgment criteria to locate the valve area short circuit fault point.

8. A converter valve zone short-circuit fault location device as described in claim 7, characterized in that, The typical valve area short-circuit faults include: phase-to-phase short circuit on the AC side of the converter valve, single-phase ground short circuit on the AC side of the converter transformer valve, ground short circuit on the high-voltage side of the converter valve, ground short circuit on the low-voltage side of the converter valve, ground short circuit at the midpoint of the converter valve, single-valve short circuit in the converter valve, single-bridge short circuit in the converter valve, and double-bridge short circuit in the converter valve.

9. An electronic device, characterized in that, Including processor and storage media; The storage medium is used to store instructions; The processor is configured to operate according to the instructions to perform the steps of the method according to any one of claims 1-6.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the program implements the steps of the method according to any one of claims 1-6.

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