Earth leakage protection adaptive setting method and system based on ground capacitance parameter identification

Abstract

The invention discloses an earth leakage protection self-adaptive setting method and system based on earth capacitance parameter identification, and belongs to the technical field of low-voltage power distribution network protection. In order to solve the problems that manual setting of a traditional leakage protection device is easy to make mistakes and override tripping occurs frequently, the method comprises the steps that when a leakage protector is switched on, one phase of live wire is switched on, and other phases and null lines are switched off; detecting residual current, and calculating line ground capacitance based on the residual current and voltage parameters when a steady state condition is satisfied; and the action current threshold and the action time are automatically set according to the capacitance. Manual intervention is not needed, power grid working conditions can be dynamically adapted, a three-level protection framework can be accurately matched, override tripping is effectively avoided, the power failure range is narrowed, the fault recovery time is shortened, the power supply reliability and the power utilization safety of the power distribution network are remarkably improved, and the method is suitable for various low-voltage power distribution network leakage protection scenes.

Description

Technical Field

[0001] This invention belongs to the field of power system protection technology, specifically relating to an adaptive setting method and system for leakage current protection based on ground capacitance parameter identification. Background Technology

[0002] In urban and rural low-voltage power distribution networks, residual current devices (RCDs) are the first line of defense for protecting residents' personal safety and the stability of electrical equipment. By monitoring the leakage current in the line in real time and triggering tripping actions, they can effectively prevent safety accidents such as electric shock, equipment insulation damage, and electrical fires, playing an irreplaceable and significant role in ensuring the safety of electricity use for residents. my country's low-voltage power distribution networks generally adopt a three-level protection architecture of "main protection - branch protection - household protection." Each level of protector needs to coordinate precise settings to isolate the fault point nearby, ensuring that a local fault does not affect the overall operation of the power grid.

[0003] However, the core settings of traditional residual current devices (RCDs) widely used today, such as operating current and operating time, rely entirely on manual adjustment. The adjustment results are highly dependent on the operator's experience level; different personnel may interpret the parameters and design the coordination logic for the same power grid differently, amplifying the risk of setting errors. More seriously, incorrect setting directly disrupts the coordination logic of the three-level RCD system, inducing cascading tripping. When a leakage fault occurs in a line, the lower-level protector, which should operate first, fails to operate due to setting mismatch, allowing the fault current to continue spreading to the upper-level protector, causing it to trip erroneously. This cascading tripping phenomenon expands the power outage area originally limited to a single household or branch line to the entire residential community or even a whole area, affecting the normal power supply of dozens to thousands of households, not only triggering public complaints but also causing economic losses to commercial users. Simultaneously, cascading tripping disrupts the hierarchical characteristics of fault occurrence, requiring maintenance personnel to check multiple levels of lines and equipment one by one, significantly prolonging fault location and power restoration time, and severely reducing the power supply reliability of the distribution network.

[0004] To address the core pain points of traditional manual setting mode, such as complex setting, easy error, and frequent over-level tripping, there is an urgent need to develop a new leakage current protection setting technology that can automatically adapt to the power grid conditions. Summary of the Invention

[0005] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing an adaptive setting method and system for leakage current protection based on the identification of ground capacitance parameters. By accurately sensing the core characteristic parameter of line-to-ground capacitance, the method enables automatic calculation and dynamic coordination of the settings of leakage current protection devices at all levels. This solves the technical problems of safety and operation and maintenance caused by the defects of manual setting, and avoids the problems of protection devices failing to operate or operating falsely due to the complexity and error of manual setting.

[0006] The present invention adopts the following technical solution: The adaptive setting method for leakage current protection based on ground capacitance parameter identification includes the following steps: When the residual current device (RCD) is closed, the RCD is controlled to first close one phase of the live wire and disconnect the other two phases of the live wire and the neutral wire. The residual current after the live wire of one phase is closed is detected. When the preset steady-state condition is met, the capacitance to ground of the line is calculated based on the detected residual current and voltage parameters. Based on the calculated capacitance to ground, the operating current threshold and operating time of the residual current device are automatically set.

[0007] Preferably, the preset steady-state condition is: Residual current difference between two adjacent waves The effective value of the residual current of the next cycle satisfy .

[0008] Preferably, before detecting the residual current and obtaining the voltage parameters, the method further includes: A voltage transformer is installed between the live wire and the neutral wire on the power supply side of the leakage current device. Voltage transformers are installed on the load side between the other two live wires and the target live wire, and between the neutral wire and the target live wire on the load side of the leakage current protection device. A voltage transformer and a residual current transformer are installed on the power supply side of the leakage current protection device. Voltage parameters are collected through the power supply side voltage transformer and the load side voltage transformer, and residual current is collected through the residual current transformer.

[0009] Preferably, before calculating the line-to-ground capacitance based on the detected residual current and voltage parameters, the method further includes calculating the line-to-ground voltage: Let the voltage of the target phase live wire to the neutral wire collected by the voltage transformer on the power supply side be... The voltages of the other two live wires to the target live wire, collected by the load-side voltage transformer, are respectively , The voltage between the neutral wire and the target phase live wire collected by the load-side voltage transformer is ; The voltage to ground of the other two live wires was derived by using the voltage difference relationship. , and the voltage to ground of the neutral wire .

[0010] Preferably, the capacitance to ground of the calculation circuit for:

[0011] in, The residual current value is the actual measured value of the residual current transformer inside the leakage protection device. These are the voltages to ground of each line on the load side of the residual current device (RCD). This refers to the capacitance to ground of the downstream circuit of the leakage protection device. This is the angular frequency of the power grid.

[0012] Preferably, the automatic setting of the operating time of the residual current device based on the calculated capacitance to ground is specifically as follows: When the capacitance to ground satisfy At μF, the action time is set to 0s; When the capacitance to ground satisfy At μF, the action time is set to 0.1s; When the capacitance to ground satisfy At μF, the action time is set to 0.2s.

[0013] Preferably, the automatic setting of the operating current threshold of the residual current device based on the calculated ground capacitance is specifically as follows: When the capacitance to ground satisfy At μF, the operating current threshold is set to 50mA; When the capacitance to ground satisfy At μF, the operating current threshold is set to 200mA; When the capacitance to ground satisfy At 6μF, the operating current threshold is set to 500mA.

[0014] Preferably, after calculating the capacitance to ground, the leakage current protector is controlled to close the other two live wires and the neutral wire.

[0015] Preferably, the live wire is phase A.

[0016] Secondly, embodiments of the present invention provide a leakage current protection adaptive setting system based on ground capacitance parameter identification, comprising: The control module is used to control the residual current device (RCD) to close one phase of the live wire first and disconnect the other two phases of the live wire and the neutral wire when the RCD is closed. The detection module is used to detect the residual current after one phase of the live wire is closed; The calculation module is used to calculate the line's capacitance to ground based on the detected residual current and voltage parameters when the preset steady-state conditions are met. The setting module is used to automatically set the operating current threshold and operating time of the leakage current protector based on the calculated capacitance to ground.

[0017] Thirdly, a computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the steps of the above-described adaptive setting method for leakage protection based on ground capacitance parameter identification.

[0018] Fourthly, embodiments of the present invention provide a computer-readable storage medium including a computer program, which, when executed by a processor, implements the steps of the above-described adaptive setting method for leakage protection based on ground capacitance parameter identification.

[0019] Fifthly, a chip includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the steps of the above-described adaptive setting method for leakage protection based on ground capacitance parameter identification.

[0020] In a sixth aspect, embodiments of the present invention provide an electronic device, including a computer program, which, when executed by the electronic device, implements the steps of the above-described adaptive setting method for leakage protection based on ground capacitance parameter identification.

[0021] Compared with the prior art, the present invention has at least the following beneficial effects: An adaptive setting method for leakage current protection based on ground capacitance parameter identification achieves adaptive setting through single-phase closing, residual current detection, and capacitance parameter calculation. This method overcomes the limitations of traditional manual setting by automatically identifying the protection level using the stable parameter of ground capacitance, avoiding setting errors caused by human factors. This method can automatically adjust protection settings according to actual line parameters, ensuring coordinated operation of the three-level protection and effectively preventing cascading tripping. Furthermore, it is universally applicable, adaptable to distribution networks of different sizes, and greatly improves the accuracy and reliability of the protection.

[0022] Furthermore, by using quantitative indicators to ensure that the system has reached a stable state during measurement, the influence of transient processes on the measurement results is avoided, thus improving the accuracy of capacitance parameter identification. This judgment condition is simple and effective, easy to implement in protection devices, and ensures the reliability of adaptive tuning.

[0023] Furthermore, through a well-planned sensor arrangement, the voltage parameters required for calculation can be accurately obtained, providing a data foundation for precise calculation of the capacitance to ground. This configuration approach considers both measurement accuracy and the feasibility of engineering implementation.

[0024] Furthermore, through mathematical transformations, the voltage to ground of each line was derived using the actual measured voltage differences, solving the technical challenge of directly measuring the voltage to ground. The calculations are simple and the results are accurate, laying a solid foundation for subsequent capacitance calculations.

[0025] Furthermore, based on Kirchhoff's current law, a precise mathematical relationship between residual current and ground capacitance was established, enabling accurate calculation of the line's ground capacitance parameters. The calculation process is simple and easy to implement in protection devices.

[0026] Furthermore, a stepped setting logic is adopted, dividing the system into three intervals based on the size of the ground capacitance, corresponding to different operating times (0s, 0.1s, 0.2s), precisely matching the selectivity requirements of the three-level protection architecture of main protection-branch protection-customer protection. Smaller capacitance corresponds to smaller line scale (last protection), with the shortest operating time, ensuring rapid isolation of faults nearby; larger capacitance corresponds to larger line scale (main protection), with a longer operating time, avoiding false tripping. This rule is simple, clear, and highly operable, requiring no manual adjustment, and the setting time is compatible with existing three-level protection standards. It not only solves the traditional setting mismatch problem but also seamlessly integrates into the existing distribution network system, ensuring the continuity and stability of power grid operation.

[0027] Furthermore, in coordination with the operating time setting logic, three intervals are defined based on the ground capacitance, corresponding to operating current thresholds of 50mA, 200mA, and 500mA, achieving dual selectivity in current and time. The last protection corresponds to a small capacitance and a small current threshold, enabling rapid response to minor leakage faults; the main protection corresponds to a large capacitance and a large current threshold, avoiding non-fault-related tripping. This rule aligns with the fault response requirements of different levels of protection in the distribution network, and the current threshold settings comply with national low-voltage distribution network safety standards. It ensures the safety of personnel and equipment while effectively reducing the probability of false tripping and failure to trip, solving the core pain point of the mismatch between traditional manually set current thresholds and line scale.

[0028] Furthermore, while ensuring the completion of adaptive tuning, the system can be restored to normal operation in a timely manner, minimizing the impact on users' power consumption, demonstrating good practicality and user experience.

[0029] Furthermore, phase A, as a commonly used reference phase in low-voltage distribution networks, has stable voltage and is easy to acquire. Selecting phase A as the first phase to close the circuit can improve the consistency and reliability of parameter acquisition. This limitation is not an excessive narrowing of the protection scope, but rather provides clear support for the instruction manual by specifying concrete implementation methods. It also facilitates device design and commissioning for engineers, improving operability and scalability.

[0030] It is understood that the beneficial effects of the second to sixth aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here.

[0031] In summary, the method of this invention breaks through the limitations of traditional manual setting by using single-phase closing and capacitor identification, ensures setting accuracy with quantitative standards and precise algorithms, adapts to the three-level protection architecture through a tiered rule system, and realizes the implementation of the technology through a modular system, comprehensively solving problems such as setting mismatch and over-level tripping, while taking into account both reliability and practicality.

[0032] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0033] Figure 1 This is a flowchart of the adaptive leakage current protection process of the present invention; Figure 2 This is a model diagram of a 220 / 380V AC distribution network; Figure 3 This is a waveform diagram of the residual current during single-phase closing. Figure 4 A schematic diagram of a computer device provided in an embodiment of the present invention; Figure 5 This is a block diagram of a chip provided according to an embodiment of the present invention.

[0034] Among them, 60. Computer equipment; 61. Processor; 62. Memory; 63. Computer program; 600. Electronic device; 610. Processing unit; 620. Storage unit; 6201. Random access memory unit; 6202. Cache memory unit; 6203. Read-only memory unit; 6204. Program / utility; 6205. Program module; 630. Bus; 640. Display unit; 650. Input / output interface; 660. Network adapter; 700. External device. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0037] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0038] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0039] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0040] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0041] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0042] Low-voltage leakage protection devices are generally configured according to a three-level principle, with different levels of protection devices ensuring selectivity through leakage current settings and operating delays. Since the scale of the downstream lines varies depending on the level of the protection device, higher-level protection devices have larger downstream line scales and greater line-to-ground capacitance. This invention provides an adaptive setting method for leakage protection based on ground capacitance parameter identification. It uses the magnitude of the line's ground capacitance to infer the installation location of the protection device, and then automatically sets the protection device's settings, thus avoiding the problems of complex and error-prone manual setting that can lead to protection device malfunctions or failures to operate.

[0043] According to Kirchhoff's Current Law, during normal operation of a single-phase system, the load currents on the live wire and neutral wire are equal in magnitude and opposite in direction, with a vector sum of zero. However, due to the distributed capacitance to ground and the direct grounding of the transformer neutral point, the voltage to ground of the live wire is approximately 220V, while the voltage to ground of the neutral wire is approximately 0V. Therefore, a portion of the current in the live wire will flow into the ground through the distributed capacitance and eventually to the transformer neutral point. The neutral wire, due to its very low voltage to ground, has almost no capacitance current to ground. Thus, a certain residual current exists during normal operation of a single-phase system. Its magnitude depends on the line size, and the installation level of the protection system can be determined by the magnitude of the leakage current during normal operation. This allows for automatic adjustment of the leakage current and operating time.

[0044] During normal operation of a three-phase system, although there is a capacitive current to ground, theoretically, these currents can cancel each other out because the three-phase voltages are symmetrical and the line-to-ground capacitance parameters are basically the same. The residual current that occurs in actual operation is mainly caused by the asymmetry of the line-to-ground parameters. However, this parameter asymmetry varies greatly under different operating conditions and lacks regularity; therefore, the residual current during normal operation of a three-phase system cannot be used as a basis for determining the protection level.

[0045] To address the above problems, this invention proposes to adjust the structure of the traditional three-phase switch in a residual current device (RCD) to phase-by-phase switching. When the RCD is closed, one phase of the live wire is closed first, while the other two phases of the live wire and the neutral wire are all disconnected. After a delay to allow the system to reach a steady state, the residual current is sampled and calculated, and then all other contacts are closed. The residual current measured by the RCD after closing one phase is the ground capacitance current of all downstream lines of the protection device. Using the magnitude of this capacitance current, the ground distributed capacitance of the downstream lines of the protection device can be calculated, thereby inferring the size of the downstream lines and the protection device's level, and thus automatically adjusting the leakage current and operating time.

[0046] Please see Figure 1 The present invention provides an adaptive setting method for leakage protection based on ground capacitance parameter identification, comprising the following steps: S1. A voltage transformer is installed between phase A and the neutral line on the power supply side of the residual current device (RCD). Voltage transformers are installed between phase A and phases B, C, and N on the load side of the RCD. A residual current transformer is installed on the power supply side of the RCD.

[0047] S2. When the residual current device (RCD) closing button is pressed, phase A is closed first. When equation (1) is satisfied, the distributed capacitance of the downstream line of the protection device is calculated based on the voltage measured by the sensor and the residual current value.

[0048] (1) in, The difference in residual current between two adjacent wave cycles. This is the effective value of the residual current for the next cycle.

[0049] S3. Calculate the voltage to ground of each line in the residual current device (RCD) load test based on the voltage value measured by the voltage transformer. The calculation method is as follows: The voltage measurement value of the voltage transformer on the load side of the residual current device (RCD) can be expressed as: (2) Simplifying equation (2), we get: (3) in, The voltage between the live wire and the neutral wire of phase A, measured on the power supply side of the residual current device (RCD), is low due to the low voltage. The system neutral point is directly grounded, and the three-phase loads are basically symmetrical. Therefore, the voltage drop from the protection installation point to the transformer neutral line can be ignored. It is assumed that the voltage of phase A live wire to the neutral line measured on the power supply side of the leakage protection device is the voltage of phase A live wire to ground. , , These are the voltages of phase B, phase C, and neutral to phase A measured on the load side of the leakage protection device. , , These are the voltages to ground for phase B, phase C, and the neutral wire, respectively.

[0050] S4. Based on the measured values ​​of ground voltage and residual current of each line on the load side of the residual current device (RCD) calculated in step S3, calculate the ground capacitance of the downstream line of the RCD. The calculation method is as follows: The residual current measurement value of the leakage protection device can be expressed as: (4) Therefore, the capacitance to ground of the three-phase line can be calculated as follows: (5) in, The residual current value is the actual measured value of the residual current transformer inside the leakage protection device. These are the voltages to ground of each line on the load side of the residual current device (RCD). This refers to the capacitance to ground of the downstream circuit of the leakage protection device. This is the angular frequency of the power grid.

[0051] S5. Save the calculation results of the line-to-ground distributed capacitance in step S4, and close all other contacts of the leakage protection device to meet the user's power needs.

[0052] S6. Determine the protection setting value based on the line-to-ground distributed capacitance calculated in step S4. The higher the protection level, the larger the residual current setting value and the longer the operating time.

[0053] The adaptive motion time tuning method is as follows: (6) in, The delay time for each level of leakage protection is measured in seconds. To protect the ground capacitance of downstream lines, the unit is... The action time setting values ​​for each level of leakage protection should be set with reference to the existing setting values ​​for the three-level leakage protection.

[0054] The adaptive operating current setting method is as follows: (7) in, The operating current threshold for each level of leakage protection device, in units of , To protect the ground capacitance of downstream lines, the unit is... The operating current setting values ​​for each level of leakage protection circuit breaker should be set with reference to the existing setting values ​​for the three-level leakage protection circuit breaker.

[0055] In another embodiment of the present invention, a leakage current protection adaptive setting system based on ground capacitance parameter identification is provided. This system can be used to implement the above-mentioned leakage current protection adaptive setting method based on ground capacitance parameter identification. Specifically, the leakage current protection adaptive setting system based on ground capacitance parameter identification includes a control module, a detection module, a calculation module, and a setting module.

[0056] The control module is used to control the residual current device (RCD) to close one phase of the live wire and disconnect the other two phases of the live wire and the neutral wire when the RCD is closed. The detection module is used to detect the residual current after one phase of the live wire is closed; The calculation module is used to calculate the line's capacitance to ground based on the detected residual current and voltage parameters when the preset steady-state conditions are met. The setting module is used to automatically set the operating current threshold and operating time of the leakage current protector based on the calculated capacitance to ground.

[0057] This invention provides a terminal device comprising a processor and a memory. The memory stores a computer program, which includes program instructions. The processor executes the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or other general-purpose processors, graphics processing units (GPUs), tensor processing units (TPUs), digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing and control core of the terminal, suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions to achieve a corresponding method flow or corresponding function. The processor described in this embodiment can be used in the operation of a leakage current protection adaptive setting method based on ground capacitance parameter identification, including: When the residual current device (RCD) is closed, the RCD is controlled to first close one phase of the live wire and disconnect the other two phases of the live wire and the neutral wire; the residual current after the closed phase of the live wire is detected, and when the preset steady-state conditions are met, the capacitance to ground of the line is calculated based on the detected residual current and voltage parameters; based on the calculated capacitance to ground, the operating current threshold and operating time of the RCD are automatically adjusted.

[0058] Please see Figure 4 The terminal device is a computer device. In this embodiment, the computer device 60 includes a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61. When executed by the processor 61, the computer program 63 implements the adaptive setting method for leakage protection based on ground capacitance parameter identification in this embodiment. To avoid repetition, these details are not elaborated here. Alternatively, when executed by the processor 61, the computer program 63 implements the functions of each model / unit in the adaptive setting system for leakage protection based on ground capacitance parameter identification in this embodiment. To avoid repetition, these details are not elaborated here.

[0059] Computer device 60 can be a desktop computer, laptop, handheld computer, cloud server, or other computing device. Computer device 60 may include, but is not limited to, a processor 61 and a memory 62. Those skilled in the art will understand that... Figure 4This is merely an example of computer device 60 and does not constitute a limitation on computer device 60. It may include more or fewer components than shown, or combine certain components, or different components. For example, computer device may also include input / output devices, network access devices, buses, etc.

[0060] The processor 61 may be a Central Processing Unit (CPU), or other general-purpose processors, graphics processing units (GPUs), tensor processing units (TPUs), digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0061] The memory 62 can be an internal storage unit of the computer device 60, such as a hard disk or RAM of the computer device 60. The memory 62 can also be an external storage device of the computer device 60, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc., provided on the computer device 60.

[0062] Furthermore, the memory 62 may include both internal storage units of the computer device 60 and external storage devices. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 can also be used to temporarily store data that has been output or will be output.

[0063] Please see Figure 5 The terminal device is an electronic device 600, which is manifested in the form of a general-purpose computing device. The components of the electronic device may include, but are not limited to: at least one processing unit 610, at least one storage unit 620, a bus 630 connecting different platform components (including storage unit 620 and processing unit 610), a display unit 640, etc.

[0064] The storage unit stores program code, which can be executed by the processing unit 610 to perform the steps described in the method section of this specification according to various exemplary embodiments of the present invention. For example, the processing unit 610 can perform actions such as... Figure 1 The steps are shown in the figure.

[0065] Storage unit 620 may include a readable medium in the form of a volatile storage unit, such as random access memory (RAM) 6201 and / or cache memory 6202, and may further include a read-only memory (ROM) 6203.

[0066] Storage unit 620 may also include a program / utility 6204 having a set (at least one) program module 6205, such program module 6205 including but not limited to: operating system, one or more application programs, other program modules and program data, each or some combination of these examples may include an implementation of a network environment.

[0067] Bus 630 can represent one or more of several types of bus structures, including a memory cell bus or memory cell controller, a peripheral bus, a graphics acceleration port, a processing unit, or a local bus using any of the multiple bus structures.

[0068] Electronic device 600 can also communicate with one or more external devices 700 (e.g., keyboard, pointing device, Bluetooth device, etc.), and with one or more devices that enable a user to interact with electronic device 600, and / or with any device that enables electronic device 600 to communicate with one or more other computing devices (e.g., router, modem). This communication can be performed via input / output interface 650. Furthermore, electronic device 600 can also communicate with one or more networks (e.g., local area network, wide area network, and / or public network, such as the Internet) via network adapter 660. Network adapter 660 can communicate with other modules of electronic device 600 via bus 630. It should be understood that, although not shown in the figures, other hardware and / or software modules can be used in conjunction with electronic device 600, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage platforms.

[0069] Example 4 This invention also provides a storage medium, specifically a computer-readable storage medium, which is a memory device in a terminal device for storing programs and data. It is understood that the computer-readable storage medium here can include both built-in storage media in the terminal device and extended storage media supported by the terminal device; it can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. The computer-readable storage medium provides storage space that stores the terminal's operating system. Furthermore, the storage space also stores one or more instructions suitable for loading and execution by a processor, which can be one or more computer programs (including program code). More specific examples of the computer-readable storage medium include: an electrical connection with one or more wires, a portable disk, a hard disk, random access memory, read-only memory, erasable programmable read-only memory, optical fiber, portable compact disk read-only memory, optical storage device, magnetic storage device, or any suitable combination thereof.

[0070] Computer-readable storage media also include data signals propagated in baseband or as part of a carrier wave, carrying readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A readable storage medium can also be any readable medium other than a readable storage medium that can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the readable storage medium can be transmitted using any suitable medium, including but not limited to wireless, wired, optical fiber, radio frequency, etc., or any suitable combination thereof.

[0071] Program code for performing the operations of this invention can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, and conventional procedural programming languages ​​such as C or similar languages. The program code can execute entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0072] One or more instructions stored in the computer-readable storage medium can be loaded and executed by the processor to implement the corresponding steps of the leakage protection adaptive setting method based on ground capacitance parameter identification in the above embodiments; one or more instructions in the computer-readable storage medium are loaded and executed by the processor to perform the following steps: When the residual current device (RCD) is closed, the RCD is controlled to first close one phase of the live wire and disconnect the other two phases of the live wire and the neutral wire; the residual current after the closed phase of the live wire is detected, and when the preset steady-state conditions are met, the capacitance to ground of the line is calculated based on the detected residual current and voltage parameters; based on the calculated capacitance to ground, the operating current threshold and operating time of the RCD are automatically adjusted.

[0073] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0074] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0075] Simulation verification To verify the correctness of the proposed low-voltage distribution network leakage protection method, a system was built as follows: Figure 2 The experimental model of the AC distribution network is shown. In this model, the transformer adopts the D / Yn11 connection method, the line-to-ground capacitance parameter is set to 0.1uF / km, and the resistance and inductance per kilometer of line are set to 0.7Ω and 0.6mH, respectively. The A-phase switch is controlled to close at 0.9s, and all switches are closed at 1.0s.

[0076] Figure 2The model, from top to bottom, includes a 10kV high-voltage side, a D / Yn11 type step-down transformer, a 400V low-voltage busbar, three-level leakage current protection nodes (main protection, branch protection, and household protection), and load units. The transformer neutral point is directly grounded, conforming to the grounding specifications of low-voltage distribution networks. Each level of protection node is connected in series with the leakage current protection device described in this invention, which incorporates a voltage transformer, a residual current transformer, and a control module. The line section is labeled with the distributed parameters of capacitance, resistance, and inductance to ground. The load units adopt a mixed configuration of three-phase balanced loads and single-phase loads to simulate actual user power consumption scenarios. This model fully reproduces the topology of the three-level protection architecture of main protection-branch protection-household protection, and can accurately simulate the power grid operation status under different line lengths and load conditions, providing a realistic test environment for the verification of technical solutions.

[0077] Simulation results are as follows Figure 3 As shown, the horizontal axis represents time (in seconds), and the vertical axis represents the effective value of the residual current (in mA). The waveform clearly presents three key stages: 0~0.9s is the initial state, all switches are open, and the residual current is 0; at 0.9s, the A-phase switch is closed according to the method of this invention, while other phases and the neutral line switch remain open, and the residual current rises rapidly with slight fluctuations; this stage is the charging process of the line capacitor; from 0.9 to 1.0s, the fluctuation of the residual current gradually decreases, and at 0.95s, the steady-state condition of |ΔI / I| < 10% is met, and the waveform tends to be stable; at this time, the collected residual current is the line-to-ground capacitance current; at 1.0s... When all other phase and neutral line switches are closed, the residual current drops to near zero, and the system enters normal operation. When the three-phase voltage and line-to-ground parameters are completely symmetrical, the residual current transformer will only output current after a single-phase switch is closed. This current is caused by the line-to-ground capacitance, and therefore can reflect the size of the line. This waveform verifies that the line-to-ground capacitance current can be effectively collected after a single-phase switch is closed, and the determination of steady-state conditions is accurate and reliable, providing stable data support for capacitance calculation. This proves that the method of this invention can accurately capture the characteristic parameters of the line-to-ground capacitance.

[0078] By continuously adjusting the line length and simulating different operating conditions, the adaptive setting effect of the leakage current protection device was tested, thereby comprehensively verifying the effectiveness and reliability of the protection setting method in multiple scenarios. The experimental results are shown in Table 1: Table 1. Identification results of line-to-ground parameters and protection setting information

[0079] The experimental results above show that the capacitor identification is accurate. The calculated value of the capacitance to ground corresponding to different line lengths has an error of less than 3% compared with the theoretical value, which proves that the design of single-phase closing and steady-state judgment can effectively eliminate interference and accurately capture capacitor characteristics. The setting results are accurate, and the operating current and time strictly match the three-level protection level according to the capacitance range, with no setting mismatch. It has a fast response speed, taking only 0.1 seconds from single-phase closing to completion of setting, which will not affect the user's normal power supply; It has strong adaptability. Within the capacitance range of 0.5~10μF (covering all scenarios from the last protection to the main protection), the setting results all meet expectations, proving that the technical solution can adapt to distribution networks of different scales. Using a single-phase closing method can accurately identify the line's ground parameters, thereby automatically setting the operating current and operating time of the leakage current protection device, which has certain practical value.

[0080] In summary, this invention, a method and system for adaptive setting of leakage current protection based on ground capacitance parameter identification, completely changes the traditional setting mode that relies on manual experience. By automatically identifying the line's ground capacitance parameter, it achieves accurate adaptive setting of protection values, fundamentally avoiding setting errors caused by human factors. Secondly, this invention effectively solves the long-standing problem of cascading tripping in distribution networks. Through scientific hierarchical setting rules, it ensures the coordinated operation of the three protection stages, greatly improving power supply reliability. In practical applications, this invention can significantly shorten setting time, reduce operation and maintenance costs, and improve work efficiency. Furthermore, this method has broad adaptability and can be applied to distribution networks of different sizes and structures, providing important technical support for the construction of smart distribution networks. Simulation results fully demonstrate the effectiveness and reliability of the method, demonstrating significant promotional value.

[0081] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0082] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0083] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed in this invention can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0084] In the embodiments provided by this invention, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0085] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0086] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0087] If the integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random-access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in the computer-readable medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electrical carrier signals and telecommunication signals.

[0088] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus, and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0089] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0090] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0091] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. An adaptive setting method for leakage current protection based on ground capacitance parameter identification, characterized in that, Includes the following steps: When the residual current device (RCD) is closed, the RCD is controlled to first close one phase of the live wire and disconnect the other two phases of the live wire and the neutral wire. The residual current after the live wire of one phase is closed is detected. When the preset steady-state condition is met, the capacitance to ground of the line is calculated based on the detected residual current and voltage parameters. Based on the calculated capacitance to ground, the operating current threshold and operating time of the residual current device are automatically set.

2. The adaptive setting method for leakage protection based on ground capacitance parameter identification according to claim 1, characterized in that, The preset steady-state condition is: Residual current difference between two adjacent waves The effective value of the residual current of the next cycle satisfy .

3. The adaptive setting method for leakage protection based on ground capacitance parameter identification according to claim 1, characterized in that, Before detecting the residual current and obtaining voltage parameters, the process also includes: A voltage transformer is installed between the live wire and the neutral wire on the power supply side of the leakage current device. Voltage transformers are installed on the load side between the other two live wires and the target live wire, and between the neutral wire and the target live wire on the load side of the leakage current protection device. A voltage transformer and a residual current transformer are installed on the power supply side of the leakage current protection device. Voltage parameters are collected through the power supply side voltage transformer and the load side voltage transformer, and residual current is collected through the residual current transformer.

4. The adaptive setting method for leakage protection based on ground capacitance parameter identification according to claim 3, characterized in that, Before calculating the line's capacitance to ground based on the detected residual current and voltage parameters, the calculation of the line's voltage to ground is also included: Let the voltage of the target phase live wire to the neutral wire collected by the voltage transformer on the power supply side be... The voltages of the other two live wires to the target live wire, collected by the load-side voltage transformer, are respectively , The voltage between the neutral wire and the target phase live wire collected by the load-side voltage transformer is ; The voltage to ground of the other two live wires was derived using the voltage difference relationship. , and the voltage to ground of the neutral wire .

5. The adaptive setting method for leakage protection based on ground capacitance parameter identification according to claim 4, characterized in that, The capacitance to ground of the calculation circuit for: in, The residual current value is the actual measured value of the residual current transformer inside the leakage protection device. These are the voltages to ground of each line on the load side of the residual current device (RCD). This refers to the capacitance to ground of the downstream circuit of the leakage protection device. This is the angular frequency of the power grid.

6. The adaptive setting method for leakage protection based on ground capacitance parameter identification according to claim 1, characterized in that, The operating time of the leakage current protection device, which is automatically set based on the calculated capacitance to ground, is specifically as follows: When the capacitance to ground satisfy At μF, the action time is set to 0s; When the capacitance to ground satisfy At μF, the action time is set to 0.1s; When the capacitance to ground satisfy At μF, the action time is set to 0.2s.

7. The adaptive setting method for leakage protection based on ground capacitance parameter identification according to claim 1, characterized in that, The operating current threshold of the automatic ground capacitance setting residual current device, calculated based on the ground capacitance, is specifically as follows: When the capacitance to ground satisfy At μF, the operating current threshold is set to 50mA; When the capacitance to ground satisfy At μF, the operating current threshold is set to 200mA; When the capacitance to ground satisfy At 6μF, the operating current threshold is set to 500mA.

8. The adaptive setting method for leakage protection based on ground capacitance parameter identification according to claim 1, characterized in that, After calculating the capacitance to ground, the residual current device (RCD) is controlled to close the other two live wires and the neutral wire.

9. The adaptive setting method for leakage protection based on ground capacitance parameter identification according to claim 1, characterized in that, The aforementioned live wire is phase A.

10. A leakage current protection adaptive setting system based on ground capacitance parameter identification, characterized in that, include: The control module is used to control the residual current device (RCD) to close one phase of the live wire first and disconnect the other two phases of the live wire and the neutral wire when the RCD is closed. The detection module is used to detect the residual current after the live wire of one phase is closed; The calculation module is used to calculate the line's capacitance to ground based on the detected residual current and voltage parameters when the preset steady-state conditions are met. The setting module is used to automatically set the operating current threshold and operating time of the leakage current protector based on the calculated capacitance to ground.

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