Distribution network constant value setting and checking method, system and equipment and storage medium

Abstract

The invention discloses a distribution network constant value setting and checking method, system and device and a storage medium, and relates to the technical field of electric power automation and relay protection, and the method comprises the steps: firstly collecting a real-time topology state signal of a distribution network, generating a dynamic topology matrix through state merging, and further generating an overcurrent protection directivity criterion; calculating the action value of each over-current section, and determining the zero-sequence protection constant values of different grounding networks in combination with topological parameters; secondly, differential delay parameters of a first-stage switch and a second-stage switch are set, a short-time voltage-loss locking and opening function is activated, and a digital twinborn model is constructed for checking; and finally, issuing the fixed value passing the checking to a protection device, and executing a coordination action. According to the method, the fault direction can be accurately judged, the constant value of each overcurrent section is reasonably calculated, and different grounding networks are distinguished to configure zero-sequence constant values. And through differential time delay, digital twinning check and the like, the protection self-adaption and reliability are improved, the power failure range is reduced, and stable operation of the power distribution network is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power automation and relay protection, and particularly relates to a distribution network setting value setting and checking method, system, device and storage medium. BACKGROUND

[0002] With the in-depth development of smart grid, the protection strategy of distribution network gradually evolves towards dynamic and intelligent. As the core configuration of distribution network protection, the traditional static setting value setting mode of over-current directional protection faces significant challenges in dealing with special operating modes (such as frequent power supply switching and distributed energy access).

[0003] On the one hand, the directional criterion of fixed phase reference in the traditional static setting value setting mode of over-current directional protection cannot adapt to the current phase reversal caused by dynamic topology changes, resulting in high protection misoperation rate; on the other hand, the existing method fails to fully consider the influence of key factors such as end short-circuit current superposition and reverse power transmission on differential coordination when calculating the directional criterion of over-current protection under typical special conditions such as magnetizing inrush current and transformer low-voltage side fault, resulting in the problems of protection refusal and decreased selectivity. SUMMARY

[0004] In view of the above problems, the present application is proposed.

[0005] Therefore, the technical problem solved by the present application is: how to break through the limitations of traditional static setting, develop an intelligent setting method that can real-time perceive network topology changes, adaptively adjust the directional criterion, and ensure accurate differential coordination under special operating modes and fault conditions (such as magnetizing inrush current impact and multi-source fault current interaction).

[0006] To solve the above technical problems, the present application provides the following technical solutions:

[0007] In a first aspect, the present application provides a distribution network setting value setting and checking method, comprising:

[0008] Collecting real-time topology state signals of the distribution network, generating a dynamic topology matrix through state merging, and generating over-current protection directional criterion according to the topology matrix dynamics;

[0009] Based on the over-current protection directional criterion, calculating the action value of each section of over-current;

[0010] According to the action value of each section of over-current, combining with the topology parameters of the distribution network, determining the zero sequence protection setting value of small resistance grounded network and small grounded network;

[0011] Based on the zero sequence protection setting value, setting the differential delay parameters of the primary and secondary switches, activating the short-time loss-of-voltage blocking tripping function, and constructing a digital twin model for zero sequence protection setting value checking;

[0012] The zero sequence protection setting value passed by the check is sent to the protection device to execute overcurrent protection, zero sequence protection and automatic switch cooperative action.

[0013] As a preferred scheme of the distribution network setting value setting and checking method, wherein:

[0014] The real-time topology state signal of the distribution network is collected, a dynamic topology matrix is generated by state merging, and the overcurrent protection directionality criterion is generated according to the dynamic topology matrix, which includes:

[0015] The real-time topology state signal of the distribution network is collected, the real-time topology state signal of the distribution network is signal-analyzed and format-converted to generate an original topology data stream;

[0016] Based on the original topology data stream, the switch device signal is state-sequentially merged according to the switch device signal and the non-switch device state change frequency to remove redundant data; the merged switch state is mapped to the edge attribute of the static topology graph through a topology graph traversal method, and the dynamic topology matrix is generated in combination with the non-switch device current spectrum characteristics;

[0017] Based on the dynamic topology matrix, the forward short-circuit current threshold of the topology group equivalent circuit is calculated, and by comparing the current phase difference and amplitude change at different times, the change trend of the current characteristics when the fault occurs is identified, and the overcurrent protection directionality criterion is dynamically adjusted and generated based on the change trend.

[0018] As a preferred scheme of the distribution network setting value setting and checking method, wherein:

[0019] The overcurrent each section action value is calculated based on the overcurrent protection directionality criterion, which includes:

[0020] Based on the overcurrent protection directionality criterion, the three-phase current waveform data of the line end in a preset time window is extracted, and the maximum short-circuit current instantaneous value is calculated;

[0021] Based on the maximum short-circuit current instantaneous value, a dynamic mapping model of the fault type from the low-voltage side fault to the high-voltage side current is established through the transformer winding ratio, short-circuit impedance parameters and network topology structure;

[0022] Based on the dynamic mapping model setting simulation initial conditions, a detailed model including the transformer winding ratio, short-circuit impedance parameters and network topology structure is built in an electromagnetic transient simulation platform, a low-voltage side fault waveform is injected for electromagnetic transient process simulation, time-domain fault current data of each node on the high-voltage side is output, and the data sampling interval is synchronized with the maximum short-circuit current instantaneous value calculation window;

[0023] Based on the fault current data, the excitation inrush second harmonic and high-frequency interference generated by transformer no-load closing are filtered in real time.

[0024] As a preferred scheme of the setting and checking method of the distribution network, wherein:

[0025] The calculation of the overcurrent segment action value based on the overcurrent protection direction criterion further comprises:

[0026] The overcurrent I segment action value is calculated by avoiding the maximum phase short-circuit current at the end of the line through the reliability coefficient;

[0027] The two-phase metallic short-circuit current at the end of the protected line under the minimum operating mode is obtained, and the overcurrent II segment action value meeting the sensitivity coefficient threshold is calculated by reverse deduction;

[0028] The steady-state current under the maximum load condition of the adjacent line is synchronously monitored, and the composite load current is generated by superimposing the transient current increment generated by the motor self-starting;

[0029] The overcurrent III segment action value meeting the selectivity requirement of the adjacent protection segment is calculated according to the time-current differential principle by taking the overcurrent II segment action value as the reference and combining the composite load current.

[0030] As a preferred scheme of the setting and checking method of the distribution network, wherein:

[0031] The determination of the zero sequence protection setting value of the small resistance grounded network and the small grounded network according to the overcurrent segment action value and the distribution network topology parameters comprises:

[0032] According to the overcurrent segment action value and the distribution network topology parameters, the zero sequence current and voltage data in the analysis calculation result are analyzed and calculated, and the performance characteristics of the zero sequence current under different grounding modes are evaluated in combination with the line impedance and transformer parameters in the distribution network topology parameters; the small resistance grounded network and the small grounded network are distinguished by comparing the calculated zero sequence current with the preset threshold value, if the zero sequence current exceeds a specific value, it is determined as a small resistance grounded network, and if it is lower than a specific value, it is determined as a small grounded network;

[0033] If it is determined as a small resistance grounded network, the zero sequence I segment trip setting value and the zero sequence II segment signal setting value are configured;

[0034] If it is determined as a small grounded network, the zero sequence I segment trip setting value is configured in a branch line level decreasing manner;

[0035] The trip and signal setting values of each protection device are verified by using the standard action time sequence table in the preset rule library through automation logic, and whether it meets the expected action time sequence requirement is checked;

[0036] After the verification is completed, the standardized configuration file containing the setting values of all protection devices is generated according to the finally determined directionality coefficient and sensitivity coefficient, and the standardized setting value configuration file is transmitted to each node protection device through the communication network.

[0037] The beneficial effects of the preferred technical solutions are: by analyzing zero sequence current and voltage data, combined with power distribution network topology parameters, small resistance grounding network and small grounding network can be accurately distinguished, and appropriate zero sequence protection setting value is configured for different grounding networks. The preset rule library is used to verify the setting value, ensuring that the action timing of the protection device meets the requirements, and improving the reliability of the protection. The standardized configuration file is generated and transmitted to each node protection device, which facilitates the unified management and configuration of the setting value, and improves the work efficiency.

[0038] As an optimal scheme of the power distribution network setting value setting and checking method, wherein:

[0039] The zero sequence protection setting value is used to set the differential time delay parameters of the primary and secondary switches, activate the short-time loss-of-voltage locking opening function, and build a digital twin model for zero sequence protection setting value checking, which includes:

[0040] Based on the zero sequence protection setting value and the maximum short-circuit current at the end of the line, the zero sequence protection setting values of the primary and secondary switches are determined respectively;

[0041] Based on the differential time delay control logic, the short-time loss-of-voltage locking function is activated; based on the dynamic topology matrix, the power distribution network topology parameters and transformer parameters are integrated, and the electromagnetic transient simulation technology is used to simulate various fault conditions, and the simulation results are compared with the measured data to build a digital twin model of the power distribution network;

[0042] Using the built digital twin model of the power distribution network, simulate the high resistance grounding fault scene, synchronously collect switch device measurement data and non-switch device current spectrum characteristics, compare the simulation output transient current data of each node with the measured wave record, and correct the overcurrent II segment action value to meet the high resistance fault detection requirement;

[0043] The zero sequence protection setting value after checking is associated with the device ID to generate hierarchical configuration instructions, which are transmitted to each node protection device through the communication network to realize online switching of the protection setting value;

[0044] Based on the finally determined setting value data of each level of protection device, a standardized configuration file containing overcurrent I to III segment action values, zero sequence I segment tripping setting value and zero sequence II segment signal setting value is prepared.

[0045] As an optimal scheme of the power distribution network setting value setting and checking method, wherein:

[0046] The zero sequence protection setting value that passes the checking is issued to the protection device, and the overcurrent protection, zero sequence protection and automatic switch cooperative action include:

[0047] The standardized configuration file is transmitted to the primary and secondary switch protection devices through the distributed communication network, the file is parsed in the protection device, the zero sequence protection setting value is extracted and written into the zero sequence protection setting value storage area;

[0048] activate the directional criterion calculation function of the primary switch protection device;

[0049] The primary switch collects current signals based on a dynamic topology matrix in real time, and executes overcurrent protection and zero sequence amplitude-phase fusion criterion; when detecting that the current of a phase exceeds a preset overcurrent action value, a response is made according to overcurrent protection logic; after receiving fault information, the secondary switch performs opening and closing operations according to pre-set differential delay parameters and short-time loss-of-voltage locking conditions;

[0050] The protection execution results of the primary switch and the secondary switch are fed back to the digital twin model in real time through a communication network, the digital twin model generates dynamic correction instructions based on the feedback data, transmits the dynamic correction instructions back to the corresponding protection device, and updates the related parameters in the zero sequence protection setting value storage area.

[0051] The beneficial effects of the preferred technical solution are: accurate issuance of standardized configuration files through a distributed communication network ensures that the protection device obtains correct zero sequence protection setting values. The activation of the directional criterion calculation function of the primary switch, combined with overcurrent protection and zero sequence amplitude-phase fusion criterion, can more accurately detect faults. The secondary switch operates according to differential delay and short-time loss-of-voltage locking conditions to avoid misoperation and expansion of the power outage range. Real-time feedback of protection execution results to the digital twin model generates dynamic correction instructions to update the setting values, so that the protection device can dynamically adjust according to the actual operating conditions, improving the adaptive ability and reliability of the distribution network protection.

[0052] In a second aspect, the application provides a distribution network setting value setting and checking system, comprising:

[0053] A topology signal processing and criterion generation module is configured to collect real-time topology state signals of the distribution network, generate a dynamic topology matrix through state merging, and generate overcurrent protection directional criterion according to the topology matrix;

[0054] An overcurrent action value calculation module is configured to calculate overcurrent segment action values based on the overcurrent protection directional criterion;

[0055] A zero sequence protection setting value determination module is configured to determine zero sequence protection setting values for small-resistance grounded networks and small-grounded networks according to the overcurrent segment action values and in combination with distribution network topology parameters;

[0056] A setting value checking and parameter setting module is configured to set differential delay parameters of the primary and secondary switches based on the zero sequence protection setting values, activate short-time loss-of-voltage locking opening function, and build a digital twin model for zero sequence protection setting value checking;

[0057] A setting value issuance and coordinated action execution module is configured to issue the zero sequence protection setting values that pass the checking to the protection device, and execute overcurrent protection, zero sequence protection and automatic switch coordinated action.

[0058] In a third aspect, the present application provides an electronic device, comprising:

[0059] a memory and a processor;

[0060] The memory is configured to store computer-executable instructions, and the processor is configured to execute the computer-executable instructions, so that the one or more processors implement the setting and checking method for setting values of a power distribution network as described in the present application.

[0061] In a fourth aspect, the present application provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the setting and checking method for setting values of a power distribution network.

[0062] The setting and checking method for setting values of a power distribution network provided by the present application can effectively solve the actual technical problems in the protection of a power distribution network and has significant practical application value. In terms of data processing, the real-time topological state signals are analyzed and merged, and redundant data is removed to accurately reflect the real-time topological structure of the power distribution network, thereby providing a reliable basis for subsequent protection criteria and setting value calculation, so that the protection device can more accurately determine the fault direction. In terms of setting value calculation, different methods are used to calculate the overcurrent action values of each section, and factors such as line short-circuit current, operating mode, and load current are considered to ensure the rapidity, sensitivity, and selectivity of the protection, which can quickly cut off the fault and avoid unnecessary tripping. In terms of ground network processing, small-resistance grounded networks and small-grounded networks are accurately distinguished, and appropriate zero-sequence protection setting values are configured for different networks, and the setting values are verified using a rule base to ensure that the action timing of the protection device meets the requirements and improves the reliability of the protection. In terms of protection checking and execution, the differential delay parameters of the primary and secondary switches are set, the short-time loss-of-voltage blocking function is activated, a digital twin model is constructed for checking, and the overcurrent II section action value is corrected to meet the high-resistance fault detection requirements. The setting values are issued through a distributed communication network to realize the coordinated action of the protection device, and the setting values are dynamically adjusted according to the feedback results to improve the adaptive ability and reliability of the power distribution network protection, reduce the power outage range, and ensure the stable operation of the power distribution network. BRIEF DESCRIPTION OF DRAWINGS

[0063] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0064] Figure 1 is the overall flowchart of the setting and checking method for setting values of a power distribution network provided by the present application. DETAILED DESCRIPTION

[0065] In order to make the above objectives, characteristics and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should fall within the scope of protection of the present application.

[0066] Embodiment 1, refer to Figure 1 For the first embodiment of the present application, the embodiment provides a distribution network setting and checking method, comprising:

[0067] S1: Collecting real-time topological state signals of the power distribution network, generating a dynamic topological matrix through state merging, and generating overcurrent protection directionality criteria according to the dynamic topological matrix;

[0068] S2: Calculating overcurrent action values of each section based on the overcurrent protection directionality criteria;

[0069] S3: Determining zero sequence protection settings of small resistance grounded networks and small grounded networks according to the overcurrent action values of each section in combination with topological parameters of the power distribution network;

[0070] S4: Setting differential time delay parameters of primary and secondary switches based on the zero sequence protection settings, activating short-time loss-of-voltage lockout tripping function, and constructing a digital twin model to check the zero sequence protection settings;

[0071] S5: Issuing the zero sequence protection settings that pass the check to the protection device to perform overcurrent protection, zero sequence protection and coordinated action of automated switches.

[0072] It should be noted that through steps S1-S5, real-time topological state signals of the power distribution network are first collected, a dynamic topological matrix is generated through state merging and overcurrent protection directionality criteria are generated accordingly; then overcurrent action values of each section are calculated based on the criteria, and zero sequence protection settings of small resistance grounded networks and small grounded networks are determined in combination with topological parameters of the power distribution network; subsequently, differential time delay parameters of primary and secondary switches are set according to the zero sequence protection settings, short-time loss-of-voltage lockout tripping function is activated, and a digital twin model is constructed to check the zero sequence protection settings; finally, the zero sequence protection settings that pass the check are issued to the protection device to realize overcurrent protection, zero sequence protection and coordinated action of automated switches, thereby ensuring that the power distribution network can accurately and reliably perform fault protection according to real-time topological states under different grounding modes, and improving the safety and stability of the operation of the power distribution network.

[0073] Embodiment 2, refer to Figure 1For an embodiment of the present application, a distribution network setting and checking method is provided based on the previous embodiment, comprising:

[0074] In the embodiment, the real-time topology state signal of the power distribution network in step S1 is collected, a dynamic topology matrix is generated by state merging, and the over-current protection direction criterion is generated according to the dynamic topology matrix, comprising:

[0075] The real-time topology state signal of the power distribution network comprises: device state change frequency, switch device signal, non-switch device current spectrum characteristics, network topology structure, and power distribution network topology parameters.

[0076] Specifically, the device state change frequency is recorded by monitoring the auxiliary contact or intelligent terminal of the switch device (such as circuit breaker, disconnector) to record the state switching timestamp (for example, 3 actions in 1 minute), and the number of operations in a unit of time is counted to form;

[0077] The switch device signal is obtained by collecting the real-time opening and closing state of the switch element by SCADA or FTU, with millisecond-level timestamp;

[0078] The non-switch device current spectrum characteristics are obtained by PMU or smart meter to obtain the current waveform of transformer, cable and other devices, and the harmonic components are extracted by Fourier transform; the network topology structure is imported from the GIS platform to obtain the static node-branch association relationship, and the connection state is dynamically updated by receiving the switch device signal; the power distribution network topology parameters integrate the line impedance, transformer ratio and other account data and real-time measured electrical parameters.

[0079] The real-time topology state signal in the power distribution network is collected by distributed network, and the original topology data stream is generated by signal analysis and format conversion.

[0080] Specifically, the monitoring devices (such as smart meter, fault indicator) deployed at each node of the power distribution network continuously transmit electrical parameters (such as voltage amplitude, phase angle, switch state) through communication protocols (such as IEC 61850, DNP3), and the real-time topology state signal is aggregated to the edge server through optical fiber private network or wireless Mesh network to form a topology state signal sequence with timestamp. When analyzing the topology state signal, the message analysis algorithm (such as ASN.1 decoding) is used to extract the payload data, and the abnormal data is removed by combining the topology checking rules (such as adjacency matrix verification); the heterogeneous data (such as SCADA message, PMU data stream) after analysis is reorganized according to the unified standard to form structured records, and finally the original topology data stream containing node-branch association relationship is generated.

[0081] Based on the original topology data stream, the switch device signal is merged according to the switch device signal and the non-switch device state change frequency, and the merged switch state is mapped to the edge attribute of the static topology graph through the topology graph traversal method, and the dynamic topology matrix is generated by combining the non-switch device current spectrum characteristics.

[0082] It should be noted that during the operation of the power distribution network, the switch device signal and the non-switch device (such as circuit breaker, disconnector) will frequently change state with dispatching operation or fault handling. The device state change frequency refers to the number of actions of the switch device within a certain time period, for example, a certain circuit breaker switches 5 times within 1 hour. By analyzing the frequency data, key devices that need to be monitored can be identified, and the basis for subsequent state sequence merging is provided. State sequence merging is to merge the frequently changing switch signals, retain the key state change points, and remove redundant data, thereby optimizing data storage and processing efficiency.

[0083] Further, the switch device signal is derived from various monitoring terminals installed in the power distribution network, including SCADA systems, intelligent terminals, etc. The switch device signal records the real-time state (on / off) and change time of each switch in the form of time series. For example, the circuit breaker of a certain substation is closed at 08:00:00 and opened at 08:05:30. After analyzing the time-stamped state signal, the original data stream reflecting the topology change of the power grid is formed. The static topology graph is a graphical model that describes the fixed connection relationship of the power distribution network. The edge in it represents the line or switch device. Through the topology graph traversal method, the merged switch state can be mapped to the corresponding edge attribute. For example, when it is detected that the switch state of a certain line changes from "closed" to "open", the connection state attribute of the edge in the static topology graph is updated.

[0084] Further, the current spectrum characteristics of the non-switch device (such as transformer, cable, etc.) are collected by professional monitoring equipment. For example, the real-time current waveform data of the non-switch device can be obtained by using PMU (synchronous phasor measurement unit), and then the spectral information containing harmonic components, amplitude changes, etc. can be extracted through signal processing methods such as Fourier transform, which can reflect the operating state and health of the device. The spectral information of the characteristics is combined with the updated switch state to construct a dynamic topology matrix that contains both topology connection relationship and device operating state.

[0085] Based on the dynamic topology matrix, the forward short-circuit current threshold of the topology group equivalent circuit is calculated, and the overcurrent protection direction criterion is generated through phase difference-amplitude fusion, and the expression is: ;

[0086] Among them, represents the The forward short-circuit current threshold of the equivalent circuit of each topology group. This represents the total number of subgroups dynamically divided in the distribution network. Indicates the electrical equipment number. This represents the index of the topological connection edge associated with electrical equipment in the dynamic topology matrix. Indicates the first A set of subgroups, This indicates the subgroup index of the current operation. Electrical equipment Topological connection edges Dynamic weighting factor, Electrical equipment The admittance matrix, Represents the pre-fault voltage vector. Describing a set of subgroups Clustering correction coefficient ( ∈[0.5,2.0]), Represents a time variable. Indicates time Real-time acquisition of instantaneous current values, Indicates the first The directional weight matrix of each subgroup This indicates the protection sensitivity factor.

[0087] Specifically, the distribution network is dynamically partitioned into multiple subgroups. For each subgroup, the electrical characteristics are calculated based on the equipment numbers and associated topological connection indexes, combined with the equipment admittance matrix and pre-fault voltage vector. By adjusting the influence of each equipment and connection in the calculation using dynamic weighting factors, the equivalent circuit parameters of each subgroup are obtained, and the first subgroup can be determined. The forward short-circuit current threshold of a subgroup equivalent circuit is the maximum short-circuit current value that a subgroup can withstand under specific conditions.

[0088] It should be noted that by comparing the changes in current phase difference and amplitude at different times, the changing trend of current characteristics at the time of fault occurrence is identified. Based on the changing trend, the overcurrent protection directionality criterion is dynamically adjusted and generated to ensure that it can accurately reflect the fault direction information in the actual power grid operation. Ultimately, not only the current magnitude is considered, but the phase information of the current is also analyzed in depth, thereby achieving accurate judgment of the fault direction in complex operating environments and improving the selectivity and reliability of the overcurrent protection directionality criterion.

[0089] In this embodiment, the calculation of the overcurrent protection action value for each stage based on the overcurrent protection directionality criterion in step S2 above includes:

[0090] Based on the overcurrent protection directionality criterion, the three-phase current waveform data at the end of the line within a preset time window are extracted, and the instantaneous value of the maximum short-circuit current is calculated. The expression is as follows: ;

[0091] in, Indicates the first The maximum instantaneous value of the short-circuit current at each short-circuit point. Indicates the number of the short circuit point. Indicates the time tuning level. The phase angle represents the current waveform. Indicates the reference phase in a three-phase system. Indicates lag 120° phase Indicates lag 120° phase Indicates the length of the integration window. This indicates the sensitivity coefficient of the protection device. Represents a complex current phasor. This indicates the corrected phase angle. Represents the decay time constant. Indicates a specific slip ratio The square of the equivalent impedance Indicates slip ratio. Indicates the first The square of the equivalent reactance at each short-circuit point Represents the directional coefficient ( ∈[0.7,1.3]), Indicates the sensitivity coefficient ( ∈[1.0,2.0]). This represents the historical time variable in the integration operation.

[0092] Specifically, the execution process of the overcurrent protection directional criterion first requires extracting the three-phase current waveform data at the end of the line within a preset time window. The preset time window is a time range (e.g., 80ms) pre-set based on the operating characteristics of the protection device. Its function is to limit the sampling interval for short-circuit current analysis and ensure the capture of transient characteristics at the initial stage of a fault. The three-phase current waveform data consists of real-time current signals (e.g., discrete waveform sequences with a sampling rate of 4kHz) of phases A, B, and C collected at the measurement points at the end of the line. These real-time current signals constitute the raw input for calculating the instantaneous value of the maximum short-circuit current.

[0093] Further, in the calculation process, the three-phase current waveform data participates in the operation through the following steps: first, the reference phase current waveform is integrated by sliding window, and the integration window length matches the preset time window (for example, 10 power frequency periods are taken); At the same time, the current waveform component lagging 120° is extracted, and the complex current phasor is combined for phasor synthesis. The directional coefficient and the sensitivity coefficient correct the phase angle together, wherein the directional coefficient reflects the fault direction characteristic (for example, 1.2 for forward fault and 0.8 for reverse fault), and the sensitivity coefficient adjusts the protection action threshold (for example, 0.95-1.05). The slip rate and the equivalent reactance square term are used to compensate the system dynamic impedance change, and the damping ratio correction coefficient is used to suppress the high-frequency oscillation component. Finally, the maximum short-circuit current instantaneous value at the first

[0094] Based on the maximum short-circuit current instantaneous value, the low-voltage side fault to high-voltage side current dynamic mapping model of fault type is established through the transformer winding ratio, short-circuit impedance parameters and network topology structure, and the electromagnetic transient simulation is used to generate fault current data.

[0095] Specifically, the low-voltage side maximum short-circuit current instantaneous value is converted to the high-voltage side reference value by using the transformer winding ratio (for example, 110kV / 10kV=11), and then the high-voltage side equivalent fault current amplitude is analyzed in combination with the short-circuit impedance parameters (for example, transformer short-circuit impedance percentage 6%); The network topology structure provides the fault propagation path (for example, the electrical distance from the fault point to the main transformer), and the node impedance matrix is used to correct the short-circuit current distribution, and finally the dynamic mapping relationship reflecting the current response of the low-voltage side different types of faults (for example, three-phase short-circuit, single-phase grounding) at the high-voltage side is formed. The mapping relationship expresses the amplitude and phase characteristics of each node current in the form of transfer function matrix.

[0096] Further, when the electromagnetic transient simulation is used to generate fault current data, the simulation initial conditions (for example, fault starting angle 0°) are set based on the dynamic mapping model, and a detailed electromagnetic transient model including transformer winding ratio, short-circuit impedance parameters and network topology structure is built in PSCAD / EMTP and the like. During the simulation process, the low-voltage side fault waveform (for example, A-phase grounding current with amplitude of 10kA) is injected, and through electromagnetic transient process simulation, the time-domain fault current data of each node at the high-voltage side (for example, decaying DC component superimposed on power frequency AC component) is output. The data sampling interval is synchronized with the maximum short-circuit current instantaneous value calculation window, and is used to verify the accuracy of the dynamic mapping model.

[0097] Based on the fault current data, the differential integral algorithm is used to filter out the excitation surge second harmonic and high-frequency interference generated by transformer no-load closing in real time, and the reliable coefficient is used to avoid the maximum phase short-circuit current calculation overcurrent I segment action value at the end of the line, and the expression is: ​ ;

[0098] wherein, represents the overcurrent I segment action value, represents the reliability coefficient in the relay protection setting calculation, represents the differential current instantaneous value within the integral window length , represents the harmonic attenuation coefficient, represents the harmonic component amplitude times, represents the fundamental current effective value, represents the harmonic component amplitude.

[0099] Specifically, when filtering the excitation inrush current interference based on the fault current data, the differential integral algorithm performs sliding window processing on the sampling sequence (for example, a sampling rate of 4 kHz), and the window length matches the power frequency period (for example, 20 ms); the differential integral algorithm extracts the fundamental current effective value and the amplitude of each harmonic component (for example, the second harmonic accounts for 15%), suppresses the second and above harmonic components according to the exponential law through the harmonic attenuation coefficient, and retains the fundamental component; the high-frequency interference is directly eliminated by the differential operator, and the differential current instantaneous value reflects the pure fault component, ensuring that the output waveform only retains the effective fault characteristics.

[0100] Further, the reliability coefficient is a safety margin parameter in the relay protection setting calculation, which is set according to the DL / T 584 standard (for example, in the range of 1.2~1.5), and functions to cover the uncertainty factors such as mutual inductor error and calculation deviation; the expression of the overcurrent I segment action value multiplies the reliability coefficient and the filtered differential current instantaneous value, ensuring that the action value is always higher than the maximum phase short-circuit current at the end of the line (for example, the calculation value of 3kA corresponds to the action value of 3.6kA), avoiding misoperation while ensuring rapidity; the harmonic times and the harmonic attenuation coefficient jointly constrain the harmonic influence domain, so that the setting value calculation only responds to the power frequency fault component.

[0101] The two-phase metallic short-circuit current at the end of the protected line under the minimum operating mode is obtained, and the overcurrent II segment action value meeting the sensitivity coefficient threshold is calculated by reverse deduction, and the expression is: ;

[0102] wherein, represents the overcurrent II segment action value, represents the minimum two-phase short-circuit current at the end of the line, represents the impedance fluctuation correction factor, represents the sensitivity coefficient ( ∈[1.0,2.0]), represents the load fluctuation correction factor.

[0103] ​Specifically, the two-phase metallic short-circuit current of the protected line end under the minimum operating mode is obtained, and the minimum operating mode refers to the operating state in which the power output of the power grid is minimum and the equivalent impedance is maximum (for example, only a single main transformer operates, and the distributed power supply exits), at which time the short-circuit current level is lowest; the network topology parameters (for example, line impedance 0.15 Ω / km) and the equivalent impedance of the power supply (for example, main transformer impedance 10%) are input through a short-circuit current calculation program, the two-phase non-grounded short-circuit condition (for example, BC phase short-circuit) is solved by using the symmetrical component method, and the short-circuit current effective value (for example, 1.2 kA) of the line end is output, which is taken as the reference data for the setting of the overcurrent II section.

[0104] Further, when the overcurrent II section action value is inversely deduced, the sensitivity coefficient threshold is set as a fixed value (for example, 1.3-1.5) according to the DL / T 584 standard, which functions to ensure that the protection can still reliably act under the minimum short-circuit current; the minimum two-phase short-circuit current of the line end is divided by the sensitivity coefficient, and then multiplied by an impedance fluctuation correction factor (for example, 1.1) to compensate for the line parameter deviation, and a load fluctuation correction factor (for example, 0.9) is superimposed to suppress the influence of the load current, and finally the overcurrent II section action value (for example, 1.2 kA / 1.3×1.1×0.9=0.92 kA) is obtained; the overcurrent II section action value needs to be checked whether it is lower than the rated current of the protected line to avoid overlapping with the load current.

[0105] The steady-state current under the maximum load condition of the adjacent line is synchronously monitored, and the transient current increment generated by the motor self-starting is superimposed to generate the composite load current.

[0106] Further, when the steady-state current under the maximum load condition of the adjacent line is synchronously monitored, the SCADA or PMU device is used to collect the three-phase current effective value (for example, 500 A) of the line head at a fixed sampling interval (for example, 1 second), and the current maximum value (for example, 800 A) during the period of continuous peak load (for example, summer afternoon) is recorded, and the steady-state current data reflects the continuous ampacity of the line under the normal operating limit state. The steady-state current monitoring needs to be compared with the load prediction curve to ensure that the steady-state current data is taken from the actual maximum load working condition (for example, load rate 95%).

[0107] Further, when the transient current increment generated by the motor self-starting is superimposed, the transient current increment refers to the impact current (for example, 4-6 times the steady-state current) generated by the motor group at the voltage recovery moment (for example, within 0.2 seconds), and the characteristic waveform (for example, decay period component) of the motor starting is captured through the fault recording device; the peak value (for example, 3200 A) of the transient current increment is attenuated according to the time constant (for example, 0.5 seconds) and is algebraically superimposed with the steady-state current to generate the composite load current containing the transient component. The role of the transient current increment is to simulate the most severe load impact condition and verify the reliability of the protection setting value in the transient process.

[0108] The overcurrent III segment action value is calculated according to the overcurrent II segment action value as a reference and combined with the composite load current according to the time-current differential principle to meet the selectivity requirement of the adjacent protection segment, and the expression is as follows: ;

[0109] Among them, represents the overcurrent III segment action value, represents a time-current coupling factor, represents a time attenuation coefficient, represents an action time differential between adjacent protection segments, represents a load fluctuation suppression factor, represents a real-time load peak current, represents a historical average load current.

[0110] Specifically, when the overcurrent III segment action value is calculated according to the overcurrent II segment action value as a reference, the selectivity requirement of the adjacent protection segment refers to ensuring that the protection of the nearest fault point is preferentially acted under the fault condition (for example, the first-level switch is tripped in 0 seconds), the upper-level protection is acted in a ladder time delay manner (for example, the secondary switch is delayed for 0.3 seconds), and the overstep tripping is avoided; the overcurrent II segment action value is multiplied by the time-current coupling factor (for example, 1.2) to reflect the current-time inverse time limit characteristic, the time attenuation coefficient (for example, 0.8) is superimposed to compensate for the inherent delay of the protection device, and the load fluctuation suppression factor (for example, 0.9) is multiplied to suppress the influence of the transient component in the composite load current; the ratio (for example, 1.5 times) of the real-time load peak current to the historical average load current is used to dynamically adjust the action threshold, to ensure that the overcurrent III segment action value (for example, 1.1 times the overcurrent II segment value) can reliably act under the fault and reliably not misact under the maximum composite load current (for example, 1.8 times the rated current), and finally realize the time-current double cooperation with the adjacent protection segment.

[0111] In the embodiment, the determination of the zero sequence protection setting value of the small resistance grounding network and the small grounding network according to the overcurrent segment action value and the distribution network topology parameter in the step S3 comprises the following steps.

[0112] The distribution network grounding mode is determined to be the small resistance grounding network and the small grounding network according to the overcurrent segment action value and the distribution network topology parameter.

[0113] Specifically, first, the zero sequence current and voltage data in the calculation result are analyzed and calculated, combined with the line impedance and transformer parameters in the distribution network topology parameter. By evaluating the performance characteristics of the zero sequence current under different grounding modes, the specific conditions of the small resistance grounding network and the small grounding network are distinguished. For example, in the small resistance grounding network, the zero sequence current is usually large because the grounding resistance is small, allowing a larger fault current to pass through; while in the small grounding network, the zero sequence current is relatively small because the grounding resistance is large, limiting the flow of fault current.

[0114] Specifically, by comparing the calculated zero sequence current with the preset threshold value, if the zero sequence current exceeds a certain specific value, it is determined as a small resistance grounded network; otherwise, if the zero sequence current is lower than the value, it is determined as a small grounded network. The preset threshold value is set based on the standard operating procedures and equipment parameters of the distribution network, and its role is to distinguish different grounding modes to ensure that the protection device can accurately respond. In addition, historical operation data and equipment parameters of the distribution network can also be combined to further confirm the grounding mode. For example, the nameplate parameters of some equipment explicitly mark the grounding resistance value, which can be directly used to assist in judgment.

[0115] If it is a small resistance grounded network, configure the zero sequence I segment trip setting and the zero sequence II segment signal setting, and if it is a small grounded network, configure the zero sequence I segment trip setting in descending order of branch line level.

[0116] Specifically, for a small resistance grounded network, since a larger fault current is allowed to pass through, a higher zero sequence I segment trip setting needs to be set to ensure that the fault circuit can be quickly cut off when a high resistance grounded fault occurs, and appropriate zero sequence II segment signal settings are configured for monitoring lower level fault conditions. Conversely, if it is a small grounded network, the zero sequence I segment trip setting is configured in descending order of branch line level. In this case, considering that the grounding resistance is large, the flow of fault current is limited, so the zero sequence I segment trip setting is gradually reduced along the branch line level to ensure that the protection devices at each level can accurately respond to fault currents of different levels. For example, in one example, a higher zero sequence I segment trip setting can be set on the main line, and the branch line is sequentially decreased to adapt to the fault current characteristics at different positions. Ultimately, through this targeted configuration method, the protection devices of the distribution network under different grounding modes can effectively identify and respond to various types of grounding faults, improving the overall protection performance and reliability.

[0117] The action timing of the trip and signal settings is verified by the preset rule base and automated logic, the directionality coefficient and sensitivity coefficient are dynamically adjusted, and a standardized setting configuration file is generated and issued to each node protection device.

[0118] Specifically, first, the tripping and signal setting values of each protection device are verified one by one by using the standard action time sequence table in the preset rule base. The preset rule base is set according to the standard operating procedures and historical operation data of the power industry, and contains the standard action time sequence requirements of various protection devices under different operating conditions. Specifically, the calculated zero sequence I section tripping setting value and zero sequence II section signal setting value are input into the preset rule base, and whether the setting value meets the expected action time sequence requirement is checked through automation logic. The automation logic refers to automatically executing a series of logical judgments and verification processes by using a programmed algorithm to ensure that the action time sequence of each protection device meets the standard in the preset rule base. In this process, the directional coefficient and the sensitivity coefficient are dynamically adjusted. The directional coefficient is set according to the fault direction discrimination requirement (for example, 1.2 for a forward fault and 0.8 for a reverse fault), which is used to enhance the directional selectivity of the protection; the sensitivity coefficient is set according to the minimum action current multiple (for example, 1.5 times) in the DL / T 584 standard, which is used to ensure that the protection can be reliably started under the minimum short-circuit condition. It ensures that protection devices at different levels can respond to fault currents at the correct time point, avoiding misoperation or refusal to operate. For example, in some cases, it may be necessary to increase the differential coefficient to prolong the action delay of the next level protection device, thereby ensuring selectivity.

[0119] Further, after the verification process is completed, a standardized configuration file containing the setting values of all protection devices is generated according to the finally determined directional coefficient and sensitivity coefficient. The standardized configuration file lists in detail the specific tripping and signal setting values of each node protection device, and is classified and arranged according to the node number, ensuring that each protection device can receive setting values matching its location and function. Subsequently, the standardized setting value configuration file is transmitted to each node protection device through the communication network, realizing remote updating and configuration.

[0120] In the embodiment, the step S4 of setting the differential delay parameters of the primary and secondary switches based on the zero sequence protection setting value, activating the short-time loss-of-voltage blocking tripping function, and constructing a digital twin model for zero sequence protection setting value checking includes:

[0121] Based on the zero sequence protection setting value and the maximum short-circuit current at the end of the line, the zero sequence protection setting value of the primary and secondary switches is determined, and the primary switch delay and secondary switch delay are set to form a differential delay control logic.

[0122] The zero sequence protection setting value includes a zero sequence I section tripping setting value and a zero sequence II section signal setting value.

[0123] Specifically, first, the obtained zero sequence protection setting value is analyzed, and the specific value of the maximum short-circuit current at the end of the line is combined. For the primary switch, since it directly faces the main line, a higher zero sequence protection setting value is required to cope with larger fault currents; for the secondary switch, according to the actual load condition of the branch line and the maximum short-circuit current that may be encountered, a relatively lower zero sequence protection setting value is set. Specifically, by comparing the relationship between the zero sequence protection setting value and the maximum short-circuit current at the end of the line, it is ensured that each level of switch can accurately respond when a fault occurs, and the occurrence of misoperation or refusal to operate is avoided. For example, in some cases, the zero sequence protection setting value of the primary switch can be set to 1.5 times that of the secondary switch to adapt to different current levels.

[0124] Further, the primary switch delay and the secondary switch delay are set, and a differentiated delay control logic is formed, which is performed after the zero sequence protection setting value of each level of switch is determined. In order to ensure selectivity and rapidity, the primary switch is usually set to a shorter delay so as to act quickly when a fault is detected and cut off the fault current; and the secondary switch is set to a relatively longer delay according to the position and functional requirements to prevent unnecessary tripping operations. The specific method is to set appropriate delay parameters by analyzing the time difference requirements between each level of switch. For example, the primary switch delay can be set to 0.2 seconds, and the secondary switch delay can be set to 0.4 seconds, thereby forming a differentiated delay control logic.

[0125] Based on the differentiated delay control logic, the short-time loss-of-voltage blocking function is activated, and the digital twin model of the distribution network is constructed synchronously to simulate the high-resistance ground fault scenario to check the zero sequence protection setting value.

[0126] Based on the dynamic topology matrix, the topology parameters and transformer parameters of the distribution network are integrated, and the electromagnetic transient simulation technology is used to simulate various fault conditions, and the digital twin model of the distribution network is constructed by comparing the simulation results with the measured data.

[0127] Specifically, when the short-time loss-of-voltage blocking function is activated based on the differentiated delay control logic, first, the primary switch instantaneous trip (delay 0 seconds) and the secondary switch step delay (for example, 0.3 seconds) are set according to the zero sequence protection setting value, when the voltage drop duration exceeds the blocking threshold (for example, 100 ms) and the current does not reach the fault setting value, the blocking element outputs a blocking signal to inhibit protection misoperation; the blocking sensitivity is dynamically adjusted by the directionality coefficient (for example, 1.2) and the sensitivity coefficient (for example, 1.5) to ensure that the blocking is triggered only in the real loss-of-voltage condition. The short-time loss-of-voltage blocking function refers to a protection control strategy that blocks protection misoperation through delay logic and dynamic coefficient when the distribution network detects a short-term voltage drop (such as within 100 ms) but does not reach the fault current threshold, and only allows tripping in the actual fault.

[0128] Further, when constructing the digital twin model of the power distribution network and checking the setting value, the switch device measurement data (such as circuit breaker position) and non-switch device current spectrum characteristics (such as transformer harmonic content) are synchronously collected, a dynamic topology matrix is generated through a topology graph traversal method, the transformer winding ratio (for example, 110kV / 10kV) and the power distribution network topology parameters are imported based on the matrix, a high resistance ground fault waveform (for example, transition resistance 500Ω) is injected in an electromagnetic transient simulation platform, the transient current data (for example, zero sequence current amplitude 15A) of each node is output, the simulation results are compared with the measured wave recording, and the overcurrent II section action value (for example, adjusted from 1.2kA to 1.05kA) is corrected to meet the high resistance fault detection requirement.

[0129] The checked zero sequence protection setting value associated with the device ID generates a hierarchical configuration instruction, switches the zero sequence protection setting value online, and generates a standardized configuration file containing the overcurrent I to III section action values, the zero sequence I section tripping setting value, and the zero sequence II section signal setting value.

[0130] Specifically, according to the device ID and the position in the network of each protection device, the checked zero sequence protection setting value and the overcurrent protection action value are matched with the corresponding device, and specific hierarchical configuration instructions are generated for each device, ensuring that each instruction accurately corresponds to a specific protection device. For example, for the first-level switch located on the main line, the hierarchical configuration instruction will contain a higher overcurrent I section action value and a shorter action delay; while for the secondary switch, a lower action value and a longer action delay are set according to the actual needs of the branch line. Each instruction is then transmitted to each node protection device through the communication network, realizing online switching of the protection setting value and quickly updating the protection parameters of each device.

[0131] Further, based on the final determined setting value data of each level of protection device, a detailed standardized configuration file is prepared after the matching process is completed. The standardized configuration file lists the specific parameters of each protection device in detail according to the device ID and hierarchical structure, such as overcurrent I section action value, overcurrent II section action value, overcurrent III section action value, zero sequence I section tripping setting value, and zero sequence II section signal setting value. For example, for a specific device, the standardized configuration file will explicitly record that the overcurrent I section action value is 10A, the overcurrent II section action value is 8A, the overcurrent III section action value is 6A, the zero sequence I section tripping setting value is 2A, and the zero sequence II section signal setting value is 1.5A. Through the standardized configuration file, not only can the setting value of all protection devices be ensured to be accurate and correct, but also the subsequent maintenance and management can be facilitated.

[0132] In the embodiment, the step S5 of issuing the checked zero sequence protection setting value to the protection device to execute overcurrent protection, zero sequence protection, and automatic switch coordinated action includes:

[0133] Based on the standardized configuration file, the directional criterion for triggering the primary switch is initialized after being transmitted to the primary and secondary switch protection devices through the distributed communication network, parsed and input into the zero sequence protection setting storage area.

[0134] Specifically, the directional criterion parameters generated based on the standardized configuration file are transmitted to the primary and secondary switch protection devices through the distributed communication network. The standardized configuration file extracts the zero sequence protection settings after being parsed in the protection device and writes them into the zero sequence protection setting storage area. After the zero sequence protection setting storage area is initialized, the directional criterion calculation function of the primary switch protection device is activated. The directional criterion calculation function evaluates the primary switch triggering condition in real time according to the parameters in the zero sequence protection setting storage area. When a fault current that meets the preset directional characteristics in the zero sequence protection setting storage area is detected, the directional criterion calculation function outputs an action signal to the primary switch tripping circuit and simultaneously sends a blocking signal to the secondary switch protection device through the distributed communication network to coordinate the delay action.

[0135] After initialization, the primary switch performs overcurrent protection and zero sequence amplitude-phase fusion criterion based on real-time current signal acquisition from the dynamic topology matrix. The secondary switch performs coordinated opening and closing actions according to differentiated delay and short-time voltage loss blocking conditions.

[0136] Specifically, when the current of a certain phase exceeds the preset overcurrent I segment action value, the primary switch will respond quickly according to the overcurrent protection logic. The preset overcurrent I segment action value is preset based on the maximum load current of the distribution network, the differential between adjacent protection segments, and the protection sensitivity requirements, ensuring that the fault circuit can be quickly and accurately disconnected when a short-circuit fault occurs. At the same time, by analyzing the amplitude and phase of the zero sequence current and combining the zero sequence amplitude-phase fusion criterion, it is ensured that the zero sequence protection action can also be triggered in time when a ground fault occurs. For example, when the zero sequence current amplitude significantly increases and the phase meets certain conditions, the zero sequence protection action is triggered, thereby achieving comprehensive coverage of complex fault types. The dual protection mechanism not only covers phase-to-phase short-circuit faults but also effectively deals with ground faults, enabling the primary switch to have efficient action performance under different types of fault conditions.

[0137] Further, according to the differential delay and short-time loss-of-voltage blocking condition cooperative on-off action, after receiving the fault information transmitted by the backbone line or the superior device, the operation is performed according to the pre-set differential delay parameter and the short-time loss-of-voltage blocking condition. The pre-set differential delay parameter is pre-set according to the topological structure of the power distribution network, the distance between the switches at each level, and the protection sensitivity requirement, which ensures the time coordination between the switches at each level and avoids the expansion of the power cut range caused by the simultaneous tripping of multiple switches. For example, the delay of the secondary switch may be 0.2 seconds longer than that of the primary switch, so that the primary switch can handle the fault first. The short-time loss-of-voltage blocking condition is pre-set based on the experience data of the power grid operation and the characteristics of the equipment, which is used to prevent misoperation caused by transient voltage drop. When a short-term voltage drop is detected but does not reach the fault threshold, the secondary switch will remain in the blocking state and will not perform unnecessary tripping operation.

[0138] The protection execution results of the primary switch and the secondary switch are fed back to the digital twin model in real time to generate dynamic correction instructions and update the zero sequence protection setting value storage area of the protection device.

[0139] Specifically, the protection execution results of the primary switch and the secondary switch are fed back to the digital twin model in real time. First, after the protection device performs the protection action, the specific execution results (such as tripping, alarm, etc.) are sent to the digital twin model through the communication network. This ensures that the digital twin model can obtain the latest protection operation data for further analysis and optimization. Based on the feedback data, the digital twin model can generate dynamic correction instructions. The dynamic correction instructions are derived according to the actual operation and optimization target, aiming to adjust the working parameters of the protection device to better adapt to the current power grid state. For example, in the case of detecting frequent transient voltage drop in a certain area but not reaching the fault threshold, the digital twin model may generate new delay settings or loss-of-voltage blocking conditions. Subsequently, the generated dynamic correction instructions are transmitted back to the corresponding protection device, and the related parameters in the zero sequence protection setting value storage area are updated.

[0140] Embodiment 3, the above is a schematic scheme of the power distribution network setting value setting and checking method of the embodiment. It should be noted that the technical scheme of the power distribution network setting value setting and checking system belongs to the same concept as the technical scheme of the power distribution network setting value setting and checking method described above. The technical scheme of the power distribution network setting value setting and checking system in this embodiment is not described in detail. The details can be referred to the description of the technical scheme of the power distribution network setting value setting and checking method described above.

[0141] The embodiment also provides a power distribution network setting value setting and checking system, which comprises:

[0142] A topological signal processing and criterion generation module is configured to collect real-time topological state signals of the power distribution network, generate a dynamic topological matrix through state merging, and generate overcurrent protection directionality criteria according to the dynamic topological matrix.

[0143] An overcurrent action value calculation module is configured to calculate overcurrent segment action values based on the overcurrent protection directionality criteria.

[0144] A zero sequence protection setting value determination module is configured to determine zero sequence protection setting values for small-resistance grounded networks and small-grounded networks according to the overcurrent segment action values and in combination with topological parameters of the power distribution network.

[0145] A setting value checking and parameter setting module is configured to set differential time delay parameters of primary and secondary switches based on the zero sequence protection setting values, activate a short-time loss-of-voltage blocking tripping function, and construct a digital twin model to check the zero sequence protection setting values.

[0146] A setting value issuing and cooperative action execution module is configured to issue the zero sequence protection setting values that pass the checking to the protection device and execute overcurrent protection, zero sequence protection, and automatic switch cooperative action.

[0147] The embodiment also provides an electronic device suitable for the power distribution network setting value setting and checking method, which comprises:

[0148] A memory and a processor, the memory is configured to store computer executable instructions, and the processor is configured to execute the computer executable instructions to implement the power distribution network setting value setting and checking method proposed in the above embodiment.

[0149] The embodiment also provides a storage medium having a computer program stored thereon, the program being executed by a processor to implement the power distribution network setting value setting and checking method proposed in the above embodiment.

[0150] The storage medium proposed in the embodiment and the power distribution network setting value setting and checking method proposed in the above embodiment belong to the same inventive concept, and the technical details not described in detail in the embodiment can be referred to the above embodiment, and the embodiment has the same beneficial effects as the above embodiment.

[0151] Embodiment 4, referring to Table 1, provides a power distribution network setting value setting and checking method as an embodiment of the application, and scientific demonstration is performed through simulation experiments to verify the beneficial effects of the application.

[0152] The embodiment selects a 10kV distribution network of a coastal industrial park as a test object. The region contains a distributed photovoltaic power station (penetration rate 35%), a multi-linkage switch segmented operation architecture, and seasonal load fluctuations (load rate 45%-98%). The test equipment includes an RTDS real-time simulation system (configured with an IEEE 33-node model), a SEL-487E protection device, a fault recorder (accuracy 0.5ms), and a setting software V4.0. The simulation reference parameters are as follows: short-circuit current reference value 6.3kA, line impedance calculated based on the measured 240mm2 copper core cable, and load density set at 2.8MW / km2 in summer peak.

[0153] Five typical operation scenarios are constructed: ① normal loop network operation (linkage switch closed); ② distributed energy island operation (photovoltaic output ratio 40%); ③ load mutation condition (load surge 50% in 0.5 seconds); ④ network topology after fault reconstruction (N-1 operation); and ⑤ N-2 extreme operation mode. The traditional method uses the IEC 60255-151 standard time limit cooperation, while the present application is based on a dynamic impedance trajectory prediction algorithm combined with a real-time topology identification module for parameter self-correction. The experimental comparison indicators include action time, misoperation times, and setting adaptation rate.

[0154] Specifically as shown in Table 1: Table 1 Comparison of experimental data of distribution network protection setting scheme under different operation scenarios

[0155] Through analysis of the experimental data, it can be seen that the optimized distribution network protection setting method has significantly improved in various performance indicators. The present application realizes faster action speed, higher reliability, and better adaptability through dynamic impedance trajectory prediction and real-time topology identification technology. For example, in the distributed energy island scenario, the action time is shortened from 118.5ms to 71.4ms (reduction of 39.8%), the misoperation times are reduced from 3 to 0, and the setting adaptation rate is increased to 98.2%; in the fault reconstruction scenario, the action time is optimized from 132.7ms to 76.5ms (improvement of 42.4%), the setting adaptation rate reaches 99.1%, fully demonstrating the technical advantages and innovation of the present application.

[0156] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and not to limit it. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the present application, which should be covered in the scope of the claims of the present application.

Claims

1. A method for setting and checking the setting of a network, characterized in that The method comprises the following steps: Collecting real-time topology state signals of the power distribution network, generating a dynamic topology matrix through state merging, and generating overcurrent protection directionality criteria according to the dynamic topology matrix; Based on the overcurrent protection directionality criteria, calculating the action value of each overcurrent section; According to the action value of each overcurrent section, combined with the topology parameters of the power distribution network, the zero sequence protection setting value of the small resistance grounding network and the small grounding network is determined; Based on the zero sequence protection setting value, the differential time parameters of the primary and secondary switches are set, the short-time loss-of-voltage locking opening function is activated, and a digital twin model is constructed for zero sequence protection setting value checking; The zero sequence protection setting value that passes the checking is sent to the protection device to execute overcurrent protection, zero sequence protection and automatic switch coordinated action.

2. The setting and checking method of a network setting value according to claim 1, characterized in that, The method comprises the following steps: Collecting real-time topology state signals of the power distribution network, performing signal analysis and format conversion on the real-time topology state signals of the power distribution network, and generating original topology data stream; Based on the original topology data stream, the state sequence of the switch device signal is merged according to the switch device signal and the state change frequency of the non-switch device, and the redundant data is removed; the merged switch state is mapped to the edge attribute of the static topology graph through the topology graph traversal method, and the dynamic topology matrix is generated combined with the current frequency spectrum characteristics of the non-switch device; Based on the dynamic topology matrix, the forward short-circuit current threshold of the topology group equivalent circuit is calculated, and by comparing the current phase difference and amplitude change at different times, the change trend of the current characteristics when the fault occurs is identified, and the overcurrent protection directionality criteria is dynamically adjusted and generated based on the change trend.

3. The setting and checking method of a setting value of a distribution network according to claim 2, characterized in that, The method comprises the following steps: Based on the overcurrent protection directionality criteria, the three-phase current waveform data of the line end in the preset time window is extracted, and the maximum short-circuit current instantaneous value is calculated; Based on the maximum short-circuit current instantaneous value, a low-voltage side fault to high-voltage side current dynamic mapping model of fault type is established through the transformer winding ratio, short-circuit impedance parameters and network topology structure; Based on the dynamic mapping model, the simulation initial conditions are set, a detailed model including the transformer winding ratio, short-circuit impedance parameters and network topology structure is built in the electromagnetic transient simulation platform, the low-voltage side fault waveform is injected for electromagnetic transient process simulation, and the high-voltage side node time-domain fault current data is output, and the data sampling interval is synchronized with the maximum short-circuit current instantaneous value calculation window; Based on the fault current data, the excitation inrush current second harmonic and high-frequency interference generated by transformer no-load closing are filtered in real time.

4. The setting and checking method of a setting value of a distribution network according to claim 3, wherein, The method comprises the following steps: The overcurrent I section action value is calculated by avoiding the line end maximum phase short-circuit current through the reliability coefficient; The two-phase metallic short-circuit current of the protected line end under the minimum operating mode is obtained, and the overcurrent II section action value meeting the sensitivity coefficient threshold is calculated by reverse deduction; The steady-state current under the maximum load condition of the adjacent line is monitored synchronously, and the transient current increment generated by the motor self-starting is superimposed to generate a composite load current; The overcurrent III segment action value meeting the selectivity requirement of adjacent protection segments is calculated according to the time-current differential principle, taking the overcurrent II segment action value as a reference and combining with the composite load current.

5. The setting and checking method of a setting value of a distribution network according to claim 4, wherein, The determination of the zero sequence protection setting value of the small resistance grounded network and the small grounded network according to the action value of each overcurrent segment and the distribution network topology parameters comprises: According to the action value of each overcurrent segment and the distribution network topology parameters, the zero sequence current and voltage data in the analysis calculation result are analyzed and calculated, and the performance characteristics of the zero sequence current under different grounding modes are evaluated in combination with the line impedance and transformer parameters in the distribution network topology parameters; the small resistance grounded network and the small grounded network are distinguished by comparing the calculated zero sequence current with the preset threshold value; if the zero sequence current exceeds a specific value, the small resistance grounded network is determined; if the zero sequence current is lower than the specific value, the small grounded network is determined; If the small resistance grounded network is determined, the zero sequence I segment trip setting value and the zero sequence II segment signal setting value are configured; If the small grounded network is determined, the zero sequence I segment trip setting value is configured in a branch line level decreasing manner; The trip and signal setting values of each protection device are verified by using the standard action time sequence table in the preset rule library through automation logic, and whether the expected action time sequence requirement is met is checked; After the verification is completed, the standardized configuration file containing all protection device setting values is generated according to the finally determined directionality coefficient and sensitivity coefficient, and the standardized setting value configuration file is transmitted to each node protection device through a communication network.

6. The setting and checking method of a setting value of a distribution network according to claim 5, wherein, The differential time delay parameters of the primary and secondary switches are set based on the zero sequence protection setting value, the short-time loss-of-voltage blocking tripping function is activated, and the digital twin model is constructed for zero sequence protection setting value checking, which comprises: The zero sequence protection setting values of the primary and secondary switches are determined respectively based on the zero sequence protection setting value and the maximum short-circuit current at the end of the line; The short-time loss-of-voltage blocking function is activated based on the differential time delay control logic; the distribution network topology parameters and transformer parameters are integrated based on the dynamic topology matrix, and various fault conditions are simulated by using electromagnetic transient simulation technology, and the simulation results are compared with the measured data to construct the distribution network digital twin model; The high resistance grounding fault scenario is simulated by using the constructed distribution network digital twin model, the switch device measurement data and the current frequency spectrum characteristics of non-switch devices are synchronously collected, the transient current data of each node output by simulation are compared with the measured recording wave, and the overcurrent II segment action value is corrected to meet the high resistance fault detection requirement; The checked zero sequence protection setting value is associated with the device ID to generate hierarchical configuration instructions, which are transmitted to each node protection device through a communication network to realize online switching of protection setting values; Based on the finally determined setting value data of each level of protection device, a standardized configuration file containing the overcurrent I to III segment action values, the zero sequence I segment trip setting value and the zero sequence II segment signal setting value is prepared.

7. The setting and checking method of a setting value of a distribution network according to claim 6, wherein, The zero sequence protection setting value that passes the checking is issued to the protection device to execute overcurrent protection, zero sequence protection and automatic switch cooperative action, which comprises: ​ The standardized configuration file is transmitted to the primary and secondary switch protection devices through a distributed communication network, the file is parsed in the protection device, the zero sequence protection setting value is extracted and written into the zero sequence protection setting value storage area; The directionality criterion calculation function of the primary switch protection device is activated; The primary switch collects current signals in real time based on a dynamic topology matrix, performs overcurrent protection and zero sequence amplitude-phase fusion criterion; when detecting that the current of a phase exceeds a preset overcurrent action value, it responds according to the overcurrent protection logic; the secondary switch performs opening and closing operations according to the pre-set differential delay parameters and short-time loss-of-voltage locking conditions after receiving the fault information; The protection execution results of the primary switch and the secondary switch are fed back to the digital twin model in real time through the communication network, the digital twin model generates dynamic correction instructions based on the feedback data, and transmits the dynamic correction instructions back to the corresponding protection device to update the related parameters in the zero sequence protection setting storage area.

8. A network setting value setting and checking system, which applies the method according to any one of claims 1 to 7, characterized in that, It comprises: a topology signal processing and criterion generation module for collecting real-time topology state signals of the power distribution network, generating a dynamic topology matrix through state merging, and dynamically generating overcurrent protection directionality criterion according to the topology matrix; an overcurrent action value calculation module for calculating overcurrent segment action values based on the overcurrent protection directionality criterion; a zero sequence protection setting determination module for determining the zero sequence protection settings of small-resistance grounded networks and small-grounded networks according to the overcurrent segment action values and in combination with the topology parameters of the power distribution network; a setting review and parameter setting module for setting the differential delay parameters of the primary and secondary switches based on the zero sequence protection settings, activating the short-time loss-of-voltage locking opening function, and constructing a digital twin model for zero sequence protection setting review; a setting issuing and coordinated action execution module for issuing the zero sequence protection settings that pass the review to the protection device and executing overcurrent protection, zero sequence protection and automatic switch coordinated action.

9. An electronic device, comprising: It comprises: a memory and a processor; the memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions, which realize the steps of the method of any one of claims 1 to 7 when executed by the processor.

10. A computer-readable storage medium, characterized in that, It stores computer executable instructions, which realize the steps of the method of any one of claims 1 to 7 when executed by the processor.

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