Ground fault judgment method and device for two-phase power transmission line
By calculating the zero-sequence compensation coefficient and measured impedance of two-phase transmission lines, and combining current and voltage judgment methods, the problem of accuracy in judging grounding faults in two-phase electric railway transmission lines was solved, achieving efficient fault detection and protection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NR ELECTRIC CO LTD
- Filing Date
- 2024-11-11
- Publication Date
- 2026-05-12
AI Technical Summary
In the existing technology, the grounding fault judgment method for two-phase electric railway transmission lines is difficult to accurately judge, which leads to the risk of protection devices failing to operate and cannot effectively identify grounding faults.
By calculating the zero-sequence compensation coefficient, measured self-impedance, and mutual impedance of a two-phase transmission line, and combining the measured two-phase current with the preset sum-current calculation method, the working voltage and polarization voltage are determined. The accurate judgment of grounding faults is achieved by using the phase angle difference and sum-current judgment method.
It improves the sensitivity and accuracy of grounding fault detection, ensures the reliability and sensitivity of fault judgment, reduces false alarms and missed alarms, responds to faults in a timely manner, and prevents faults from escalating.
Smart Images
Figure CN122017442A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of power system technology, for example to a method and apparatus for determining grounding faults in two-phase transmission lines. Background Technology
[0002] Two-phase electric railway transmission lines typically refer to power transmission lines that use a two-phase power supply method to provide electricity to electrified railways (such as high-speed railways and electric railways). With the rapid development of high-speed railways, two-phase power supply lines have been widely used in railway systems. However, two-phase transmission lines are asymmetrical lines, and the grounding distance protection principle based on three-phase symmetrical systems cannot be directly applied to two-phase electric railway transmission lines.
[0003] In related technologies, for two-phase electric railway transmission lines, protection devices that only collect electrical quantities at one end are usually configured on the system side. The current protection and overcurrent protection under this configuration can detect ground faults, but there is a risk of failure to operate. Therefore, the current ground fault judgment method is difficult to accurately judge the ground fault of two-phase transmission lines. Summary of the Invention
[0004] This application aims to provide a distance protection method, device, electronic equipment, and storage medium for ground faults in two-phase transmission lines.
[0005] According to one aspect of this application, a distance protection method for ground faults in two-phase transmission lines is proposed, comprising: determining the zero-sequence compensation coefficient of the two-phase transmission line based on the measured self-impedance and measured mutual impedance of the two-phase transmission line; determining the sum current of the operating phase based on the measured two-phase current of the operating phase and a preset sum current calculation method when a fault occurs in the two-phase transmission line; determining the operating voltage and polarization voltage of the operating phase based on the zero-sequence compensation coefficient, the measured two-phase current, the sum current, the measured three-phase voltage on the power supply side bus of the two-phase transmission line, a preset operating voltage calculation method, and a preset polarization voltage calculation method; and determining whether a fault in the two-phase transmission line within a preset protection range is a ground fault based on a preset ground fault judgment method, combined with the sum current, operating voltage, and polarization voltage.
[0006] According to some embodiments, the zero-sequence compensation coefficient of a two-phase transmission line is determined based on the measured self-impedance and measured mutual impedance of the two-phase transmission line, including: determining the positive-sequence impedance and zero-sequence impedance of the two-phase transmission line based on the measured self-impedance and measured mutual impedance; and determining the zero-sequence compensation coefficient based on the positive-sequence impedance and zero-sequence impedance.
[0007] According to some embodiments, the above method further includes: determining whether a fault has occurred in the two-phase transmission line based on the measured two-phase current of the operating phase in the two-phase transmission line and preset fault judgment conditions.
[0008] According to some embodiments, the preset fault judgment conditions include a first fault judgment condition and a second fault judgment condition. The determination of whether a fault has occurred in a two-phase transmission line based on the measured two-phase current of the operating phase and the preset fault judgment conditions includes: determining the change in measured current based on the measured two-phase current and a preset calculation method for the change; determining whether the two-phase transmission line meets the first fault judgment condition based on the change and the preset first fault judgment method; determining whether the two-phase transmission line meets the first fault judgment condition based on the calculated current and the preset second fault judgment method; determining that a fault has occurred in the two-phase transmission line under a first condition; wherein the first condition is the condition that the first fault judgment condition and / or the second fault judgment condition are met; and determining that no fault has occurred in the two-phase transmission line under other than the first condition.
[0009] According to some embodiments, based on a preset ground fault judgment method, and in combination with the sum current, operating voltage, and polarization voltage, it is determined whether a fault in a two-phase transmission line within a preset protection range is a ground fault. This includes: determining a phase angle difference judgment method and a sum current judgment method based on the ground fault judgment method; determining whether the two-phase transmission line within the preset protection range meets the first ground fault judgment condition based on the phase angle difference judgment method, operating voltage, and polarization voltage; determining whether the two-phase transmission line within the preset protection range meets the second ground fault judgment condition based on the sum current judgment method, a preset rated current amplitude, and sum current; if both the first and second ground fault judgment conditions are met simultaneously, the fault in the two-phase transmission line within the preset protection range is determined to be a ground fault; if neither the first nor the second ground fault judgment condition is met simultaneously, the fault in the two-phase transmission line within the preset protection range is determined not to be a ground fault.
[0010] According to some embodiments, based on the phase angle difference judgment method, operating voltage, and polarization voltage, it is determined whether a two-phase transmission line meets the first ground fault judgment condition within a preset protection range. This includes: obtaining the phase angle difference threshold range based on the preset protection range; determining whether the phase angle difference between the operating voltage and polarization voltage is within the phase angle difference threshold range based on the phase angle difference judgment method; and determining that the two-phase transmission line meets the first ground fault judgment condition within the preset protection range if the phase angle difference is within the phase angle difference threshold range.
[0011] According to some embodiments, based on the sum-current judgment method, the preset rated current amplitude and sum-current are used to determine whether a two-phase transmission line meets the second ground fault judgment condition within a preset protection range. This includes: obtaining sum-current parameters and rated current parameters based on the sum-current judgment method; and determining whether a two-phase transmission line meets the second ground fault judgment condition within a preset protection range based on the sum-current, sum-current parameters, rated current amplitude and rated current parameters.
[0012] According to one aspect of this application, a distance protection device for ground faults in two-phase transmission lines is provided, comprising:
[0013] The impedance determination module is used to determine the zero-sequence compensation coefficient of a two-phase transmission line based on its measured self-impedance and measured mutual impedance.
[0014] The sum-current determination module is used to determine the sum-current of the operating phase in a two-phase transmission line based on the measured two-phase current of the operating phase and the preset sum-current calculation method.
[0015] The voltage determination module is used to determine the working voltage and polarization voltage based on the zero-sequence compensation coefficient, measured two-phase current, sum current, measured three-phase voltage on the power supply side bus of the two-phase transmission line, preset working voltage calculation method and preset polarization voltage calculation method.
[0016] The fault diagnosis module is used to determine whether a fault in a two-phase transmission line within a preset protection range is a ground fault, based on a preset ground fault diagnosis method, combined with current, operating voltage, and polarization voltage.
[0017] Optionally, the impedance determination module can be specifically used for:
[0018] Based on the measured self-impedance and measured mutual impedance, determine the positive sequence impedance and zero sequence impedance of the two-phase transmission line.
[0019] Determine the zero-sequence compensation coefficient based on the positive-sequence impedance and the zero-sequence impedance.
[0020] Optionally, the distance protection device for ground faults in two-phase transmission lines also includes a fault judgment module, used for:
[0021] Based on the measured two-phase current of the operating phase in a two-phase transmission line and the preset fault judgment conditions, determine whether a fault has occurred in the two-phase transmission line.
[0022] Optionally, the preset fault judgment conditions include a first fault judgment condition and a second fault judgment condition; wherein, the fault judgment module is specifically used for:
[0023] The change in measured current is determined based on the measured two-phase current and the preset calculation method for current change.
[0024] Based on the change and the preset first fault judgment method, determine whether the two-phase transmission line meets the first fault judgment condition.
[0025] Based on the calculated current and the preset second fault judgment method, determine whether the two-phase transmission line meets the first fault judgment condition;
[0026] In the first case, it is determined that a fault has occurred in the two-phase transmission line; wherein, the first case is the case that meets the first fault judgment condition and / or the second fault judgment condition.
[0027] In cases other than the first scenario, it is determined that no fault has occurred in the two-phase transmission line.
[0028] Optionally, the fault diagnosis module is specifically used for:
[0029] Based on the ground fault judgment method, determine the phase angle difference judgment method and the current judgment method;
[0030] Based on the phase angle difference judgment method, working voltage and polarization voltage, determine whether the two-phase transmission line meets the first ground fault judgment condition within the preset protection range;
[0031] Based on the current and current judgment method, the preset rated current amplitude and current, determine whether the two-phase transmission line meets the second ground fault judgment condition within the preset protection range;
[0032] If both the first and second ground fault judgment conditions are met, the fault in the two-phase transmission line within the preset protection range is determined to be a ground fault.
[0033] If both the first ground fault judgment condition and the first ground fault judgment condition are not met simultaneously, the fault in the two-phase transmission line within the preset protection range is determined not to be a ground fault.
[0034] Optionally, the fault judgment module, after determining whether the two-phase transmission line meets the first ground fault judgment condition within the preset protection range based on the phase angle difference judgment method, operating voltage, and polarization voltage, is specifically used for:
[0035] Based on the preset protection range, the phase angle difference threshold range is obtained;
[0036] Based on the phase angle difference judgment method, determine whether the phase angle difference between the working voltage and the polarization voltage is within the phase angle difference threshold range;
[0037] If the phase angle difference is within the phase angle difference threshold range, it is determined that the two-phase transmission line meets the first ground fault judgment condition within the preset protection range.
[0038] Optionally, the fault judgment module, based on the current judgment method, the preset rated current amplitude, and the current, determines whether the two-phase transmission line meets the second ground fault judgment condition within the preset protection range.
[0039] Based on the sum-current determination method, obtain the sum-current parameters and rated current parameters;
[0040] Based on the sum of current, sum of current parameters, rated current amplitude, and rated current parameters, determine whether the two-phase transmission line meets the second ground fault judgment condition within the preset protection range.
[0041] According to one aspect of this application, an electronic device is proposed, comprising: a processor; and a memory storing a computer program, which, when executed by the processor, causes the processor to perform the distance protection method for two-phase transmission line grounding faults as described above.
[0042] According to one aspect of this application, a non-transient computer-readable medium is proposed, on which readable instructions are stored, which, when executed by a processor, cause the processor to perform the distance protection method for ground faults in two-phase transmission lines as described above.
[0043] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application.
[0044] Beneficial effects:
[0045] The embodiments provided in this application, by introducing positive-sequence impedance, zero-sequence impedance, and zero-sequence compensation coefficient, comprehensively consider the electrical characteristics of transmission lines. Especially in the case of ground faults, these parameters are crucial for accurately determining the fault type, effectively improving the reliability and sensitivity of protection under ground fault conditions. By utilizing measured two-phase currents combined with a preset sum-current calculation method, the sum-current of the operating phase can be accurately calculated. Furthermore, by combining the zero-sequence compensation coefficient, three-phase voltage, and complex calculations involving operating voltage and polarization voltage, a comprehensive analysis of fault characteristics can be achieved. This not only improves the sensitivity of ground fault detection but also ensures the accuracy of fault diagnosis. Overall, it improves the distance protection effect and reliability of two-phase transmission lines against ground faults. Attached Figure Description
[0046] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings, without exceeding the scope of protection claimed by this application.
[0047] Figure 1A flowchart illustrating a distance protection method for ground faults in two-phase transmission lines provided in this application embodiment;
[0048] Figure 2 A flowchart illustrating the implementation of step S14 provided in the embodiments of this application;
[0049] Figure 3 A flowchart illustrating the implementation of step S13 provided in the embodiments of this application;
[0050] Figure 4 A flowchart illustrating the implementation of step S131 provided in the embodiments of this application;
[0051] Figure 5 A flowchart illustrating the implementation of step S132 provided in this application embodiment;
[0052] Figure 6 A block diagram of a distance protection device for a two-phase transmission line ground fault provided in an embodiment of this application;
[0053] Figure 7 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation
[0054] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0055] For specific implementation details, please refer to the following examples.
[0056] Figure 1 A flowchart illustrating a distance protection method for a two-phase transmission line ground fault according to an exemplary embodiment is shown. Figure 1 As shown, the method includes steps S10, S11, S12 and S13.
[0057] In step S10, the zero-sequence compensation coefficient of the two-phase transmission line is determined based on the measured self-impedance and measured mutual impedance of the two-phase transmission line.
[0058] Two-phase electric railway transmission lines are transmission lines that use a two-phase power supply method to provide power to electrified railways, and are referred to as two-phase transmission lines in this application.
[0059] According to the example embodiment, a calculation method can be preset, and the measured self impedance and measured mutual impedance can be substituted into the preset calculation method to obtain the positive sequence impedance, zero sequence impedance and zero sequence compensation coefficient of the two-phase transmission line.
[0060] According to some embodiments, a model can be pre-set, and the measured self-impedance and measured mutual impedance of a two-phase transmission line can be input into the model to directly output the positive sequence impedance, zero sequence impedance, and zero sequence compensation coefficient of the two-phase transmission line.
[0061] In step S11, in the event of a fault in a two-phase transmission line, the sum current of the operating phase is determined based on the measured two-phase current of the operating phase in the two-phase transmission line and the preset sum current calculation method.
[0062] According to the example embodiment, a fault detection device can be pre-configured to receive detection results. Upon detecting a fault in a two-phase transmission line, the sum and current can be calculated. The preset sum and current calculation method is as follows:
[0063]
[0064] in, and These are the measured first-phase current and the measured second-phase current, respectively, of the operating phase currents in a two-phase transmission line. Using the above sum-current calculation method, the sum-current of the operating phase is calculated.
[0065] In step S12, the operating voltage and polarization voltage of the operating phase are determined based on the zero-sequence compensation coefficient, the measured two-phase current, the sum current, the measured three-phase voltage on the power supply side bus of the two-phase transmission line, the preset operating voltage calculation method, and the preset polarization voltage calculation method.
[0066] In this application, the measured three-phase voltage on the power supply side bus of a two-phase transmission line can be detected by a pre-set detection device.
[0067] According to the example embodiment, the preset operating voltage calculation method is as follows:
[0068]
[0069] in, The measured three-phase voltages are on the power supply side busbar of a two-phase transmission line. This refers to the measured two-phase current of the operating phase in a two-phase transmission line. The set impedance for grounding distance protection, i.e. the protection range of the impedance, can be preset to a value.
[0070] By substituting the measured three-phase voltage, measured two-phase current, and zero-sequence compensation coefficient into the above calculation method, the operating voltage of the running phase can be calculated.
[0071] The default polarization voltage calculation method is as follows:
[0072]
[0073] in, The positive sequence voltage can be obtained by detecting and calculating the three-phase voltage on the bus. Using the above-described method for calculating the planned voltage, the polarization voltage of the operating phase can be obtained.
[0074] In step S13, based on the preset ground fault judgment method, and in combination with the current, working voltage and polarization voltage, it is determined whether the fault in the two-phase transmission line within the preset protection range is a ground fault.
[0075] According to the example embodiment, a ground fault judgment model can be preset. By inputting a preset ground fault judgment method, current, operating voltage, and polarization voltage into the ground fault judgment model, it directly outputs "yes" or "no," thereby determining whether a fault in a two-phase transmission line within a preset protection range is a ground fault. The preset protection range can be...
[0076] This application introduces positive-sequence impedance, zero-sequence impedance, and zero-sequence compensation coefficient, comprehensively considering the electrical characteristics of transmission lines. Especially under ground fault conditions, these parameters are crucial for accurately determining the fault type, effectively improving the reliability and sensitivity of protection during ground faults. By utilizing measured two-phase currents combined with a preset sum-current calculation method, the sum-current of the operating phase can be accurately calculated. Furthermore, by combining the zero-sequence compensation coefficient, three-phase voltage, and complex calculations involving operating voltage and polarization voltage, a comprehensive analysis of fault characteristics is achieved. This not only improves the sensitivity of ground fault detection but also ensures the accuracy of fault diagnosis. Overall, it enhances the distance protection effect and reliability of two-phase transmission lines against ground faults.
[0077] According to some embodiments, the positive sequence impedance and zero sequence impedance of a two-phase transmission line can be determined based on the measured self impedance and measured mutual impedance; and the zero sequence compensation coefficient can be determined based on the positive sequence impedance and zero sequence impedance.
[0078] In this application, positive sequence impedance refers to the impedance of the equivalent circuit formed by three-phase symmetrical positive sequence elements in a power system, and zero sequence impedance is a parameter describing the impedance characteristics when zero sequence current passes through a power system.
[0079] According to an example embodiment, the measured self-impedance and measured mutual impedance of a two-phase transmission line can be detected using pre-set equipment. The measured self-impedance of a two-phase transmission line can be... This means that the measured mutual impedance can be expressed as... Represents positive sequence impedance Zero-sequence impedance and zero-sequence compensation coefficient The following formula can be used for calculation:
[0080]
[0081] This application utilizes measured self-impedance and mutual impedance data of two-phase transmission lines to more accurately calculate positive-sequence impedance and zero-sequence impedance. Since different lines have varying operating conditions and electrical characteristics, the positive-sequence and zero-sequence impedances calculated from measured data more accurately reflect the current electrical state of the line, improving the protection system's adaptability to different line conditions and ensuring effective protection under various operating conditions. Calculating the zero-sequence compensation coefficient based on measured positive-sequence and zero-sequence impedances ensures that the coefficient matches the actual electrical characteristics of the line, thereby improving the accuracy and reliability of ground fault protection.
[0082] According to some embodiments, the distance protection method for ground faults in two-phase transmission lines may further include step S14.
[0083] In step S14, based on the measured two-phase current of the operating phase in the two-phase transmission line and the preset fault judgment conditions, it is determined whether a fault has occurred in the two-phase transmission line.
[0084] According to the example embodiment, fault judgment conditions can be preset based on historical measured two-phase currents. These fault judgment conditions may be a current threshold range or other types of conditions based on current information. Based on this, it is possible to preset whether a fault occurs in different situations between the measured two-phase current and the preset fault judgment conditions. For example, if the measured two-phase current is within the range of the preset fault judgment conditions, it indicates that a fault has occurred in the two-phase transmission line.
[0085] According to the example embodiment, a preset fault judgment condition can be obtained, and the measured two-phase current of the operating phase in the two-phase transmission line can be compared with the preset fault judgment condition. Then, the fault of the two-phase transmission line can be determined based on the comparison result.
[0086] This application utilizes real-time monitoring of the current in the operating phase of a two-phase transmission line and compares it with preset fault detection conditions. This method can quickly detect whether a fault has occurred in the line. This immediacy is crucial for the stable operation of the power system, enabling rapid response and measures to prevent the fault from escalating.
[0087] According to some embodiments, the preset fault judgment conditions include a first preset fault judgment condition and a second preset fault judgment condition. (See reference...) Figure 2 Step S14 can be implemented through steps S140, S141, S142 and S143.
[0088] In step S140, the change in measured current is determined based on the measured two-phase current and the preset current change calculation method.
[0089] In this application, the current change calculation method is used to calculate the change value of the two-phase current within a preset time, that is, the change of the measured current.
[0090] In some implementations, the measured two-phase currents can be directly substituted into the current change calculation method, and the change in operating phase current can be obtained through half-wave integration.
[0091] In step S141, based on the change amount and the preset first fault judgment method, it is determined whether the two-phase transmission line meets the first fault judgment condition.
[0092] In this application, the preset first fault determination method is:
[0093]
[0094] in, ΔI is the change in measured current. se t is the adjustable current threshold value, ΔI T The threshold is floating.
[0095] According to the example embodiment, the calculated Substituting the above first fault judgment method, if the following conditions are met... This indicates that the two-phase transmission line meets the first fault judgment condition; if it does not meet the condition... This indicates that the two-phase transmission line does not meet the first fault judgment condition.
[0096] In step S142, based on the measured two-phase current and the preset second fault judgment method, it is determined whether the two-phase transmission line meets the second fault judgment condition.
[0097] In this application, the preset second fault determination method is:
[0098]
[0099] Where I0 is the amplitude of the sum current, I 0_set It is an adjustable zero-sequence current threshold setting.
[0100] According to the example embodiment, the measured two-phase current is substituted into the above-mentioned preset second fault judgment method. If the conditions are met... This indicates that the two-phase transmission line meets the second fault judgment condition; if it does not meet the condition... This indicates that the two-phase transmission line does not meet the second fault judgment condition.
[0101] In step S143, under a first condition, it is determined that a fault has occurred in the two-phase transmission line; wherein, the first condition is that the first fault judgment condition and / or the second fault judgment condition are met; under a non-first condition, it is determined that no fault has occurred in the two-phase transmission line.
[0102] According to the example embodiment, if at least one of the first fault judgment condition and the second fault judgment condition is met, it indicates that a fault has occurred in the two-phase transmission line. If neither the first fault judgment condition nor the second fault judgment condition is met, it indicates that no fault has occurred in the two-phase transmission line.
[0103] This application establishes a first fault judgment condition and a second fault judgment condition, and determines whether these conditions are met based on measured two-phase currents and their changes, thereby enabling a more comprehensive identification of fault conditions in transmission lines. This dual detection mechanism enhances the accuracy of fault identification and reduces the possibility of false alarms or missed alarms.
[0104] According to some embodiments, reference Figure 3 Step S13 can be implemented through steps S130, S131, S132 and S133.
[0105] In step S130, the phase angle difference judgment method and the current judgment method are determined according to the ground fault judgment method.
[0106] In this application, the phase angle difference judgment method can be used to determine whether there is a possibility of a ground fault at the current moment from the perspective of the phase angle difference of a two-phase transmission line; the sum current judgment method can be used to determine whether there is a possibility of a ground fault from the perspective of the sum current of a two-phase transmission line.
[0107] According to the example embodiment, the ground fault judgment method includes the phase angle difference judgment method and the current judgment method, which can be directly extracted.
[0108] In step S131, based on the phase angle difference judgment method, working voltage, and polarization voltage, it is determined whether the two-phase transmission line meets the first ground fault judgment condition within the preset protection range.
[0109] According to the example embodiment, the operating voltage and polarization voltage are processed according to the phase angle difference judgment method. If the method is satisfied, it means that the two-phase transmission line meets the first ground fault judgment condition within the preset protection range; if the method is not satisfied, it means that the two-phase transmission line does not meet the first ground fault judgment condition within the preset protection range.
[0110] In step S132, based on the current and current judgment method, the preset rated current amplitude and current are used to determine whether the two-phase transmission line meets the second ground fault judgment condition within the preset protection range.
[0111] According to the example embodiment, the preset rated current amplitude and current are processed according to the current judgment method. If the method is satisfied, it means that the two-phase transmission line meets the second ground fault judgment condition within the preset protection range; if the method is not satisfied, it means that the two-phase transmission line does not meet the second ground fault judgment condition within the preset protection range.
[0112] In step S133, if both the first and second ground fault judgment conditions are met simultaneously, the fault in the two-phase transmission line within the preset protection range is determined to be a ground fault; if neither the first nor the second ground fault judgment condition is met simultaneously, the fault in the two-phase transmission line within the preset protection range is determined not to be a ground fault.
[0113] According to the example embodiment, if both the first and second ground fault judgment conditions are met, then the fault in the two-phase transmission line within the preset protection range can be determined to be a ground fault. If neither the first nor the second ground fault judgment conditions are met simultaneously, then the fault in the two-phase transmission line within the preset protection range can be determined to be a non-ground fault. In this case, other preset methods can be invoked to determine the specific type of fault occurring at the current moment.
[0114] This application employs a dual verification method, combining phase angle difference and current judgment, to identify faults in transmission lines within a preset protection range. This composite judgment mechanism effectively reduces the potential for misjudgments from a single judgment method, improving the accuracy and reliability of ground fault identification. Timely and accurate identification of ground faults can rapidly trigger corresponding protection measures, such as disconnecting the faulty line or isolating the faulty area, thereby preventing the fault from escalating, protecting the stable operation of the entire power system, and reducing power outage time and economic losses caused by the fault.
[0115] According to some embodiments, reference Figure 4 Step S131 can be implemented through steps S1310 and S1311.
[0116] In step S1310, the phase angle difference threshold range is obtained according to the preset protection range.
[0117] According to the example embodiment, a pre-stored phase angle difference threshold range can be obtained by searching according to a preset protection range. In this application, the range can be -90° to 90°.
[0118] The specific methods for determining the corresponding phase angle difference are as follows:
[0119]
[0120] In step S1311, based on the phase angle difference judgment method, it is determined whether the phase angle difference between the working voltage and the polarization voltage is within the phase angle difference threshold range; if the phase angle difference is within the phase angle difference threshold range, it is determined that the two-phase transmission line meets the first ground fault judgment condition within the preset protection range.
[0121] According to the example embodiment, the phase angle difference between the operating voltage and the planned voltage is first calculated, i.e. Then, the phase angle difference is compared with the phase angle difference threshold range. If the phase angle difference is within the phase angle difference threshold range, it indicates that the two-phase transmission line meets the first ground fault judgment condition within the preset protection range. If the phase angle difference is not within the phase angle difference threshold range, it indicates that the two-phase transmission line does not meet the first ground fault judgment condition within the preset protection range.
[0122] This application, by setting a preset protection range and determining the phase angle difference threshold range accordingly, enables the determination of whether a ground fault has occurred in a two-phase transmission line based on a specific and reasonably set phase angle difference range. This significantly improves the accuracy of fault detection, reduces false alarms, and ensures the safe and stable operation of the power grid. Once the phase angle difference is detected to be within the preset threshold range, it can be quickly determined that the two-phase transmission line meets the first ground fault judgment condition within the preset protection range. This rapid response mechanism helps to isolate the fault area in a timely manner, reduce the impact of the fault on the overall power grid, and provide a valuable time window for subsequent fault handling.
[0123] According to some embodiments, reference Figure 5 Step S132 can be specifically implemented through steps S1320 and S1321.
[0124] In step S1320, the current parameters and rated current parameters are determined based on the current and current determination method.
[0125] In this application, the specific method for determining the sum and flow can be:
[0126]
[0127] Among them, I n This is the preset rated current amplitude. 3 corresponds to the sum current parameter, and 0.1 corresponds to the rated current parameter. The sum current parameter and the rated current parameter can be preset based on the specific application scenario and the relevant performance parameters of the circuit.
[0128] In step S1321, based on the sum current, sum current parameters, rated current amplitude, and rated current parameters, it is determined whether the two-phase transmission line meets the second ground fault judgment condition within the preset protection range.
[0129] According to the example embodiment, the sum current, sum current parameters, rated current amplitude, and rated current parameters are substituted into the above formula. If the conditions corresponding to the formula are met, it is determined that the two-phase transmission line meets the second ground fault judgment condition within the preset protection range; if the conditions corresponding to the formula are not met, it is determined that the two-phase transmission line does not meet the second ground fault judgment condition within the preset protection range.
[0130] This application, by introducing a sum-current judgment method and combining it with a preset rated current amplitude, can more accurately capture the characteristics of ground faults in two-phase transmission lines. This comparative analysis based on sum-current and rated current improves the sensitivity of fault detection. Based on the comparison results of sum-current and rated current, the system can automatically adjust the protection strategy to adapt to different fault conditions. For example, when an abnormal increase in sum-current is detected, protection actions can be quickly triggered to isolate the fault area and prevent the fault from expanding; while when sum-current is within the normal range, the system maintains normal operation, reducing unnecessary intervention.
[0131] The following describes an apparatus embodiment of this application, which can be used to perform the method embodiment of this application. For details not disclosed in the apparatus embodiment of this application, please refer to the method embodiment of this application.
[0132] Figure 6 A block diagram is shown of a distance protection device for a two-phase transmission line ground fault according to an exemplary embodiment. Figure 6 As shown, the distance protection device 600 for ground faults in two-phase transmission lines includes an impedance determination module 601, a current determination module 602, a voltage determination module 603, and a fault judgment module 604.
[0133] Impedance determination module 601 is used to determine the zero-sequence compensation coefficient of a two-phase transmission line based on the measured self-impedance and measured mutual impedance of the two-phase transmission line.
[0134] The sum-current determination module 602 is used to determine the sum-current of the operating phase in a two-phase transmission line based on the measured two-phase current of the operating phase and the preset sum-current calculation method.
[0135] The voltage determination module 603 is used to determine the working voltage and polarization voltage based on the zero-sequence compensation coefficient, the measured two-phase current, the sum current, the measured three-phase voltage on the power supply side bus of the two-phase transmission line, the preset working voltage calculation method, and the preset polarization voltage calculation method.
[0136] The fault judgment module 604 is used to determine whether a fault in a two-phase transmission line within a preset protection range is a ground fault, based on a preset ground fault judgment method, combined with current, operating voltage and polarization voltage.
[0137] Optionally, the impedance determination module 601 can be specifically used for:
[0138] Based on the measured self-impedance and measured mutual impedance, determine the positive sequence impedance and zero sequence impedance of the two-phase transmission line.
[0139] Determine the zero-sequence compensation coefficient based on the positive-sequence impedance and the zero-sequence impedance.
[0140] Optionally, the distance protection device 600 for ground faults in two-phase transmission lines also includes a fault judgment module 605, used for:
[0141] Based on the measured two-phase current of the operating phase in a two-phase transmission line and the preset fault judgment conditions, determine whether a fault has occurred in the two-phase transmission line.
[0142] Optionally, the preset fault judgment conditions include a first preset fault judgment condition and a second preset fault judgment condition; wherein, the fault judgment module 604 is specifically used for:
[0143] The change in measured current is determined based on the measured two-phase current and the preset calculation method for current change.
[0144] Based on the change and the preset first fault judgment method, determine whether the two-phase transmission line meets the first fault judgment condition.
[0145] Based on the measured two-phase current and the preset second fault judgment method, determine whether the two-phase transmission line meets the second preset fault condition;
[0146] In the first case, it is determined that a fault has occurred in the two-phase transmission line; wherein, the first case is the case that meets the first fault judgment condition and / or the second fault judgment condition.
[0147] In cases other than the first scenario, it is determined that no fault has occurred in the two-phase transmission line.
[0148] Optionally, the fault diagnosis module 604 is specifically used for:
[0149] Based on the ground fault judgment method, determine the phase angle difference judgment method and the current judgment method;
[0150] Based on the phase angle difference judgment method, working voltage and polarization voltage, determine whether the two-phase transmission line meets the first ground fault judgment condition within the preset protection range;
[0151] Based on the current and current judgment method, the preset rated current amplitude and current, determine whether the two-phase transmission line meets the second ground fault judgment condition within the preset protection range;
[0152] If both the first and second ground fault judgment conditions are met, the fault in the two-phase transmission line within the preset protection range is determined to be a ground fault.
[0153] If both the first ground fault judgment condition and the first ground fault judgment condition are not met simultaneously, the fault in the two-phase transmission line within the preset protection range is determined not to be a ground fault.
[0154] Optionally, the fault judgment module 604, after determining whether the two-phase transmission line meets the first ground fault judgment condition within the preset protection range based on the phase angle difference judgment method, operating voltage, and polarization voltage, is specifically used for:
[0155] Based on the preset protection range, the phase angle difference threshold range is obtained;
[0156] Based on the phase angle difference judgment method, determine whether the phase angle difference between the working voltage and the polarization voltage is within the phase angle difference threshold range;
[0157] If the phase angle difference is within the phase angle difference threshold range, it is determined that the two-phase transmission line meets the first ground fault judgment condition within the preset protection range.
[0158] Optionally, the fault judgment module 604, based on the current judgment method, the preset rated current amplitude, and the current, determines whether the two-phase transmission line meets the second ground fault judgment condition within the preset protection range.
[0159] Based on the sum-current determination method, obtain the sum-current parameters and rated current parameters;
[0160] Based on the sum of current, sum of current parameters, rated current amplitude, and rated current parameters, determine whether the two-phase transmission line meets the second ground fault judgment condition within the preset protection range.
[0161] The device performs functions similar to those described above; other functions are described in the preceding descriptions and will not be repeated here.
[0162] Figure 7 This diagram illustrates the structure of an electronic device according to an exemplary embodiment, such as... Figure 7 As shown, the electronic device 700 of this embodiment may include a memory 701 and a processor 702.
[0163] The memory 701 stores a computer program, which, when executed by the processor 702, causes the processor 702 to perform the method described in the above embodiments.
[0164] The processor 702 and the memory 701 are connected, for example, via a bus.
[0165] Optionally, the electronic device 700 may also include a transceiver. It should be noted that in practical applications, the transceiver is not limited to one, and the structure of the electronic device 700 does not constitute a limitation on the embodiments of this application.
[0166] Processor 702 may be a CPU (Central Processing Unit), a general-purpose processor, a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It can implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. Processor 702 may also be a combination that implements computational functions, such as including one or more microprocessor combinations, a combination of a DSP and a microprocessor, etc.
[0167] A bus can include a pathway for transmitting information between the aforementioned components. The bus can be a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, only one thick line is used in the diagram, but this does not imply that there is only one bus or one type of bus.
[0168] The memory 701 may be a ROM (Read Only Memory) or other type of static storage device capable of storing static information and instructions, RAM (Random Access Memory) or other type of dynamic storage device capable of storing information and instructions, or an EEPROM (Electrically Erasable Programmable Read Only Memory), CD-ROM (Compact Disc Read Only Memory) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but not limited thereto.
[0169] The memory 701 is used to store application code that executes the solution of this application, and its execution is controlled by the processor 702. The processor 702 is used to execute the application code stored in the memory 701 to implement the content shown in the foregoing method embodiments.
[0170] Electronic devices include, but are not limited to: mobile terminals such as mobile phones, laptops, digital radio receivers, PDAs (personal digital assistants), PADs (tablet computers), PMPs (portable multimedia players), and in-vehicle terminals (such as in-vehicle navigation terminals), as well as fixed terminals such as digital TVs and desktop computers. Servers can also be included. Figure 7 The electronic device shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of this application.
[0171] The electronic device in this embodiment can be used to execute the method of any of the above embodiments, and its implementation principle and technical effect are similar, so they will not be described again here.
[0172] This application also provides a non-transitory computer-readable storage medium storing computer-readable instructions thereon, which, when executed by a processor, cause the processor to perform the method as described in the above embodiments.
[0173] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a non-transitory computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.
[0174] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this application. Furthermore, any changes or modifications made by those skilled in the art based on the ideas of this application, and on the specific implementation methods and application scope of this application, are all within the scope of protection of this application. Therefore, the content of this specification should not be construed as a limitation of this application.
Claims
1. A method for determining grounding faults in a two-phase transmission line, characterized in that, include: The zero-sequence compensation coefficient of the two-phase transmission line is determined based on the measured self-impedance and measured mutual impedance of the two-phase transmission line. In the event of a fault in the two-phase transmission line, the sum current of the operating phase is determined based on the measured two-phase current of the operating phase and a preset sum current calculation method. The operating voltage and polarization voltage of the operating phase are determined based on the zero-sequence compensation coefficient, the measured two-phase current, the sum current, the measured three-phase voltage on the power supply side bus of the two-phase transmission line, the preset operating voltage calculation method, and the preset polarization voltage calculation method. Based on the preset ground fault judgment method, and in combination with the sum current, the operating voltage and the polarization voltage, it is determined whether the fault of the two-phase transmission line within the preset protection range is a ground fault.
2. The method according to claim 1, characterized in that, The determination of the zero-sequence compensation coefficient of the two-phase transmission line based on the measured self-impedance and measured mutual impedance of the two-phase transmission line includes: Based on the measured self-impedance and the measured mutual impedance, determine the positive sequence impedance and zero sequence impedance of the two-phase transmission line. The zero-sequence compensation coefficient is determined based on the positive-sequence impedance and the zero-sequence impedance.
3. The method according to claim 1, characterized in that, Also includes: Based on the measured two-phase current of the operating phase in the two-phase transmission line and the preset fault judgment conditions, it is determined whether a fault has occurred in the two-phase transmission line.
4. The method according to claim 3, characterized in that, The preset fault judgment conditions include a first fault judgment condition and a second fault judgment condition. The step of determining whether a fault has occurred in the two-phase transmission line based on the measured two-phase current of the operating phase and preset fault judgment conditions includes: The change in measured current is determined based on the measured two-phase current and the preset calculation method for current change. Based on the change and the preset first fault judgment method, determine whether the two-phase transmission line meets the first fault judgment condition; Based on the measured two-phase current and the preset second fault judgment method, determine whether the two-phase transmission line meets the second preset fault condition; In a first scenario, it is determined that a fault has occurred in the two-phase transmission line; wherein, the first scenario is a situation where the first fault judgment condition is met and / or the second fault judgment condition is met. In cases other than the first one, it is determined that the two-phase transmission line has not experienced a fault.
5. The method according to claim 1, characterized in that, The step of determining whether a fault in the two-phase transmission line within a preset protection range is a ground fault, based on a preset ground fault judgment method and in conjunction with the sum current, the operating voltage, and the polarization voltage, includes: Based on the aforementioned ground fault judgment method, determine the phase angle difference judgment method and the current judgment method; Based on the phase angle difference judgment method, the operating voltage, and the polarization voltage, determine whether the two-phase transmission line meets the first ground fault judgment condition within the preset protection range; Based on the sum and current judgment method, the preset rated current amplitude, and the sum and current, determine whether the two-phase transmission line meets the second ground fault judgment condition within the preset protection range; If both the first ground fault judgment condition and the second ground fault judgment condition are met simultaneously, the fault of the two-phase transmission line within the preset protection range is determined to be a ground fault. If neither the first ground fault judgment condition nor the first ground fault judgment condition is met simultaneously, the fault of the two-phase transmission line within the preset protection range is determined not to be a ground fault.
6. The method according to claim 5, characterized in that, The step of determining whether the two-phase transmission line meets the first ground fault judgment condition within the preset protection range based on the phase angle difference judgment method, the operating voltage, and the polarization voltage includes: Based on the preset protection range, the phase angle difference threshold range is obtained; Based on the phase angle difference judgment method, determine whether the phase angle difference between the operating voltage and the polarization voltage is within the phase angle difference threshold range; If the phase angle difference is within the phase angle difference threshold range, it is determined that the two-phase transmission line meets the first ground fault judgment condition within the preset protection range.
7. The method according to claim 5, characterized in that, The step of determining whether the two-phase transmission line meets the second ground fault judgment condition within the preset protection range based on the sum-current judgment method, the preset rated current amplitude, and the sum-current includes: Based on the aforementioned current determination method, the current parameters and rated current parameters are obtained; Based on the sum current, the sum current parameter, the rated current amplitude, and the rated current parameter, determine whether the two-phase transmission line meets the second ground fault judgment condition within the preset protection range.
8. A distance protection device for ground faults in two-phase transmission lines, characterized in that, include: The impedance determination module is used to determine the zero-sequence compensation coefficient of the two-phase transmission line based on the measured self-impedance and measured mutual impedance of the two-phase transmission line. The sum-current determination module is used to determine the sum-current of the operating phase under the two-phase transmission line based on the measured two-phase current of the operating phase in the two-phase transmission line and a preset sum-current calculation method; The voltage determination module is used to determine the working voltage and polarization voltage based on the zero-sequence compensation coefficient, the measured two-phase current, the sum current, the measured three-phase voltage on the power supply side bus of the two-phase transmission line, the preset working voltage calculation method, and the preset polarization voltage calculation method. The fault judgment module is used to determine whether the fault of the two-phase transmission line within the preset protection range is a ground fault, based on a preset ground fault judgment method and in combination with the sum current, the operating voltage and the polarization voltage.
9. An electronic device, characterized in that, include: processor; The memory stores a computer program that, when executed by the processor, causes the processor to perform the distance protection method for ground faults in two-phase transmission lines as described in any one of claims 1-7.
10. A non-transitory computer-readable storage medium, characterized in that, It stores computer-readable instructions that, when executed by a processor, cause the processor to perform the distance protection method for ground faults in two-phase transmission lines as described in any one of claims 1-7.