A comprehensive state self-checking system before operation of a box-type substation

Abstract

The application discloses a kind of comprehensive state self-checking system before box-type substation commissioning, including branch configuration module, benchmark fingerprint module, low-energy excitation module, fingerprint acquisition module, abnormal screening module, microenvironment disturbance module, compensation determination module and conclusion output module.The application relates to the technical field of box-type substation commissioning detection.This kind of comprehensive state self-checking system before box-type substation commissioning uses low-energy test pulse with voltage limiting, current limiting and short pulse width to stimulate the transient response of each branch under the condition of box-type substation not being grid-connected and commissioned, which can avoid the protection misoperation, defect expansion and equipment life influence caused by high-energy test or live commissioning, improve the safety of pre-commissioning detection, use environmental interference deduction and compensation response fingerprint generation mechanism to correct environmental sensitive characteristic quantity, while keeping strict determination on structure connection sensitive characteristic quantity, avoid weakening single key abnormality through weighted average method, and improve the reliability of commissioning permission conclusion.

Description

Technical Field

[0001] This invention relates to the field of commissioning testing of prefabricated substations, and more specifically, to a comprehensive self-inspection system for the prefabricated substation before commissioning. Background Technology

[0002] After on-site installation, transportation, hoisting, and wiring are completed, prefabricated substations typically require insulation, grounding, terminal connection, and protection interlock checks before commissioning. In existing technologies, CN216159923U discloses a comprehensive intelligent monitoring system for the operational status of prefabricated substations, which connects an intelligent dehumidifier, partial discharge sensor, high-frequency current sensor, and temperature sensor to a data processing host, focusing on operational status monitoring; CN110336188B discloses a moisture-proof and dehumidification method for 10kV prefabricated substations, mainly controlling dehumidification, heating, and ventilation based on temperature, humidity, and dew point; CN116577618A discloses a method for partial discharge detection and interference suppression in switchgear, determining partial discharge or interference through the polarity of the pulse current time-domain waveform. The above solutions focus on operation monitoring, environmental dehumidification, or partial discharge identification, respectively. They do not apply low-energy pulses to the high-voltage incoming line, transformer winding, low-voltage outgoing line, and grounding branch to form a response fingerprint when the equipment is not in operation. They also do not deduct condensation, humidity, and temperature difference interference by retesting the recovery after micro-environmental disturbances in the cabinet. Therefore, it is difficult to distinguish between transient environmental anomalies and actual equipment defects. Thus, a comprehensive condition self-inspection system suitable for pre-operation is still needed. Summary of the Invention

[0003] The purpose of this invention is to provide a comprehensive self-inspection system for the prefabricated substation before commissioning, which solves the problem that existing pre-commissioning inspections rely on single insulation tests or manual verification, and are difficult to distinguish between transient environmental anomalies and actual equipment defects.

[0004] This invention achieves the above objective through the following technical solution: a comprehensive condition self-inspection system for prefabricated substations before commissioning, the system comprising: The branch configuration module is used to configure the high-voltage incoming branch, transformer winding branch, low-voltage outgoing branch and grounding branch as branches to be tested before the prefabricated substation is connected to the grid and put into operation, and to establish branch identification for each branch to be tested. The reference fingerprint module is used to read at least one of the factory test data, installation and commissioning data and historical qualified data of each branch to be tested, and generate a reference response fingerprint that includes the attenuation time constant reference range, leakage current envelope reference range, reflection waveform inflection point reference range, peak delay time reference range and equivalent capacitance to ground reference range. The low-energy excitation module is used to apply low-energy test pulses with voltage limiting, current limiting and short pulse width to each branch to be tested after confirming that the prefabricated substation is in an off-line state, so as to excite the transient response of the branch to be tested. The energy of the low-energy test pulse is lower than the operating energy of the corresponding protection device. The fingerprint acquisition module is used to acquire the transient voltage decay curve, leakage current envelope, pulse reflection waveform, peak delay time and change of equivalent capacitance to ground of each branch under test under the action of low-energy test pulse, and generate the current response fingerprint. An anomaly screening module is used to compare the current response fingerprint with the baseline response fingerprint, and mark suspected anomaly branches when at least one feature in the current response fingerprint exceeds the corresponding baseline interval. The microenvironment disturbance module is used to perform at least one of the following disturbances on the cabinet where the suspected abnormal branch is located: heating, dehumidification, air circulation, and micro-wind drying of the terminal area; The compensation determination module is used to subtract environmental interference from the current response fingerprint based on the changes in environmental parameters before and after the disturbance and the retest response fingerprint of suspected abnormal branches, to obtain the compensated response fingerprint and determine the source of the anomaly. The conclusion output module is used to output a conclusion that allows commissioning, postpones commissioning, or prohibits commissioning based on the compensation response fingerprint and the source of the anomaly.

[0005] Furthermore, the branch configuration module includes: Topology resolution unit and detection isolation unit; The topology parsing unit is used to generate a branch topology table based on the connection relationship between the high-voltage incoming terminal, the primary side of the transformer, the secondary side of the transformer, the low-voltage outgoing terminal, and the grounding terminal. The detection isolation unit is used to disconnect the operating loop between the branch under test and the external load before the low-energy test pulse is applied, while maintaining the test loop between the branch under test and the detection port.

[0006] Furthermore, the reference fingerprint module includes: Data filtering unit, feature extraction unit, and interval construction unit; The data filtering unit is used to remove data from factory test data, installation and commissioning data, and historical qualified data that have missing items, excessive range, or timestamp conflicts. The feature extraction unit is used to extract the decay time constant, leakage current envelope area, first-order inflection point position of the reflection waveform, peak delay time and rate of change of equivalent capacitance to ground from the filtered data. The interval construction unit is used to generate a corresponding benchmark interval based on the mean and dispersion of qualified samples under the same branch identifier.

[0007] Furthermore, the low-energy excitation module includes: Pulse parameter setting unit, branch switching unit, and safety interlocking unit; The pulse parameter setting unit is used to set the upper limit of the amplitude, the upper limit of the current, and the upper limit of the pulse width of the low-energy test pulse according to the rated voltage, insulation withstand voltage, and protection action threshold of the branch to be tested. The branch switching unit is used to sequentially connect to each branch to be detected according to the branch topology table; The safety interlocking unit is used to stop the low-energy test pulse output when a live signal, grounding unconfirmed signal, overvoltage signal, overcurrent signal, or protection interlock signal is detected.

[0008] Furthermore, the fingerprint acquisition module includes: Synchronous sampling unit, waveform shaping unit, and fingerprint packaging unit; The synchronous sampling unit is used to collect transient voltage, leakage current, reflected waveform and ground capacitance response at the same trigger time. The waveform shaping unit is used to perform amplitude limiting, baseline correction, and time alignment on the acquired signals. The fingerprint encapsulation unit is used to encapsulate the decay time constant, leakage current envelope area, first-order inflection point position of the reflected waveform, peak delay time, equivalent capacitance change rate to ground, and branch identifier into the current response fingerprint.

[0009] Furthermore, the anomaly filtering module includes: Single deviation judgment unit and anomaly type mapping unit; The single-item deviation judgment unit is used to determine whether each feature quantity in the current response fingerprint exceeds the corresponding benchmark interval; The anomaly type mapping unit is used to generate an insulation dampness type when the leakage current envelope area and attenuation time constant both exceed the corresponding reference range, to generate a connection contact anomaly type when the first inflection point position or peak delay time of the reflected waveform exceeds the corresponding reference range, and to generate a grounding anomaly type when the change rate of the ground equivalent capacitance of the grounding branch exceeds the corresponding reference range.

[0010] Furthermore, the microenvironment disturbance module includes: Disturbance strategy unit, disturbance execution unit, and disturbance limit unit; The disturbance strategy unit is used to select the disturbance method based on the cabinet location of the suspected abnormal branch, the abnormality type, the relative humidity inside the cabinet, the temperature inside the cabinet, the dew point temperature, and the terminal surface temperature. The disturbance execution unit is used to change the relative humidity, dew point difference, temperature gradient and terminal surface dryness of the cabinet where the suspected abnormal branch is located within a preset disturbance duration. The disturbance limit unit is used to reduce the disturbance power or stop the disturbance when the temperature inside the cabinet reaches the upper limit of the temperature, the rate of decrease of relative humidity reaches the upper limit of the humidity change, or the terminal surface temperature reaches the upper limit of the terminal temperature.

[0011] Furthermore, the compensation determination module includes: Disturbance data unit, retest unit, restoring calculation unit, and source determination unit; The disturbance data unit is used to collect the cabinet temperature, relative humidity, dew point temperature, dew point difference, cabinet wall temperature, terminal surface temperature, leakage current change rate, and insulation resistance recovery rate before and after the disturbance. The retesting unit is used to apply a low-energy test pulse to the suspected abnormal branch again with the same pulse parameters after the disturbance ends and generate a retesting response fingerprint. The recovery calculation unit is used to calculate the recovery of the retest response fingerprint relative to the reference response fingerprint; The source determination unit is used to determine that the source of the anomaly is environmental interference when the recovery degree is not less than the first threshold and the leakage current change rate is not less than the second threshold, and to determine that the source of the anomaly is equipment defect when the recovery degree is less than the first threshold and the deviation from the characteristic quantity still exceeds the corresponding reference range.

[0012] Furthermore, the compensation determination module also includes: Environmental deduction unit and margin correction unit; The environmental subtraction unit is used to subtract environmentally sensitive components from the current response fingerprint, which are characterized by changes in relative humidity, changes in dew point difference, changes in terminal surface temperature, leakage current rate of change, and insulation resistance recovery rate. The margin correction unit is used to generate a compensation response fingerprint based on the deducted decay time constant, leakage current envelope area, peak delay time, and rate of change of equivalent capacitance to ground, and sends the compensation response fingerprint to the conclusion output module.

[0013] Furthermore, the conclusion output module includes: Risk classification unit, permit determination unit, and suggestion generation unit; The risk classification unit is used to map the compensation response fingerprint and anomaly source into six states: allowed to operate, environmental interference requires re-inspection, insulation dampness requires treatment, connection anomaly requires tightening and re-inspection, grounding anomaly requires maintenance, and actual insulation defect prohibits operation. The permission determination unit is used to output a permission to operate conclusion when the compensation response fingerprints of each branch to be tested are all within the corresponding reference range and there are no equipment defects; output a postponement to operate conclusion when there is environmental interference requiring re-inspection, insulation dampness requiring treatment, connection abnormality requiring tightening and re-inspection, or grounding abnormality requiring maintenance; and output a prohibition to operate conclusion when there is a real insulation defect prohibiting operation. The suggestion generation unit is used to output abnormal branch identification, abnormal characteristic quantity, abnormal source, retest time and handling suggestions. The handling suggestions include at least one of the following: dehumidification and ventilation retest, insulation retest after drying treatment, connection terminal tightening retest, grounding circuit repair and insulation defect investigation.

[0014] The beneficial effects of this invention are as follows: 1. This invention uses low-energy test pulses with voltage limiting, current limiting, and short pulse width to excite the transient response of each branch in the unconnected state of the prefabricated substation. This can avoid the protection malfunctions, defect expansion, and equipment lifespan impact caused by high-energy tests or live-line testing, and improve the safety of pre-commissioning testing.

[0015] 2. This invention encapsulates the decay time constant, leakage current envelope area, first-order inflection point position of the reflected waveform, peak delay time and change rate of equivalent capacitance to ground as a response fingerprint. Compared with relying solely on insulation resistance, grounding resistance or manual visual inspection, it can identify potential hazards from multiple dimensions such as insulation status, connection continuity, grounding coupling status and branch structure changes.

[0016] 3. After identifying suspected abnormal branches, this invention introduces micro-environmental disturbances in the cabinet room. By changing the temperature, relative humidity, dew point difference, and terminal surface dryness through heating, dehumidification, air duct circulation, and micro-wind drying in the terminal area, and combining the recovery degree of retesting to determine the source of the abnormality, it can distinguish between transient abnormalities caused by condensation, humidity, or temperature difference and real equipment defects.

[0017] 4. This invention employs an environmental interference deduction and compensation response fingerprint generation mechanism to correct environmentally sensitive features while maintaining strict judgment on structural connection sensitive features. This avoids weakening individual key anomalies through weighted averaging and improves the reliability of commissioning permit conclusions.

[0018] 5. This invention can output six states: allowed to operate, environmental interference requiring re-inspection, insulation dampness requiring treatment, abnormal connection requiring tightening and re-inspection, abnormal grounding requiring maintenance, and actual insulation defects prohibiting operation. It also provides abnormal branch identification, abnormal characteristic quantity, and handling suggestions simultaneously, which facilitates quick re-inspection and closed-loop handling by on-site operation and maintenance personnel. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a system block diagram of the present invention; Figure 2 This is a flowchart illustrating the overall method of the present invention; Figure 3 This is a schematic diagram of the branch detection topology of the present invention; Figure 4 This is a flowchart of the response fingerprint construction and anomaly screening process of the present invention; Figure 5 This is a schematic diagram illustrating the principle of microenvironmental disturbance and retesting in substation enclosures according to the present invention. Figure 6This is a flowchart of the compensation determination, risk classification, and conclusion output of the present invention. Detailed Implementation

[0020] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0021] Example 1: Please see Figure 1-6 This invention provides a comprehensive self-inspection system for prefabricated substations before commissioning. It is applicable to comprehensive self-inspection scenarios after on-site installation, primary wiring, grounding connection, and protection interlock confirmation of the prefabricated substation, but before formal grid connection and commissioning. The system includes a branch configuration module, a reference fingerprint module, a low-energy excitation module, a fingerprint acquisition module, an anomaly screening module, a micro-environmental disturbance module, a compensation judgment module, and a conclusion output module. This system can be integrated into a portable testing terminal or can be composed of a testing host, a branch switching device, a low-energy pulse generator, an environmental disturbance device, a sensor acquisition device, and a host computer analysis device.

[0022] In this embodiment, the system establishes a unified parameter dimension before detection. The voltage unit of the low-energy test pulse is [missing value]. The unit of current is The pulse width and delay time units are uniformly converted to The leakage current envelope area is in units of The rate of change of the equivalent capacitance to ground is in units of The unit of temperature is The unit of relative humidity is For the original sampled data, The recorded pulse reflection time and peak delay time are first converted to a unified value. Then participate in the calculation; for those using The recorded leakage current was first converted to a uniform value. Then, the leakage current envelope area is formed to avoid judgment bias caused by direct comparison of different dimensions.

[0023] The branch configuration module is used to configure branches to be tested before the prefabricated substation is connected to the grid and put into operation. Specifically, the branch configuration module reads the primary wiring information of the prefabricated substation, generates a branch topology table based on the connection relationships between the high-voltage incoming terminal, the transformer primary side, the transformer secondary side, the low-voltage outgoing terminal, and the grounding terminal, and configures the high-voltage incoming branch, transformer winding branch, low-voltage outgoing branch, and grounding branch as independent branches to be tested. Each branch to be tested is assigned a unique branch identifier, which is used to bind the branch's topology location, rated voltage, insulation class, grounding method, detection port, and response fingerprint data.

[0024] Before the test begins, the test isolation unit in the branch configuration module performs isolation verification. The test isolation unit disconnects the operating loop between the branch under test and the external load, while maintaining the test loop between the branch under test and the test port. For low-voltage outgoing branches, the test isolation unit confirms that the load side is disconnected; for grounding branches, the test isolation unit confirms that the grounding terminal connection is valid; for transformer winding branches, the test isolation unit confirms that neither the primary nor secondary side is in actual operating power supply status. Through the above processing, it is ensured that the low-energy test pulse only acts on the target branch under test and does not enter the external load or the actual operating loop.

[0025] The reference fingerprint module is used to establish a reference response fingerprint for each branch to be tested. Specifically, the reference fingerprint module reads at least one of the following: factory test data, installation and commissioning data, and historical qualified data. Factory test data includes insulation test data, winding test data, grounding test data, and terminal connection test data; installation and commissioning data includes initial inspection data after on-site wiring is completed; historical qualified data includes test records saved for the same equipment or equipment of the same model in a qualified state. When both factory test data and installation and commissioning data are available for the same branch, the installation and commissioning data is used first to correct the factory test data on-site, in order to reduce reference offset caused by differences in transportation, hoisting, and on-site wiring.

[0026] The benchmark fingerprint module includes a data filtering unit, a feature extraction unit, and an interval construction unit. The data filtering unit removes data with missing items, excessive range, timestamp conflicts, and inconsistent branch identifiers. The feature extraction unit extracts the decay time constant, leakage current envelope area, first-order inflection point location of the reflected waveform, peak delay time, and rate of change of equivalent capacitance to ground from the filtered data. The interval construction unit establishes benchmark intervals based on the mean and dispersion of qualified samples under the same branch identifier. Each response feature independently establishes a benchmark interval without weighted synthesis.

[0027] Specifically, no. The first branch to be tested The reference interval for the response characteristic quantity is determined according to formula (1):

[0028] in, Indicates the first The first branch to be tested The baseline interval for the response characteristic quantity; This represents the mean of this feature value for that branch in the qualified samples; This represents the standard deviation of this feature quantity in the qualified samples for that branch; This represents the interval coefficient. The units of each characteristic quantity remain consistent with the original characteristic quantity; for example, the unit of the decay time constant is... The leakage current envelope area is in units of The peak delay time unit is The rate of change of the equivalent capacitance to ground is in units of .

[0029] The determination rule is: when the number of historical qualified samples of the same model or the same equipment is not less than 30 groups, Take 2.0; when the number of qualified samples is between 10 and 29, Take 2.5; when the number of qualified samples is less than 10, the initial benchmark interval is determined by combining the manufacturer's allowable deviation, the qualified data from on-site installation and commissioning, and qualified samples of the same model of equipment, and is updated after subsequent qualified re-inspection. The above rules are used to improve the identification sensitivity when there are sufficient samples and to reduce the false judgment rate when there are insufficient samples.

[0030] The low-energy excitation module is used to apply low-energy test pulses to each branch under test. The low-energy test pulses are voltage-limiting, current-limiting, and short-pulse-width pulses, designed to excite the transient response of the branch under test, rather than to bring the prefabricated substation into actual operating condition. The pulse parameter setting unit sets the upper limit of the low-energy test pulse amplitude, upper limit of the current, and upper limit of the pulse width based on the rated voltage, insulation withstand voltage, and protection action threshold of the branch under test.

[0031] As one implementation method, for a rated voltage of The branch to be tested, pulse amplitude Take 0.01 Up to 0.10 And not higher than the operating voltage threshold of the protection device for that branch. of Pulse current Pick to Pulse width Pick to When the protection device has a fast-acting characteristic, the pulse width... The energy should be less than 1 / 5 of the protection identification time. The above value is based on the fact that the low-energy test pulse only needs to excite the transient response of the branch under test and is not used to form the operating voltage or continuous operating current. Therefore, its energy should be lower than the protection action energy and lower than the energy required for the equipment insulation withstand test.

[0032] In practice, the pulse amplitude of the high-voltage incoming branch and the transformer winding branch should preferably be taken from the rated voltage. to The low-voltage outgoing branch line takes the rated voltage. to The grounding branch should not exceed A low-voltage pulse; if the field protection device's operating threshold is lower than the above amplitude, then the protection operating threshold will be used. As an upper limit, the branch switching unit is connected sequentially to the high-voltage incoming branch, transformer winding branch, low-voltage outgoing branch, and grounding branch according to the branch topology table. To avoid coupling effects between adjacent branches, the branch switching unit is set after each switching. to The settling time is used to eliminate residual charge and coupling response in the previous branch.

[0033] The safety interlock unit in the low-energy excitation module is used to detect live signals, unconfirmed grounding signals, overvoltage signals, overcurrent signals, and protection interlock signals. When any of these signals is triggered, the safety interlock unit stops the low-energy test pulse output and marks that branch as incomplete. This safety interlock logic prevents low-energy test pulses from being output when the equipment is not isolated or when there are abnormal field wiring.

[0034] The fingerprint acquisition module generates the current response fingerprint for each branch under test. The synchronous sampling unit uses the rising edge of a low-energy test pulse as the unified trigger time to acquire transient voltage, leakage current, reflected waveform, and capacitance-to-ground response. The sampling frequency is set according to the branch length and pulse width; for example, the low-voltage outgoing branch uses... to Sampling frequency, high voltage incoming branch and transformer winding branch adopt to Sampling frequency. The waveform shaping unit performs amplitude limiting, baseline correction, and time alignment on the acquired signal, removing sampling start offset, zero-point drift, and spikes. The fingerprint encapsulation unit encapsulates the decay time constant, leakage current envelope area, first-order inflection point position of the reflected waveform, peak delay time, rate of change of equivalent capacitance to ground, and branch identifier into the current response fingerprint.

[0035] The anomaly filtering module compares the current response fingerprint with the baseline response fingerprint. To enable comparison of features with different dimensions under the same judgment logic, the anomaly filtering module first performs dimensionless processing on each feature. The first branch to be tested The deviation of the characteristic quantity is calculated according to formula (2):

[0036] in, Indicates a dimensionless deviation; Indicates the first fingerprint in the current response. The first branch to be tested Measured characteristic quantities; , and The meaning is consistent with formula (1); This represents a tiny constant used to prevent the denominator from being zero, and its value is 1 / 10 of the minimum resolution of the corresponding feature quantity. This indicates that the characteristic quantity is within the reference interval; This indicates that the characteristic value exceeds the baseline range. Because... Since it is a dimensionless numerical value, different characteristic quantities can be used uniformly for deviation judgment, but no weighted summation is performed.

[0037] In this embodiment, when a branch to be detected has at least one When the anomaly filtering module marks the branch as a suspected anomaly branch; when When this occurs, the feature value is marked as a significantly deviated feature value. A significant deviation threshold of 0.50 indicates that the measured value exceeds the outer width of the reference interval by half the reference width. This threshold is determined by the historical false alarm records, on-site re-inspection records, and operation and maintenance safety margin of the same type of prefabricated substation. When it is deployed for the first time and there are no historical re-inspection records, 0.50 can be used as the initial value, and then it can be corrected according to the results of the commissioning re-inspection.

[0038] The anomaly type mapping unit in the anomaly screening module generates preliminary anomaly types based on deviations from characteristic values. When both the leakage current envelope area and the decay time constant exceed the corresponding reference range, an insulation dampness type is generated; when the first-order inflection point position or peak delay time of the reflected waveform exceeds the corresponding reference range, a connection contact anomaly type is generated; when the change rate of the equivalent capacitance to ground of the grounding branch exceeds the corresponding reference range, a grounding anomaly type is generated; when the leakage current envelope area continuously exceeds the reference range and the decay time constant fails to recover after subsequent micro-environmental disturbances, a suspected insulation defect type is generated. Through this mapping method, the system can establish targeted retest directions before entering a micro-environmental disturbance.

[0039] The microenvironment disturbance module is used to perform controlled disturbances on the cabinet containing suspected abnormal branches. Disturbance methods include at least one of heating, dehumidification, airflow circulation, and micro-air drying of the terminal area. The disturbance strategy unit selects the disturbance method based on the cabinet location of the suspected abnormal branch, the type of abnormality, the relative humidity inside the cabinet, the temperature inside the cabinet, the dew point temperature, and the terminal surface temperature. When the relative humidity inside the cabinet is not lower than... Or the dew point difference is no greater than Or the difference between the terminal surface temperature and the dew point temperature is not greater than At this time, the microenvironment disturbance module initiates disturbance. The dew point difference is the difference between the cabinet temperature and the dew point temperature, used to determine the risk of condensation; the smaller the dew point difference, the higher the risk of condensation inside the cabinet.

[0040] When the relative humidity inside the cabinet is high and the dew point difference is small, the disturbance strategy unit prioritizes dehumidification and air circulation; when the terminal surface temperature is close to the dew point temperature and the anomaly type is insulation dampness, it selects a gentle breeze to dry the terminal area; when the difference between the cabinet wall temperature and the dew point temperature is small and there is a risk of condensation, it selects a combination of short-term heating and air circulation. The disturbance execution unit changes the relative humidity, dew point difference, temperature gradient, and terminal surface dryness status of the cabinet containing the suspected abnormal branch within a preset disturbance duration. The preset disturbance duration is... to The upper limit of the cabinet temperature is taken as follows: The upper limit of the terminal surface temperature is taken as follows: The rate of decrease in relative humidity does not exceed ; Air circulation speed in the duct to .

[0041] The above disturbance parameters are determined based on the following: ensuring detectable changes in relative humidity, dew point difference, and terminal surface dryness within the cabinet without altering the equipment's insulation structure, generating thermal shock, or introducing external contamination. If the cabinet temperature reaches... Terminal surface temperature reaches Or the rate of decrease in relative humidity exceeds The disturbance limit unit reduces the disturbance power or stops the disturbance altogether. This setting ensures that microenvironmental disturbances are used only to identify sources of anomalies without causing thermal shock or insulation stress to components inside the cabinet.

[0042] The compensation judgment module is used to collect environmental parameters before and after the disturbance and perform retesting. The disturbance data unit collects cabinet temperature, relative humidity, dew point temperature, dew point difference, cabinet wall temperature, terminal surface temperature, leakage current change rate, and insulation resistance recovery rate. After the disturbance ends, the retesting unit applies a low-energy test pulse to the suspected abnormal branch with the same pulse amplitude, current limit, and pulse width as the initial test, and generates a retest response fingerprint. Since the retest pulse parameters, sampling frequency, trigger time, and waveform shaping rules are consistent with the initial test, the retest response fingerprint can be directly compared with the current response fingerprint to determine whether the abnormal change is caused by a change in the microenvironment.

[0043] The deviation of the branch before and after the retest is represented by the maximum deviation of each characteristic quantity of the branch, and is calculated according to formula (3):

[0044] in, Indicates the first The maximum dimensionless deviation of the branch to be tested; Indicates the number of features involved in the judgment; to These represent the attenuation time constant, leakage current envelope area, first-order inflection point position of the reflected waveform, peak delay time, and deviation corresponding to the rate of change of equivalent capacitance to ground, respectively. The reason for using the maximum value instead of weighted summation is that pre-commissioning self-inspection is a safety permitting judgment; if a single key characteristic continuously exceeds the limit, it is not appropriate to weaken the anomaly through weighted averaging.

[0045] The retest recovery rate is calculated according to formula (4):

[0046] in, Indicates the first The recovery rate of a suspected abnormal branch was retested. This indicates the maximum dimensionless deviation of the branch before microenvironmental disturbance; This indicates the maximum dimensionless deviation of the branch after microenvironmental disturbance; This represents a small constant used to prevent the denominator from being zero, taken as... . The closer it is to 1, the closer the response of that branch is to the baseline response fingerprint after micro-environmental disturbance; The closer it is to 0, the weaker the improvement effect of microenvironmental disturbance on abnormal deviation.

[0047] The source determination unit is used to determine the source of the anomaly based on the retest recovery rate and the change in leakage current. In this embodiment, the first recovery rate threshold... Set the threshold value to 0.80 for leakage current reduction. Pick .in, This indicates that the maximum deviation after the disturbance is lower than before the disturbance. The above demonstrates a strong correlation between anomalies and environmental factors. This indicates that the leakage current envelope area or the mean leakage current has decreased by at least [amount missing] compared to before the disturbance. This indicates that dehumidification, ventilation, or gentle drying effectively mitigates leakage anomalies. The aforementioned thresholds are determined jointly by the pre-commissioning inspection records of the same model of prefabricated substation, the manufacturer's insulation test pass range, and on-site operation and maintenance experience. Once at least 30 verified operational samples have been accumulated on-site, recalibration can be performed based on the statistical distribution of qualified samples. However, after calibration... Not less than 0.75 Not less than .

[0048] when And the leakage current decrease ratio is not less than When the source determination unit determines the source of the anomaly to be environmental interference, environmental interference includes condensation interference, humidity interference, and temperature difference interference; when And at least one of the following after the perturbation When the value is still greater than 0, the source determination unit determines the source of the anomaly to be a device defect, which includes insulation defects, connection contact defects, and grounding defects; when However, the leakage current decrease rate is less than At this time, the system does not directly output a conclusion that it can be put into operation. Instead, it classifies the status as environmental interference pending re-inspection, requiring an extension of the dehumidification and ventilation time and a second re-test.

[0049] The compensation determination module also includes an environmental deduction unit and a margin correction unit. For suspected abnormal branches identified as being affected by environmental interference, the environmental deduction unit uses the post-disturbance response fingerprint as the basis for correction, deducting and correcting features in the current response fingerprint that are significantly affected by the environment. Specifically, the leakage current envelope area, decay time constant, and insulation resistance recovery rate are defined as environmentally sensitive features; the first-order inflection point position and peak delay time of the reflected waveform are defined as structural connection sensitive features. If only the environmentally sensitive features recover after the environmental disturbance, while the structural connection sensitive features do not exceed the baseline range, a compensation response fingerprint is generated and used for risk classification; if the structural connection sensitive features continuously exceed the baseline range, no commissioning and release compensation is performed, and the connection contact is still treated as abnormal.

[0050] The rules for generating the compensated response fingerprint are as follows: for environmentally sensitive features, the retested value after disturbance is used as the compensated feature; for structural connection sensitive features, the value with the larger deviation between the initial detection value and the retested value is used as the compensated feature. This rule is based on the fact that environmentally sensitive features are significantly affected by humidity, condensation, and temperature differences, and can reflect the true insulation margin through disturbance retesting; structural connection sensitive features reflect the continuity of terminals, busbars, winding leads, or grounding connections, and should not be weakened by improvements due to environmental disturbances.

[0051] The conclusion output module outputs a commissioning conclusion based on the compensation response fingerprint and the source of the anomaly. The risk classification unit maps the compensation response fingerprint and the source of the anomaly into six states: commissioning permitted, environmental interference requiring re-inspection, insulation dampness requiring treatment, connection anomaly requiring tightening and re-inspection, grounding anomaly requiring maintenance, and actual insulation defect prohibiting commissioning. The permission determination unit outputs a commissioning permitted conclusion when the compensation response fingerprints of each branch under test are all within the corresponding reference range and there are no equipment defects; outputs a commissioning postponed conclusion when there are environmental interference requiring re-inspection, insulation dampness requiring treatment, connection anomaly requiring tightening and re-inspection, or grounding anomaly requiring maintenance; and outputs a commissioning prohibited conclusion when there is an actual insulation defect prohibiting commissioning.

[0052] It is recommended that the generation unit be used to output abnormal branch identification, abnormal characteristic quantity, abnormal source, retest time, and handling suggestions. For environmental interference requiring retesting, it is recommended that the generation unit output dehumidification and ventilation retest suggestions; for insulation dampness requiring treatment, it is recommended that the generation unit output insulation retest suggestions after drying treatment; for connection abnormalities requiring tightening and rechecking, it is recommended that the generation unit output connection terminal tightening and rechecking suggestions; for grounding abnormalities requiring maintenance, it is recommended that the generation unit output grounding circuit maintenance suggestions; for actual insulation defects prohibiting operation, it is recommended that the generation unit output insulation defect investigation suggestions, and it is prohibited to generate a conclusion allowing operation.

[0053] In a specific application example, a certain / The prefabricated substation has not yet been put into operation after on-site installation. The system first generates branch identifiers for the high-voltage incoming branch, transformer winding branch, low-voltage outgoing branch, and grounding branch, and reads the factory test data and installation and commissioning data. The reference fingerprint module establishes the reference response fingerprint for each branch according to formula (1). Since this type of prefabricated substation has 35 sets of historical qualified samples, Take 2.0.

[0054] The low-energy excitation module applies a pulse amplitude of [value missing] to the low-voltage outgoing branch. The upper limit of current is Pulse width is A low-energy test pulse; applying a pulse amplitude of [value missing] to the high-voltage incoming branch. The upper limit of current is Pulse width is A low-energy test pulse; applying a pulse amplitude of [value missing] to the grounding branch. The upper limit of current is Pulse width is The low-energy test pulse. All of the above pulse parameters are below the corresponding protection action threshold. And it is lower than the branch insulation withstand test energy.

[0055] The test results showed that the leakage current envelope area and decay time constant of the low-voltage outgoing branch both exceeded the reference range. The anomaly screening module calculated the leakage current envelope area deviation as 0.62 and the decay time constant deviation as 0.41 according to formula (2). Therefore, the low-voltage outgoing branch was marked as a suspected anomaly branch and initially classified as an insulation moisture-affected type. At this time, the relative humidity inside the cabinet was... Dew point difference is This satisfies the initiation conditions for microenvironmental disturbances.

[0056] The microenvironment disturbance module performs dehumidification and air circulation in the low-voltage cabinet compartment, with a disturbance duration of [duration missing]. Wind speed is The temperature inside the cabinet is controlled at The terminal surface temperature is controlled at the following levels. The following is an example. After the disturbance, the relative humidity inside the cabinet dropped to [a certain value]. The dew point difference rose to The retest unit uses the same pulse parameters to retest the low-voltage outgoing branch, and obtains the maximum deviation before the disturbance according to formula (3). Maximum deviation after disturbance Then, calculate the retest recovery rate according to formula (4). At the same time, the leakage current envelope area decreased by a certain percentage. .because And the leakage current decrease ratio ≥ The source determination unit determines that the anomaly is mainly caused by humidity and condensation interference, and generates a compensation response fingerprint. If the compensation response fingerprints of other branches are all within the baseline range, the conclusion output module outputs a conclusion that operation is permitted; if the on-site procedures require observation and confirmation, the conclusion that environmental interference needs to be re-inspected is output, and it is recommended to continue ventilation and dehumidification before retesting.

[0057] Example 2: In another specific application example, the deviation of the first-order inflection point position of the reflected waveform in the transformer winding branch is 0.58, and the deviation of the peak delay time is 0.36. Micro-environmental disturbance execution. Afterwards, a retest was conducted. , Retest recovery Furthermore, the first inflection point of the reflected waveform still exceeds the reference range. Because... Furthermore, if the deviation from the characteristic value after the disturbance is still greater than 0, the source determination unit determines that the source of the anomaly is an equipment defect, the risk classification unit classifies it as a connection anomaly requiring tightening and re-inspection, and the conclusion output module outputs a conclusion to temporarily suspend commissioning, and prompts to check the tightness of the transformer winding lead-out terminal, busbar connection point and terminal.

[0058] Example 3: In this embodiment, the integrated status self-inspection system is applied to the pre-commissioning inspection scenario of the ZBW series high-voltage / low-voltage prefabricated box-type substation. This box-type substation includes a high-voltage switchgear, a low-voltage distribution cabinet, a distribution transformer, and a box enclosure. The box contains a high-voltage compartment, a transformer compartment, and a low-voltage compartment. Ventilation louvers are installed on the outer door panel, and at least one of a fan, temperature control, condensation control, or heating device is installed inside the box. This type of box-type substation is suitable for rated voltage... and below, rated capacity For outdoor power supply locations of 1000 ohms and below, the high-voltage side can adopt ring network power supply, terminal power supply, or dual power supply methods, while the low-voltage side can be equipped with power distribution, lighting distribution, reactive power compensation, energy metering, and power measurement units. The on-site prefabricated substation has a multi-compartment outdoor enclosure structure. After opening the cabinet doors, the high-voltage switchgear, low-voltage distribution cabinet, instrument display area, ventilation louvers, and enclosure partition structure can be observed. It is suitable to use each compartment as a spatial object for branch circuit modeling and micro-environmental disturbance.

[0059] Before testing, the branch configuration module establishes the high-voltage incoming branch corresponding to the high-voltage incoming cabinet, the transformer winding branch corresponding to the primary and secondary sides of the distribution transformer, the low-voltage outgoing branch corresponding to the low-voltage distribution cabinet, and the grounding branch corresponding to the cabinet base frame and grounding terminal as branches to be tested, based on the primary wiring relationship within the box. Since this type of box-type substation requires a secure connection between the grounding system and the substation grounding terminal during installation, and the cable shielding and armor should also be grounded, the grounding branch includes not only the box grounding terminal but also the metal frame of the high and low voltage cabinets, the transformer shell, the metal parts of the base frame, and the cable shielding grounding path. The system assigns branch identifiers to each of these branches and binds the high-voltage incoming branch, transformer winding branch, low-voltage outgoing branch, and grounding branch to their corresponding rated voltage, rated current, insulation class, and installation location parameters.

[0060] During the baseline fingerprint establishment phase, the baseline fingerprint module reads the factory test report, installation and commissioning records, and pre-commissioning manual inspection records of the ZBW prefabricated substation. The manual inspection records include: whether the surfaces of internal components are clean, dry, and free of foreign matter; whether the operating mechanisms and switches are flexible and reliable; whether the main circuit and grounding circuit connections are secure; whether the mounting screws of the transformer and high / low voltage switchgear are secure; and whether the auxiliary circuit and control circuit settings are correct. These items serve as screening criteria for baseline data: if the installation inspection record for a branch contains marks indicating looseness, dryness, or abnormal components, the data for that branch is not considered a qualified sample; only records that pass manual inspection, insulation resistance test, and pre-commissioning test are used to extract the attenuation time constant, leakage current envelope area, first-order inflection point position of the reflected waveform, peak delay time, and rate of change of equivalent capacitance to ground, for establishing the baseline response fingerprint.

[0061] During the low-energy pulse detection phase, the system confirms that the prefabricated substation has not been energized, disconnects all high- and low-voltage switches, and confirms that the high-voltage cabinet door, low-voltage cabinet door, and transformer room door are in a state that meets the detection requirements. The high-voltage incoming branch, the low-energy excitation module applies a pulse amplitude of The upper limit of current is Pulse width is Low-energy test pulses; for The low-voltage outgoing branch is given a pulse amplitude of The upper limit of current is Pulse width is A low-energy test pulse; for the grounding branch, the applied pulse amplitude is [value missing]. The upper limit of current is Pulse width is The low-energy test pulses are used to excite the transient response of the branch, not to generate operating voltage or actual load current, and are lower than the operating energy of the protection device. If a live indication signal, unconfirmed grounding signal, overvoltage signal, overcurrent signal, or protection interlock signal is detected, the safety interlock unit immediately stops the low-energy test pulse output.

[0062] The fingerprint acquisition module uses the rising edge of a low-energy test pulse as the unified trigger moment to collect transient voltage decay curves, leakage current envelopes, pulse reflection waveforms, peak delay times, and the rate of change of equivalent capacitance to ground for the high-voltage incoming branch, transformer winding branch, low-voltage outgoing branch, and grounding branch. For the high-voltage and low-voltage compartments near the cabinet door ventilation louvers, the system synchronously binds the cabinet internal temperature, relative humidity, dew point temperature, dew point difference, cabinet wall temperature, and terminal surface temperature to the corresponding compartments to subsequently determine whether the abnormal response fingerprint is related to condensation, humidity, or temperature difference inside the cabinet.

[0063] In a specific test, the leakage current envelope area and attenuation time constant of the low-voltage outgoing branch both exceeded the corresponding reference range. Specifically, the leakage current envelope area deviation was 0.64, and the attenuation time constant deviation was 0.43. The first-order inflection point position and peak delay time of the reflected waveform did not exceed the reference range. Based on this, the anomaly screening module marked the low-voltage outgoing branch as a suspected anomaly and preliminarily determined it to be of the insulation dampness type. At this time, the relative humidity of the low-voltage room was [missing information]. The temperature inside the cabinet is Dew point temperature is Dew point difference is The terminal surface temperature is Since the dew point difference is no greater than Furthermore, the terminal surface temperature is close to the dew point temperature, and the system determines that there is a risk of condensation in the cabinet.

[0064] Subsequently, the microenvironment disturbance module invokes the low-pressure chamber heater, fan, or external dehumidification duct to perform [actions] on the low-pressure chamber. Short-term microenvironmental disturbances. During the disturbance, the temperature inside the cabinet is controlled at... The terminal surface temperature is controlled at the following levels. The following is the air circulation speed control in the air duct: The rate of decrease in relative humidity does not exceed After the disturbance ended, the relative humidity in the low-pressure chamber decreased from... Descending to Dew point difference Increase to The retest unit applied low-energy test pulses to the low-voltage outgoing branch again using the same pulse parameters as the initial test. The retest showed that the leakage current envelope area deviation decreased to 0.12, the decay time constant deviation decreased to 0.08, the maximum dimensionless deviation decreased from 0.64 to 0.12, the retest recovery rate was 0.81, and the leakage current envelope area decreased by a certain percentage. .

[0065] Since the recovery rate of the retest is not less than 0.80, and the percentage decrease in the leakage current envelope area is not less than The source determination unit determines that the anomaly in the low-voltage outgoing branch is mainly caused by humidity and condensation interference. The environment subtraction unit uses the leakage current envelope area and decay time constant obtained after the disturbance retest as the compensated environmental sensitive characteristic quantity. Since the first-order inflection point position and peak delay time of the reflected waveform do not exceed the reference range, the margin correction unit generates a compensation response fingerprint and marks the branch status as environmental interference pending retesting. The conclusion output module outputs a conclusion to temporarily suspend commissioning and provides suggestions for continuing dehumidification and ventilation, keeping the cabinet door closed, and retesting the insulation status of the low-voltage outgoing line. When all compensation response fingerprints are within the reference range in the second retest, and manual inspection confirms that the surfaces of the low-voltage room components are clean, dry, and free of foreign matter, the conclusion output module allows the branch status to be updated to allow commissioning.

[0066] In another testing scenario at the same prefabricated substation, the deviation of the first-order inflection point of the reflected waveform in the transformer winding branch was 0.57, the deviation of the peak delay time was 0.34, and the leakage current envelope area did not significantly exceed the reference range. The micro-environmental disturbance module performs [measures] on the transformer compartment. After air circulation and short-term heating, the recovery rate was only 0.18, and the first inflection point of the reflected waveform still exceeded the reference range. Since this anomaly did not recover with decreasing humidity or increasing dew point difference, the source determination unit determined that the anomaly was not due to environmental interference, but rather a connection contact anomaly. The conclusion output module output a decision to temporarily suspend operation and prompted the user to check the transformer winding leads, busbar connection points, the tightness of the terminals inside the cabinet, and related grounding connections.

[0067] In the grounding branch detection scenario, the system establishes a grounding branch response fingerprint based on the grounding connection relationships between the enclosure frame, metal door, high and low voltage electrical equipment metal frame, and transformer casing. If the change rate of the grounding branch's equivalent capacitance to ground continuously exceeds the reference range, and the recovery rate after micro-environmental disturbance is less than 0.80, the system determines that the anomaly is not due to transient interference caused by condensation or humidity, but rather a grounding anomaly. The conclusion output module outputs a conclusion to temporarily suspend commissioning and prompts for a re-inspection of the transformer grounding terminal, enclosure grounding connection, cable shielding layer, and armor grounding connection. If, after the re-inspection, the grounding branch compensation response fingerprint recovers to the reference range, and the grounding resistance verification is not greater than [value missing], the system will determine the grounding branch response fingerprint. If so, the final confirmation process before power transmission and commissioning is allowed.

[0068] As can be seen from this embodiment, the ZBW prefabricated substation data can be used to define the actual application objects, cabinet structure, pre-commissioning inspection items, insulation verification conditions, grounding verification conditions, and condensation treatment scenarios. The core of this invention is not to repeat the conventional commissioning inspection, but to introduce low-energy pulse response fingerprinting, cabinet micro-environmental disturbance, post-disturbance retest recovery degree, and environmental interference deduction compensation on the basis of the above conventional inspections. In this way, it can distinguish between environmental transient anomalies and real equipment defects before formal commissioning, thereby improving the accuracy of commissioning permit conclusions.

[0069] As can be seen from the above embodiments, the present invention can acquire multi-branch response fingerprints using low-energy test pulses under safe conditions where the prefabricated substation is not connected to the grid. It then determines the source of anomalies through micro-environmental disturbances and retest recovery, and generates compensated response fingerprints through environmental subtraction and margin correction, thereby achieving a graded judgment of the pre-commissioning state. Compared with solutions that only perform operational monitoring, separate dehumidification control, or single-phase partial discharge identification, the present invention can more accurately distinguish between transient environmental anomalies and actual equipment defects, reducing the risks of erroneous commissioning, erroneous shutdown, and repeated maintenance.

[0070] The above embodiments provide a detailed description of the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A comprehensive self-inspection system for the pre-commissioning status of a prefabricated substation, characterized in that, The system includes: The branch configuration module is used to configure the high-voltage incoming branch, transformer winding branch, low-voltage outgoing branch and grounding branch as branches to be tested before the prefabricated substation is connected to the grid and put into operation, and to establish branch identification for each branch to be tested. The reference fingerprint module is used to read at least one of the factory test data, installation and commissioning data and historical qualified data of each branch to be tested, and generate a reference response fingerprint that includes the attenuation time constant reference range, leakage current envelope reference range, reflection waveform inflection point reference range, peak delay time reference range and equivalent capacitance to ground reference range. The low-energy excitation module is used to apply low-energy test pulses with voltage limiting, current limiting and short pulse width sequentially to each branch to be tested after confirming that the prefabricated substation is in an off-line state, so as to excite the transient response of the branch to be tested. The energy of the low-energy test pulse is lower than the operating energy of the corresponding protection device. The fingerprint acquisition module is used to acquire the transient voltage decay curve, leakage current envelope, pulse reflection waveform, peak delay time and equivalent capacitance change rate to ground of each branch under test under the action of low-energy test pulse, and generate the current response fingerprint. An anomaly screening module is used to compare the current response fingerprint with the baseline response fingerprint, and mark suspected anomaly branches when at least one feature in the current response fingerprint exceeds the corresponding baseline interval. The microenvironment disturbance module is used to perform at least one of the following disturbances on the cabinet where the suspected abnormal branch is located: heating, dehumidification, air circulation, and micro-wind drying of the terminal area; The compensation determination module is used to subtract environmental interference from the current response fingerprint based on the changes in environmental parameters before and after the disturbance and the retest response fingerprint of suspected abnormal branches, to obtain the compensated response fingerprint and determine the source of the anomaly. The generation rule for the compensation response fingerprint is as follows: for the leakage current envelope area and decay time constant, the re-measured value after disturbance is used as the compensation feature quantity; for the first-order inflection point position and peak delay time of the reflected waveform, the value with the larger deviation between the first detection value and the re-measured value is used as the compensation feature quantity. The conclusion output module is used to output a conclusion that allows commissioning, postpones commissioning, or prohibits commissioning based on the compensation response fingerprint and the source of the anomaly.

2. The comprehensive status self-inspection system for prefabricated substations before commissioning as described in claim 1, characterized in that, The branch configuration module includes: Topology resolution unit and detection isolation unit; The topology parsing unit is used to generate a branch topology table based on the connection relationship between the high-voltage incoming terminal, the primary side of the transformer, the secondary side of the transformer, the low-voltage outgoing terminal, and the grounding terminal. The detection isolation unit is used to disconnect the operating loop between the branch under test and the external load before the low-energy test pulse is applied, while maintaining the test loop between the branch under test and the detection port.

3. The comprehensive status self-inspection system for prefabricated substations before commissioning as described in claim 2, characterized in that, The reference fingerprint module includes: Data filtering unit, feature extraction unit, and interval construction unit; The data filtering unit is used to remove data from factory test data, installation and commissioning data, and historical qualified data that have missing items, excessive range, or timestamp conflicts. The feature extraction unit is used to extract the decay time constant, leakage current envelope area, first-order inflection point position of the reflection waveform, peak delay time and rate of change of equivalent capacitance to ground from the filtered data. The interval construction unit is used to generate a corresponding benchmark interval based on the mean and dispersion of qualified samples under the same branch identifier.

4. The comprehensive status self-inspection system for prefabricated substations before commissioning as described in claim 1, characterized in that, The low-energy excitation module includes: Pulse parameter setting unit, branch switching unit, and safety interlocking unit; The pulse parameter setting unit is used to set the upper limit of the amplitude, the upper limit of the current, and the upper limit of the pulse width of the low-energy test pulse according to the rated voltage, insulation withstand voltage, and protection action threshold of the branch to be tested. The branch switching unit is used to sequentially connect to each branch to be detected according to the branch topology table; The safety interlocking unit is used to stop the low-energy test pulse output when a live signal, grounding unconfirmed signal, overvoltage signal, overcurrent signal, or protection interlock signal is detected.

5. The comprehensive status self-inspection system for prefabricated substations before commissioning as described in claim 4, characterized in that, The fingerprint acquisition module includes: Synchronous sampling unit, waveform shaping unit, and fingerprint packaging unit; The synchronous sampling unit is used to collect transient voltage, leakage current, reflected waveform and ground capacitance response at the same trigger time. The waveform shaping unit is used to perform amplitude limiting, baseline correction, and time alignment on the acquired signals; The fingerprint encapsulation unit is used to encapsulate the decay time constant, leakage current envelope area, first-order inflection point position of the reflected waveform, peak delay time, equivalent capacitance change rate to ground, and branch identifier into the current response fingerprint.

6. The comprehensive status self-inspection system for prefabricated substations before commissioning as described in claim 5, characterized in that, The anomaly filtering module includes: Single deviation judgment unit and anomaly type mapping unit; The single-item deviation judgment unit is used to determine whether each feature quantity in the current response fingerprint exceeds the corresponding benchmark interval; The anomaly type mapping unit is used to generate an insulation dampness type when the leakage current envelope area and attenuation time constant both exceed the corresponding reference range, to generate a connection contact anomaly type when the first inflection point position or peak delay time of the reflected waveform exceeds the corresponding reference range, and to generate a grounding anomaly type when the change rate of the ground equivalent capacitance of the grounding branch exceeds the corresponding reference range.

7. The comprehensive status self-inspection system for prefabricated substations before commissioning as described in claim 6, characterized in that, The microenvironment disturbance module includes: Disturbance strategy unit, disturbance execution unit, and disturbance limit unit; The disturbance strategy unit is used to select the disturbance method based on the cabinet location of the suspected abnormal branch, the abnormality type, the relative humidity inside the cabinet, the temperature inside the cabinet, the dew point temperature, and the terminal surface temperature. The disturbance execution unit is used to change the relative humidity, dew point difference, temperature gradient and terminal surface dryness of the cabinet where the suspected abnormal branch is located within a preset disturbance duration. The disturbance limit unit is used to reduce the disturbance power or stop the disturbance when the temperature inside the cabinet reaches the upper limit of the temperature, the rate of decrease of relative humidity reaches the upper limit of the humidity change, or the terminal surface temperature reaches the upper limit of the terminal temperature.

8. The comprehensive status self-inspection system for prefabricated substations before commissioning as described in claim 7, characterized in that, The compensation determination module includes: Disturbance data unit, retest unit, restoring calculation unit, and source determination unit; The disturbance data unit is used to collect the cabinet temperature, relative humidity, dew point temperature, dew point difference, cabinet wall temperature, terminal surface temperature, leakage current change rate, and insulation resistance recovery rate before and after the disturbance. The retesting unit is used to apply a low-energy test pulse to the suspected abnormal branch again with the same pulse parameters after the disturbance ends and generate a retesting response fingerprint. The recovery calculation unit is used to calculate the recovery of the retest response fingerprint relative to the reference response fingerprint; The source determination unit is used to determine that the source of the anomaly is environmental interference when the recovery degree is not less than the first threshold and the leakage current change rate is not less than the second threshold, and to determine that the source of the anomaly is equipment defect when the recovery degree is less than the first threshold and the deviation from the characteristic quantity still exceeds the corresponding reference range.

9. The comprehensive status self-inspection system for prefabricated substations before commissioning as described in claim 8, characterized in that, The compensation determination module also includes: Environmental deduction unit and margin correction unit; The environmental subtraction unit is used to subtract environmentally sensitive components from the current response fingerprint, which are characterized by changes in relative humidity, changes in dew point difference, changes in terminal surface temperature, leakage current rate of change, and insulation resistance recovery rate. The margin correction unit is used to generate a compensation response fingerprint based on the deducted decay time constant, leakage current envelope area, peak delay time, and rate of change of equivalent capacitance to ground, and sends the compensation response fingerprint to the conclusion output module.

10. The comprehensive status self-inspection system for prefabricated substations before commissioning according to claim 9, characterized in that, The conclusion output module includes: Risk classification unit, permit determination unit, and suggestion generation unit; The risk classification unit is used to map the compensation response fingerprint and anomaly source into six states: allowed to operate, environmental interference requires re-inspection, insulation dampness requires treatment, connection anomaly requires tightening and re-inspection, grounding anomaly requires maintenance, and actual insulation defect prohibits operation. The permission determination unit is used to output a permission to operate conclusion when the compensation response fingerprints of each branch to be tested are all within the corresponding reference range and there are no equipment defects; output a postponement to operate conclusion when there is environmental interference requiring re-inspection, insulation dampness requiring treatment, connection abnormality requiring tightening and re-inspection, or grounding abnormality requiring maintenance; and output a prohibition to operate conclusion when there is a real insulation defect prohibiting operation. The suggestion generation unit is used to output abnormal branch identification, abnormal characteristic quantity, abnormal source, retest time and handling suggestions. The handling suggestions include at least one of the following: dehumidification and ventilation retest, insulation retest after drying treatment, connection terminal tightening retest, grounding circuit repair and insulation defect investigation.

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