A charging pile electric leakage detection method and system

Abstract

The application discloses a charging pile electric leakage detection method and system, relates to the technical field of charging pile safety detection, and comprises the following steps: acquiring a current temperature, relative humidity and salt mist concentration combination of an environment where a charging socket is located as a first state; comparing the current temperature, relative humidity and salt mist concentration, and generating a terminal surface condensation state identifier; in response to an electric leakage trigger signal, acquiring a residual current phase feature; based on the condensation state identifier and the residual current phase feature, performing spatial recognition to determine that the electric leakage channel type is terminal surface interphase bridge electric leakage or cable-to-ground electric leakage; and according to the electric leakage channel type, outputting corresponding internal heating and dehumidification instructions or power-off isolation instructions. The method synchronously engages the environmental salt mist phase change state and the electric leakage occurrence node, implements directional dehumidification for terminal surface bridge electric leakage, implements power-off isolation for cable-to-ground electric leakage, and eliminates the problems of blind power-off and misplacing cables.

Description

Technical Field

[0001] This application relates to the field of charging pile safety testing technology, and in particular to a method and system for detecting leakage current in charging piles. Background Technology

[0002] New energy vehicle AC charging facilities face severe electrical safety challenges in the high-humidity, high-salt coastal environment. In coastal areas, the air is filled with salt-containing suspended particles. When nighttime temperatures drop sharply, water vapor condenses into droplets on the cold surfaces of the live and neutral terminals inside open charging sockets. The salt quickly dissolves in the water droplets, forming a highly conductive electrolyte. Existing conventional leakage current detection systems mainly rely on residual current transformers to detect differences in incoming and outgoing currents to determine whether leakage has occurred. Conventional leakage current detection methods are completely unable to identify the exact physical path of the leakage.

[0003] If a leakage occurs, it may occur at the electrolyte bridging point on the surface of the live wire terminal and the neutral wire terminal, or it may occur at the point where the external cable is damaged and discharges to ground.

[0004] Because conventional residual current transformers can only output current difference results, they fail to semantically correlate the physical phase change of environmental condensation with the timing of leakage, leaving conventional leakage detection systems in a passive response state. Conventional leakage judgment logic cannot distinguish between phase-to-phase bridging limited to the terminal surface and ground discharge penetrating to the ground at the moment of leakage. Once electrolyte bridging leakage occurs on the terminal surface, conventional leakage detection systems cannot implement targeted dehumidification protection for the inside of the socket. Maintenance personnel, relying on a single leakage alarm, misjudge it as cable dampness and take ineffective measures such as replacing cables, resulting in charging facilities operating with defects for extended periods, facing a serious risk of electrical fires. Summary of the Invention

[0005] In view of the aforementioned problems, this application is hereby filed.

[0006] Therefore, this application provides a method and system for detecting leakage current in charging piles, which can solve the problem that leakage current detection systems cannot identify the physical channels of terminal condensation bridging leakage current and cable-to-ground leakage current, leading to blind power outages and incorrect cable replacements.

[0007] To solve the above-mentioned technical problems, this application provides the following technical solution:

[0008] In a first aspect, this application provides a method for detecting leakage current in a charging pile, comprising: acquiring the current temperature, relative humidity and salt spray concentration of the environment where the charging socket is located, and combining the current temperature, the relative humidity and the salt spray concentration as a first state;

[0009] Based on the comparison of the current temperature, relative humidity and salt spray concentration contained in the first state, a condensation status identifier is generated on the terminal surface, and the condensation status identifier is used as the first identifier.

[0010] In response to the leakage current trigger signal output by the residual current transformer, the residual current phase characteristics at the moment of leakage current occurrence are obtained, and the residual current phase characteristics are used as the first characteristic.

[0011] Based on the first identifier and the first feature, the physical leakage current channel is spatially identified to determine the leakage current channel type, which includes terminal surface phase-to-phase bridging leakage current and cable-to-ground leakage current.

[0012] Match and output the corresponding first or second instruction based on the leakage current channel type. The first instruction is an internal heating and dehumidification instruction, and the second instruction is a power-off isolation instruction.

[0013] Preferably, the step of comparing the current temperature, relative humidity, and salt spray concentration included in the first state to generate a condensation status indicator on the terminal surface, and using the condensation status indicator as the first indicator, includes:

[0014] Obtain the current temperature, relative humidity, and salt spray concentration contained in the first state, and use the salt spray concentration as the first concentration;

[0015] Based on the current temperature and relative humidity, a preset dew point temperature lookup table is consulted to determine the pure water dew point temperature of the current environment, and the pure water dew point temperature is used as the second temperature.

[0016] Based on the first concentration, a preset salt deliquescence correction reference relationship is found, and the dew point correction value corresponding to the first concentration is determined, and the dew point correction value is used as the first correction value.

[0017] The first correction value is superimposed on the second temperature to obtain the critical temperature of salt spray condensation, and the critical temperature of salt spray condensation is used as the third temperature.

[0018] The current temperature is compared with the third temperature to generate a first comparison result.

[0019] In response to the first comparison result that the current temperature is lower than the third temperature, a condensation status identifier representing condensation on the terminal surface is generated, and the condensation status identifier is used as the first identifier.

[0020] In response to the first comparison result that the current temperature is higher than the third temperature, a drying status identifier characterizing the dryness of the terminal surface is generated, and the drying status identifier is used as the first identifier.

[0021] Preferably, the step of responding to the leakage current trigger signal output by the residual current transformer, acquiring the residual current phase characteristics at the moment of leakage, and using the residual current phase characteristics as the first feature includes:

[0022] In response to the leakage current trigger signal output by the residual current transformer, the phase of the live wire current and the phase of the neutral wire current at the moment the leakage occurs are obtained.

[0023] The phase difference between the live wire current and the neutral wire current is compared to generate a second comparison result;

[0024] Based on the second comparison result, the residual current phase characteristics at the moment of leakage are determined, and the residual current phase characteristics are used as the first feature.

[0025] The first feature includes phase-to-phase leakage current feature and phase-to-ground leakage current feature.

[0026] Preferably, the step of spatially identifying the leakage current physical channel based on the first identifier and the first feature to determine the leakage current channel type includes:

[0027] The first identifier is read and determined to be either a condensation state identifier or a dry state identifier.

[0028] In response to the first identifier being the condensation state identifier, the type of the first feature is determined;

[0029] In response to the first feature being a phase-to-phase leakage feature, the leakage channel type is determined to be a terminal surface phase-to-phase bridging leakage, and the terminal surface phase-to-phase bridging leakage is taken as the first type;

[0030] In response to the first feature being a leakage current to ground feature, the leakage current channel type is determined to be cable to ground leakage current, and the cable to ground leakage current is classified as the second type.

[0031] In response to the first identifier being the dry state identifier, the leakage current channel type is directly determined to be the second type.

[0032] Preferably, the step of matching and outputting a corresponding first or second instruction based on the leakage current channel type includes:

[0033] In response to determining that the leakage current channel type is the first type, a corresponding first instruction is generated;

[0034] The first instruction is sent to the heating and dehumidifying component inside the charging socket, controlling the heating and dehumidifying component to perform heating and dehumidifying operation on the terminal surface;

[0035] Obtain the updated first state after the heating and dehumidification operation is executed;

[0036] The first identifier is regenerated based on the updated first state, and in response to the updated first identifier being converted to the dry state identifier, the output of the first instruction is terminated.

[0037] Preferably, the step of matching and outputting a corresponding first instruction or second instruction based on the leakage current channel type further includes:

[0038] In response to determining that the leakage current channel type is the second type, a corresponding second instruction is generated;

[0039] The second instruction is sent to the main control switch of the charging pile to control the main control switch to perform a power-off isolation operation;

[0040] Generate a cable troubleshooting instruction corresponding to the second type, and send the cable troubleshooting instruction to the operation and maintenance management terminal;

[0041] In response to receiving the troubleshooting completion signal from the operation and maintenance management terminal, the second instruction is released and the main control switch is restored to its on state.

[0042] Preferably, in response to the first identifier being the condensation state identifier and determining the leakage current channel type to be the second type, the method further includes:

[0043] In response to the first identifier being the condensation state identifier and the leakage current channel type being the second type, a third instruction is generated and the third instruction is used as a forced power-off isolation instruction.

[0044] The third instruction is sent to the main control switch of the charging pile to control the main control switch to perform a power-off operation.

[0045] Generate a ground leakage warning message, bind and package the ground leakage warning message with the condensation status identifier, and send it to the operation and maintenance management terminal;

[0046] In response to the cable replacement confirmation signal fed back by the operation and maintenance management terminal based on the ground leakage warning information, the third instruction is cancelled.

[0047] Preferably, the step of determining the pure water dew point temperature of the current environment by looking up a preset dew point temperature comparison table based on the current temperature and the relative humidity, and using the pure water dew point temperature as the second temperature, and the step of determining the dew point correction value corresponding to the first concentration by looking up a preset salt deliquescence correction comparison table based on the first concentration, and using the dew point correction value as the first correction value, includes:

[0048] Obtain a dew point temperature data table that is cross-mapped with multiple pre-calibrated temperature ranges and multiple humidity ranges, and use the dew point temperature data table as a preset dew point temperature reference table.

[0049] The current temperature is range-based to determine the first target temperature range to which the current temperature belongs;

[0050] The relative humidity is range-based to determine the first target humidity range to which the relative humidity belongs;

[0051] Extract the dew point temperature data at the intersection of the first target temperature range and the first target humidity range from the preset dew point temperature reference table, and use the dew point temperature data as the second temperature.

[0052] Obtain a deliquescence correction data table that maps multiple pre-calibrated concentration ranges to multiple correction values, and use the deliquescence correction data table as a preset salt deliquescence correction reference relationship;

[0053] The first concentration is range-based to determine the first target concentration range to which the first concentration belongs;

[0054] Extract the correction value corresponding to the first target concentration range from the preset salt deliquescence correction control relationship, and use the correction value as the first correction value.

[0055] Preferably, the step of comparing the phase difference between the live wire current and the neutral wire current to generate a second comparison result includes:

[0056] Obtain the instantaneous phase angle of the live wire current and the instantaneous phase angle of the neutral wire current at the same moment of leakage occurrence;

[0057] The instantaneous phase angle of the live wire current and the instantaneous phase angle of the neutral wire current are compared to generate phase difference data.

[0058] The phase difference data is compared with a preset interphase leakage phase threshold range. In response to the phase difference data falling within the preset interphase leakage phase threshold range, a second comparison result characterizing interphase leakage is generated.

[0059] The phase difference data is compared with a preset ground leakage phase threshold range. In response to the phase difference data falling within the preset ground leakage phase threshold range, a second comparison result characterizing ground leakage is generated.

[0060] Secondly, this application also provides a charging pile leakage detection system, including: a status acquisition module, used to acquire the current temperature, relative humidity and salt spray concentration of the environment where the charging socket is located, and to combine the current temperature, the relative humidity and the salt spray concentration as a first state;

[0061] The status identifier generation module is used to compare the current temperature, relative humidity and salt spray concentration contained in the first status to generate a condensation status identifier on the terminal surface, and use the condensation status identifier as the first identifier.

[0062] The leakage current feature acquisition module is used to acquire the residual current phase feature at the moment of leakage in response to the leakage current trigger signal output by the residual current transformer, and to use the residual current phase feature as the first feature.

[0063] The channel type determination module is used to spatially identify the leakage physical channel based on the first identifier and the first feature, and determine the leakage channel type, wherein the leakage channel type includes terminal surface phase-to-phase bridging leakage and cable-to-ground leakage;

[0064] The disposal instruction output module is used to match and output a corresponding first instruction or second instruction according to the leakage current channel type. The first instruction is an internal heating and dehumidification instruction, and the second instruction is a power-off isolation instruction.

[0065] Implementing this application will have the following beneficial effects:

[0066] This application provides a method and system for detecting leakage current in charging piles. This application maps ambient temperature, humidity, and salt spray concentration data to the physical phase change state of the microscopic terminal surface. It corrects the pure water dew point temperature using a salt deliquescence correction value, capturing the phase change conditions of condensation in coastal salt spray, thus overcoming the limitation of conventional methods in detecting electrolyte formation conditions on the terminal surface. At the moment of leakage, the system separates the interphase bridging leakage current on the terminal surface based on the condensation state indicator and the phase characteristics of the residual current, completing the spatial identification of the physical channel. For bridging leakage current on the terminal surface, the system outputs a heating and dehumidification command to eliminate condensation conditions at the source; for cable-to-ground leakage, it outputs a power-off isolation command. This solution avoids maintenance personnel blindly replacing cables, blocks corrosion and heat generation caused by hidden leakage current on the terminal surface, and reduces the risk of electrical fires. Attached Figure Description

[0067] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0068] Figure 1 This is a flowchart of a method for detecting leakage current in a charging pile, which is involved in this application;

[0069] Figure 2 This is an application environment diagram of a charging pile leakage detection method involved in this application;

[0070] Figure 3 This is an abstract relational diagram of a charging pile leakage detection method involved in this application;

[0071] Figure 4 This is a mathematical transformation matrix diagram for solving the critical temperature of salt spray condensation in a charging pile leakage detection method involved in this application.

[0072] Figure 5 This is a schematic diagram illustrating the contribution of each functional module of the charging pile leakage detection method involved in this application to the system performance.

[0073] Figure 6 This is a schematic diagram illustrating the comprehensive evaluation of multiple indicators of the present invention and baseline method for a charging pile leakage detection method involved in this application;

[0074] Figure 7 This is a schematic diagram illustrating the impact of multi-dimensional parameters of a charging pile leakage detection method involved in this application on system performance;

[0075] Figure 8 This is a schematic diagram of the system stability under noise / harmonic / sudden temperature change / repeated experiment of a charging pile leakage detection method involved in this application.

[0076] Figure 9 This is a schematic diagram illustrating the threshold sensitivity, estimation error, and timing stability of a charging pile leakage detection method involved in this application. Detailed Implementation

[0077] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0078] Example 1, referring to Figures 1-9 This is the first embodiment of the present application, which provides a method for detecting leakage current in a charging pile, including:

[0079] This application provides a method that can effectively solve the problems mentioned above. The following will describe in detail how to implement the charging pile leakage detection method with reference to several embodiments.

[0080] Figure 1 A flowchart of a method for detecting leakage current in charging piles is shown, with applications such as... Figure 2 The application environment diagram shows a coastal high-humidity, high-salt charging environment, indicated by a dashed box, as its outer boundary. This environment is filled with air containing salt-laden suspended particles. A sudden drop in temperature at night causes water vapor to condense and undergo a phase change on the cold terminal surfaces. The charging pile, as the core physical carrier, is deployed within this charging environment. A multi-functional weather sensor and a residual current transformer are installed on the top of the charging pile. The multi-functional weather sensor collects current, relative humidity, and salt mist concentration data, encapsulates them as a first state, and transmits them to the control processor. The residual current transformer monitors the current difference of the open charging socket, outputting a leakage trigger signal and residual current phase characteristics when leakage is detected. The open charging socket contains a live wire terminal, a neutral wire terminal, and a ground wire terminal. After the temperature drops at night, salt mist condensation forms on the surfaces of the live and neutral wire terminals, bridging them with electrolyte and creating an interphase bridging leakage path. A heating and dehumidifying component is installed on the inner wall of the charging socket. An external charging cable is led out from the charging socket and connected to the new energy vehicle. Damaged insulation on the external charging cable forms a leakage path to the ground. AC power supplies the charging pile via a main control switch. The control processor identifies the leakage path type based on condensation status indicators and leakage phase characteristics, then outputs an internal heating and dehumidification command to drive the heating and dehumidification component, or outputs a power-off isolation command to control the main control switch to perform a power-off operation. The output of the main control switch is connected to a voltage detection circuit; when the residual voltage has not decayed to a safe threshold, a local audible and visual alarm is triggered. The control processor interacts with an operation and maintenance management terminal deployed outside the charging environment via a wireless communication link, sending cable troubleshooting commands or ground leakage warning information to the operation and maintenance management terminal, and receiving a troubleshooting completion signal or cable replacement confirmation signal from the operation and maintenance management terminal to release the forced power-off isolation state. The method includes:

[0081] Step S1: Obtain the current temperature, relative humidity, and salt spray concentration of the environment where the charging socket is located, and combine the current temperature, relative humidity, and salt spray concentration as the first state;

[0082] Understandably, monitoring single meteorological data points cannot fully depict the complex physical phase transition processes faced by charging facilities in coastal high-humidity and high-salt environments. The first state refers to a data set formed by packaging and aggregating multi-dimensional environmental sensor data, serving as the benchmark data source for subsequent physical phase transition determination and channel spatial identification. Specifically, through a multi-functional meteorological sensor probe deployed outside the charging socket, the current temperature, relative humidity, and salt spray concentration are simultaneously collected. These three physical values ​​are encapsulated into a first state with a fixed byte length, thus providing complete environmental state input support for subsequent logical calculations.

[0083] Step S2: Based on the current temperature, relative humidity and salt spray concentration contained in the first state, a condensation status identifier on the terminal surface is generated, and the condensation status identifier is used as the first identifier.

[0084] It should be pointed out that relying solely on the physical theory of pure water dew point cannot accurately reflect the lowering effect of salt presence on the condensation critical condition. The condensation state identifier refers to a logical label used to characterize whether the terminal surface has crossed the critical point of water vapor condensation phase transition. To establish a precise mapping between the macroscopic environment and the physical state of the microscopic terminal surface, the salt spray concentration in the first state needs to be used as a correction parameter in the condensation determination process, thereby generating a high-fidelity first identifier and providing a fundamental preliminary state benchmark for subsequently distinguishing leakage current physical channels.

[0085] Optionally, the step of comparing the current temperature, relative humidity, and salt spray concentration included in the first state to generate a condensation status indicator on the terminal surface, and using the condensation status indicator as the first indicator, includes:

[0086] Step S2.1: Obtain the current temperature, relative humidity and salt spray concentration contained in the first state, and use the salt spray concentration as the first concentration;

[0087] Specifically, the first state serves as an encapsulated set of multidimensional data, storing environmental physical values ​​of different dimensions according to preset field offsets. The first concentration refers to the salt spray concentration value extracted and independently identified from the first state. Upon receiving the first state data packet, the current temperature, relative humidity, and salt spray concentration are extracted according to a predefined data parsing protocol, and the salt spray concentration is assigned to a variable. This allows it to participate in logical operations as an independent corrective input variable in subsequent mathematical derivations.

[0088] Step S2.2: Based on the current temperature and relative humidity, look up a preset dew point temperature lookup table to determine the pure water dew point temperature of the current environment, and use the pure water dew point temperature as the second temperature.

[0089] Furthermore, the pure water dew point temperature refers to the critical temperature at which water vapor begins to condense into liquid water droplets under standard physical conditions, without considering the hygroscopic and deliquescent effects of salt. The preset dew point temperature lookup table refers to a two-dimensional data matrix pre-discretized based on the classical thermodynamic Magnus formula. The current temperature... With the relative humidity As input, a cross-referencing search is performed in the preset dew point temperature lookup table, and the precise critical temperature value is calculated using the bilinear interpolation method, which is defined as the second temperature. .

[0090] Specifically, let the dew point data of the four adjacent grid points retrieved from the lookup table be as follows: Current temperature The weight within the interval is Current humidity The weight within the interval is The mathematical expression for the bilinear interpolation solution is shown in the table below:

[0091]

[0092] In the above formula (1), the variable Represents the uncorrected pure water dew point temperature, a variable. The offline calibration dew point data represents the current temperature and humidity at the bottom left node of the grid. (Variable) The calibration data representing the top-left node, variables The calibration data representing the bottom right node, variables The calibration data representing the top right node, variables The variable represents the proportional weight of the current temperature relative to the temperature of the bottom left node. This represents the proportional weight of the current humidity relative to the humidity of the bottom left node.

[0093] Furthermore, through weighted summation, the discrete grid data is smoothly mapped to continuous pure water dew point temperature. In this application, the offline calibration dew point data is acquired using a high-precision temperature and humidity dew point meter under standard atmospheric pressure.

[0094] Optionally, the step of determining the pure water dew point temperature of the current environment by looking up a preset dew point temperature lookup table based on the current temperature and relative humidity, and using the pure water dew point temperature as the second temperature, and the step of determining the dew point correction value corresponding to the first concentration by looking up a preset salt deliquescence correction lookup table based on the first concentration, and using the dew point correction value as the first correction value, includes:

[0095] Step S2.21: Obtain a dew point temperature data table that is cross-mapped with multiple temperature ranges and multiple humidity ranges in advance, and use the dew point temperature data table as a preset dew point temperature reference table.

[0096] In this embodiment, the continuous temperature and humidity space is discretized into a finite grid to reduce the resource overhead of real-time calculation. A temperature interval refers to a continuous sub-segment obtained by equally dividing the entire temperature range according to a fixed step size. Similarly, a humidity interval refers to a continuous sub-segment obtained by equally dividing the entire humidity range according to a fixed step size. The dew point temperature data table is a two-dimensional matrix structure, where row indices represent different temperature intervals, column indices represent different humidity intervals, and the values ​​in the matrix cells represent the pure water dew point temperature calculated offline using the Magnus formula for that temperature and humidity combination. Here, the fixed step size is set comprehensively by combining the sensor's measurement resolution and the controller's memory capacity.

[0097] Step S2.22: Perform interval positioning on the current temperature to determine the first target temperature interval to which the current temperature belongs;

[0098] Furthermore, interval positioning refers to the process of assigning continuous measurement values ​​to a preset discrete grid. The first target temperature interval refers to the row index position of the current temperature in the dew point temperature data table. The current temperature is compared with the upper and lower limits of each temperature interval one by one. When the current temperature falls within the closed interval of a certain temperature interval, the temperature interval is marked as the first target temperature interval, thereby completing the discretization mapping of the temperature dimension.

[0099] Step S2.23: Perform interval positioning on the relative humidity to determine the first target humidity interval to which the relative humidity belongs;

[0100] Meanwhile, the first target humidity range refers to the column index position of the relative humidity in the dew point temperature data table. The relative humidity is compared with the upper and lower limits of each humidity range one by one. When the relative humidity falls within the closed interval of a certain humidity range, the humidity range is marked as the first target humidity range, thereby completing the discretization mapping of the humidity dimension.

[0101] Step S2.24: Extract the dew point temperature data at the intersection of the first target temperature range and the first target humidity range from the preset dew point temperature reference table, and use the dew point temperature data as the second temperature.

[0102] On the other hand, the intersection point refers to the matrix cell where the row determined by the first target temperature range intersects with the column determined by the first target humidity range. Using the first target temperature range as the row number and the first target humidity range as the column number, a two-dimensional array addressing operation is performed on the preset dew point temperature lookup table to read the dew point temperature data stored at the intersection point, and this data is used as the value in the aforementioned formula (1). Data from adjacent grid points were extracted in the same way, and the continuous second temperature was finally calculated. Thus, the critical reference value for pure water condensation without considering the salt effect is obtained.

[0103] Step S2.3: Based on the first concentration, find the preset salt deliquescence correction reference relationship, determine the dew point correction value corresponding to the first concentration, and use the dew point correction value as the first correction value.

[0104] Furthermore, the salt deliquescence correction control relationship refers to a one-dimensional data table, pre-calibrated experimentally, reflecting the mapping relationship between different sodium chloride concentrations and dew point rise. The dew point correction value refers to the amount of temperature compensation that needs to be added to the pure water dew point temperature to compensate for the hygroscopic properties of salt. The first concentration... As input, the corresponding dew point correction value is calculated by fitting a pre-defined piecewise function relationship. This was used to quantify the effect of salt spray environment on lowering the condensation threshold.

[0105] Specifically, the mathematical expression of the piecewise fitting relationship is shown in the table below:

[0106]

[0107] In the above formula (2), the variable The first concentration extracted from the first state is represented by the variable. The lower limit threshold of concentration at which sodium chloride begins to exhibit significant deliquescence is a variable. The upper limit of the concentration threshold representing the saturation of sodium chloride's deliquescent effect; variables. Represents the linear growth slope constant, variable Represents the maximum correction value under saturation conditions, variable This represents the first correction value generated by the calculation.

[0108] Furthermore, when the concentration is low, the correction value is 0; when the concentration is in the middle range, the correction value increases linearly with the concentration; when the concentration exceeds the upper limit, the correction value is locked at the saturation maximum value. In this embodiment, the lower limit threshold concentration is... upper limit of concentration threshold linear growth slope constant and the maximum correction value The condensation critical point of sodium chloride aerosols at different concentrations in a closed chamber was obtained by optical observation and calibration.

[0109] Step S2.31: Obtain a deliquescence correction data table that maps multiple pre-calibrated concentration ranges to multiple correction values, and use the deliquescence correction data table as a preset salt deliquescence correction reference relationship;

[0110] Specifically, the concentration range refers to a continuous segment obtained by dividing the salt spray concentration measurement range according to a linear or logarithmic step size. The correction value refers to the dew point rise measured by a physical experiment on the saturated vapor pressure of a salt solution under a specific concentration range. The deliquescence correction data table refers to a one-dimensional lookup table with the concentration range as the index and the correction value as the mapping value, used for offline storage of the segment boundary parameters in the aforementioned formula (2). Here, the multiple concentration ranges and multiple correction values ​​are obtained by optical observation and calibration of the condensation critical point of sodium chloride aerosols of different concentrations in a closed chamber.

[0111] Step S2.32: Analyze the first concentration range to determine the first target concentration range to which the first concentration belongs;

[0112] Furthermore, the first target concentration range refers to the index position of the first concentration in the deliquescence correction data table. The first concentration is compared with the boundary values ​​of each concentration range one by one. When the first concentration falls within the closed interval of a certain concentration range, the concentration range is marked as the first target concentration range, thereby completing the discretization mapping of the concentration dimension.

[0113] Step S2.33: Extract the correction value corresponding to the first target concentration range from the preset salt deliquescence correction control relationship, and use the correction value as the first correction value;

[0114] Simultaneously, using the first target concentration range as the query key, a one-dimensional array addressing operation is performed in the preset salinity deliquescence correction control relationship to read the segmentation parameters mapped to that range, and substitute them into the aforementioned formula (2) to calculate the correction value. This allows us to obtain dynamic phase transition compensation parameters for the current salt spray environment.

[0115] Step S2.4: Add the first correction value to the second temperature to obtain the critical temperature of salt spray condensation, and use the critical temperature of salt spray condensation as the third temperature;

[0116] It should be noted that the second temperature This only reflects the phase transition critical point of a pure water system. However, in coastal salt spray environments, due to the strong hygroscopicity of sodium chloride particles, the terminal surface begins to absorb moisture and deliquesce to form an electrolyte at temperatures far above the dew point of pure water. The salt spray condensation critical temperature refers to the actual physical temperature at which a conductive liquid film begins to form on the terminal surface, taking into account both ambient temperature and humidity as well as the deliquescent characteristics of salt. (First correction value) As a compensation for the quantification of salt deliquescence effect, its physical meaning is the temperature value that raises the dew point temperature of pure water.

[0117] Specifically, based on the output results of the aforementioned formulas (1) and (2), the mathematical expression of the superposition operation is shown in the following table:

[0118]

[0119] In the above formula (3), the variable Represents the uncorrected pure water dew point temperature, a variable. This represents the dew point correction value calculated based on the current salt spray concentration; the variable is... This represents the critical temperature at which salt fog condensation is generated after compensation for the salt deliquescence effect.

[0120] Furthermore, the dew point temperature of the pure water... With the dew point correction value Perform arithmetic addition, and directly assign the result to the variable. This completes the mathematical mapping from the pure water phase transition model to the salt spray phase transition model. In this embodiment, the dew point correction value... The value range is calibrated based on the extreme value distribution of historical salt fog concentration in coastal areas to ensure that effective phase transition critical compensation can still be provided under extremely high salinity environments.

[0121] Furthermore, under specific operating conditions, the critical temperature for salt spray condensation... If the temperature exceeds the preset reasonable physical range, in order to avoid over-correction leading to misjudgment of the state, it is also necessary to determine the critical temperature of salt spray condensation after completing the superposition operation. Numerical cutoff control is performed. On the other hand, if the critical temperature for salt spray condensation is detected... If the temperature exceeds the upper limit of the current ambient temperature, it is forcibly assigned the upper limit of the current ambient temperature. This boundary limitation method ensures that the data input to the next stage has a high degree of physical determinism. In this embodiment, the reasonable physical range is specifically obtained based on historical meteorological data of the charging facility's operating environment.

[0122] Step S2.5: Compare the current temperature with the third temperature to generate a first comparison result;

[0123] In this application, the first comparison result refers to a Boolean state quantity used to characterize whether the current ambient temperature has crossed the critical temperature for salt spray condensation. To accurately capture the instantaneous physical phase transition at the terminal surface, it is necessary to input the current temperature... The third temperature calculated using the aforementioned formula (3) A rigorous numerical comparison is performed. Specifically, the mathematical expression of the numerical comparison operation is shown in the table below:

[0124]

[0125] In the above formula (4), the variable Represents the current temperature, variable The variable represents the critical temperature at which salt spray condensation is generated, calculated in the preceding steps. This represents the first alignment result generated.

[0126] If the current temperature Greater than or equal to the critical temperature of salt spray condensation When the current temperature is 0, the output value is 0, indicating that the current environment has not crossed the phase transition critical point; when the current temperature is 0... Less than the critical temperature for salt spray condensation When the time is reached, the output value is 1, indicating that the current environment has crossed the phase transition critical point.

[0127] Furthermore, the pseudocode is expressed as follows:

[0128]

[0129] Furthermore, in the input / output definition stage, the input source is explicitly defined as the real-time acquired current temperature and the previously calculated critical temperature for salt spray condensation. In the conditional judgment line, a numerical comparison logic is established; if the current temperature is strictly less than the critical temperature for salt spray condensation, it is determined that the surface of the micro-terminal has the conditions for condensation. In the result assignment line, a Boolean variable is... The value is assigned to 1, indicating that the condensation condition is met; if the condition is not met, the Boolean variable is set to 1. A value of 0 indicates that the terminal surface is in a dry state.

[0130] In particular, when in a coastal area where sea breezes prevail, if the current temperature drops sharply in a very short period of time due to the passage of cold air, and when the current temperature... With respect to the critical temperature of salt spray condensation If the absolute value of the difference is less than the preset phase transition blur band threshold, then directly output If the value is 1, the state may be reversed due to instantaneous temperature fluctuations; if the current temperature The temperature remains below the critical temperature for salt spray condensation. And if the lock is engaged when the duration exceeds the preset hysteresis time. If the value is 1, it can effectively filter instantaneous interference; if the current temperature If the phase transition ambiguity band is repeatedly oscillated, then the previous moment's state is maintained. The value remains unchanged; if the current temperature Significantly higher than the critical temperature for salt spray condensation. Then force Zeroing. In this application, the preset phase transition ambiguity threshold and the preset hysteresis duration are obtained by optical observation and statistical analysis of the liquid film formation and evaporation process on the terminal surface under typical salt spray climate conditions.

[0131] Step S2.6: In response to the first comparison result that the current temperature is lower than the third temperature, a condensation status identifier representing condensation on the terminal surface is generated, and the condensation status identifier is used as the first identifier.

[0132] For example, condensation status identification refers to tag data used to mark the physical state of the terminal surface in subsequent logic flows.

[0133] If the first comparison result is received A value of 1 indicates that the current temperature is below the critical temperature for salt spray condensation, and the physical phase transition process of salt deliquescence and water vapor condensation has begun on the terminal surface. Specifically, in response to the first comparison result... If the value is 1, a specific status code is generated in memory, the status code is defined as the condensation status identifier, and the condensation status identifier is assigned to the variable first identifier.

[0134] Furthermore, the first identifier not only includes the Boolean state of condensation occurrence, but also includes the timestamp information of the current moment, so as to perform semantic matching of the time dimension when leakage occurs.

[0135] Furthermore, the first identifier is pushed into the high-order byte of the status register for real-time reading by the leakage current channel identification module. In this embodiment, the length and format of the status code are uniformly set through the data frame specification of the underlying communication protocol.

[0136] It should be noted that, in order to ensure the continuity of status determination, a timed monitoring task needs to be started after the condensation status identifier is generated.

[0137] Furthermore, the current temperature and the critical temperature for salt spray condensation are reacquired according to the preset refresh cycle, and the aforementioned comparison operation is performed.

[0138] Furthermore, as long as the first comparison result is obtained in multiple consecutive refresh cycles... If the value is 1, the first identifier is continuously locked as the condensation state identifier to avoid state fluctuations caused by noise from a single acquisition. In this application, the preset refresh cycle is set according to the response delay of the meteorological sensor.

[0139] Step S2.7: In response to the first comparison result that the current temperature is higher than the third temperature, a drying status identifier characterizing the dryness of the terminal surface is generated, and the drying status identifier is used as the first identifier;

[0140] Preferably, the dryness status indicator refers to label data used to mark that no condensation has occurred on the terminal surface during subsequent logic flows.

[0141] If the first comparison result is received A value of 0 indicates that the current temperature is above the critical temperature for salt spray condensation, and the terminal surface does not possess the physical conditions for forming an electrolyte bridge. Specifically, in response to the first comparison result... If the value is 0, another specific status code is generated in memory, the status code is defined as the drying status identifier, and the drying status identifier is assigned to the variable first identifier, overwriting the original status value in the register.

[0142] Furthermore, the drying status identifier is also appended with the current time's timestamp information.

[0143] Furthermore, if the first comparison result If the status code remains 0, the timestamp information in the first identifier is periodically refreshed to ensure the real-time nature of the status data. In this application, the update frequency of the status code is synchronized with the sampling frequency of the residual current transformer to eliminate logical deviations caused by timestamp misalignment.

[0144] Furthermore, after generating the drying status identifier, if a heating dehumidification operation has been performed previously, a dehumidification completion event identifier needs to be generated simultaneously.

[0145] Furthermore, the dehumidification completion event flag is bound to the drying status flag and written into the log storage area to trace the complete time chain of condensation elimination. In this embodiment, the log storage area is managed using a ring-shaped overwrite writing method.

[0146] For example, in a coastal area where the temperature drops sharply at night, the current temperature drops to 18°C, the relative humidity rises to 90%, and the salt spray concentration is detected as 5%. By looking up the calibration table, the pure water dew point temperature is found to be 16°C, and a correction value of 3°C is obtained based on the salt spray concentration. The critical temperature for salt spray condensation is calculated to be 19°C. Since the current temperature is below this critical temperature, a condensation status indicator is generated. When the daytime temperature rises back to 25°C, which is above the critical temperature for salt spray condensation, a dry status indicator is generated.

[0147] Step S3: In response to the leakage current trigger signal output by the residual current transformer, obtain the residual current phase characteristics at the moment of leakage current occurrence, and use the residual current phase characteristics as the first feature.

[0148] Understandably, a simple anomaly in current amplitude cannot reflect the exact physical path of leakage. The leakage trigger signal refers to the interrupt level issued by the residual current transformer hardware when the difference between the incoming and outgoing currents exceeds a safety threshold. The first characteristic refers to the characteristic quantity used to characterize the phase relationship between the leakage current waveform and the reference voltage vector. To establish a mapping between leakage phenomena and the physical path, it is necessary to capture the phase characteristics of the residual current at the moment of leakage, thus providing a core basis for subsequent spatial identification.

[0149] Optionally, the step of responding to the leakage current trigger signal output by the residual current transformer, acquiring the residual current phase characteristics at the moment of leakage, and using the residual current phase characteristics as the first feature, includes:

[0150] Step S3.1: In response to the leakage current trigger signal output by the residual current transformer, obtain the phase of the live wire current and the phase of the neutral wire current at the moment the leakage occurs.

[0151] Specifically, the phase of the live wire current refers to the phase angle of the live wire current waveform relative to the reference synchronization signal. Similarly, the phase of the neutral wire current refers to the phase angle of the neutral wire current waveform relative to the reference synchronization signal.

[0152] When the residual current transformer outputs a high-level interrupt signal, it triggers the data acquisition unit to latch the instantaneous phase angle of the live wire current and the instantaneous phase angle of the neutral wire current at the current moment, and stores the two phase angle values ​​into the dual-port register for subsequent processing modules to read.

[0153] Step S3.2: Compare the phase difference between the live wire current and the neutral wire current to generate a second comparison result;

[0154] Furthermore, the second comparison result refers to the classification label used to characterize the phase-to-phase bridging or ground discharge characteristics when leakage occurs. Under purely resistive ground leakage conditions, the phase of the residual current is close to 0 degrees; however, under terminal surface phase-to-phase bridging leakage conditions, due to the capacitive characteristics of the electrolyte impedance, the phase of the residual current will shift significantly. By comparing the phase difference between the live wire and neutral wire currents, characteristic parameters that distinguish physical channels can be extracted.

[0155] Optionally, the step of comparing the phase difference between the live wire current and the neutral wire current to generate a second comparison result includes:

[0156] Step S3.21: Obtain the instantaneous phase angle of the live wire current and the instantaneous phase angle of the neutral wire current at the same moment of leakage.

[0157] Specifically, the instantaneous phase angle refers to the angle of the current vector extracted by the phase-locked loop circuit at the instant of leakage triggering. To obtain a high-precision phase angle, it is calculated by capturing the difference between the zero-crossing time of the voltage reference waveform and the zero-crossing time of the current waveform. Under the same clock cycle, the zero-crossing time of the reference voltage is obtained. Zero-crossing time of live wire current and the zero-crossing time of the neutral current Combined with power frequency cycle The mathematical expression for solving the instantaneous phase angle is shown in the table below:

[0158]

[0159]

[0160] In formulas (5) and (6), the variables Represents the voltage zero-crossing timestamp under the same clock reference, variable Represents the zero-crossing timestamp of the live wire current, variable Represents the zero-crossing timestamp of the neutral current, variable Represents the power frequency period constant, variable Represents the instantaneous phase angle of the calculated live wire current, variable This represents the instantaneous phase angle of the calculated neutral current.

[0161] Furthermore, by multiplying the ratio of the time difference to the period by the circumferential angle, the physical quantity in the time domain is mapped to an angular value in the phase domain. In this application, the acquisition accuracy of the timestamp is jointly determined by the clock frequencies of the front-end comparator and the high-frequency counter.

[0162] Step S3.22: Compare the instantaneous phase angle of the live wire current with the instantaneous phase angle of the neutral wire current to generate phase difference data;

[0163] In practical applications, due to the nonlinear impedance characteristics of the electrolyte bridging on the terminal surface, the leakage current flowing between the live wire and the neutral wire will cause a drastic difference in their instantaneous phase. This is based on the outputs of the aforementioned formulas (5) and (6). and The mathematical expressions for the difference comparison and normalization operations are shown in the table below:

[0164]

[0165]

[0166] In the above formula (7), the variable Represents the instantaneous phase angle of the live wire current, variable Represents the instantaneous phase angle of the neutral current, variable This represents the absolute value of the calculated phase difference. In formula (8), the variable... Represents the preset maximum possible phase difference constant, variable This represents the normalized phase difference data.

[0167] Furthermore, the instantaneous phase angle of the live wire current... The instantaneous phase angle with the neutral current The subtraction operation is performed and the absolute value is taken to eliminate the ambiguity of the positive and negative signs caused by the definition of the current direction. Then, it is divided by the maximum possible phase difference constant to map it to a standardized range of zero to one, facilitating subsequent unified threshold comparison. In this application, the instantaneous phase angle... and The accuracy of the acquisition is determined by the frequency multiplication factor of the front-end phase-locked loop.

[0168] Furthermore, due to potential high-order harmonic interference in the power grid, the directly calculated phase difference data... It may contain transient glitches. To eliminate this interference, a median filter is performed after obtaining the phase difference over several consecutive clock cycles.

[0169] Furthermore, multiple normallyized phase difference data acquired consecutively are... Sort the data, remove the maximum and minimum values, take the average of the remaining data, and then reassign the filtered result to the variable. In this embodiment, the window length of the median filter is set according to the harmonic distribution characteristics of the power grid.

[0170] Step S3.23: Compare the phase difference data with a preset interphase leakage phase threshold range. In response to the phase difference data falling into the preset interphase leakage phase threshold range, generate a second comparison result characterizing the interphase leakage.

[0171] Furthermore, the phase-to-phase leakage current threshold range refers to the normalized phase difference distribution range obtained from historical terminal surface salt spray condensation leakage current data. This is based on the normalized phase difference value data output from the aforementioned formula (8). The mathematical expression of the landing area determination operation is shown in the table below:

[0172]

[0173] In the above formula (9), the variable The variable represents the normalized phase difference data generated by the preceding steps. Represents the preset normalized phase lower limit threshold for inter-phase leakage current, variable Represents the preset normalized phase upper limit threshold for inter-phase leakage current, variable This represents the generated second alignment result.

[0174] If the normalized phase difference data satisfy If the current leakage is determined to be caused by electrolyte bridging on the terminal surface, the output will be... A value of 1 indicates the phase-to-phase leakage current attribute. In this embodiment, the preset phase-to-phase leakage current normalized lower limit threshold is... With upper limit threshold This data was obtained through statistical analysis of a large number of leakage current phase difference samples obtained by applying electrolytes of different concentrations between the live and neutral terminals under simulated salt spray conditions.

[0175] It should be noted that the range of interphase leakage phase threshold is not fixed, but rather varies slightly with changes in ambient temperature.

[0176] Furthermore, before performing the comparison operation, the upper and lower limits of the interphase leakage phase threshold range are dynamically fine-tuned by querying the preset temperature compensation coefficient table based on the current temperature.

[0177] Furthermore, the finely adjusted threshold is incorporated into the comparison logic, thereby improving the accuracy of discrimination under extreme temperatures. In this application, the temperature compensation coefficient table is obtained through a variable-temperature leakage current simulation experiment conducted in a constant-temperature chamber.

[0178] Step S3.24: Compare the phase difference data with a preset ground leakage phase threshold range. In response to the phase difference data falling into the preset ground leakage phase threshold range, generate a second comparison result characterizing ground leakage.

[0179] To establish a complete closed-loop discrimination mechanism, the ground leakage phase threshold range refers to the normalized phase difference distribution range obtained from the statistical analysis of historical data on ground discharge due to cable insulation damage, which is typically close to the low phase difference region of a purely resistive load. This follows the output of the aforementioned formula (8). The branch in the aforementioned formula (9) is expanded into a comprehensive piecewise function that includes the determination of leakage current to ground:

[0180]

[0181] In the formula (10), the variable Represents the preset normalized phase lower limit threshold for leakage current to ground, variable This represents the preset normalized phase upper limit threshold for leakage current to ground.

[0182] If the normalized phase difference data satisfy If the current leakage is determined to be caused by damage to the insulation of the external cable, the output will be... A value of 2 indicates leakage current to ground; if none of these conditions are met, then the output is... A value of 0 indicates an abnormal, unknown state. In this application, the normalized phase lower limit threshold for ground leakage current... With upper limit threshold This was achieved by simulating cable insulation failure discharge under different soil moisture conditions and collecting leakage current phase difference samples.

[0183] Furthermore, if the output of the second alignment result A value of 0 indicates that the current leakage type is unknown or that a complex leakage path exists.

[0184] Furthermore, a feature code representing the abnormal state is generated and written into the second comparison result, triggering the hardware verification process. In this embodiment, the hardware verification process performs a retest by increasing the sampling rate of the residual current transformer.

[0185] Step S3.3: Based on the second comparison result, determine the residual current phase characteristics at the moment of leakage, and use the residual current phase characteristics as the first feature;

[0186] Furthermore, the second alignment result, which includes the classification values, is output from the aforementioned formula (10). A structure variable is constructed in memory, and the value is written into the identifier field of the structure. The structure variable is defined as the residual current phase feature, and its value is assigned to the first feature of the variable, thereby transforming the phase difference comparison result of the lower layer into an abstract feature quantity that can be directly called by the upper layer logic.

[0187] Step S3.4, the first feature includes phase-to-phase leakage current feature and ground leakage current feature;

[0188] It should be noted that the first feature, serving as the carrier of logical classification, has its internal values ​​strictly limited to two enumerated values: phase-to-phase leakage current characteristic and phase-to-ground leakage current characteristic. The phase-to-phase leakage current characteristic corresponds to the second comparison result. The state of 1 corresponds to the second comparison result in terms of leakage current to ground. The state is 2. This binary enumeration design ensures that the decision logic in the subsequent channel type identification step has absolute determinism and unambiguity.

[0189] For example, when a leakage current trigger occurs, the zero-crossing time of the live wire current differs from the reference by 2 milliseconds, the zero-crossing time of the neutral wire current differs from the reference by 6 milliseconds, the power frequency cycle is 20 milliseconds, the instantaneous phase angle of the live wire is calculated to be 36 degrees, the instantaneous phase angle of the neutral wire is calculated to be 108 degrees, the phase difference value is calculated to be 72 degrees, and after normalization it is 0.2. This value falls within the phase threshold range of interphase leakage current, generating a second comparison result characterizing interphase leakage current, and determining the first feature as interphase leakage current feature; if the calculated normalized phase difference value is 0.01, it falls within the phase threshold range of leakage to ground, generating a second comparison result characterizing leakage to ground, and determining the first feature as leakage to ground feature.

[0190] Step S4: Based on the first identifier and the first feature, spatial identification of the leakage physical channel is performed to determine the leakage channel type. The leakage channel type includes terminal surface phase-to-phase bridging leakage and cable-to-ground leakage.

[0191] It should be pointed out that a single-dimensional state or feature cannot support highly reliable physical channel identification. Leakage channel type refers to a classification label for the precise spatial physical location of the leakage. To eliminate the risk of misjudgment from blindly cutting off power, it is necessary to perform multi-dimensional coupling analysis between the first identifier of the environmental phase transition state and the first feature at the moment of leakage, thereby accurately pinpointing the leakage channel type in the spatial dimension.

[0192] Optionally, the step of spatially identifying the leakage current physical channel based on the first identifier and the first feature to determine the leakage current channel type includes:

[0193] Step S4.1: Read and determine the first identifier to identify whether it is a condensation state identifier or a dry state identifier.

[0194] Specifically, the first identifier value at the current time or the leakage trigger time is read from the status register. The read identifier value is compared bit by bit with the preset condensation status code and dryness status code. If it matches the condensation status code, the first identifier is determined to be the condensation status identifier, and the value in the aforementioned formula (4) is used. Assign a value of 1; if it matches the drying status code, then determine that the first identifier is the drying status identifier, and... The value is assigned to 0, thus providing the environmental state premise for subsequent branch logic.

[0195] Step S4.2: In response to the first identifier being the condensation state identifier, the type of the first feature is determined;

[0196] Furthermore, when the first identifier is determined to be a condensation status identifier, that is... When the value is 1, it indicates that the terminal surface has the physical conditions to form an electrolyte bridge. At this time, leakage may occur on the terminal surface or in the external cable. Therefore, it is necessary to further extract the first feature of the leakage occurrence time from memory, parse and determine the type of the feature code contained in the first feature, in order to distinguish between phase-to-phase leakage and phase-to-ground leakage.

[0197] Step S4.3: In response to the first feature being a phase-to-phase leakage feature, determine the leakage channel type as terminal surface phase-to-phase bridging leakage, and take the terminal surface phase-to-phase bridging leakage as the first type;

[0198] Furthermore, when the environmental condition is determined to be a condensation state and the leakage phase characteristic is determined to be a phase-to-phase leakage characteristic, that is... and At that time, the environmental factors and the physical characteristics of leakage current achieved a perfect match. Terminal surface phase-to-phase bridging leakage current refers to the physical phenomenon where the leakage current channel is limited to the electrolyte bridging point on the surface of the live wire and neutral wire terminals inside the charging socket. Based on the output results of the aforementioned formulas (4) and (10), the comprehensive identification mathematical expression is shown in the following table:

[0199]

[0200] In the above formula (11), the variable Boolean value representing the state of condensation in the environment, variable Represents leakage current phase classification quantity, variable This represents the final determined leakage current path type.

[0201] If the first branch condition is met, the leakage current path type is defined as the first type, i.e., output. This information is then written into the type register, thus precisely pinpointing the location of the leakage inside the socket in the spatial dimension.

[0202] It should be noted that after determining that the leakage current channel type is the first type, an internal fault flag bit also needs to be set in the register.

[0203] Furthermore, the internal fault flag is used to prevent the subsequent automatic reclosing logic from being triggered, thus avoiding blindly restoring power supply before the condensation conditions are eliminated.

[0204] Furthermore, the internal fault flag can only be cleared after a dehumidification completion signal is received. In this embodiment, the type register is backed up using non-volatile storage media.

[0205] Step S4.4: In response to the first feature being a leakage current to ground feature, determine the leakage current channel type as cable to ground leakage current, and classify the cable to ground leakage current as the second type;

[0206] On the other hand, when the environmental condition is determined to be a condensation state, but the leakage phase characteristic is determined to be a ground leakage characteristic, that is, when the second branch condition in the aforementioned formula (11) is met, it indicates that although there is condensation on the terminal surface, the leakage is not limited to phase-to-phase, but extends to the ground. Cable-to-ground leakage refers to the phenomenon of external charging cable insulation failure and ground discharge when the leakage channel extends to the ground. This leakage channel type is defined as the second type, output It also overwrites the value in the type register, thereby precisely pinpointing the location of the leakage in the external cable in the spatial dimension.

[0207] Furthermore, after determining that the leakage current path type is type II, it is also necessary to assess the duration of the leakage current.

[0208] Furthermore, if the leakage current persists after the circuit breaker trips, it indicates that there may be severe metallic adhesion at the cable breakage point. In this case, a severe fault level flag is added to the type register to increase the priority of subsequent maintenance. In this application, the duration of the leakage current is obtained by monitoring the residual output of the zero-sequence current transformer after a power outage.

[0209] Step S4.5: In response to the first identifier being the dry state identifier, directly determine the leakage current channel type as the second type;

[0210] At the same time, when the first identifier is determined to be a dry state identifier, that is When this condition is met, it indicates that the terminal surface does not meet the conditions for electrolyte formation, and the possibility of interphase bridging leakage at the terminal surface is physically eliminated. At this time, there is no need to perform complex analysis on the first feature, and the second branch condition of the aforementioned formula (11) is directly satisfied, forcibly determining the leakage channel type as the second type, that is, cable-to-ground leakage. Through this short-circuit logic, the computational overhead in the dry state is greatly reduced.

[0211] It should be noted that, in order to prevent the dryness determination logic from being interfered with by occasional features, while forcibly determining it as the second type, the current first feature will still be recorded in the background.

[0212] Furthermore, the first feature recorded in the background and the second type determined are uploaded together to the operation and maintenance management terminal for manual review.

[0213] Furthermore, if there is a logical contradiction between the first characteristic and the second type recorded in the background, an exception review work order is generated. In this embodiment, the background record is written asynchronously, without blocking the main control logic.

[0214] For example, if the first identifier is read as a condensation state identifier and the first feature is a phase-to-phase leakage feature, the leakage path type is determined to be the first type after the two are matched, that is, phase-to-phase bridging leakage on the terminal surface; if the first identifier is read as a dry state identifier, the leakage path type is directly determined to be the second type regardless of the first feature; if the first identifier is read as a condensation state identifier and the first feature is a ground leakage feature, the leakage path type is determined to be the second type.

[0215] Step S5: Match and output the corresponding first instruction or second instruction according to the leakage current channel type. The first instruction is an internal heating and dehumidification instruction, and the second instruction is a power-off isolation instruction.

[0216] It is understandable that drastically different protective actions must be taken for leakage paths in different physical locations to avoid ineffective operation and maintenance. The first command refers to the dehumidification control signal used to drive the internal heating component of the socket. The second command refers to the power-off control signal used to cut off the main power supply circuit. The leakage path type is output by the aforementioned formula (11). By accurately mapping specific protection instructions, the problems of blindly cutting off power and mistakenly replacing cables can be eliminated at the source.

[0217] Optionally, the step of matching and outputting a corresponding first instruction or second instruction based on the leakage current channel type includes:

[0218] Step S5.1: In response to determining that the leakage current channel type is the first type, a corresponding first instruction is generated.

[0219] Specifically, when the leakage channel type is read from the type register When the value is 1, the control code bound to the first type is extracted from the instruction mapping table. The control code is encapsulated into a first instruction in a standard format, which includes the target relay address and duty cycle parameters, thereby providing precise control signaling for subsequent heating and dehumidification operations.

[0220] Step S5.2: Send the first instruction to the heating and dehumidifying component inside the charging socket, and control the heating and dehumidifying component to perform heating and dehumidifying operation on the terminal surface;

[0221] Furthermore, the heating and dehumidifying component refers to an electric heating film or a miniature fan built into the cavity of the charging socket. The first command is sent to the drive circuit of the heating and dehumidifying component via an internal serial bus. The drive circuit analyzes the duty cycle parameter in the first command and outputs a corresponding pulse width modulation waveform to drive the electric heating film to heat up, thereby increasing the local temperature of the terminal surface, breaking the phase change condition of salt spray condensation, and eliminating the electrolyte bridging channel from its physical source.

[0222] Step S5.3: Obtain the updated first state after the heating and dehumidification operation is executed;

[0223] Furthermore, after the heating and dehumidification operation is initiated, the weather sensor probe continuously monitors changes in ambient temperature, humidity, and salt spray concentration. The current temperature, relative humidity, and salt spray concentration, collected again after a period of operation, are combined into a new initial state to enable closed-loop evaluation of the dehumidification effect.

[0224] Step S5.4: Regenerate the first identifier based on the updated first state; in response to the updated first identifier being converted into the drying state identifier, terminate the output of the first instruction.

[0225] At the same time, the updated first state is input into the aforementioned condensation determination logic link, and the aforementioned formulas (1) to (4) are recalculated to generate the updated first identifier.

[0226] If the updated first indicator changes from a condensation state indicator to a dry state indicator, it indicates that the electrolyte on the terminal surface has been completely evaporated. At this point, a command termination signal is generated, stopping the transmission of the first command to the heating and dehumidifying component, thus completing a precise directional dehumidification closed-loop control cycle.

[0227] Optionally, the step of matching and outputting the corresponding first or second instruction based on the leakage current channel type further includes:

[0228] Step S5.5: In response to determining that the leakage current channel type is the second type, a corresponding second instruction is generated.

[0229] On the other hand, when the leakage channel type is read from the type register A value of 2 indicates a substantial insulation failure in the external cable. The emergency control code bound to the second type is extracted from the instruction mapping table. This control code is encapsulated into a standard-format second instruction, which includes the target circuit breaker address and the highest tripping priority flag.

[0230] Step S5.6: Send the second instruction to the main control switch of the charging pile to control the main control switch to perform a power-off isolation operation;

[0231] Specifically, the main control switch refers to an electromagnetic relay or solid-state switch connected in series in the main power supply circuit of the charging pile. The second command is sent directly to the control coil of the main control switch via a hard-wired interrupt pin. Upon receiving the second command, the main control switch, regardless of the current charging task status, immediately cuts off the power supply circuit between the live wire and the neutral wire, physically blocking the discharge path to ground and preventing the spread of electrical fires.

[0232] Step S5.7: Generate a cable troubleshooting instruction corresponding to the second type and send the cable troubleshooting instruction to the operation and maintenance management terminal;

[0233] Furthermore, the cable troubleshooting instruction refers to maintenance work order data containing the faulty charging pile number, the time of leakage occurrence, and the channel type label. This cable troubleshooting instruction is sent to a remote maintenance management terminal via a wireless communication module. Upon receiving the cable troubleshooting instruction, the maintenance management terminal highlights the location information of the corresponding charging pile on its display interface and prompts maintenance personnel to bring cable insulation testing equipment to the site for troubleshooting.

[0234] Step S5.8: In response to receiving the troubleshooting completion signal from the operation and maintenance management terminal, release the second instruction and restore the conduction state of the main control switch;

[0235] Furthermore, the completed signal refers to the reset confirmation command issued by the maintenance personnel through the maintenance management terminal after replacing the damaged cable and passing the insulation test.

[0236] If the investigation completion signal is received, it is determined that the potential for cable-to-ground leakage has been physically eliminated. At this time, the trip holding level of the second command is canceled, and a conduction drive signal is sent back to the main control switch to restore normal power supply service to the charging pile.

[0237] For example, when the leakage current channel type is determined to be the first type, a first instruction is generated and the heating and dehumidification component is controlled to work for 5 minutes. The first state is re-collected and converted to a dry state indicator, and then dehumidification is terminated. When the leakage current channel type is determined to be the second type, a second instruction is generated to cut off the main control switch and a cable troubleshooting instruction is sent to the operation and maintenance management terminal. Power is restored after the troubleshooting completion signal is received.

[0238] Optionally, in response to the first identifier being the condensation state identifier and determining the leakage current path type to be the second type, the method further includes:

[0239] Step S6: In response to the first identifier being the condensation state identifier and the leakage current channel type being the second type, a third instruction is generated and the third instruction is used as a forced power-off isolation instruction.

[0240] In this application, the third instruction refers to the highest level power-off control signal with anti-misoperation cancellation properties.

[0241] If the first identifier is detected as a condensation status identifier and the leakage current channel type is the second type, that is... and This indicates that the external cable has experienced a grounding leakage under extremely harsh, humid, and condensing conditions. In this case, the leakage path may be accompanied by a serious risk of arcing. A third instruction containing an anti-reset flag is generated to ensure that the power supply circuit is absolutely locked in the disconnected state until the serious hidden danger is completely eliminated.

[0242] It should be noted that while generating the third instruction, a lock word that cannot be automatically cleared is also written into the local memory.

[0243] Furthermore, the locked word can only be cleared via a specific hardware reset button or a remote command with encryption verification.

[0244] Furthermore, by introducing a dual-locking mechanism, the risk of accidental power restoration due to software crashes or communication interference is eliminated. In this embodiment, the encryption verification uses an asymmetric encryption algorithm to generate a dynamic password.

[0245] Step S7: Send the third instruction to the main control switch of the charging pile to control the main control switch to perform a power-off operation;

[0246] Specifically, the third instruction is sent to the main control switch via a dedicated isolated communication channel. Upon receiving the third instruction, the main control switch performs a forced tripping action and locks the tripping mechanism at the hardware level, rendering the ordinary automatic reset logic ineffective, thereby ensuring that the ground discharge channel is completely physically blocked under complex operating conditions.

[0247] Furthermore, after the power-off operation is performed, the residual voltage at the output terminal of the main control switch needs to be continuously monitored through the voltage detection circuit.

[0248] Furthermore, if the residual voltage does not decay to below a safety threshold within a preset time, a local audible and visual alarm is triggered to alert on-site personnel of a physical contact adhesion fault. In this application, the preset time is calculated based on the resistance-capacitance attenuation constant of the power supply circuit.

[0249] Step S8: Generate ground leakage warning information, bind and package the ground leakage warning information with the condensation status identifier, and send it to the operation and maintenance management terminal;

[0250] Furthermore, the ground leakage warning information refers to an emergency alarm data frame containing a high-risk level identifier and a description of the on-site condensation conditions. The ground leakage warning information and the current condensation status identifier are bound and packaged in memory to form a composite work order with contextual information. This composite work order is pushed to the operation and maintenance management terminal to remind maintenance personnel that this cable leakage is accompanied by condensation, and that they should also check whether the internal terminals of the socket are damaged by an arc caused by the leakage.

[0251] It should be noted that a multi-channel redundancy transmission strategy is adopted when sending composite work orders.

[0252] Furthermore, if the primary communication link fails to transmit, it will automatically switch to the backup cellular network for retransmission.

[0253] Furthermore, during the retransmission process, the number of failed transmissions is appended to the end of the composite work order so that the operation and maintenance management terminal can assess the stability of the communication link. In this embodiment, the priority of the primary communication link and the backup cellular network is preset at the factory.

[0254] Step S9: In response to the cable replacement confirmation signal fed back by the operation and maintenance management terminal based on the ground leakage warning information, the third instruction is released;

[0255] Furthermore, the cable replacement confirmation signal refers to the unlocking command issued by the maintenance personnel through the maintenance management terminal after completing the cable replacement and confirming that there is no burning on the terminal surface.

[0256] If the cable replacement confirmation signal is received, the password is verified for correctness. Upon successful verification, the anti-reset flag in the third instruction is cleared, the hardware lock on the main control switch is released, and subsequent normal power restoration logic is allowed to intervene, thereby restoring charging facility service while ensuring absolute safety.

[0257] Furthermore, after releasing the third instruction, a test power-on sequence is generated.

[0258] Furthermore, the system controls the main control switch to close for a preset short period of time, collecting zero-sequence current data under no-load conditions. If the zero-sequence current data is normal, power supply is fully restored; if the zero-sequence current is still abnormal, a third instruction is immediately triggered again, and a test failure report is generated. In this application, the preset short period of time is limited to several cycles of the power frequency to avoid mechanical shock.

[0259] For example, when a cable leaks to ground under the condensation status indicator, a third command is generated to force a power outage, and the condensation status and the ground leakage warning information are packaged and sent. The forced power outage is lifted only after the maintenance personnel replace the cable on-site and enter the password to provide a confirmation signal. If an abnormal zero-sequence current is found during the power-on test after the power outage is lifted, the power is forced to be cut off again.

[0260] like Figure 3The diagram illustrates the abstract relationship of this invention. Taking the first state collected from the external environment as the starting point of the data flow, the first state is input into the calculation of pure water dew point temperature and salt deliquescence correction value, respectively. A preset dew point comparison table and salt deliquescence correction comparison table are then linked to calculate the critical temperature for salt mist condensation. The current temperature in the first state and the critical temperature for salt mist condensation are input into a first comparison result determination, generating a first identifier characterizing the environmental phase change state. Simultaneously, the leakage current trigger signal and the residual current phase are calculated using phase difference and input into a second comparison result determination. The first identifier and the second comparison result output from the second comparison result determination are jointly input into the leakage current channel type identification for multi-dimensional coupling, outputting a corresponding set of disposal instructions. This set of disposal instructions is used to generate an updated first state for the physical entity. The updated first state is then fed back to the first state input, forming a complete closed-loop data flow for leakage current detection and protection.

[0261] like Figure 4 As shown, this embodiment constructs a mathematical transformation matrix for calculating the critical temperature of salt fog condensation, with four sub-figures corresponding to the four core transformation links in the calculation process. Sub-figure (a) shows the pure water dew point temperature matrix T2, where the horizontal axis represents the current temperature and the vertical axis represents the relative humidity. The values ​​in the matrix cells are obtained offline by the Magnus formula, representing the baseline critical temperature for water vapor condensation without considering the salt effect. Sub-figure (b) shows the piecewise function C1 for salt deliquescence correction, where the horizontal axis represents the salt fog concentration c and the vertical axis represents the dew point correction value C1. When the concentration is below the lower limit threshold L1, the correction value is zero; when the concentration is between L1 and L2, the correction value increases linearly with the concentration; and when the concentration exceeds L2, the correction value is locked at the saturated maximum value m. Sub-figure (c) shows the superimposed critical temperature matrix T3 for salt fog condensation. By arithmetically adding the T2 matrix to the C1 values ​​of the corresponding concentration intervals, the mathematical mapping from the pure water phase change model to the salt fog phase change model is completed. Subgraph (d) shows the piecewise function R1 for determining condensation state. The horizontal axis represents the current temperature T, and the vertical axis represents the first comparison result R1. When T is strictly less than T3, the output is 1, indicating that the condensation condition is met. When T is greater than or equal to T3, the output is 0, indicating that the terminal surface is dry. From the correspondence between the stepped transition boundary of the data curve in the figure and the T3 parameter, it can be seen that the method of this application effectively overcomes the misjudgment defect caused by the condensation threshold shift in the pure water dew point determination method under salt spray environment by introducing a salt deliquescence correction value to dynamically compensate for the pure water dew point temperature. This provides a high-fidelity pre-state benchmark for subsequent spatial identification of leakage current physical channels.

[0262] like Figure 5As shown, this application's embodiments construct a comparative bar chart of ablation experiments, where sub-chart (a) corresponds to the ablation experiment of the condensation determination module, and sub-chart (b) corresponds to the ablation experiment of the channel identification module. In sub-chart (a), the horizontal axis represents the five configuration schemes, the vertical axis represents the accuracy rate of condensation state determination, and the error bars represent the standard deviation of 30 independent repeated experiments. The complete scheme achieves an accuracy rate of 97.8%. After removing the salt correction module, the accuracy rate drops sharply to 82.3%, a decrease of 15.5 percentage points, proving that the compensation effect of the salt deliquescence correction value on the pure water dew point temperature is the core innovative feature of condensation determination. After removing the temperature compensation module, the accuracy rate drops to 91.5%, after removing the median filtering module, it drops to 94.2%, and after removing the hysteresis determination module, it drops to 93.1%, with each module making a significant contribution. In sub-figure (b), the channel identification accuracy of the complete scheme is 96.5%. After removing the phase normalization module, it drops to 85.7%; after removing the temperature compensation threshold module, it drops to 89.3%; after replacing it with the fixed threshold method, it drops to 78.2%; and after removing the anomaly verification module, it drops to 92.8%. From the attenuation trend of the error bar range and bar height in the figure, it can be seen that each functional module in this application makes an irreplaceable contribution to the overall system performance. Optimal detection accuracy can only be achieved when all modules work together, effectively overcoming the redundancy and blind spots inherent in single-dimensional judgment in existing technologies.

[0263] like Figure 6 As shown, this application's embodiments construct a comparative experimental multi-index comprehensive evaluation bar chart, where four sub-charts correspond to four core evaluation indicators: condensation state determination accuracy, leakage current detection false alarm rate, average response time, and comprehensive F1 score. In sub-chart (a), the condensation determination accuracy of this application's method reaches 97.8%, an improvement of 42.6 percentage points compared to the conventional RCD detection's 55.2%, an improvement of 21.3 percentage points compared to the pure water dew point determination's 76.5%, and an improvement of 26.5 percentage points compared to the fixed threshold phase method's 71.3%. In sub-chart (b), the false alarm rate of this application's method is only 2.1%, a decrease of 26.4 percentage points compared to the conventional RCD detection's 28.5%. In sub-chart (c), the average response time of this application's method is 85ms, slightly higher than the conventional RCD detection's 45ms, but far lower than the pure water dew point determination's 320ms and the fixed threshold phase method's 210ms, meeting real-time protection requirements while ensuring detection accuracy. In subgraph (d), the overall F1 score of the proposed method reaches 0.972, which is 56.5% higher than the 0.621 of conventional RCD detection. As can be seen from the difference between the error bar range and the column height in the figure, the proposed method is significantly better than the three baseline methods in all four indicators, effectively overcoming the defect of conventional leakage current detection systems in the prior art that cannot identify the physical path of terminal condensation bridging leakage and cable-to-ground leakage.

[0264] like Figure 7 As shown, this application constructs a multi-dimensional parameter sensitivity analysis line graph, where six sub-graphs correspond to the response curves of three key environmental parameters—salt spray concentration, ambient temperature, and relative humidity—on different performance indicators. Sub-graphs (a) to (c) show the performance changes as the salt spray concentration increases from 0.5 mg / m³ to 20 mg / m³. The condensation determination accuracy of the method in this application remains within a narrow band of 96% to 98%, while the accuracy of the pure water dew point determination method drops sharply from 95.8% to 51.5%, and the false alarm rate climbs from 2.5% to 42.8%. Sub-graph (d) shows that when the ambient temperature changes from 5°C to 35°C, the accuracy of the method in this application remains stable above 97%, while the fixed threshold phase method shows a significant downward trend in the high-temperature range. Sub-graph (e) shows that when the relative humidity changes from 40% to 95%, the channel identification accuracy of the method in this application remains above 96%, while the pure water dew point determination method drops to 68.3% in the high-humidity range. Subplot (f) shows that the response time of the method in this application remains stable between 82 ms and 86 ms across the entire concentration range. As can be seen from the error bar range and curve convergence trend in the figure, the method in this application maintains highly stable detection performance under a wide range of salt spray concentration, temperature, and humidity parameter variations, effectively overcoming the defect of the pure water dew point determination method in the prior art, which suffers from drastic performance degradation under extreme high-salt and high-humidity environments.

[0265] like Figure 8As shown, this application's embodiments constructed robustness test line graphs and box plots, with four sub-graphs corresponding to four severe operating conditions: noise interference, harmonic distortion, sudden temperature change, and repeated experiments. Sub-graph (a) shows that as the Gaussian noise standard deviation increases from 0 dB to 30 dB, the condensation detection accuracy of this application's method gradually decreases from 97.8% to 91.2%, while the fixed threshold phase method drops sharply from 91.5% to 55.8%. The confidence interval filling indicates that the variance of this application's method under noise disturbance is much smaller than that of the comparative method. Sub-graph (b) shows that as the total harmonic distortion increases from 0% to 20%, the channel identification accuracy of this application's method decreases from 96.5% to 89.5%, while the fixed threshold phase method drops sharply from 88.5% to 48.5%, proving that the median filtering module has an effective ability to suppress high-order harmonic glitches. Subplot (c) shows that in a scenario of sudden temperature change, the R1 state without hysteresis judgment frequently flips near the critical temperature. However, after introducing hysteresis judgment logic, the R1 state remains stable and locked, effectively filtering out state oscillations caused by instantaneous temperature fluctuations. Subplot (d) shows the box plot of the F1 score distribution for 30 independent repeated experiments. The median of the method in this application is 0.973 and the interquartile range is only 0.016, while the median of the pure water dew point determination method is 0.618 and the interquartile range reaches 0.062. As can be seen from the error bar range and box width in the figure, the method in this application maintains highly stable detection performance under various harsh working conditions, effectively overcoming the defect of the fixed threshold method in the prior art, which suffers from a sharp deterioration in performance under noise and harmonic interference.

[0266] like Figure 9As shown, this application embodiment constructs a line graph of error and boundary analysis, where three sub-graphs correspond to the phase threshold boundary sensitivity, the impact of salt spray concentration estimation error propagation, and the sequence stability during 72 hours of continuous operation, respectively. Sub-graph (a) shows the curves of channel identification accuracy and false alarm rate as the normalized phase lower limit threshold A1 for interphase leakage current increases from 0.05 to 0.25. The accuracy reaches a peak of 96.5% when A1 equals 0.15. The optimal range marked by the shaded area is 0.12 to 0.18. Within this range, the accuracy is always higher than 94% and the false alarm rate is lower than 4%, indicating that the system has sufficient tolerance for the A1 parameter. Subfigure (b) shows that as the salt spray concentration sensor estimation error changes from -3 mg / m³ to +3 mg / m³, the accuracy of condensation detection symmetrically decreases from 97.8% to 97.0%, while the false alarm rate symmetrically increases from 2.1% to 3.6%. The confidence interval filling indicates that within an estimation error range of ±2 mg / m³, the system performance degradation does not exceed 1 percentage point, demonstrating that this application has good tolerance for sensor measurement accuracy. Subfigure (c) shows the time-series curves of the current temperature T and the critical salt spray condensation temperature T3 during 72 hours of continuous operation. The condensation state indicator R1 of this application's method is accurately triggered when the nighttime temperature is lower than T3, while the pure water dew point determination method, due to the lack of salt correction, results in T3 being 2.5℃ lower, leading to missed condensation states in multiple time windows. From the convergence trend of the curves and the width of the filled interval in the figure, it can be seen that the method of this application maintains highly stable detection performance under parameter boundary disturbances and long-term continuous operation scenarios, effectively overcoming the defects of the fixed threshold method in the prior art, such as performance abrupt changes near boundary conditions and long-term operational state drift.

[0267] Example 2, this example also provides a charging pile leakage detection system, including: a status acquisition module, used to acquire the current temperature, relative humidity and salt spray concentration of the environment where the charging socket is located, and to combine the current temperature, the relative humidity and the salt spray concentration as a first state;

[0268] The status identifier generation module is used to compare the current temperature, relative humidity and salt spray concentration contained in the first status to generate a condensation status identifier on the terminal surface, and use the condensation status identifier as the first identifier.

[0269] The leakage current feature acquisition module is used to acquire the residual current phase feature at the moment of leakage in response to the leakage current trigger signal output by the residual current transformer, and to use the residual current phase feature as the first feature.

[0270] The channel type determination module is used to spatially identify the leakage physical channel based on the first identifier and the first feature, and determine the leakage channel type, wherein the leakage channel type includes terminal surface phase-to-phase bridging leakage and cable-to-ground leakage;

[0271] The disposal instruction output module is used to match and output a corresponding first instruction or second instruction according to the leakage current channel type. The first instruction is an internal heating and dehumidification instruction, and the second instruction is a power-off isolation instruction.

[0272] The above-mentioned unit modules can be embedded in the processor of the electronic device in hardware form or independent of it, or they can be stored in the memory of the electronic device in software form, so that the processor can call and execute the corresponding operations of the above modules.

[0273] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0274] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for detecting leakage current in a charging pile, characterized in that, include: The current temperature, relative humidity, and salt spray concentration of the environment where the charging socket is located are obtained, and the current temperature, relative humidity, and salt spray concentration are combined as the first state; Based on the comparison of the current temperature, relative humidity and salt spray concentration contained in the first state, a condensation status identifier is generated on the terminal surface, and the condensation status identifier is used as the first identifier. In response to the leakage current trigger signal output by the residual current transformer, the residual current phase characteristics at the moment of leakage current occurrence are obtained, and the residual current phase characteristics are used as the first characteristic. Based on the first identifier and the first feature, the physical leakage current channel is spatially identified to determine the leakage current channel type, which includes terminal surface phase-to-phase bridging leakage current and cable-to-ground leakage current. Match and output the corresponding first or second instruction based on the leakage current channel type. The first instruction is an internal heating and dehumidification instruction, and the second instruction is a power-off isolation instruction.

2. The method for detecting leakage current in a charging pile as described in claim 1, characterized in that: The process involves comparing the current temperature, relative humidity, and salt spray concentration included in the first state to generate a condensation status indicator on the terminal surface. This condensation status indicator is then used as the first indicator. Obtain the current temperature, relative humidity, and salt spray concentration contained in the first state, and use the salt spray concentration as the first concentration; Based on the current temperature and relative humidity, a preset dew point temperature lookup table is consulted to determine the pure water dew point temperature of the current environment, and the pure water dew point temperature is used as the second temperature. Based on the first concentration, a preset salt deliquescence correction reference relationship is found, and the dew point correction value corresponding to the first concentration is determined, and the dew point correction value is used as the first correction value. The first correction value is superimposed on the second temperature to obtain the critical temperature of salt spray condensation, and the critical temperature of salt spray condensation is used as the third temperature. The current temperature is compared with the third temperature to generate a first comparison result. In response to the first comparison result that the current temperature is lower than the third temperature, a condensation status identifier representing condensation on the terminal surface is generated, and the condensation status identifier is used as the first identifier. In response to the first comparison result that the current temperature is higher than the third temperature, a drying status identifier characterizing the dryness of the terminal surface is generated, and the drying status identifier is used as the first identifier.

3. The method for detecting leakage current in a charging pile as described in claim 1, characterized in that: The process of responding to a leakage current trigger signal output by a residual current transformer, acquiring the residual current phase characteristics at the moment of leakage, and using these residual current phase characteristics as a first feature includes: In response to the leakage current trigger signal output by the residual current transformer, the phase of the live wire current and the phase of the neutral wire current at the moment the leakage occurs are obtained. The phase difference between the live wire current and the neutral wire current is compared to generate a second comparison result; Based on the second comparison result, the residual current phase characteristics at the moment of leakage are determined, and the residual current phase characteristics are used as the first feature. The first feature includes phase-to-phase leakage current feature and phase-to-ground leakage current feature.

4. The method for detecting leakage current in a charging pile as described in claim 1, characterized in that: The step of spatially identifying the leakage current physical channel based on the first identifier and the first feature to determine the leakage current channel type includes: The first identifier is read and determined to be either a condensation state identifier or a dry state identifier. In response to the first identifier being the condensation state identifier, the type of the first feature is determined; In response to the first feature being a phase-to-phase leakage feature, the leakage channel type is determined to be a terminal surface phase-to-phase bridging leakage, and the terminal surface phase-to-phase bridging leakage is taken as the first type; In response to the first feature being a leakage current to ground feature, the leakage current channel type is determined to be cable to ground leakage current, and the cable to ground leakage current is classified as the second type. In response to the first identifier being the dry state identifier, the leakage current channel type is directly determined to be the second type.

5. The method for detecting leakage current in a charging pile as described in claim 4, characterized in that: The step of matching and outputting the corresponding first or second instruction based on the leakage current channel type includes: In response to determining that the leakage current channel type is the first type, a corresponding first instruction is generated; The first instruction is sent to the heating and dehumidifying component inside the charging socket, controlling the heating and dehumidifying component to perform heating and dehumidifying operation on the terminal surface; Obtain the updated first state after the heating and dehumidification operation is executed; The first identifier is regenerated based on the updated first state, and in response to the updated first identifier being converted to the dry state identifier, the output of the first instruction is terminated.

6. The method for detecting leakage current in a charging pile as described in claim 4, characterized in that: The step of matching and outputting the corresponding first or second instruction based on the leakage current channel type further includes: In response to determining that the leakage current channel type is the second type, a corresponding second instruction is generated; The second instruction is sent to the main control switch of the charging pile to control the main control switch to perform a power-off isolation operation; Generate a cable troubleshooting instruction corresponding to the second type, and send the cable troubleshooting instruction to the operation and maintenance management terminal; In response to receiving the troubleshooting completion signal from the operation and maintenance management terminal, the second instruction is released and the main control switch is restored to its on state.

7. The method for detecting leakage current in a charging pile as described in claim 4, characterized in that: In response to the first identifier being the condensation state identifier, and determining the leakage current path type to be the second type, the method further includes: In response to the first identifier being the condensation state identifier and the leakage current channel type being the second type, a third instruction is generated and the third instruction is used as a forced power-off isolation instruction. The third instruction is sent to the main control switch of the charging pile to control the main control switch to perform a power-off operation. Generate a ground leakage warning message, bind and package the ground leakage warning message with the condensation status identifier, and send it to the operation and maintenance management terminal; In response to the cable replacement confirmation signal fed back by the operation and maintenance management terminal based on the ground leakage warning information, the third instruction is cancelled.

8. The method for detecting leakage current in a charging pile as described in claim 2, characterized in that: The process of determining the pure water dew point temperature of the current environment by looking up a preset dew point temperature lookup table based on the current temperature and relative humidity, and using the pure water dew point temperature as the second temperature, and the process of determining the dew point correction value corresponding to the first concentration by looking up a preset salt deliquescence correction lookup table based on the first concentration, and using the dew point correction value as the first correction value, includes: Obtain a dew point temperature data table that is cross-mapped with multiple pre-calibrated temperature ranges and multiple humidity ranges, and use the dew point temperature data table as a preset dew point temperature reference table. The current temperature is range-based to determine the first target temperature range to which the current temperature belongs; The relative humidity is range-based to determine the first target humidity range to which the relative humidity belongs; Extract the dew point temperature data at the intersection of the first target temperature range and the first target humidity range from the preset dew point temperature reference table, and use the dew point temperature data as the second temperature. Obtain a deliquescence correction data table that maps multiple pre-calibrated concentration ranges to multiple correction values, and use the deliquescence correction data table as a preset salt deliquescence correction reference relationship; The first concentration is range-based to determine the first target concentration range to which the first concentration belongs; Extract the correction value corresponding to the first target concentration range from the preset salt deliquescence correction control relationship, and use the correction value as the first correction value.

9. The method for detecting leakage current in a charging pile as described in claim 3, characterized in that: The step of comparing the phase difference between the live wire current and the neutral wire current to generate a second comparison result includes: Obtain the instantaneous phase angle of the live wire current and the instantaneous phase angle of the neutral wire current at the same moment of leakage occurrence; The instantaneous phase angle of the live wire current and the instantaneous phase angle of the neutral wire current are compared to generate phase difference data. The phase difference data is compared with a preset interphase leakage phase threshold range. In response to the phase difference data falling within the preset interphase leakage phase threshold range, a second comparison result characterizing interphase leakage is generated. The phase difference data is compared with a preset ground leakage phase threshold range. In response to the phase difference data falling within the preset ground leakage phase threshold range, a second comparison result characterizing ground leakage is generated.

10. A charging pile leakage detection system, employing the charging pile leakage detection method as described in any one of claims 1 to 9, characterized in that, include: The status acquisition module is used to acquire the current temperature, relative humidity and salt spray concentration of the environment where the charging socket is located, and to combine the current temperature, relative humidity and salt spray concentration as the first status; The status identifier generation module is used to compare the current temperature, relative humidity and salt spray concentration contained in the first status to generate a condensation status identifier on the terminal surface, and use the condensation status identifier as the first identifier. The leakage current feature acquisition module is used to acquire the residual current phase feature at the moment of leakage in response to the leakage current trigger signal output by the residual current transformer, and to use the residual current phase feature as the first feature. The channel type determination module is used to spatially identify the leakage physical channel based on the first identifier and the first feature, and determine the leakage channel type, wherein the leakage channel type includes terminal surface phase-to-phase bridging leakage and cable-to-ground leakage; The disposal instruction output module is used to match and output a corresponding first instruction or second instruction according to the leakage current channel type. The first instruction is an internal heating and dehumidification instruction, and the second instruction is a power-off isolation instruction.

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