A photovoltaic substation fault tracing remote operation and maintenance method and system

Abstract

The application discloses a kind of photovoltaic substation fault tracing remote operation and maintenance method and system, belong to substation fault diagnosis technical field, including obtaining wiring information, measuring point configuration information and communication configuration information, and with electrical equipment association generation equipment data chain;Local operating data and remote operating data of the same measuring point are obtained along the equipment data chain, the difference of double-end data is calculated, and the steps of calculating electrical balance residual according to wiring information and local operating data, solve the problem that only according to single operating data or passive abnormal characteristics, it is difficult to distinguish primary equipment fault, secondary system fault and composite fault, and multiple candidate fault positions are confused and cannot be accurately positioned, realize the progressive fault tracing from passive abnormal analysis to active coding verification, can determine the final fault position and final fault category, improve the accuracy of photovoltaic substation fault positioning and fault classification.

Description

Technical Field

[0001] This invention belongs to the field of substation fault diagnosis technology, specifically relating to a remote operation and maintenance method and system for tracing faults in photovoltaic substations. Background Technology

[0002] Photovoltaic substations typically include photovoltaic inverters, box-type transformers, collector lines, busbars, main transformers, and protection, monitoring, and communication equipment. The sheer number of devices and the complex electrical and data transmission relationships make them highly susceptible to failure. During operation, factors such as equipment aging, environmental changes, measurement deviations, and communication anomalies can lead to primary equipment failures, secondary system failures, or combined failures in photovoltaic substations. Timely identification of fault locations and fault types is crucial for ensuring the safe and stable operation of photovoltaic substations.

[0003] Existing fault diagnosis in photovoltaic substations typically relies on alarm information, protection action information, or abnormal changes in operational data. Since different types of faults may exhibit similar abnormal characteristics, and the impact of faults may spread along electrical connections or data transmission links, relying solely on data from a single source or existing anomalies usually only identifies a relatively large fault area. When anomalies occur simultaneously in multiple locations, fault location confusion can easily arise, making it difficult to accurately distinguish between primary equipment faults, secondary system faults, and combined faults, resulting in insufficient accuracy in fault location and classification. Therefore, improving the accuracy of fault location and fault category determination in photovoltaic substations has become a pressing technical problem to be solved in this field. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention aims to provide a remote operation and maintenance method and system for fault tracing in photovoltaic substations. This solves the problems of difficulty in distinguishing multiple candidate fault locations and differentiating between primary equipment faults and secondary system faults relying solely on passive operational data. The specific solution is as follows:

[0005] In a first aspect, embodiments of this application provide a remote operation and maintenance method for tracing faults in photovoltaic substations, comprising the following steps:

[0006] Acquire wiring information, measurement point configuration information, and communication configuration information, and associate them with electrical equipment to generate a device data chain;

[0007] Acquire local and remote operating data of the same measuring point along the equipment data chain, calculate the difference between the two ends of the data, and calculate the electrical balance residual based on the wiring information and local operating data;

[0008] Based on the difference between the two ends of the data and the electrical balance residual, the candidate fault location and candidate fault category are determined. When the candidate fault location is unique, the candidate fault location and candidate fault category are determined as the final fault location and final fault category, respectively. When the candidate fault location is not unique, reactive power coding perturbation is applied, and the local coding response and remote coding response are obtained to determine the final fault location and final fault category.

[0009] Perform remote operations based on the final fault location and final fault category, obtain post-operation operational data, and generate fault tracing remote operation and maintenance results.

[0010] Optionally, a device data chain is generated in association with electrical equipment, including:

[0011] Determine the electrical connection relationships between the photovoltaic inverter, box-type transformer, collector lines, busbar and main transformer based on the wiring information;

[0012] Determine the correspondence between electrical equipment and measuring points based on the measuring point configuration information;

[0013] The data transmission relationship between the measuring points, protection and control devices, communication paths, and remote operation and maintenance terminals is determined based on the communication configuration information.

[0014] By associating electrical equipment, measuring points, and communication paths based on electrical connection relationships, correspondence relationships, and data transmission relationships, the equipment data chain is obtained.

[0015] Optionally, local and remote operating data for the same measurement point are acquired along the device data link, and the differences between the two sets of data are calculated, including:

[0016] Acquire local and remote operating data for the same measurement point along the equipment data link;

[0017] Data alignment is performed based on the time information of local and remote operating data.

[0018] The difference between the aligned local running data and the remote running data is calculated to obtain the difference between the two ends of the data.

[0019] Optionally, electrical balance residuals are calculated based on wiring information and local operating data, including:

[0020] The photovoltaic substation is divided into multiple electrical sections based on the wiring information;

[0021] Extract the inflow active power, outflow active power, and loss power of each electrical section from the local operation data;

[0022] Calculate the power difference between the inflow active power, the outflow active power, and the power loss;

[0023] The power difference is normalized based on the incoming active power to obtain the electrical balance residual for each electrical section.

[0024] Optionally, candidate fault locations and candidate fault categories are determined based on the differences between the two-end data and the electrical balance residuals, including:

[0025] Based on the equipment data link, determine the electrical equipment, measuring points or communication paths corresponding to the differences between each pair of data points, and determine the electrical sections corresponding to each electrical balance residual based on the wiring information;

[0026] Compare the differences between the data at each end and the changes in each electrical balance residual;

[0027] When the electrical balance residual of the target electrical section changes abnormally and the difference between the two ends of the data associated with the target electrical section does not change abnormally, the target electrical section is identified as a candidate fault location and the candidate fault category is identified as a primary equipment fault.

[0028] When the difference between the two ends of the target measurement point or the target communication path changes abnormally, and the electrical balance residual of the associated electrical section does not change abnormally, the target measurement point or the target communication path is identified as a candidate fault location, and the candidate fault category is identified as a secondary system fault.

[0029] When both the electrical balance residual of the target electrical section and the difference in the two-end data associated with the target electrical section change abnormally, the target electrical section and the measurement points or communication paths associated with the target electrical section are identified as candidate fault locations, and the candidate fault category is identified as a composite fault.

[0030] Optionally, when the candidate fault location is not unique, a reactive power coding perturbation is applied, including:

[0031] Based on the equipment data link, determine the electrical section associated with each candidate fault location, and then select candidate perturbation devices from the electrical equipment associated with the electrical section.

[0032] Based on the local operating data corresponding to the candidate perturbation devices, determine the operating status of the candidate perturbation devices, and identify the perturbation execution device from the candidate perturbation devices;

[0033] Based on the distribution relationship of each candidate fault location in the equipment data link, a reactive power coding sequence is determined to distinguish each candidate fault location;

[0034] The reactive power perturbation amplitude is determined based on the operating status of the perturbation execution device and the reactive power coding sequence;

[0035] A reactive power command is generated based on the reactive power coding sequence and the reactive power perturbation amplitude, and then sent to the perturbation execution device to apply the reactive power coding perturbation.

[0036] Optionally, the encoded local response and encoded remote response are obtained to determine the final fault location and final fault category, including:

[0037] During the application of reactive power coding perturbation, local and remote operating data are acquired along the electrical equipment, measuring points, or communication paths associated with each candidate fault location in the equipment data chain;

[0038] The changes in local and remote operating data caused by reactive power coding perturbations are extracted separately and arranged in the order of changes in reactive power coding perturbations to obtain the local coded response and the remote coded response.

[0039] The propagation of reactive coded perturbations in electrical equipment is determined based on the local coded response, and the transmission of reactive coded perturbations in the communication path is determined based on the difference between the local coded response and the remote coded response.

[0040] Based on the propagation and transmission conditions, the final fault location is determined from the candidate fault locations, and the final fault category is determined as primary equipment fault, secondary system fault, or combined fault.

[0041] Optionally, remote operations may be performed based on the final fault location and the final fault category, including:

[0042] Based on the location of the final fault in the equipment data link and the final fault category, determine the corresponding electrical equipment, measuring points, protection and control devices or communication paths;

[0043] When the final fault category is a primary equipment fault, remote operation is performed on the electrical equipment corresponding to the final fault location;

[0044] When the final fault category is a secondary system fault, remote operation is performed on the measuring point, protection and control device or communication path corresponding to the final fault location.

[0045] When the final fault category is a compound fault, remote operations are performed on the electrical equipment, measuring points, protection and control devices, or communication paths corresponding to the final fault location.

[0046] Optionally, acquire post-operation operational data and generate remote operation and maintenance results for fault tracing, including:

[0047] After the remote operation is completed, the local and remote operating data are retrieved again along the device data chain corresponding to the final fault location;

[0048] The difference between the two ends of the data after the operation is calculated based on the reacquired local operating data and remote operating data, and the electrical balance residual after the operation is calculated based on the wiring information and the reacquired local operating data.

[0049] Based on the difference in data between the two ends after the operation and the electrical balance residual after the operation, it is determined whether the fault or abnormality has been eliminated, and the remote operation verification result is obtained.

[0050] By associating the device data chain, final fault location, final fault category, remote operation, and remote operation review results, a fault tracing remote operation and maintenance result is generated.

[0051] Secondly, embodiments of this application provide a remote operation and maintenance system for tracing faults in photovoltaic substations, including:

[0052] The data link generation module is used to acquire wiring information, measurement point configuration information and communication configuration information, and associate them with electrical equipment to generate equipment data links.

[0053] The difference and residual calculation module is used to acquire local and remote operating data of the same measurement point along the equipment data chain, calculate the difference between the two ends of the data, and calculate the electrical balance residual based on the wiring information and local operating data.

[0054] The fault determination module is used to determine the candidate fault location and candidate fault category based on the difference between the two-end data and the electrical balance residual. When the candidate fault location is unique, the candidate fault location and candidate fault category are determined as the final fault location and final fault category, respectively. When the candidate fault location is not unique, reactive power coding perturbation is applied to obtain the local coding response and the remote coding response to determine the final fault location and final fault category.

[0055] The remote operation and maintenance module is used to perform remote operations based on the final fault location and final fault type, obtain the operation data after the operation, and generate remote operation and maintenance results for fault tracing.

[0056] Beneficial effects of the invention

[0057] 1. This invention combines equipment data links, dual-end data differences, and electrical balance residuals. First, it uses dual-end data differences to characterize the consistency between local and remote operating data at the same measuring point. Then, it uses electrical balance residuals to characterize the balance of active power within an electrical section. Based on this, it determines the location and category of candidate faults. When the location of a candidate fault is not unique, reactive power coding perturbation is applied. The perturbation propagation reflected by the local coding response and the perturbation transmission reflected by the remote coding response are combined to further screen the location of candidate faults. This invention solves the problem that it is difficult to distinguish between primary equipment faults, secondary system faults, and compound faults based on a single operating data or passive anomaly characteristics, and that multiple candidate fault locations are confused and cannot be accurately located. It realizes a progressive fault tracing from passive anomaly analysis to active coding verification, which can determine the final fault location and the final fault category, and improve the accuracy of fault location and fault classification in photovoltaic substations.

[0058] 2. This invention forms an equipment data chain by associating the electrical connection relationship of the photovoltaic substation, the correspondence between equipment and measuring points, and the data transmission relationship from the measuring points to the remote operation and maintenance terminal. It also performs corresponding analysis on the differences between the two ends of the data and the electrical balance residuals, which solves the problem that the electrical equipment operation data and the measurement, protection and control and communication path data are isolated from each other and difficult to cross-verify. This invention realizes the correlation analysis between electrical section anomalies and measurement or communication anomalies and the effective differentiation of candidate fault categories.

[0059] 3. This invention determines the remote operation object based on the final fault location and the final fault category, and recalculates the difference between the two ends of the data and the electrical balance residual after the remote operation is completed to determine whether the fault has been eliminated. This solves the problems of mismatch between the fault tracing results and the remote operation object and lack of verification of the operation effect, and realizes remote operation and maintenance and closed-loop verification after operation that are adapted to the fault category. Attached Figure Description

[0060] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0061] Figure 1 The overall flowchart provided for this invention;

[0062] Figure 2 This is a schematic diagram of the device data link structure provided by the present invention;

[0063] Figure 3 The flowchart for calculating the difference between two ends provided by this invention;

[0064] Figure 4 The flowchart for calculating electrical balance residuals provided by this invention;

[0065] Figure 5 The flowchart for determining candidate fault locations and categories provided by this invention;

[0066] Figure 6 The flowchart of reactive power coding perturbation control provided by the present invention;

[0067] Figure 7 The flowchart of the encoding response and final positioning provided by this invention;

[0068] Figure 8 The flowchart for remote operation and verification provided by this invention;

[0069] Figure 9 The system structure block diagram provided by the present invention. Detailed Implementation

[0070] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present application.

[0071] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components throughout, or components having the same or similar functions. The embodiments described below in conjunction with the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting the scope of protection of this application.

[0072] In a photovoltaic substation, photovoltaic inverters, box-type transformers, collector lines, busbars, and main transformers transmit electrical energy according to a primary wiring relationship. Operating data such as voltage, current, active power, and reactive power are collected by measuring devices and transmitted to remote operation and maintenance terminals via protection and control devices, switches, remote control gateways, and communication networks. Therefore, the same operating state propagates simultaneously along both the primary electrical path and the secondary communication path. Although the two types of paths differ in spatial location and information transmission method, they have a definite correlation in terms of corresponding equipment, corresponding measuring points, and corresponding time periods.

[0073] In actual operation, a primary equipment failure can cause continuous changes in the electrical quantities of adjacent measuring points. Failures in measuring devices, protection and control devices, or communication paths can also cause sudden changes, freezing, interruption, or distortion in remote operation data. If judgment is made based solely on remote alarms or data from a single measuring point, it is difficult to distinguish whether the data anomaly originates from the primary equipment or from the data acquisition and communication links. Especially when multiple related locations can explain the current anomaly, multiple candidate fault locations are easily formed, which makes remote operation and maintenance operations lack sufficient evidence.

[0074] Based on the above issues, please refer to Figure 1 This application provides a remote operation and maintenance method for tracing faults in photovoltaic substations, the method comprising:

[0075] Step 01: Obtain wiring information, measurement point configuration information, and communication configuration information, and associate them with electrical equipment to generate a device data chain;

[0076] Step 02: Obtain local and remote operating data for the same measurement point along the equipment data chain, calculate the difference between the two ends of the data, and calculate the electrical balance residual based on the wiring information and local operating data;

[0077] Step 03: Based on the difference between the two-end data and the electrical balance residual, determine the candidate fault location and candidate fault category. When the candidate fault location is unique, determine the candidate fault location and candidate fault category as the final fault location and final fault category, respectively. When the candidate fault location is not unique, apply reactive power coding perturbation, obtain the coding local response and coding remote response, and determine the final fault location and final fault category.

[0078] Step 04: Perform remote operations based on the final fault location and final fault category, obtain post-operation operation data, and generate fault tracing remote operation and maintenance results.

[0079] This application also provides a remote operation and maintenance system for tracing faults in photovoltaic substations. The system includes a data link generation module, a difference and residual calculation module, a fault determination module, and a remote operation and maintenance module. The data link generation module is used to execute step 01, the difference and residual calculation module is used to execute step 02, the fault determination module is used to execute step 03, and the remote operation and maintenance module is used to execute step 04.

[0080] Specifically, wiring information is used to represent the electrical connection relationships between photovoltaic inverters, box-type transformers, collector lines, busbars, and main transformers. Wiring information can be obtained from the primary wiring diagram of the photovoltaic substation, equipment ledger, and substation topology database. Measurement point configuration information is used to represent the correspondence between electrical equipment and measurement points for voltage, current, active power, reactive power, and switch status. Communication configuration information is used to represent the data transmission relationships between measurement points, protection and control devices, communication paths, and remote operation and maintenance terminals. Communication configuration information can be obtained from substation configuration description files, switch configuration tables, remote control point tables, and communication channel configuration tables.

[0081] Please see Figure 2 In some implementations, step 01 includes:

[0082] Step 011: Determine the electrical connection relationship between the photovoltaic inverter, box-type transformer, collector line, busbar and main transformer based on the wiring information;

[0083] Step 012: Determine the correspondence between electrical equipment and measuring points based on the measuring point configuration information;

[0084] Step 013: Determine the data transmission relationship between the measuring points, protection and control devices, communication paths, and remote operation and maintenance terminals based on the communication configuration information;

[0085] Step 014: Based on the electrical connection relationship, correspondence relationship and data transmission relationship, associate electrical equipment, measuring points and communication paths to obtain the equipment data chain.

[0086] In some implementations, the data link generation module is also used to determine the electrical connection relationship between each electrical device based on the wiring information, determine the correspondence between the electrical device and the measuring point based on the measuring point configuration information, determine the data transmission relationship between the measuring point, the protection and control device, the communication path and the remote operation and maintenance terminal based on the communication configuration information, and generate the device data link based on the aforementioned relationship.

[0087] Specifically, no. A single device data link is represented as follows:

[0088] ;

[0089] in, Indicates the first One device data link; Indicates the relationship with the first The electrical equipment corresponding to each equipment data link; This refers to a measuring device that collects operational data from the corresponding electrical equipment. This refers to a protection and control device that receives and processes measurement data. This indicates the communication path through which measurement data is transmitted from the protection and control device to the remote operation and maintenance terminal; This indicates the remote operation and maintenance terminal that receives the corresponding operational data; This represents the device data link number, which is a positive integer.

[0090] The above expression is derived from the ordered path representation in graph theory. Classical graph theory uses vertices and edges to represent objects and the connections between them. Based on this, this application writes primary electrical objects and secondary communication objects into the same ordered data chain in the order of data generation, acquisition, processing, transmission and reception, so that each piece of remote operation data can be traced back to the corresponding electrical equipment, measuring device, protection and control device and communication path.

[0091] When generating the device data chain, the unique identifier of the electrical equipment is used as the primary index, and the unique identifier of the measuring point, the unique identifier of the protection and control device, the communication port identifier, and the remote point number are sequentially associated. If multiple measuring points are set for the same electrical equipment, measuring point branches are generated separately, and the electrical equipment identifier corresponding to each branch is retained. If the same measuring point has a primary communication path and a backup communication path, the primary communication path and the backup communication path are recorded in the corresponding device data chain respectively, so as to perform communication path switching after a secondary system fault is determined. In this way, a queryable correspondence is established between the primary electrical connection relationship and the secondary communication transmission relationship through the device data chain. When abnormal operating data occurs, the corresponding electrical equipment, measuring point, protection and control device, and communication path can be determined, providing a unified data foundation for mutual verification and fault location tracing.

[0092] Please see Figure 3In some implementations, the process of calculating the difference between the two sets of data in step 02 includes:

[0093] Step 021: Acquire local and remote operating data for the same measurement point along the device data link;

[0094] Step 022: Align the data based on the time information of the local and remote running data;

[0095] Step 023: Calculate the difference between the aligned local running data and the remote running data to obtain the difference between the two ends of the data.

[0096] In some implementations, the difference and residual calculation module is also used to acquire local and remote operating data of the same measurement point along the device data link, complete data alignment based on data time information, and calculate the difference between the aligned two-end data.

[0097] Local operation data is data directly read by the protection and control device or the edge operation and maintenance terminal within the station, while remote operation data is data from the same measurement point that is transmitted through the protection and control device and communication path and then read by the remote operation and maintenance terminal. Both use the same unit of measurement. Local operation data retains the sampling time within the station, while remote operation data retains both the source time and the remote receiving time.

[0098] For the The first in the device data chain Class runtime data, local runtime data is represented as Remote operation data is represented as ; It represents the running data type number, and is used only to represent the running data type in this application.

[0099] When the sampling time of remote running data is inconsistent with the sampling time of local running data, a piecewise linear interpolation formula from mathematical numerical analysis is used to map the remote running data to the local sampling time:

[0100] ;

[0101] in, Indicates alignment to the local sampling time Remote operation data, unit and the first The units of measurement for the class's runtime data are the same; Indicates the first Each local sampling time is measured in seconds. and They respectively represent the locations The remote sampling times on both sides are in seconds; This represents the local sampling sequence number, which is a positive integer; The remote sampling sequence number is represented by a positive integer. The above formula is derived from the two-point linear interpolation formula in numerical analysis. The modification made in this application is to limit the interpolation function to a remote time series corresponding to the same device data link, the same measurement point, and the same operating data type, and to use the local sampling time as a unified comparison time base.

[0102] When the interval between adjacent remote sampling times exceeds the maximum message interval allowed by the communication system, interpolation is no longer performed, and the time period is marked as a data interruption. The maximum message interval is determined based on the transmission cycle configured for the measurement point and the number of timeouts specified in the communication protocol, and no uniform fixed value is set that is out of the communication configuration.

[0103] After completing time alignment, calculate the first... The first device data link Differences between the two ends of the class's runtime data:

[0104] ;

[0105] in, Indicates the first The first device data link Differences in data between the two ends of the class's runtime data; This represents locally running data, with units and timestamps. The units of measurement for the class's runtime data are the same; This represents the total number of sampling points involved in the calculation during the anomaly analysis period, and is a positive integer. This represents the minimum resolution of the corresponding measurement channel, with units equal to the [number]th [channel]. The units of measurement for all types of operational data are the same. The initial source of the above formula is the mathematical formula for relative error. Traditional relative error is calculated by dividing the difference between the measured value and the reference value by the reference value. This application considers that occasional noise at a single moment should not directly trigger fault judgment, and changes the single-point relative error to the ratio of the sum of absolute differences within the anomaly analysis period to the sum of absolute values ​​of local data, and introduces a factor into the denominator. This prevents the difference value from increasing unbounded when the local running data is close to zero. The minimum display resolution of the corresponding acquisition device or the minimum engineering quantity change value corresponding to the analog-to-digital conversion channel is taken from this parameter. This parameter reflects the data change that the device can actually distinguish and is not used as a manually set fault judgment threshold.

[0106] To avoid using a uniform threshold due to differences in accuracy and normal communication fluctuations at different measurement points, this implementation method establishes an adaptive difference threshold based on the differences between the two ends of the data during fault-free historical periods:

[0107] ;

[0108] ;

[0109] ;

[0110] in, This represents the median of the historical difference between the two ends of the data. Indicates the first The difference between the two ends of the data corresponding to each fault-free historical time window; This represents the total number of historical time windows, and is a positive integer. This represents the historical time window number, which is a positive integer; Median absolute deviation representing historical differences; Indicates the threshold for the difference between the two sets of data; This indicates the relative allowable error of the local acquisition channel; This represents the relative allowable error in remote data processing and quantification. The threshold formula above is derived from the median and median absolute deviation methods in robust statistics. Compared with the mean and standard deviation, the median and median absolute deviation are less likely to be inflated by a small number of historical outliers. This application further compares the upper bound of statistical fluctuation with the sum of the allowable errors of the acquisition link, taking the larger of the two values ​​to avoid judging normal differences within the accuracy range of the equipment as faults. Coefficient 3 is derived from the robust coverage requirement of the normal fluctuation range. Under an approximately symmetrical single-peak noise distribution, the three median absolute deviations can cover most normal fluctuations without masking persistent anomalies like excessively large multiples. In actual deployment, this coefficient should be verified using labeled normal operating data. If the false alarm rate of the normal validation set is higher than the allowable value within the site, the coefficient should be increased step by step. If the false alarm rate of the known fault validation set is too high, the coefficient should be decreased step by step without increasing the false alarm rate of the normal validation set. The adjustment results and verification data should be written into the parameter configuration record.

[0111] When the following formula is satisfied, it is determined that the difference between the corresponding two-end data has changed abnormally:

[0112] .

[0113] Please see Figure 4 In some implementations, the process of calculating the electrical balance residual in step 02 includes:

[0114] Step 024: Divide the photovoltaic substation into multiple electrical sections according to the wiring information;

[0115] Step 025: Extract the inflow active power, outflow active power, and loss power of each electrical section from the local operation data;

[0116] Step 026: Calculate the power difference between the inflow active power, the outflow active power, and the loss power;

[0117] Step 027: Normalize the power difference based on the incoming active power to obtain the electrical balance residual for each electrical section.

[0118] An electrical section is a power balance analysis area consisting of an electrical device or a continuous electrical connection with clearly defined entry and exit measuring points. For example, a box-type transformer and its high- and low-voltage connection can be classified as an electrical section, or the portion of a collector line between adjacent measuring points can be classified as an electrical section.

[0119] According to the law of conservation of energy, assuming no unmetered branches or equipment malfunctions, the inflow active power of an electrical section equals the sum of the outflow active power and the section's power loss. Therefore, the first... Each electrical section at the sampling time The power difference is expressed as:

[0120] ;

[0121] in, Indicates the first The power difference between electrical sections, in watts; Indicates the inflow of the first The active power of each electrical section, in watts; Indicates the outflow of the first The active power of each electrical section, in watts; Indicates the first The power loss of each electrical section, in watts; This represents the electrical section number, which is a positive integer.

[0122] When the electrical section is a three-phase collector line, the line loss power can be calculated according to Joule's law:

[0123] ;

[0124] ;

[0125] in, Indicates the first The effective value of the three-phase line current in each electrical section, in amperes; Indicates the temperature of a single-phase conductor in a circuit. The resistance is measured in ohms. Indicates the single-phase conductor of the line at the reference temperature The resistance is measured in ohms. Indicates the temperature of the conductor in the circuit, in degrees Celsius; This indicates the reference temperature corresponding to the resistance parameters, in degrees Celsius. This represents the temperature coefficient of conductor resistance, expressed in degrees Celsius. The first formula is derived from Joule's law, where the power loss of a single-phase conductor is the product of the square of the current and the resistance. This application addresses three-phase current-balanced collector circuits, summing the three-phase losses to obtain a coefficient of 3. The second formula is derived from a first-order approximation of the resistance of a metallic conductor with temperature, used to correct the reference temperature resistance in the nameplate or test report to the current temperature resistance. Both formulas output watts.

[0126] When the conductor temperature of the line cannot be obtained, the resistance value obtained from the most recent line inspection can be used, or the power loss generated by the power metering system in the same load range within the station can be used; when the electrical section includes a transformer, the transformer no-load loss and load loss can be used for calculation.

[0127] ;

[0128] in, This indicates the no-load loss of the transformer, measured in watts. This indicates the rated load loss of the transformer, in watts. The rated current of the transformer is expressed in amperes. The above formula is derived from the transformer loss model. The no-load loss remains approximately constant near the rated voltage, and the winding load loss is proportional to the square of the current. This application uses this model to estimate the section loss at the current sampling time. The no-load loss, rated load loss, and rated current used are all obtained from the transformer type test report or nameplate parameters.

[0129] Calculate the first based on the power difference within the anomaly analysis time period. Electrical balance residuals for each electrical section:

[0130] ;

[0131] in, Indicates the first Electrical balance residuals for each electrical section; Indicates the first The minimum power resolution of the power measurement point at the entrance of each electrical section, in watts; the meanings of the other parameters are the same as those defined above. The above formula is derived by introducing a relative error normalization method based on the power difference formed by energy conservation. The power difference is normalized by the incoming active power, so that the residuals of electrical sections with different capacities can be compared on the same scale. The units of the numerator and denominator are watts, and the calculation result is dimensionless.

[0132] The electrical balance residual threshold is determined based on the normal historical residual and the measurement uncertainty of the section:

[0133] ;

[0134] ;

[0135] ;

[0136] in, This represents the median of the normal historical electrical balance residuals; Indicates the first Electrical balance residuals corresponding to a normal historical time window; This represents the median absolute deviation of the historical electrical balance residuals; Indicates the electrical balance residual threshold; This represents the relative permissible error of the section obtained by combining the uncertainties of the inlet measuring point, the outlet measuring point, and the loss calculation.

[0137] When the uncertainties of the inlet measuring point, the outlet measuring point, and the loss parameter are independent of each other, the following calculations are performed based on the principle of measurement uncertainty propagation:

[0138] ;

[0139] in, This indicates the relative allowable error of the inlet power measurement point; This indicates the relative permissible error of the outlet power measurement point; This indicates the relative allowable error in loss calculation; This indicates the reference power flowing into the section, in watts. This indicates the reference power output of the section, in watts. The reference power for section loss is expressed in watts. The above formula is derived from the sum of squares of uncertainties of independent measurements; the numerator is the power uncertainty in watts, which, when divided by the inflow reference power, yields the dimensionless relative permissible error.

[0140] When the following formula is satisfied, the electrical balance residual of the corresponding electrical section is determined to have undergone an abnormal change:

[0141] ;

[0142] Thus, the difference between the two ends of the data reflects the integrity of the data transmission from the station measurement end to the remote operation and maintenance end, and the electrical balance residual reflects whether the actual transfer of electrical energy in the primary equipment conforms to the law of conservation of energy. The two results have different fault indications and can provide independent but corresponding evidence for distinguishing between primary equipment faults and secondary system faults.

[0143] Please see Figure 5 In some implementations, the process of determining the candidate fault location and candidate fault category in step 03 includes:

[0144] Step 031: Determine the electrical equipment, measuring points or communication paths corresponding to the data differences between each pair of ends based on the equipment data link, and determine the electrical sections corresponding to each electrical balance residual based on the wiring information;

[0145] Step 032: Compare the differences between each pair of data and the changes in each electrical balance residual;

[0146] Step 033: When the electrical balance residual of the target electrical section changes abnormally and the difference between the two ends of the data associated with the target electrical section does not change abnormally, the target electrical section is identified as a candidate fault location and the candidate fault category is identified as a primary equipment fault.

[0147] Step 034: When the difference between the two ends of the target measurement point or the target communication path changes abnormally, and the electrical balance residual of the associated electrical section does not change abnormally, the target measurement point or the target communication path is identified as a candidate fault location, and the candidate fault category is identified as a secondary system fault.

[0148] Step 035: When both the electrical balance residual of the target electrical section and the difference between the two ends of the data associated with the target electrical section change abnormally, the target electrical section and the measurement point or communication path associated with the target electrical section are identified as candidate fault locations, and the candidate fault category is identified as a composite fault.

[0149] In some implementations, the fault determination module is also used to map the two-end data difference and electrical balance residual to the corresponding positions in the device data link, compare the abnormal changes of the two, and determine the candidate fault location and candidate fault category accordingly.

[0150] Specifically, primary equipment failure refers to failures in photovoltaic inverters, box-type transformers, collector lines, busbars, or main transformers that affect the state of power transmission; secondary system failure refers to data acquisition, processing, or transmission failures in measuring devices, protection and control devices, or communication paths; and compound failure refers to situations where both primary equipment and secondary systems experience abnormalities within the same anomaly analysis period, or where a primary equipment abnormality causes secondary data abnormalities and existing passive evidence cannot rule out independent secondary system failures.

[0151] To enable comparison of anomalies, the degree of exceedance of the two-end difference and the degree of exceedance of the electrical residual can be calculated:

[0152] ;

[0153] ;

[0154] in, Indicates the degree to which the difference between the two sets of data exceeds the limit; This indicates the degree to which the electrical balance residual exceeds the limit; when the corresponding degree of exceeding the limit is greater than 1, it indicates that the corresponding index exceeds its abnormal threshold. The above formula is derived from the dimensionless ratio comparison method in mathematics. This application divides the current index by the index's own threshold, so that measurement points with different accuracies and electrical sections with different capacities can be sorted according to the degree of exceeding the limit.

[0155] In some implementations, if there is only one measuring point Greater than 1, the section corresponding to this measuring point and its upstream and downstream sections If all values ​​are no greater than 1, and no other measuring points on the same electrical equipment show a consistent change in direction, then the measuring point is identified as a candidate fault location. This judgment is based on the fact that a genuine change in the state of primary equipment usually affects adjacent measuring points through electrical connections. An isolated measuring point anomaly while the power in the section remains balanced is more consistent with the behavior of an abnormal measuring device or measuring point mapping.

[0156] If there is only one candidate fault location, reactive power coding perturbation is not implemented; the candidate fault location is directly determined as the final fault location, and the corresponding candidate fault category is determined as the final fault category. If two or more candidate fault locations can simultaneously explain the existing two-end data differences and electrical balance residuals, the active verification process is initiated. Active verification is not used for fault handling during short circuits, insulation breakdowns, protection activation, or protection operation. The aforementioned emergency faults are still cleared by the relay protection device according to the protection settings. The reactive power coding perturbation in this application is mainly used for intermittent anomalies, measurement anomalies, and communication anomalies where equipment maintains stable grid connection, protection does not operate, and passive data cannot uniquely determine the fault location.

[0157] Please see Figure 6 In some implementations, when the candidate fault location is not unique, a reactive power coding perturbation is applied, including:

[0158] Step 036: Determine the electrical sections associated with each candidate fault location based on the equipment data link, and filter candidate disturbance devices from the electrical equipment associated with the electrical sections;

[0159] Step 037: Determine the operating status of the candidate perturbation devices based on the local operating data corresponding to the candidate perturbation devices, and determine the perturbation execution device from the candidate perturbation devices;

[0160] Step 038: Determine the reactive power coding sequence used to distinguish each candidate fault location based on the distribution relationship of each candidate fault location in the equipment data link;

[0161] Step 039: Determine the reactive power perturbation amplitude based on the operating status of the perturbation execution device and the reactive power coding sequence;

[0162] Step 0310: Generate a reactive power command based on the reactive power coding sequence and the reactive power perturbation amplitude, and send it to the perturbation execution device to apply the reactive power coding perturbation.

[0163] Candidate disturbance devices can be photovoltaic inverters located on the same or adjacent collector branches as the candidate fault location; the disturbance execution device should be in normal grid-connected state, not in shutdown, lockout or maintenance state, the relay protection device should not be started or operated, the collector bus voltage should be within the dispatch allowable range, the inverter should have residual reactive power regulation capacity, the station-level automatic voltage control system should be allowed to perform reactive power regulation, and it should have obtained the verification permission of the dispatch or station-level control system.

[0164] If any of the aforementioned conditions are not met, active verification will not be performed, multiple candidate fault locations will be retained, and maintenance results requiring manual review will be generated. This restriction ensures that the diagnostic process conforms to the boundaries of relay protection and scheduling control, avoiding the expansion of equipment operation risks in order to obtain location evidence.

[0165] To determine the amplitude of reactive power disturbance, the reactive power change is first obtained from the most recent normal reactive power adjustment record of the disturbance actuator. and the corresponding bus voltage change Calculate the voltage response coefficient near the current operating point:

[0166] ;

[0167] in, Represents the voltage response coefficient; This indicates the change in bus voltage in the normal adjustment record, in volts. This represents the reactive power change in the normal regulation record, expressed in var. The above formula is derived from the local incremental linearization method in control theory and numerical analysis. Under small-scale reactive power regulation conditions, the bus voltage change in a power system can be approximated as the product of reactive power change and local sensitivity. This application uses the most recent normal regulation record to calculate the local sensitivity, making it correspond to the current network structure and recent operating mode.

[0168] Let the current reactive power of the perturbation actuator be... The maximum allowable reactive power output is The lower limit of the permissible reactive power output is The current bus voltage is The upper limit of bus voltage allowed by dispatch is The lower limit of the bus voltage allowed by dispatch is The allowable reactive power perturbation amplitude jointly categorized by the equipment reactive power boundary and the bus voltage boundary is:

[0169] ;

[0170] in, This represents the amplitude of reactive power perturbation, in volt-amperes (VA). This represents the safety retention factor; among the other parameters, , and The units are all 0. , and The units are all volts. This formula is derived from the relationship between the reactive power boundary of the equipment and the local voltage response. The positive perturbation cannot exceed [a certain value]. The reverse perturbation cannot exceed ,according to The forward and reverse perturbations are also limited by the upper and lower boundaries of the bus voltage. Taking the minimum value among the four terms can simultaneously satisfy the equipment capacity and bus voltage constraints. Then, multiply by the safety retention factor to absorb the sensitivity estimation error and the fluctuation of normal operating conditions during the verification period.

[0171] In one possible implementation method The value of 0.5 is not arbitrarily set based on subjective experience. Instead, half of the calculated minimum available adjustment space is used for this verification, while the other half is reserved for automatic voltage control actions, photovoltaic power output fluctuations, and local linearization errors. This ensures that even if the predicted voltage change and the actual voltage change have the same order of magnitude deviation, the operating point after perturbation will not directly cross the known boundary.

[0172] when Less than the inverter's reactive power control resolution At that time, reactive power coding perturbation is not performed; This represents the minimum reactive power change that the inverter can perform, measured in vars, and is derived from the inverter controller's technical parameters.

[0173] To distinguish multiple candidate fault locations, a reactive power coding sequence is constructed using a binary orthogonal coding method from digital communication and orthogonal signal detection. When the number of candidate fault locations is C, the coding length N is determined by the following formula:

[0174] ;

[0175] Where C represents the number of candidate fault locations, which is a positive integer; N represents the total number of coding cycles, which is a positive integer; This indicates the rounding up operation.

[0176] The encoding length is a power of least two that is not less than the number of candidate fault locations, so that the encoding matrix can form mutually orthogonal encoding rows through recursion. At the same time, it avoids using adjustment cycles that are significantly longer than the number of candidate locations, thus reducing the duration of active verification.

[0177] The encoded sequence corresponding to the m-th candidate fault location is represented as:

[0178] ;

[0179] ;

[0180] ;

[0181] in, Indicates the first The candidate fault location is at the... The coded value for each adjustment cycle; and This represents the candidate fault location number, which is a positive integer; The value represents the adjustment cycle number and is a positive integer. The first constraint ensures that the coded value only represents an increase or decrease in reactive power. The second constraint ensures that the number of forward and reverse adjustments within a complete coded cycle is the same, thus making the cumulative reactive power offset close to zero. The third constraint ensures that the codes corresponding to different candidate positions are orthogonal to each other, making it easier to distinguish different propagation responses through correlation calculations.

[0182] The perturbation actuator in the first The reactive power command received in each adjustment cycle is:

[0183] ;

[0184] in, Indicates the first The reactive power command for each adjustment cycle, in volts (var).

[0185] Within each adjustment cycle, the controller first issues a reactive power command. After the inverter's reactive power output enters the allowable stable band, it collects local and remote operating data. The allowable stable band is determined based on the inverter's reactive power control error and the accuracy of the measuring device. The sampling duration covers at least one complete uploading cycle configured for the measuring point to ensure that the remote end has time to receive the response of this cycle.

[0186] Please see Figure 7 In some implementations, acquiring encoded local responses and encoded remote responses and determining the final fault location and final fault category includes:

[0187] Step 0311: During the application of reactive power coding perturbation, acquire local operation data and remote operation data along the electrical equipment, measuring points or communication paths associated with each candidate fault location in the equipment data link;

[0188] Step 0312: Extract the data changes of local operation data and remote operation data caused by reactive power coding perturbation, and arrange them according to the change order of reactive power coding perturbation to obtain the local coded response and the remote coded response.

[0189] Step 0313: Determine the propagation of reactive coded perturbations in electrical equipment based on the local coded response, and determine the transmission of reactive coded perturbations in the communication path based on the difference between the local coded response and the remote coded response.

[0190] Step 0314: Based on the propagation and transmission conditions, determine the final fault location from the candidate fault locations, and classify the final fault as a primary equipment fault, a secondary system fault, or a combined fault.

[0191] For the The first in the device data chain Class runtime data, calculate local and remote averages during the verification period:

[0192] ;

[0193] ;

[0194] in, Indicates the first Local operating data obtained in the first adjustment cycle, unit is the same as the first adjustment cycle. The units of measurement for the class's runtime data are the same; This indicates the corresponding remote running data, with the same units; and These represent the local average and remote average during the verification period, respectively, with the same unit.

[0195] No. The device data link is for the first The local encoded response of each encoded sequence is:

[0196] ;

[0197] The remote encoding response is:

[0198] ;

[0199] in, This indicates a locally encoded response, in units of [number]. The unit of measurement for class-based runtime data is per volt; This represents the remote encoded response, with the same units. The above formula is derived from classical least squares parameter estimation and correlation detection algorithms; if the changes in the running data satisfy a local linear relationship:

[0200] ;

[0201] in, This indicates local measurement noise and non-coded operational fluctuations, with units equal to the [number]th [unit]. The units of measurement for the engineering quantities in the class of operational data are the same; the sum of the squared errors between the predicted and measured values ​​is used as the objective function:

[0202] ;

[0203] in, This represents the sum of squared errors, in units of the first square. The square of the unit of measurement for the class's running data engineering quantity.

[0204] right about By taking the derivative and setting it to zero, the aforementioned local coded response formula can be obtained; the remote coded response follows the same derivation process. The inputs to this algorithm are the reactive power coding sequence, the reactive power perturbation amplitude, and the operating data for each cycle, and the outputs are the local coded response and the remote coded response.

[0205] To determine whether the coded response exists, the upper bound of the response noise is calculated using the normal reactive power regulation records before verification; let the first normal record be... The spurious correlation response corresponding to the sub-uncoded fluctuation is Then the response determination threshold is:

[0206] ;

[0207] in, Indicates the threshold for determining the encoded response; This represents the normal record number, which is a positive integer; the meanings of the other parameters are the same as those defined above. This threshold is still derived from robust statistical methods and is set based on the maximum common spurious correlation response that may form between non-coded fluctuations and coded sequences under normal operating conditions. Only when the absolute value of the coded response exceeds this threshold is a valid response caused by reactive coded perturbations considered to have been detected.

[0208] When the absolute value of the local coded response is greater than the response judgment threshold, and the remote coded response is missing, its absolute value is not greater than the response judgment threshold, or its response direction is opposite to the local coded response, it indicates that the reactive power disturbance has been propagated to the local measuring point along the primary electrical connection, but has not been correctly received by the remote end along the secondary communication path. The final fault location is determined to be the corresponding measuring device, protection and control device, or communication path, and the final fault category is determined to be a secondary system fault.

[0209] When the absolute values ​​of both the local and remote encoded responses are greater than their respective response judgment thresholds, and their directions are consistent, it indicates that the corresponding device data link can correctly reflect reactive power disturbances, thus eliminating the secondary system candidate faults corresponding to the device data link.

[0210] When the perturbation actuator has confirmed receiving the reactive power command, but its adjacent local measurement point has not detected the coded response, the control execution link of the perturbation actuator, the device body, or the adjacent electrical section is determined as the final fault location, and the final fault category is determined as a primary equipment fault.

[0211] When an upstream local measuring point adjacent to the primary wiring direction detects a coded response, but a downstream local measuring point does not detect a coded response, the electrical equipment or electrical section between the two measuring points is determined as the final fault location, and the final fault category is determined as a primary equipment fault.

[0212] When the same location satisfies both the primary equipment fault criteria and the secondary system fault criteria, the electrical section, along with the corresponding measuring point, protection and control device, or communication path, is determined as the final fault location, and the final fault category is determined as a composite fault.

[0213] After active verification is completed, the reactive power command of the perturbation actuator will be restored to [previous state]. The system continuously monitors the bus voltage and inverter reactive power until both return to the allowable fluctuation range before active verification. In this way, by generating identifiable electrical responses through reactive power coded disturbances with known timing characteristics, and then extracting these responses from both the local and remote ends, it is possible to determine whether the disturbance propagates along the primary equipment and whether it is correctly transmitted along the secondary communication path. This allows for new evidence to locate multiple candidate fault locations that cannot be distinguished solely by passive data.

[0214] Please see Figure 8 In some implementations, step 04 involves performing remote operations based on the final fault location and the final fault type, including:

[0215] Step 041: Based on the location of the final fault location in the equipment data link and the final fault category, determine the corresponding electrical equipment, measuring point, protection and control device or communication path;

[0216] Step 042: When the final fault category is a primary equipment fault, perform remote operation on the electrical equipment corresponding to the final fault location;

[0217] Step 043: When the final fault category is a secondary system fault, perform remote operation on the measuring point, protection and control device or communication path corresponding to the final fault location;

[0218] Step 044: When the final fault category is a compound fault, perform remote operations on the electrical equipment, measuring points, protection and control devices, or communication paths corresponding to the final fault location.

[0219] In some implementations, the remote operation and maintenance module is also used to query the device data chain based on the final fault location and final fault category, determine the objects and scope of operation that are allowed to be operated, and send remote operation instructions to the objects that have passed the security verification.

[0220] When the final fault category is a secondary system fault and the final fault location is a communication path, remote operations include switching to a backup communication path, restarting the communication service, or switching to a backup remote control channel. When the final fault location is a single measuring point, the measuring point is marked as invalid, and a backup measuring point in the same electrical section is invoked. Circuit breaker opening and closing operations are not performed based solely on the abnormal measuring point. When the final fault location is a protection and control device, a device maintenance task is generated, control commands are blocked from being sent through the corresponding channel of the device, and a backup device is switched to if one exists.

[0221] When the final fault category is a primary equipment fault, first verify the relay protection status, circuit breaker status, equipment interlock status, and dispatch permission; only when all operating conditions are met, perform load reduction, branch isolation, standby equipment activation, or other remote operations matching the equipment type on the faulty equipment; if any operating condition is not met, do not send instructions to change the operating status of the primary equipment, but generate an on-site handling task.

[0222] When the final fault category is a compound fault, the risk of primary equipment should be handled first in accordance with the relay protection and dispatching procedures, and then the abnormality of measuring device, protection and control device or communication path should be handled. This order is adopted because the failure of primary equipment may directly affect the safety of personnel and equipment, and the operation of secondary system must not delay the isolation of primary equipment risk.

[0223] In some implementations, acquiring post-operation operational data and generating remote maintenance results for fault tracing includes:

[0224] Step 045: After the remote operation is completed, reacquire the local and remote operating data along the device data chain corresponding to the final fault location;

[0225] Step 046: Calculate the difference between the two ends of the data after the operation based on the reacquired local operating data and remote operating data, and calculate the electrical balance residual after the operation based on the wiring information and the reacquired local operating data.

[0226] Step 047: Determine whether the fault or abnormality has been eliminated based on the difference between the two ends of the data after the operation and the electrical balance residual after the operation, and obtain the remote operation verification result;

[0227] Step 048: Associate the device data chain, final fault location, final fault category, remote operation, and remote operation verification results to generate fault tracing remote operation and maintenance results.

[0228] Let the difference between the two sets of data after the operation be . The electrical balance residual after the operation is Both are recalculated according to the aforementioned formulas for the difference between the two ends and the electrical balance residual; when all are associated with the final fault location Not greater than the corresponding threshold, and all If the value is not greater than the corresponding threshold, the fault or abnormality is determined to have been eliminated; if any related indicator still exceeds the corresponding threshold, the fault or abnormality is determined to have not been eliminated, all data before and after the operation is retained, the original conclusion of the uniqueness of the final fault location is revoked, and the data is transferred to manual review.

[0229] The results of remote maintenance for fault tracing include at least the equipment data link identifier, the time of the anomaly, local operating data, remote operating data, differences between the two ends of the data, electrical balance residual, candidate fault location, candidate fault category, active verification permission status, reactive power coding sequence, reactive power perturbation amplitude, local coding response, remote coding response, final fault location, final fault category, remote operation content, and remote operation review results. By writing the aforementioned data into the same record, the fault conclusion, evidence source, operation object, and operation result can be correlated with each other.

[0230] Please refer to the following: Figure 9 This application provides a remote operation and maintenance system for tracing faults in photovoltaic substations. The system includes a data link generation module, a difference and residual calculation module, a fault determination module, and a remote operation and maintenance module.

[0231] The data link generation module is connected to the station topology database, the measurement point configuration database, and the communication configuration database respectively. It is used to obtain wiring information, measurement point configuration information, and communication configuration information, and associate them with electrical equipment to generate equipment data links.

[0232] The difference and residual calculation module is connected to the station protection and control device, the station edge operation and maintenance terminal and the remote operation and maintenance terminal respectively. It is used to obtain local operation data and remote operation data of the same measurement point along the equipment data link, calculate the difference between the two ends of the data, and calculate the electrical balance residual based on the wiring information and local operation data.

[0233] The fault determination module is connected to the data link generation module and the difference and residual calculation module. It is used to determine the candidate fault location and candidate fault category based on the difference between the two ends of the data and the electrical balance residual. The fault determination module is also connected to the photovoltaic inverter controller, the station-level automatic voltage control system and the dispatch permission interface. It is used to apply reactive power coding perturbation when the candidate fault location is not unique and the active verification conditions are met, to obtain the local coding response and the remote coding response, and to determine the final fault location and the final fault category.

[0234] The remote operation and maintenance module is connected to the fault determination module. It is used to determine the objects that can be operated on based on the final fault location and the final fault category, perform remote operations, reacquire the operation data after the operation, and generate fault tracing remote operation and maintenance results.

[0235] This application also provides an electronic device, which includes a processor and a memory; the memory stores a computer program, and when the processor executes the computer program, it implements the aforementioned remote operation and maintenance method for tracing faults in photovoltaic substations.

[0236] Specifically, the processor may include a central processing unit, a digital signal processor, or other processing unit capable of executing computer programs; the memory may include random access memory, read-only memory, non-volatile memory, or a combination of the foregoing; the electronic device may also include a communication interface for exchanging data with the station's protection and control devices, edge maintenance terminals, remote maintenance terminals, photovoltaic inverter controllers, station-level automatic voltage control systems, and dispatch control systems.

[0237] This application also provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the aforementioned remote operation and maintenance method for tracing faults in photovoltaic substations. The computer-readable storage medium may be a magnetic storage medium, an optical storage medium, a semiconductor storage medium, or other non-temporary storage medium capable of storing a computer program.

[0238] In summary, this application places the primary electrical connection relationship, the measurement point correspondence relationship, and the secondary communication transmission relationship in the same traceable structure through the equipment data link. It judges whether the data acquisition and communication process is consistent by the difference between the two ends of the data, and judges whether the primary electrical section conforms to energy conservation by the electrical balance residual. When passive analysis cannot uniquely locate the fault, it applies coded perturbations that are jointly limited by the equipment capacity and bus voltage boundary by utilizing the existing reactive power regulation capability of the photovoltaic inverter. This forms a complete closed loop of abnormal data acquisition, mutual verification between the two ends, electrical balance verification, candidate location determination, active verification when necessary, hierarchical remote operation, and post-operation review. This allows the fault conclusion to be supported by verifiable data and calculation process, while limiting the scope of remote operation when the evidence is insufficient.

Claims

1. A remote operation and maintenance method for fault tracing in photovoltaic substations, characterized in that, Includes the following steps: Acquire wiring information, measurement point configuration information, and communication configuration information, and associate them with electrical equipment to generate a device data chain; Acquire local and remote operating data of the same measuring point along the equipment data chain, calculate the difference between the two ends of the data, and calculate the electrical balance residual based on the wiring information and local operating data; Based on the difference between the two ends of the data and the electrical balance residual, the candidate fault location and candidate fault category are determined. When the candidate fault location is unique, the candidate fault location and candidate fault category are determined as the final fault location and final fault category, respectively. When the candidate fault location is not unique, reactive power coding perturbation is applied, and the coding local response and coding remote response are obtained to determine the final fault location and final fault category. Perform remote operations based on the final fault location and final fault category, obtain post-operation operational data, and generate fault tracing remote operation and maintenance results.

2. The remote operation and maintenance method for fault tracing in photovoltaic substations according to claim 1, characterized in that, The device data chain is generated in association with electrical equipment, including: Determine the electrical connection relationships between the photovoltaic inverter, box-type transformer, collector lines, busbar and main transformer based on the wiring information; Determine the correspondence between electrical equipment and measuring points based on the measuring point configuration information; The data transmission relationship between the measuring points, protection and control devices, communication paths, and remote operation and maintenance terminals is determined based on the communication configuration information. By associating electrical equipment, measuring points, and communication paths based on electrical connection relationships, correspondence relationships, and data transmission relationships, the equipment data chain is obtained.

3. The remote operation and maintenance method for fault tracing in photovoltaic substations according to claim 1, characterized in that, Acquire local and remote operating data for the same measurement point along the device data link, and calculate the differences between the two sets of data, including: Acquire local and remote operating data for the same measurement point along the equipment data link; Data alignment is performed based on the time information of local and remote operating data. The difference between the aligned local running data and the remote running data is calculated to obtain the difference between the two ends of the data.

4. The remote operation and maintenance method for fault tracing in photovoltaic substations according to claim 1, characterized in that, Calculate the electrical balance residuals based on wiring information and local operating data, including: The photovoltaic substation is divided into multiple electrical sections based on the wiring information; Extract the inflow active power, outflow active power, and loss power of each electrical section from the local operation data; Calculate the power difference between the inflow active power, the outflow active power, and the power loss; The power difference is normalized based on the incoming active power to obtain the electrical balance residual for each electrical section.

5. The remote operation and maintenance method for fault tracing in photovoltaic substations according to claim 4, characterized in that, Candidate fault locations and categories are determined based on the differences between the two-end data and the electrical balance residuals, including: Based on the equipment data link, determine the electrical equipment, measuring points or communication paths corresponding to the differences between each pair of data points, and determine the electrical sections corresponding to each electrical balance residual based on the wiring information; Compare the differences between the data at each end and the changes in each electrical balance residual; When the electrical balance residual of the target electrical section changes abnormally and the difference between the two ends of the data associated with the target electrical section does not change abnormally, the target electrical section is identified as a candidate fault location and the candidate fault category is identified as a primary equipment fault. When the difference between the two ends of the target measurement point or the target communication path changes abnormally, and the electrical balance residual of the associated electrical section does not change abnormally, the target measurement point or the target communication path is identified as a candidate fault location, and the candidate fault category is identified as a secondary system fault. When both the electrical balance residual of the target electrical section and the difference in the two-end data associated with the target electrical section change abnormally, the target electrical section and the measurement points or communication paths associated with the target electrical section are identified as candidate fault locations, and the candidate fault category is identified as a composite fault.

6. The remote operation and maintenance method for fault tracing in photovoltaic substations according to claim 5, characterized in that, When candidate fault locations are not unique, apply reactive power coding perturbations, including: Based on the equipment data link, determine the electrical section associated with each candidate fault location, and then select candidate perturbation devices from the electrical equipment associated with the electrical section. Based on the local operating data corresponding to the candidate perturbation devices, determine the operating status of the candidate perturbation devices, and identify the perturbation execution device from the candidate perturbation devices; Based on the distribution relationship of each candidate fault location in the equipment data link, a reactive power coding sequence is determined to distinguish each candidate fault location; The reactive power perturbation amplitude is determined based on the operating status of the perturbation execution device and the reactive power coding sequence; A reactive power command is generated based on the reactive power coding sequence and the reactive power perturbation amplitude, and then sent to the perturbation execution device to apply the reactive power coding perturbation.

7. The remote operation and maintenance method for fault tracing in photovoltaic substations according to claim 6, characterized in that, Obtain the encoded local response and encoded remote response to determine the final fault location and final fault category, including: During the application of reactive power coding perturbation, local and remote operating data are acquired along the electrical equipment, measuring points, or communication paths associated with each candidate fault location in the equipment data chain; The changes in local and remote operating data caused by reactive power coding perturbations are extracted separately and arranged in the order of changes in reactive power coding perturbations to obtain the local coded response and the remote coded response. The propagation of reactive coded perturbations in electrical equipment is determined based on the local coded response, and the transmission of reactive coded perturbations in the communication path is determined based on the difference between the local coded response and the remote coded response. Based on the propagation and transmission conditions, the final fault location is determined from the candidate fault locations, and the final fault category is determined as primary equipment fault, secondary system fault, or combined fault.

8. The remote operation and maintenance method for fault tracing in photovoltaic substations according to claim 2, characterized in that, Perform remote operations based on the final fault location and final fault category, including: Based on the location of the final fault in the equipment data link and the final fault category, determine the corresponding electrical equipment, measuring points, protection and control devices or communication paths; When the final fault category is a primary equipment fault, remote operation is performed on the electrical equipment corresponding to the final fault location; When the final fault category is a secondary system fault, remote operation is performed on the measuring point, protection and control device or communication path corresponding to the final fault location. When the final fault category is a compound fault, remote operations are performed on the electrical equipment, measuring points, protection and control devices, or communication paths corresponding to the final fault location.

9. The remote operation and maintenance method for fault tracing in photovoltaic substations according to claim 1, characterized in that, Acquire post-operation operational data and generate remote maintenance results for fault tracing, including: After the remote operation is completed, the local and remote operating data are retrieved again along the device data chain corresponding to the final fault location; The difference between the two ends of the data after the operation is calculated based on the reacquired local operating data and remote operating data, and the electrical balance residual after the operation is calculated based on the wiring information and the reacquired local operating data. Based on the difference in data between the two ends after the operation and the electrical balance residual after the operation, it is determined whether the fault or abnormality has been eliminated, and the remote operation verification result is obtained. By associating the device data chain, final fault location, final fault category, remote operation, and remote operation review results, a fault tracing remote operation and maintenance result is generated.

10. A remote operation and maintenance system for tracing faults in photovoltaic substations, characterized in that, include: The data link generation module is used to acquire wiring information, measurement point configuration information and communication configuration information, and associate them with electrical equipment to generate equipment data links. The difference and residual calculation module is used to acquire local and remote operating data of the same measurement point along the equipment data chain, calculate the difference between the two ends of the data, and calculate the electrical balance residual based on the wiring information and local operating data. The fault determination module is used to determine the candidate fault location and candidate fault category based on the difference between the two-end data and the electrical balance residual. When the candidate fault location is unique, the candidate fault location and candidate fault category are determined as the final fault location and final fault category, respectively. When the candidate fault location is not unique, reactive power coding perturbation is applied to obtain the local coding response and the remote coding response to determine the final fault location and final fault category. The remote operation and maintenance module is used to perform remote operations based on the final fault location and final fault type, obtain the operation data after the operation, and generate remote operation and maintenance results for fault tracing.

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