Inverse time overcurrent protection method, device and equipment for power distribution network and medium

Abstract

Embodiments of the present application provide a power distribution network inverse time overcurrent protection method, device, equipment and medium. The method first acquires bus voltage data and feeder current data when the power distribution network fails, then determines the positive sequence voltage fault component and the positive sequence current fault component according to the bus voltage data and the feeder current data, then determines the comprehensive acceleration factor according to the positive sequence voltage fault component and the positive sequence current fault component, wherein the comprehensive acceleration factor is used to reflect the fault direction information and the fault location information of the power distribution network, and finally accelerates the correction of the inverse time overcurrent protection action time based on the comprehensive acceleration factor to determine the corrected inverse time overcurrent protection action, wherein the inverse time overcurrent protection action is used for fault removal of the power distribution network. By constructing the comprehensive acceleration factor representing the fault direction and position, the inverse time overcurrent protection action time is accelerated and corrected, and the fault removal efficiency is improved.

Description

Technical Field

[0001] This application relates to the field of power system relay protection, and in particular to an inverse time overcurrent protection method, device, equipment and medium for distribution networks. Background Technology

[0002] With the large-scale integration of distributed generation (DG) into distribution networks, the traditional single-source radial distribution network structure has gradually evolved into a complex multi-source structure, significantly changing system operation and fault characteristics. In traditional distribution networks, inverse-time overcurrent protection (ITOCR) achieves its protection function through the inverse relationship between current amplitude and operating time. However, in distribution networks containing DG, the amplitude, direction, and distribution of fault current are significantly affected by the location, capacity, and control strategy of DG integration, leading to problems such as false tripping, failure to tripping, and protection coordination failures in traditional ITOCR protection.

[0003] Existing technologies for protection in distribution networks with distributed generation (DG) primarily improve operational performance through methods such as impedance correction or voltage correction. For example, impedance-based protection methods adjust operational characteristics by introducing measured impedance or impedance ratios to reflect fault location through impedance changes; voltage or load factor-based improvement methods correct protection curves through voltage dips or load changes, for example, by adjusting the operating time based on the voltage amplitude drop ratio.

[0004] However, in distribution networks containing distributed generation (DG), the existing inverse-time overcurrent protection technology has insufficient adaptability to fault characteristics, resulting in low fault clearing efficiency in the distribution network. Summary of the Invention

[0005] This application provides a method, device, equipment, and medium for inverse-time overcurrent protection of power distribution networks, in order to improve the adaptability of inverse-time overcurrent protection to fault characteristics under complex operating scenarios.

[0006] In a first aspect, embodiments of this application provide an inverse-time overcurrent protection method for a distribution network, comprising:

[0007] Acquire bus voltage and feeder current data when a fault occurs in the distribution network;

[0008] Based on the bus voltage data and the feeder current data, determine the positive sequence voltage fault component and the positive sequence current fault component;

[0009] Based on the positive sequence voltage fault component and the positive sequence current fault component, a comprehensive acceleration factor is determined, which is used to reflect the fault direction information and fault location information of the distribution network.

[0010] The inverse-time overcurrent protection action time is accelerated and corrected based on the comprehensive acceleration factor, and the corrected inverse-time overcurrent protection action is determined. The inverse-time overcurrent protection action is used to clear faults in the distribution network.

[0011] In one or more embodiments, determining the comprehensive acceleration factor based on the positive-sequence voltage fault component and the positive-sequence current fault component includes:

[0012] Determine the phase difference between the positive-sequence voltage fault component and the positive-sequence current fault component;

[0013] A phase difference acceleration factor is obtained by linearly mapping the phase difference, and the phase difference acceleration factor is used to reflect the fault direction information of the distribution network.

[0014] The comprehensive sequence voltage fault component is determined based on the amplitude difference between the positive sequence voltage fault component and the negative sequence voltage fault component. The comprehensive sequence voltage fault component is used to reflect the change in the corresponding sequence voltage before and after the fault occurs.

[0015] The comprehensive sequence voltage fault component is normalized to determine the comprehensive sequence voltage fault component coefficient, which is used to reflect the fault location information of the distribution network.

[0016] The phase difference acceleration factor and the comprehensive sequence voltage fault component coefficient are multiplied together to obtain the comprehensive acceleration factor.

[0017] In one or more embodiments, the normalization process for the composite sequence voltage fault component to determine the composite sequence voltage fault component coefficients includes:

[0018] Determine the absolute value of the difference between the integrated sequence voltage fault component and the rated voltage;

[0019] The comprehensive sequence voltage fault component coefficient is determined based on the ratio between the absolute value and the rated voltage.

[0020] In one or more embodiments, after accelerating the inverse-time overcurrent protection operation time based on the comprehensive acceleration factor and determining the corrected inverse-time overcurrent protection operation, the method further includes:

[0021] Based on the phase difference and the preset threshold, the fault direction information of the distribution network is determined;

[0022] If the fault direction information is a positive fault, the fault is cleared from the distribution network according to the corrected inverse time overcurrent protection action;

[0023] If the fault direction information is a reverse fault, the corrected inverse time overcurrent protection action will not be executed.

[0024] In one or more embodiments, before determining the phase difference between the positive-sequence voltage fault component and the positive-sequence current fault component, the method further includes:

[0025] The bus voltage data is symmetrically decomposed to obtain negative sequence voltage data;

[0026] Spectral analysis is performed on the negative sequence voltage data to determine the fault component of the negative sequence voltage.

[0027] In one or more embodiments, the step of accelerating the correction of the inverse-time overcurrent protection action time based on the comprehensive acceleration factor, and determining the corrected inverse-time overcurrent protection action, includes:

[0028] Multiply the comprehensive acceleration factor and the time constant of the inverse time overcurrent protection operation to accelerate and correct the operation time of the inverse time overcurrent protection, and obtain the corrected time constant.

[0029] The modified inverse-time overcurrent protection action is determined based on the modified time constant.

[0030] Secondly, embodiments of this application provide an inverse-time overcurrent protection device for a power distribution network, comprising:

[0031] The acquisition module is used to acquire bus voltage data and feeder current data when a fault occurs in the distribution network;

[0032] The first determining module is used to determine the positive sequence voltage fault component and the positive sequence current fault component based on the bus voltage data and the feeder current data.

[0033] The second determining module is used to determine a comprehensive acceleration factor based on the positive sequence voltage fault component and the positive sequence current fault component. The comprehensive acceleration factor is used to reflect the fault direction information and fault location information of the distribution network.

[0034] The third determining module is used to accelerate the correction of the inverse-time overcurrent protection action time based on the comprehensive acceleration factor, and to determine the corrected inverse-time overcurrent protection action, which is used to clear the fault in the distribution network.

[0035] In one or more embodiments, the second determining module is specifically used for:

[0036] Determine the phase difference between the positive-sequence voltage fault component and the positive-sequence current fault component;

[0037] A phase difference acceleration factor is obtained by linearly mapping the phase difference, and the phase difference acceleration factor is used to reflect the fault direction information of the distribution network.

[0038] The comprehensive sequence voltage fault component is determined based on the amplitude difference between the positive sequence voltage fault component and the negative sequence voltage fault component. The comprehensive sequence voltage fault component is used to reflect the change in the corresponding sequence voltage before and after the fault occurs.

[0039] The comprehensive sequence voltage fault component is normalized to determine the comprehensive sequence voltage fault component coefficient, which is used to reflect the fault location information of the distribution network.

[0040] The phase difference acceleration factor and the comprehensive sequence voltage fault component coefficient are multiplied together to obtain the comprehensive acceleration factor.

[0041] In one or more embodiments, the second determining module performs normalization processing on the comprehensive sequence voltage fault component to determine the comprehensive sequence voltage fault component coefficient, specifically for:

[0042] Determine the absolute value of the difference between the integrated sequence voltage fault component and the rated voltage;

[0043] The comprehensive sequence voltage fault component coefficient is determined based on the ratio between the absolute value and the rated voltage.

[0044] In one or more embodiments, after the inverse-time overcurrent protection action time is accelerated and corrected based on the comprehensive acceleration factor, and the corrected inverse-time overcurrent protection action is determined, the third determining module is further configured to:

[0045] Based on the phase difference and the preset threshold, the fault direction information of the distribution network is determined;

[0046] If the fault direction information is a positive fault, the fault is cleared from the distribution network according to the corrected inverse time overcurrent protection action;

[0047] If the fault direction information is a reverse fault, the corrected inverse time overcurrent protection action will not be executed.

[0048] In one or more embodiments, before determining the phase difference between the positive-sequence voltage fault component and the positive-sequence current fault component, the second determining module is further configured to:

[0049] The bus voltage data is symmetrically decomposed to obtain negative sequence voltage data;

[0050] Spectral analysis is performed on the negative sequence voltage data to determine the fault component of the negative sequence voltage.

[0051] In one or more embodiments, the third determining module is specifically used for:

[0052] Multiply the comprehensive acceleration factor and the time constant of the inverse time overcurrent protection operation to accelerate and correct the operation time of the inverse time overcurrent protection, and obtain the corrected time constant.

[0053] The modified inverse-time overcurrent protection action is determined based on the modified time constant.

[0054] Thirdly, embodiments of this application provide an electronic device, including: a memory and a processor;

[0055] The memory stores computer-executed instructions;

[0056] The processor executes computer execution instructions stored in the memory, such that the processor, when executed, is used to implement the method described in the first aspect and any of the embodiments above.

[0057] Fourthly, embodiments of this application provide a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the methods described in the first aspect and any of the embodiments above.

[0058] Fifthly, this application provides a computer program product, including a computer program that, when executed by a processor, is used to implement the inverse-time overcurrent protection method for a power distribution network as described in the first aspect and various possible implementations of the first aspect.

[0059] This application provides a method, apparatus, device, and medium for inverse-time overcurrent protection of a distribution network. The method first acquires bus voltage data and feeder current data when a fault occurs in the distribution network. Then, based on the bus voltage data and feeder current data, it determines the positive-sequence voltage fault component and the positive-sequence current fault component. Next, based on the positive-sequence voltage fault component and the positive-sequence current fault component, it determines a comprehensive acceleration factor. This comprehensive acceleration factor reflects the fault direction and location information of the distribution network. Finally, based on the comprehensive acceleration factor, it accelerates and corrects the inverse-time overcurrent protection operation time, determining the corrected inverse-time overcurrent protection operation. The inverse-time overcurrent protection operation is used to clear the fault in the distribution network. In the above method, by acquiring bus voltage data and feeder current data when a fault occurs in the distribution network, and determining the positive sequence voltage fault component and positive sequence current fault component accordingly, a comprehensive acceleration factor reflecting the fault direction and location information of the distribution network can be determined based on the effective characteristic quantities in the fault process. Then, the inverse time overcurrent protection action time is accelerated and corrected based on the comprehensive acceleration factor. Under the multi-source operation conditions with distributed power sources, the adaptability of the inverse time overcurrent protection to fault characteristics is improved, taking into account both protection speed and selectivity, and realizing reliable isolation of distribution network faults. Attached Figure Description

[0060] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0061] Figure 1 A flowchart illustrating the inverse-time overcurrent protection method for distribution networks provided in this application embodiment. Figure 1 ;

[0062] Figure 2 A schematic diagram of the IIDG output current phasor under different grid connection point voltage drops provided in the embodiments of this application;

[0063] Figure 3 This is a schematic diagram of a multi-IIDG distribution network structure provided in an embodiment of this application;

[0064] Figure 4 A schematic diagram of the network for the positive sequence fault component during an f3 fault, provided in an embodiment of this application;

[0065] Figure 5 This is a schematic diagram illustrating the distribution characteristics of the positive-sequence fault components provided in an embodiment of this application.

[0066] Figure 6 This is a schematic diagram of the network for the positive sequence fault component during an f1 fault, provided in an embodiment of this application.

[0067] Figure 7This is a schematic diagram of the positive sequence fault component phase at the BUSA bus provided in an embodiment of this application;

[0068] Figure 8 This is a schematic diagram of the positive sequence fault component phase at the BUSB bus provided in an embodiment of this application;

[0069] Figure 9 A schematic diagram of the positive sequence fault component phase at the BUSC bus provided in this application embodiment;

[0070] Figure 10 A flowchart illustrating the inverse-time overcurrent protection method for distribution networks provided in this application embodiment. Figure 2 ;

[0071] Figure 11 A graph showing the variation of the comprehensive sequence voltage fault component coefficients provided in the embodiments of this application;

[0072] Figure 12 A flowchart illustrating the inverse-time overcurrent protection method for distribution networks provided in this application embodiment. Figure 3 ;

[0073] Figure 13 A schematic diagram of the structure of the inverse-time overcurrent protection device for the power distribution network provided in the embodiments of this application;

[0074] Figure 14 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application.

[0075] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0076] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0077] Before introducing the embodiments of this application, the application background of the embodiments of this application will be explained first:

[0078] With the large-scale integration of distributed generation (DG) into distribution networks, the traditional single-source radial distribution network structure has gradually evolved into a complex multi-source structure, significantly changing the system's operation mode and fault characteristics. Typical scenarios for medium- and low-voltage power supply and distribution systems integrating DG include multi-feeder distribution networks containing power sources such as photovoltaics, wind power, and energy storage. These systems typically consist of an upstream power source, busbars, feeders, DG connection points, and protection devices installed at each feeder. Rapid fault identification and isolation are required in the event of a line short circuit or abnormal operation.

[0079] Inverse-Time Overcurrent Protection (ITOCR) is commonly used in distribution network protection, which uses the inverse relationship between fault current amplitude and operating time for protection discrimination. However, in distribution networks with distributed generation (DG), the amplitude, direction, and distribution of fault current are significantly affected by the location, capacity, and control strategy of the DG connection, leading to problems such as false tripping, failure to tripping, and protection coordination failure in traditional ITOCR protection.

[0080] Existing technologies for protection in distribution networks with distributed generation (DG) primarily improve operational performance through methods such as impedance correction or voltage correction. For example, impedance-based protection methods adjust operational characteristics by introducing measured impedance or impedance ratios to reflect fault location through impedance changes; voltage or load factor-based improvement methods correct protection curves through voltage dips or load changes, for example, by adjusting the operating time based on the voltage amplitude drop ratio.

[0081] However, in distribution networks containing distributed generation (DG), when DG participates in fault power supply, the current measured by the upstream protection may decrease, causing a delay in operation. The original timing coordination between different protection devices may also be disrupted, leading to cascading tripping or decreased selectivity. Existing inverse-time overcurrent protection technologies struggle to maintain stable protection performance during multi-source operation switching, exhibiting insufficient adaptability to fault characteristics. This, in turn, affects fault clearing speed, outage range control, and distribution network operational reliability, resulting in low fault clearing efficiency in the distribution network.

[0082] The inverse-time overcurrent protection method for distribution networks provided in this application aims to solve the aforementioned technical problems of the prior art. The technical concept of this application is as follows: When the prior art modifies inverse-time overcurrent protection, the shunting effect of the drain generator (DG) leads to a decrease in the fault current measured by the upstream protection, resulting in a prolonged operating time and an inability to quickly clear the fault. If the operating time of the inverse-time overcurrent protection can be optimized, the adaptability of the protection to fault characteristics can be effectively improved, and the fault clearing efficiency of the distribution network can be increased. Therefore, the embodiments of this application consider acquiring bus voltage data and feeder current data when a fault occurs in the distribution network, and then determining the positive-sequence voltage fault component and the positive-sequence current fault component. Then, based on the positive-sequence voltage fault component and the positive-sequence current fault component, a comprehensive acceleration factor is determined to reflect the fault direction information and fault location information of the distribution network. Finally, based on the comprehensive acceleration factor, the operating time of the inverse-time overcurrent protection is accelerated and corrected, and the corrected inverse-time overcurrent protection operation is determined, achieving adaptive optimization of the protection operating time, balancing protection speed and selectivity, and realizing reliable fault clearing of the distribution network.

[0083] The execution subject of this application embodiment is an electronic device, which can be a terminal device, such as a laptop, desktop computer, or tablet computer, or a server. In practical applications, whether the electronic device is a terminal device or a server can be determined according to the actual situation, and no specific limitation is imposed on it.

[0084] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0085] Figure 1 A flowchart illustrating the inverse-time overcurrent protection method for distribution networks provided in this application embodiment. Figure 1 .like Figure 1 As shown, the inverse-time overcurrent protection method for this distribution network includes the following steps:

[0086] S101. Obtain bus voltage data and feeder current data when a fault occurs in the distribution network.

[0087] In this step, when a fault occurs in the distribution network, the bus voltage will drop and the feeder current will surge. Therefore, in order to correct the inverse-time overcurrent protection, we can first obtain the bus voltage data and feeder current data when the fault occurs in the distribution network, so as to provide a data basis for the subsequent analysis process.

[0088] For example, bus voltage data is used to characterize the voltage change on the bus side when a fault occurs, and feeder current data is used to characterize the current change of the corresponding feeder in the distribution network during the fault process.

[0089] In one possible implementation, when a sudden increase in feeder current is detected and the bus voltage continues to drop, bus three-phase voltage sampling data and feeder three-phase current sampling data are continuously collected for a preset period before and after the fault occurs. The bus three-phase voltage sampling data and feeder three-phase current sampling data can be original waveform sampling values, discrete values ​​after discretization, phasor data, or RMS data.

[0090] In addition, outlier removal can be performed on bus voltage data and feeder current data to obtain standardized electrical quantity data and improve data quality.

[0091] S102. Based on the bus voltage data and feeder current data, determine the positive sequence voltage fault component and the positive sequence current fault component.

[0092] In this step, based on bus voltage data and feeder current data, steady-state load components are removed, and characteristic electrical quantities generated only by fault disturbances are extracted, namely positive-sequence voltage fault components and positive-sequence current fault components, thus eliminating the interference of normal load changes on fault identification.

[0093] For example, the positive sequence voltage fault component is a voltage positive sequence change characteristic extracted from bus voltage data, used to characterize the impact of faults on distribution network voltage.

[0094] The positive sequence current fault component is a characteristic quantity of positive sequence current variation extracted from feeder current data, used to characterize the distribution characteristics of fault current.

[0095] Positive sequence voltage fault components and positive sequence current fault components are used to characterize the changes in the positive sequence network state of the distribution network before and after a fault.

[0096] In one possible implementation, the electrical quantities after a fault are composed of the superposition of normal steady-state components and fault-additional components. The steady-state electrical quantities before the fault are used as reference values, and the difference between them and the real-time electrical quantities at the time of the fault is calculated to obtain the phase voltage and phase current fault components. Then, the sequence components are solved by symmetrical component transformation to obtain the positive sequence voltage fault components and the positive sequence current fault components.

[0097] Furthermore, the characteristics of the positive-sequence voltage fault component and the positive-sequence current fault component are explained:

[0098] 1) Under different fault conditions, the magnitude and phase angle of the positive sequence current fault component vary considerably.

[0099] Depending on the grid connection method, distributed generation (DG) can be classified into two types: motor-type distributed generation (MTDG) and inverter-interfaced distributed generation (IIDG). MTDG can be simulated using the voltage source series line impedance; however, IIDG is constrained by the inverter, limiting its output short-circuit current to 1.5 to 2 times the rated current, and the control strategy significantly affects its operating characteristics.

[0100] After IIDG is connected to the distribution network, most adopt constant power control (PQ) control strategy. By controlling the inverter output current, the active and reactive power output of IIDG are adjusted. Its fault output characteristics can be expressed as:

[0101]

[0102] in, and These represent the reactive current and active current output by the IIDG after a fault, respectively. This indicates the maximum fault current output by the IIDG. Indicates the magnitude of the IIDG fault current. This indicates the active power output by the IIDG before the fault. Indicates the phase of the fault current. This represents the reactive power support ratio coefficient. and These represent the IIDG grid connection point voltages before and after the fault, respectively.

[0103] Figure 2 This is a schematic diagram of the IIDG output current phasor under different grid connection point voltage drops, provided for embodiments of this application. Figure 2 As shown, the IIDG output current phasor can be divided into two categories according to the severity of the fault: small voltage drop at the grid connection point and large voltage drop.

[0104] and These represent the grid connection point voltages when the voltage drop is small and large after a fault, respectively. Indicates the voltage fault component at the grid connection point. This indicates the output current before the IIDG fault. and These represent the IIDG output fault current values ​​under different fault scenarios.

[0105] like Figure 2 As shown in (a), when the fault location is far from the IIDG, the grid connection point voltage is... The drop was relatively small. (The current is relatively large), both the active and reactive currents of the IIDG output increase. Consequently, its output positive sequence current fault component increases. and The phase difference is less than 90°.

[0106] like Figure 2 As shown in (b), when the fault location is close to the IIDG, the grid connection point voltage is... The drop was relatively large. (Larger), IIDG output fault current value At its maximum, its output positive sequence current fault component and The phase difference is greater than 90°.

[0107] Existing technologies often equate IIDG to a positive-sequence current source controlled by the grid connection point voltage, and its output current phasor It can be represented as:

[0108]

[0109] in, This represents the positive sequence voltage at the point of common coupling.

[0110] 2) When a fault occurs in a distribution network line, the closer the fault point is to the protection device, the more obvious the change in the positive sequence voltage fault component is. Its change pattern can reflect the positional relationship between the fault point and the protection device.

[0111] Figure 3 This is a schematic diagram of a multi-IIDG distribution network structure provided in an embodiment of this application. Figure 3 As shown, IIDG1 and IIDG2 are inverter-type distributed power sources, BUSA, BUSB, BUSC, and BUSD represent buses, Load1, Load2, and Load3 represent loads, and f1, f2, and f3 are all fault points that may experience short-circuit faults.

[0112] Define the positive direction of the current as from the bus to the line. Taking the fault at f3 as an example, neither f1 nor f2 will experience a short circuit fault. Consider only single-point faults and analyze the distribution characteristics of the positive sequence voltage fault components of each bus. Figure 4 This is a schematic diagram of the network for the positive-sequence fault component during an f3 fault, provided in an embodiment of this application. (See diagram below.) Figure 4 As shown, This represents the equivalent positive sequence impedance on the distribution network side. Indicates the additional impedance of the fault. and These represent the positive-sequence fault components of the output current of IIDG1 and IIDG2, respectively. and These represent the positive sequence impedances of IIDG1 and IIDG2, respectively. and These represent the additional electromotive force and additional current during the fault, respectively. This represents the equivalent positive sequence impedance of the line to the right of the fault point and the load. , ,as well as These represent the equivalent positive sequence impedances of lines AB, BC, and CD, respectively. and These represent the equivalent positive sequence impedances of loads Load1 and Load2, respectively. and These represent the positive sequence current fault components of loads Load1 and Load2, respectively. This represents the ratio of the distance between the fault location and the busbar to the total length of the line at this level, and its value ranges from [0, 1].

[0113] The positive sequence voltage fault components of the three buses BUSA, BUSB, and BUSC are as follows:

[0114]

[0115] , ,as well as Due to the influence of line voltage drop, the magnitude of the positive-sequence voltage fault component of the busbar satisfies the characteristic that "the closer the fault location is to the busbar, the larger the positive-sequence voltage fault component." That is... .

[0116] Figure 5 This is a schematic diagram illustrating the distribution characteristics of the positive-sequence fault components provided in an embodiment of this application. Figure 5 As shown, the amplitude of the positive-sequence voltage fault component of the busbar at the protection installation location is inversely proportional to the distance between the fault location and the busbar. Under PQ control, the DG only outputs the positive-sequence current component after a fault, resulting in differences in the additional networks for the positive and negative-sequence fault components during a two-phase short circuit. However, the distribution characteristics of the negative-sequence voltage fault component still follow... Figure 5 The trend shown.

[0117] 3) When a fault occurs in the distribution network, the phase difference between the positive sequence voltage fault component and the positive sequence current fault component pointing to the fault point is between -180° and -90°.

[0118] Based on the above explanation, taking a fault at point f1 on line AB as an example... Figure 6 This is a schematic diagram of the network for the positive-sequence fault component during an f1 fault, provided in an embodiment of this application. Figure 6 As shown, Positive sequence fault current component on the distribution network side , .

[0119] Figure 7 This is a schematic diagram of the positive-sequence fault component phase at the BUSA bus provided in an embodiment of this application, as shown below. Figure 7 As shown, based on the phase relationship of each fault component at the BUSA bus, the phase difference between the positive sequence voltage fault component and the positive sequence current fault component pointing to the fault point is determined to be between -180° and -90°.

[0120] Define the phase difference between the positive-sequence voltage fault component and the positive-sequence current fault component pointing to the fault point. ,in, This indicates the busbar number, with values ​​of BUSA, BUSB, or BUSC. Indicates the location of the protection device. The range is from -180° to 180°.

[0121] Figure 8 This is a schematic diagram of the positive-sequence fault component phase at the BUSB bus provided in an embodiment of this application, as shown below. Figure 8 As shown, the phase difference between the positive sequence voltage fault component and the positive sequence current fault component pointing to the fault point is between -180° and -90°.

[0122] Figure 9 This is a schematic diagram of the positive-sequence fault component phase at the BUSC bus provided in an embodiment of this application, as shown below. Figure 9 As shown, the phase difference between the positive sequence voltage fault component and the positive sequence current fault component pointing to the fault point is between -180° and -90°.

[0123] S103. Determine the comprehensive acceleration factor based on the positive sequence voltage fault component and the positive sequence current fault component;

[0124] Among them, the comprehensive acceleration factor is used to reflect the fault direction information and fault location information of the distribution network.

[0125] In this step, the direction of the protection device can be determined based on the phase relationship between the positive sequence voltage fault component and the positive sequence current fault component. The ratio of their amplitudes can characterize the electrical distance from the fault point to the bus. Based on the positive sequence voltage fault component and the positive sequence current fault component, a comprehensive acceleration factor for fault direction information and fault location information of the distribution network is constructed.

[0126] For example, the comprehensive acceleration factor considers the fault characteristics reflected by both the positive sequence voltage fault component and the positive sequence current fault component to characterize the fault direction and location, providing a quantitative basis for the dynamic correction of the inverse time protection action time.

[0127] In one possible implementation, the information quantity reflecting the fault direction can be determined based on the correlation between the positive-sequence voltage fault component and the positive-sequence current fault component. Furthermore, based on the characteristic that "the closer the fault distance, the larger the fault component amplitude," the information quantity characterizing the fault location can be determined according to the positive-sequence voltage fault component. Subsequently, a comprehensive acceleration factor can be determined based on the information quantity of the fault direction and the information quantity of the fault location through a preset relationship. This preset relationship can be a product combination, a weighted combination, or other mapping method.

[0128] S104. Accelerate the operation time of the inverse-time overcurrent protection based on the comprehensive acceleration factor, and determine the corrected inverse-time overcurrent protection operation.

[0129] Among them, the inverse-time overcurrent protection action is used to isolate faults in the distribution network.

[0130] In this step, the original inverse-time overcurrent protection action time is used as the benchmark, and a comprehensive acceleration factor is introduced for dynamic correction. After correction, a new inverse-time overcurrent protection action criterion is formed, which realizes rapid tripping of near-terminal faults and reasonable delay retention of far-terminal faults, so as to accurately complete the distribution network fault isolation.

[0131] For example, inverse-time overcurrent protection is a type of protection that determines the operating time based on the magnitude of the fault current. Its basic operating time can be calculated according to a preset inverse-time curve, such as a standard inverse-time, extreme inverse-time, or very inverse-time curve.

[0132] In one possible implementation, the protection device first calculates the basic operating time based on the real-time effective value of the fault current or the positive sequence current amplitude. Then, a comprehensive acceleration factor is introduced into the operating time correction. The basic operating time or related time parameters can be corrected based on the comprehensive acceleration factor to obtain the corrected inverse-time overcurrent protection operation. The closer the fault is to the bus, the larger the comprehensive acceleration factor is, and the greater the compression of the inverse-time overcurrent protection operation time.

[0133] In addition, to prevent the action time from repeatedly jumping due to instantaneous measurement jitter, the comprehensive acceleration factor can be smoothed or the corrected action time can be updated when preset conditions are met, and corresponding action time boundaries can be set to meet the protection coordination requirements.

[0134] The revised inverse-time overcurrent protection will activate the output trip relay when the corresponding timer is completed and the fault criterion remains valid, and send a trip command to the corresponding feeder circuit breaker to complete the fault clearing. If the fault is detected to have disappeared or the current has returned to below the set value during the timer, the timer will be cleared and the operation process will be exited.

[0135] In this embodiment, the integrated acceleration factor is coupled into the correction process of the inverse-time overcurrent protection's operating time, so that the final tripping time is simultaneously constrained by the fault current amplitude, fault direction, and fault location characteristics. When distributed power sources participate in fault power supply, causing a decrease in the fault current measured by the upstream protection, the integrated acceleration factor can still achieve targeted acceleration correction based on the fault direction and fault location characteristics, thereby compensating for the delay caused by traditional inverse-time overcurrent protection relying solely on current amplitude. It should be understood that the above example is merely illustrative and not limiting.

[0136] In one possible implementation, step S104 may include the following steps:

[0137] Step 1: Multiply the comprehensive acceleration factor and the time constant of the inverse time overcurrent protection operation to accelerate the operation time of the inverse time overcurrent protection and obtain the corrected time constant.

[0138] For example, the comprehensive acceleration factor and the time constant of the inverse-time overcurrent protection operation are multiplied together, and the time constant is adjusted to accelerate the operation time of the inverse-time overcurrent protection, thus obtaining the corrected time constant.

[0139] In one possible implementation, the comprehensive acceleration factor ranges from [0, 1], the corrected time constant decreases, and the corresponding inverse time overcurrent protection action time is shortened.

[0140] For example, the corrected time constant It can be represented as:

[0141]

[0142] in, Indicates the overall acceleration factor. This represents the time constant for the inverse-time overcurrent protection to operate.

[0143] The closer the fault point is to the busbar, The larger the value, The closer The protection action time limit is significantly compressed; the farther the fault point is from the busbar, the better. The smaller the value, Smaller size ensures coordination of protection time limits between upper and lower levels, preventing cascading tripping.

[0144] Step 2: Determine the corrected inverse-time overcurrent protection action based on the corrected time constant.

[0145] For example, the corrected time constant is substituted into the standard inverse-time overcurrent protection curve calculation formula to calculate the action time of the corrected inverse-time overcurrent protection, and the corrected inverse-time overcurrent protection action command is output accordingly.

[0146] In one possible implementation, the operating time of the modified inverse-time overcurrent protection is... It is expressed as follows:

[0147]

[0148] in, This indicates the fault current multiple; the larger the current, the faster the inverse-time overcurrent protection will operate.

[0149] In this embodiment, a comprehensive acceleration factor is introduced to directly participate in the calculation process of the inverse time overcurrent protection action time, so that the protection action time is adjusted synchronously with the changes in fault direction and fault location, ensuring that the protection action is consistent with the fault state, thereby making the fault clearing response more in line with the fault characteristics, and maintaining the original setting logic and selectivity of the inverse time overcurrent protection.

[0150] The inverse-time overcurrent protection method for distribution networks provided in this application first acquires bus voltage data and feeder current data when a fault occurs in the distribution network. Then, based on the bus voltage data and feeder current data, it determines the positive-sequence voltage fault component and the positive-sequence current fault component. Next, based on the positive-sequence voltage fault component and the positive-sequence current fault component, it determines a comprehensive acceleration factor. The comprehensive acceleration factor is used to reflect the fault direction information and fault location information of the distribution network. Finally, based on the comprehensive acceleration factor, it accelerates and corrects the inverse-time overcurrent protection action time to determine the corrected inverse-time overcurrent protection action. The inverse-time overcurrent protection action is used to clear the fault in the distribution network. In this embodiment, by acquiring bus voltage data and feeder current data when a fault occurs in the distribution network, and determining the positive sequence voltage fault component and positive sequence current fault component accordingly, a comprehensive acceleration factor reflecting the fault direction and location information of the distribution network can be determined based on the effective characteristic quantities in the fault process. This comprehensive acceleration factor is then coupled to the inverse-time overcurrent protection time calculation process, enabling the inverse-time overcurrent protection to adaptively adjust its operating time according to the fault characteristics in a multi-feeder distribution network with distributed power sources. This improves the adaptability of the inverse-time overcurrent protection to fault characteristics, thereby matching the fault clearing process with the current distribution changes under multi-power supply conditions and achieving reliable fault clearing of the distribution network.

[0151] Based on the above embodiments, Figure 10 A flowchart illustrating the inverse-time overcurrent protection method for distribution networks provided in this application embodiment. Figure 2 .like Figure 10 As shown, one possible implementation of step S103 above includes the following steps:

[0152] S201. Determine the phase difference between the positive sequence voltage fault component and the positive sequence current fault component.

[0153] In this step, phase analysis is performed on the positive sequence voltage fault component and the positive sequence current fault component, and the phase difference between the positive sequence voltage fault component and the positive sequence current fault component is calculated.

[0154] In one possible implementation, the formula for calculating the phase difference between the positive-sequence voltage fault component and the positive-sequence current fault component pointing to the fault point is as follows:

[0155]

[0156] in, This indicates the busbar number, with values ​​of BUSA, BUSB, or BUSC. Indicates the location of the protection device. The range is from -180° to 180°.

[0157] In one possible implementation, prior to step S201, the inverse-time overcurrent protection method for the distribution network further includes the following steps:

[0158] Step 1: Perform symmetrical decomposition on the bus voltage data to obtain negative sequence voltage data;

[0159] For example, after a fault occurs in the distribution network, the protection device first collects bus voltage data and feeder current data, and performs symmetrical decomposition on the bus voltage data to obtain negative sequence voltage data.

[0160] Step 2: Perform spectrum analysis on the negative sequence voltage data to determine the negative sequence voltage fault component.

[0161] For example, the negative sequence voltage fault component can be used as an input before the subsequent phase difference calculation, so that the determination of the phase difference is based on the result of the fault sequence component extraction.

[0162] In one possible implementation, when performing spectral analysis on negative sequence voltage data, Fourier transform or discrete Fourier transform can be used to map the time-domain negative sequence voltage data to the frequency domain to extract the fundamental wave and the characteristic components within the relevant fault frequency band, and identify the amplitude peak or energy concentration interval corresponding to the fault state in the frequency domain, thereby determining the negative sequence voltage fault components.

[0163] Furthermore, the distribution characteristics of the negative sequence voltage fault component are the same as those of the positive sequence voltage fault component, that is, the amplitude of the negative sequence voltage fault component at the protection installation point bus is inversely proportional to the distance between the fault location and the bus.

[0164] In this embodiment, by first performing symmetrical decomposition on the bus voltage data and then performing spectral analysis on the negative sequence voltage data, the acquisition of the negative sequence voltage fault component can simultaneously possess the ability to separate sequence components and identify frequency domain features. This provides a stable data source for subsequent phase difference calculation and makes the construction of the comprehensive acceleration factor more closely match the voltage change characteristics of asymmetrical faults in the distribution network.

[0165] S202. Perform a linear mapping on the phase difference to obtain the phase difference acceleration factor;

[0166] Among them, the phase difference acceleration factor is used to reflect the fault direction information of the distribution network.

[0167] In this step, the phase difference is linearly mapped to obtain a phase difference acceleration factor that reflects the fault direction information of the distribution network.

[0168] In one possible implementation, the phase difference between the positive-sequence voltage fault component and the positive-sequence current fault component is calculated, and the phase difference is mapped to a phase difference acceleration factor through a preset linear function.

[0169] Phase difference acceleration factor It can be represented as follows:

[0170]

[0171] because It is always within the range of -180° to -90°, therefore All are less than 1.

[0172] S203. Determine the comprehensive sequence voltage fault component based on the amplitude difference between the positive sequence voltage fault component and the negative sequence voltage fault component.

[0173] Among them, the comprehensive sequence voltage fault component is used to reflect the change in the corresponding sequence voltage before and after the fault occurs.

[0174] In this step, based on the amplitude difference between the positive-sequence voltage fault component and the negative-sequence voltage fault component, a comprehensive sequence voltage fault component is determined to reflect the change in the corresponding sequence voltage before and after the fault occurs.

[0175] In one possible implementation, this is achieved by constructing a synthetic sequence voltage fault component. To improve the impact of fault types on protection, the integrated sequence voltage fault component is used. The expression is:

[0176]

[0177] in, This represents the positive-sequence voltage fault component of the bus. This represents the negative sequence voltage fault component of the bus.

[0178] As can be seen from the above analysis, under the conditions of three-phase short circuit and two-phase short circuit, the characteristic that the magnitude of the comprehensive sequence voltage fault component is inversely proportional to the fault distance is still satisfied.

[0179] S204. Normalize the comprehensive sequence voltage fault component and determine the coefficient of the comprehensive sequence voltage fault component.

[0180] Among them, the comprehensive sequence voltage fault component coefficient is used to reflect the fault location information of the distribution network.

[0181] In this step, the comprehensive sequence voltage fault component is normalized to determine the comprehensive sequence voltage fault component coefficient, which reflects the fault location information of the distribution network.

[0182] In one possible implementation, step S204 may include the following steps:

[0183] Step 1: Determine the absolute value of the difference between the integrated sequence voltage fault component and the rated voltage;

[0184] For example, the value of the comprehensive sequence voltage fault component is first obtained, and the difference between the value and the rated voltage is calculated to obtain the deviation between the two. Then, the absolute value of the deviation is taken to eliminate the influence of the deviation direction on subsequent calculations.

[0185] Step 2: Determine the comprehensive sequence voltage fault component coefficient based on the ratio between the absolute value and the rated voltage.

[0186] For example, the absolute value is calculated as a ratio to the rated voltage to obtain a dimensionless normalized result, which is then output as the comprehensive sequence voltage fault component coefficient.

[0187] In one possible implementation, it is stipulated that when the voltage is lower than 85% of the rated voltage, it is considered an abnormal operating state. At this time, the distributed power supply is in a low voltage ride-through state, and the faulty line should be quickly disconnected to restore power supply to the non-faulty area.

[0188] Comprehensive sequence voltage fault component coefficient The expression is:

[0189]

[0190] in, Indicates the rated voltage. This represents the fault component of the overall sequence voltage.

[0191] In addition, the critical value of the system's abnormal working state will be... The absolute value of the difference between the combined sequence voltage fault component and By taking the ratio and normalizing the voltage difference, Mapped to the interval [0, 1], its value can reflect the fault location information of the distribution network.

[0192] When a fault occurs in the distribution network, the closer the fault point is to the bus, the larger the value of the comprehensive sequence voltage fault component at the protection device. The comprehensive sequence voltage fault component coefficient is calculated based on the comprehensive sequence voltage fault component. It is proportional to the distance to the fault, and its value ranges from [0, 1]. Its value can reflect the location of the fault.

[0193] Figure 11 A graph showing the variation of the comprehensive sequence voltage fault component coefficients provided in this application embodiment. Figure 11 As shown, the closer the fault is to the protection device, the more... The smaller the value, the greater the bus voltage drop when the fault occurs near the busbar, resulting in a larger overall sequence voltage fault component. The voltage is close to 0. Because the upstream protection device is far from the fault point, the voltage drop is small, and the overall sequence voltage fault component is small. The upstream protection device measures... The value is greater than that of the corresponding line but still less than 1; when the fault occurs at the end of the line, the bus voltage drop is not significant, and the overall sequence voltage fault component is relatively small. It is close to 1.

[0194] In this embodiment, by absolute value processing of the deviation between the integrated sequence voltage fault component and the rated voltage, and further using the ratio of the deviation to the rated voltage as the output integrated sequence voltage fault component coefficient, the degree of voltage change caused by the fault can be stably characterized, and a consistent input can be provided for the subsequent determination of fault location information.

[0195] S205. Multiply the phase difference acceleration factor and the comprehensive sequence voltage fault component coefficient to obtain the comprehensive acceleration factor.

[0196] In this step, since the phase difference acceleration factor can speed up the protection action but cannot reflect the fault location, while the comprehensive sequence voltage fault component coefficient can reflect the fault location, the phase difference acceleration factor is multiplied by the comprehensive sequence voltage fault component coefficient to obtain the comprehensive acceleration factor.

[0197] In one possible implementation, the Integrated Acceleration Factor (IAF) can reflect the fault direction and fault location information of the distribution network, and the calculation formula is as follows:

[0198]

[0199] In one possible implementation, prior to step S104, the inverse-time overcurrent protection method for the distribution network further includes the following steps:

[0200] Step 1: Determine the fault direction information of the distribution network based on the phase difference and preset threshold.

[0201] For example, in the case of a reverse fault, the fault current supplied by the DG may cause the protection to malfunction. Therefore, a directional element can be installed at the tie feeder protection device to determine the direction of the fault.

[0202] In one possible implementation, the preset thresholds include an upper threshold of 90° and a lower threshold of -90°. The phase difference is compared with the upper threshold of 90° and the lower threshold of -90° respectively to determine the fault direction information of the distribution network.

[0203] If the positive direction of the current is from the busbar to the feeder, when If the fault direction is positive, the fault direction information is determined to be positive; otherwise, the fault direction information is determined to be negative.

[0204] Step 2: If the fault direction information is a positive fault, the fault in the distribution network is cleared according to the corrected inverse time overcurrent protection action.

[0205] For example, when the phase difference falls into the positive judgment range corresponding to the preset threshold, the fault direction information is set to positive fault, and an execution permission signal is output so that the corrected inverse time overcurrent protection action issues a trip command according to the corrected time to clear the fault of the corresponding feeder or switch.

[0206] Step 3: If the fault direction information is a reverse fault, the corrected inverse time overcurrent protection action will not be executed.

[0207] For example, when the phase difference does not meet the positive judgment interval, the fault direction information is set to a reverse fault, and a blocking signal is output so that the corrected inverse time overcurrent protection action remains in a non-execution state.

[0208] In this embodiment, the modified inverse-time overcurrent protection operation is only activated to clear the fault when the fault direction meets the positive criterion. If the direction is incorrectly determined, the operation output is suppressed by the blocking signal, so that the protection operation is consistent with the fault direction, ensuring the directionality and selectivity of fault clearing.

[0209] The inverse-time overcurrent protection method for distribution networks provided in this application first determines the phase difference between the positive-sequence voltage fault component and the positive-sequence current fault component. Then, the phase difference is linearly mapped to obtain a phase difference acceleration factor, which reflects the fault direction information of the distribution network. Next, based on the amplitude difference between the positive-sequence voltage fault component and the negative-sequence voltage fault component, the comprehensive sequence voltage fault component is determined, which reflects the change in the corresponding sequence voltage before and after the fault occurs. Then, the comprehensive sequence voltage fault component is normalized to determine the comprehensive sequence voltage fault component coefficient, which reflects the fault location information of the distribution network. Finally, the phase difference acceleration factor and the comprehensive sequence voltage fault component coefficient are multiplied to obtain the comprehensive acceleration factor. In this embodiment, the fault direction information and fault location information are integrated into the same comprehensive acceleration factor. Based on the phase relationship and the sequence voltage change, the inverse time overcurrent protection action correction amount can be formed, so that the corrected protection action is consistent with the fault state. The comprehensive acceleration factor has strong adaptability to different fault scenarios, can provide a stable time correction basis for inverse time overcurrent protection, and improve the targeting and coordination of fault clearing.

[0210] In one possible implementation, Figure 12 A flowchart illustrating the inverse-time overcurrent protection method for distribution networks provided in this application embodiment. Figure 3 .like Figure 12 As shown, a possible implementation of the inverse-time overcurrent protection method for this distribution network includes the following steps:

[0211] S301. Obtain bus voltage data and feeder current data when a fault occurs in the distribution network.

[0212] S302. Based on the bus voltage data and feeder current data, determine the positive sequence voltage fault component and the positive sequence current fault component.

[0213] S303. Determine the phase difference between the positive sequence voltage fault component and the positive sequence current fault component, and perform a linear mapping on the phase difference to obtain the phase difference acceleration factor.

[0214] S304. Determine the composite sequence voltage fault component based on the amplitude difference between the positive sequence voltage fault component and the negative sequence voltage fault component.

[0215] S305. Normalize the comprehensive sequence voltage fault component and determine the coefficient of the comprehensive sequence voltage fault component.

[0216] S306. Multiply the phase difference acceleration factor and the comprehensive sequence voltage fault component coefficient to obtain the comprehensive acceleration factor;

[0217] S307. Accelerate the operation time of inverse-time overcurrent protection based on the comprehensive acceleration factor, and determine the corrected inverse-time overcurrent protection operation.

[0218] S308. Based on the phase difference and the preset threshold, determine whether the fault direction information of the distribution network is a positive fault. If so, the fault is cleared from the distribution network according to the corrected inverse time overcurrent protection action. Otherwise, the corrected inverse time overcurrent protection action is not executed.

[0219] Based on the above embodiments, the following are embodiments of the apparatus involved in this application:

[0220] Figure 13 This is a schematic diagram of the structure of an inverse-time overcurrent protection device for a power distribution network provided in an embodiment of this application. Figure 13 As shown, the inverse-time overcurrent protection device 1300 of this distribution network includes:

[0221] The acquisition module 1301 is used to acquire bus voltage data and feeder current data when a fault occurs in the distribution network;

[0222] The first determining module 1302 is used to determine the positive sequence voltage fault component and the positive sequence current fault component based on the bus voltage data and the feeder current data.

[0223] The second determining module 1303 is used to determine the comprehensive acceleration factor based on the positive sequence voltage fault component and the positive sequence current fault component, wherein the comprehensive acceleration factor is used to reflect the fault direction information and fault location information of the distribution network.

[0224] The third determining module 1304 is used to accelerate the correction of the inverse-time overcurrent protection action time based on the comprehensive acceleration factor, and to determine the corrected inverse-time overcurrent protection action, wherein the inverse-time overcurrent protection action is used to clear faults in the distribution network.

[0225] In one or more embodiments, the second determining module 1303 is specifically used for:

[0226] Determine the phase difference between the positive-sequence voltage fault component and the positive-sequence current fault component;

[0227] A phase difference acceleration factor is obtained by linearly mapping the phase difference, which is used to reflect the fault direction information of the distribution network.

[0228] The composite sequence voltage fault component is determined based on the amplitude difference between the positive sequence voltage fault component and the negative sequence voltage fault component. The composite sequence voltage fault component is used to reflect the change between the corresponding sequence voltages before and after the fault occurs.

[0229] The comprehensive sequence voltage fault component is normalized to determine the comprehensive sequence voltage fault component coefficient, which is used to reflect the fault location information of the distribution network.

[0230] The phase difference acceleration factor and the comprehensive sequence voltage fault component coefficient are multiplied together to obtain the comprehensive acceleration factor.

[0231] In one or more embodiments, the second determining module 1303 performs normalization processing on the comprehensive sequence voltage fault component to determine the comprehensive sequence voltage fault component coefficient, specifically for:

[0232] Determine the absolute value of the difference between the integrated sequence voltage fault component and the rated voltage;

[0233] The comprehensive sequence voltage fault component coefficient is determined based on the ratio between the absolute value and the rated voltage.

[0234] In one or more embodiments, after accelerating the correction of the inverse-time overcurrent protection action time based on a comprehensive acceleration factor and determining the corrected inverse-time overcurrent protection action, the third determining module 1304 is further configured to:

[0235] Based on the phase difference and a preset threshold, the fault direction information of the distribution network is determined;

[0236] If the fault direction information is a positive fault, the fault will be cleared from the distribution network according to the corrected inverse time overcurrent protection action.

[0237] If the fault direction information is a reverse fault, the corrected inverse time overcurrent protection action will not be executed.

[0238] In one or more embodiments, before determining the phase difference between the positive-sequence voltage fault component and the positive-sequence current fault component, the second determining module 1303 is further configured to:

[0239] Symmetric decomposition of the bus voltage data yields negative sequence voltage data;

[0240] Spectral analysis was performed on the negative sequence voltage data to determine the negative sequence voltage fault component.

[0241] In one or more embodiments, the third determining module 1304 is specifically used for:

[0242] Multiply the comprehensive acceleration factor and the time constant of the inverse time overcurrent protection operation to accelerate the operation time of the inverse time overcurrent protection and obtain the corrected time constant.

[0243] Based on the corrected time constant, determine the corrected inverse-time overcurrent protection action.

[0244] The inverse-time overcurrent protection device for the distribution network provided in this embodiment can execute the method provided in the above-described method embodiment. Its implementation principle and technical effect are similar, and will not be described in detail here.

[0245] Figure 14 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 14 As shown, the electronic device 1400 includes: a processor 1401, a memory 1402, and a bus 1403;

[0246] The memory 1402 is used to store computer-executed instructions from the processor 1401;

[0247] The processor 1401 is configured to execute the technical solutions of any of the foregoing method embodiments by executing computer execution instructions.

[0248] The specific implementation process of processor 1401 can be found in the above method embodiment, and its implementation principle and technical effect are similar, so it will not be repeated here.

[0249] In the above embodiments, it should be understood that the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor.

[0250] The memory may include random access memory (RAM) and may also include non-volatile memory (NVM), such as at least one disk storage device.

[0251] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

[0252] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method.

[0253] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-described method.

[0254] The aforementioned readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random-Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0255] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an application-specific integrated circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in the device.

[0256] The division of units is merely a logical functional division; in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0257] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0258] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0259] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory, random access memory (RAM), magnetic disks, or optical disks.

[0260] 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 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.

[0261] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A method for inverse-time overcurrent protection in a power distribution network, characterized in that, include: Acquire bus voltage and feeder current data when a fault occurs in the distribution network; Based on the bus voltage data and the feeder current data, determine the positive sequence voltage fault component and the positive sequence current fault component; Based on the positive sequence voltage fault component and the positive sequence current fault component, a comprehensive acceleration factor is determined, which is used to reflect the fault direction information and fault location information of the distribution network. The inverse-time overcurrent protection action time is accelerated and corrected based on the comprehensive acceleration factor, and the corrected inverse-time overcurrent protection action is determined. The inverse-time overcurrent protection action is used to clear faults in the distribution network.

2. The method according to claim 1, characterized in that, The step of determining the comprehensive acceleration factor based on the positive-sequence voltage fault component and the positive-sequence current fault component includes: Determine the phase difference between the positive-sequence voltage fault component and the positive-sequence current fault component; A phase difference acceleration factor is obtained by linearly mapping the phase difference, and the phase difference acceleration factor is used to reflect the fault direction information of the distribution network. The comprehensive sequence voltage fault component is determined based on the amplitude difference between the positive sequence voltage fault component and the negative sequence voltage fault component. The comprehensive sequence voltage fault component is used to reflect the change in the corresponding sequence voltage before and after the fault occurs. The comprehensive sequence voltage fault component is normalized to determine the comprehensive sequence voltage fault component coefficient, which is used to reflect the fault location information of the distribution network. The phase difference acceleration factor and the comprehensive sequence voltage fault component coefficient are multiplied together to obtain the comprehensive acceleration factor.

3. The method according to claim 2, characterized in that, The normalization process for the integrated sequence voltage fault components, and the determination of the integrated sequence voltage fault component coefficients, includes: Determine the absolute value of the difference between the integrated sequence voltage fault component and the rated voltage; The comprehensive sequence voltage fault component coefficient is determined based on the ratio between the absolute value and the rated voltage.

4. The method according to claim 3, characterized in that, After accelerating the inverse-time overcurrent protection operation time based on the comprehensive acceleration factor and determining the corrected inverse-time overcurrent protection operation, the method further includes: Based on the phase difference and the preset threshold, the fault direction information of the distribution network is determined; If the fault direction information is a positive fault, the fault is cleared from the distribution network according to the corrected inverse time overcurrent protection action; If the fault direction information is a reverse fault, the corrected inverse time overcurrent protection action will not be executed.

5. The method according to claim 4, characterized in that, Before determining the phase difference between the positive-sequence voltage fault component and the positive-sequence current fault component, the method further includes: The bus voltage data is symmetrically decomposed to obtain negative sequence voltage data; Spectral analysis is performed on the negative sequence voltage data to determine the fault component of the negative sequence voltage.

6. The method according to any one of claims 1-4, characterized in that, The step of accelerating the inverse-time overcurrent protection action based on the comprehensive acceleration factor, and determining the corrected inverse-time overcurrent protection action, includes: Multiply the comprehensive acceleration factor and the time constant of the inverse time overcurrent protection operation to accelerate and correct the operation time of the inverse time overcurrent protection, and obtain the corrected time constant. The modified inverse-time overcurrent protection action is determined based on the modified time constant.

7. An inverse-time overcurrent protection device for a power distribution network, characterized in that, include: The acquisition module is used to acquire bus voltage data and feeder current data when a fault occurs in the distribution network; The first determining module is used to determine the positive sequence voltage fault component and the positive sequence current fault component based on the bus voltage data and the feeder current data. The second determining module is used to determine a comprehensive acceleration factor based on the positive sequence voltage fault component and the positive sequence current fault component. The comprehensive acceleration factor is used to reflect the fault direction information and fault location information of the distribution network. The third determining module is used to accelerate the correction of the inverse-time overcurrent protection action time based on the comprehensive acceleration factor, and to determine the corrected inverse-time overcurrent protection action, which is used to clear the fault in the distribution network.

8. An electronic device, characterized in that, include: Memory, processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory, causing the processor to perform the method as described in any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1-6.

10. A computer program product, characterized in that, Includes a computer program that, when executed by a processor, implements the method described in any one of claims 1-6.

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