Leakage protection action method and system
By designing a leakage protection action system, including a leakage protection action and return module and a leakage protection acceleration module, the problem of slow response speed of traditional leakage protection switches is solved, and a faster protection action response is achieved.
Patent Information
- Application Number
- CN202411803456.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-09
- Publication Date
- 2025-03-18
AI Technical Summary
Traditional leakage protection switches have shortcomings in the response speed of protection operations, resulting in slow response in leakage situations.
A leakage protection action system is designed, including a leakage protection action and return module and a leakage protection acceleration module. The leakage protection action and return module is used to perform protection action when leakage occurs in the line and to perform return action when the current returns to normal; the leakage protection acceleration module calculates the magnitude of the leakage current and determines whether it is greater than the threshold, responds quickly and performs protection actions.
By increasing the leakage current calculation speed, the system can respond to leakage conditions more quickly and improve the response speed of protection operations.
Smart Images
Figure CN119651490A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of electronic information technology, and in particular to a leakage protection action method and system. Background Art
[0002] Traditional leakage protection switches work based on the protection principle of leakage relays. The leakage current transformer outputs a leakage current signal, which is introduced into the leakage protection integrated circuit. The leakage protection integrated circuit then outputs a control signal to trigger the thyristor to drive the leakage relay to trip the switch. This results in a slow protection action response speed. Summary of the invention
[0003] The purpose of the embodiments of the present invention is to provide a leakage protection action method and system to improve the protection action response speed.
[0004] To achieve the above purpose, the embodiment of the present invention provides the following solution:
[0005] A leakage protection action system, comprising:
[0006] Leakage protection action and return module, used for:
[0007] When leakage occurs in the line and the leakage current is greater than a first current threshold, a protection action is executed to disconnect the line;
[0008] After the protection action is performed, when the leakage current is less than the second current threshold, a return action is performed to turn on the circuit;
[0009] The leakage protection acceleration module is connected to the leakage protection action and return module and is used to:
[0010] Calculating the magnitude of the leakage current;
[0011] It is determined whether the leakage current is greater than a first current threshold.
[0012] Optionally, the leakage protection action and return module includes:
[0013] An equivalent circuit of the device is connected to the circuit and is used to mirror the current in the circuit;
[0014] K1 leakage protection switch, connected to the line and the distribution transformer respectively, for performing leakage protection action to disconnect or connect the line;
[0015] A grounding module, connected to the device equivalent circuit and the circuit respectively;
[0016] The load module is connected to the line.
[0017] Optionally, the device equivalent circuit includes:
[0018] The current transformer CT1 is used to collect leakage current and identify leakage fault according to the leakage current; the current detection range of the current transformer CT1 is 1-10000mA;
[0019] A current limiting resistor R1 is connected to the current transformer CT1 and is used to limit the leakage current;
[0020] A current transformer CT2 is connected to the current limiting resistor R1 and is used to detect the leakage current in the equivalent circuit of the device and identify whether the leakage fault disappears according to the leakage current; the current detection range of the current transformer CT2 is 0-2mA;
[0021] The grounding switch S1 is connected to the current transformer CT1 and the current transformer CT2 respectively, and is used for:
[0022] When the K1 leakage protection switch is closed, the neutral point of the transformer is directly grounded;
[0023] When the K1 leakage protection switch is disconnected, the main grounding circuit is switched to the current limiting grounding circuit.
[0024] Optionally, the leakage protection acceleration module includes:
[0025] The calculation module is used to calculate the current leakage current sampling point mutation value Δi in real time by using the window moving method k ;
[0026] A determination module is connected to the calculation module and is used to determine the mutation amount Δi of three consecutive leakage current sampling points. k whether they are all greater than a first current threshold;
[0027] If so, the grounding switch S1 is controlled to be disconnected, the current limiting resistor R1 suppresses the leakage current to a safe current, and the leakage protection switch K1 is closed;
[0028] If not, the grounding switch S1 is controlled to be closed, the current limiting resistor R1 is short-circuited, and the leakage protection switch K1 is closed.
[0029] Optionally, the grounding module includes:
[0030] Grounding resistor Z and grounding switch S2.
[0031] Optionally, the window moving method specifically includes:
[0032] M points are sampled per cycle, the fixed window length is N, and the number of cycles is N / M.
[0033] Optionally, the leakage protection acceleration module further includes:
[0034] A fault determination unit is used for:
[0035] After the current limiting resistor R1 suppresses the leakage current to a safe current, if the leakage current detected by the current transformer CT2 is less than the first preset current threshold, and the leakage current duration T1 is greater than the first preset time threshold, the grounding switch S2 has been disconnected, the grounding switch S1 is closed, and the neutral point of the transformer is directly grounded, then the leakage fault is eliminated and it is determined to be a transient fault;
[0036] After the current limiting resistor R1 suppresses the leakage current to a safe current, if the leakage current detected by the current transformer CT2 is greater than or equal to the second preset current threshold, and the leakage current duration T2 is greater than the second preset time threshold, the grounding switch S2 is in a closed state, the grounding switch S1 is closed, the locking device is activated again to directly ground the neutral point of the transformer, and the K1 leakage protection switch is disconnected, and it is determined to be a permanent fault;
[0037] When the K1 leakage protection switch is disconnected, the leakage current disappears and the locking device is automatically released.
[0038] To achieve the above purpose, the embodiment of the present invention also provides the following solution:
[0039] A leakage protection action method, comprising:
[0040] Obtain and calculate the magnitude of leakage current;
[0041] Determining whether the leakage current is greater than a first current threshold;
[0042] If so, when leakage occurs in the line and the leakage current is greater than the first current threshold, a protection action is performed to disconnect the line;
[0043] After the protection action is performed, when the leakage current is less than the second current threshold, a return action is performed to conduct the circuit;
[0044] If not, keep the line connected.
[0045] Optionally, the obtaining and calculating the magnitude of the leakage current specifically includes:
[0046] The window moving method is used to calculate the current leakage current sampling point mutation value Δi in real time k ;
[0047] Optionally, determining whether the leakage current is greater than a first current threshold specifically includes:
[0048] Determine the mutation value Δi of three consecutive leakage current sampling points k whether they are all greater than a first current threshold;
[0049] If so, the grounding switch S1 is controlled to be disconnected, the current limiting resistor R1 suppresses the leakage current to a safe current, and the leakage protection switch K1 is closed;
[0050] If not, the grounding switch S1 is controlled to be closed, the current limiting resistor R1 is short-circuited, and the leakage protection switch K1 is closed;
[0051] After the current limiting resistor R1 suppresses the leakage current to a safe current, if the leakage current detected by the current transformer CT2 is less than the first preset current threshold, and the leakage current duration T1 is greater than the first preset time threshold, the grounding switch S2 has been disconnected, the grounding switch S1 is closed, and the neutral point of the transformer is directly grounded, then the leakage fault is eliminated and it is determined to be a transient fault;
[0052] After the current limiting resistor R1 suppresses the leakage current to a safe current, if the leakage current detected by the current transformer CT2 is greater than or equal to the second preset current threshold, and the leakage current duration T2 is greater than the second preset time threshold, the grounding switch S2 is in a closed state, the grounding switch S1 is closed, the locking device is activated again to directly ground the neutral point of the transformer, and the K1 leakage protection switch is disconnected, and it is determined to be a permanent fault;
[0053] When the K1 leakage protection switch is disconnected, the leakage current disappears and the locking device is automatically released.
[0054] In the embodiment of the present invention, the leakage protection action and return module is used to perform a protection action and disconnect the line when leakage occurs in the line and the leakage current is greater than the first current threshold; perform a return action and conduct the line when the leakage current is less than the second current threshold after the protection action is performed; the leakage protection acceleration module is used to: calculate the magnitude of the leakage current; determine whether the leakage current is greater than the first current threshold. The application of the leakage protection acceleration module increases the speed of calculating the magnitude of the leakage current, so the protection action response speed is improved. BRIEF DESCRIPTION OF THE DRAWINGS
[0055] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.
[0056] Figure 1 A schematic diagram of the structure of a leakage protection action system provided by an embodiment of the present invention;
[0057] Figure 2 An electrical schematic diagram of a leakage protection action system provided by an embodiment of the present invention;
[0058] Figure 3A schematic diagram of a window movement method provided by an embodiment of the present invention;
[0059] Figure 4 A schematic diagram of leakage current sampling points provided by an embodiment of the present invention;
[0060] Figure 5 A schematic diagram of quarter-cycle sampling provided by an embodiment of the present invention;
[0061] Figure 6 A schematic diagram of a flow chart of a leakage protection action method provided in an embodiment of the present invention.
[0062] Explanation of symbols:
[0063] Leakage protection action and return module-1, leakage protection acceleration module-2. DETAILED DESCRIPTION
[0064] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0065] The purpose of the present invention is to provide a leakage protection action system to solve the problem of slow response speed of existing protection actions.
[0066] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.
[0067] Figure 1 An exemplary structure of the leakage protection system is shown. The following is a detailed introduction to each module.
[0068] The leakage protection action and return module 1 is used for:
[0069] When leakage occurs in the line and the leakage current is greater than a first current threshold, a protection action is executed to disconnect the line;
[0070] After the protection action is executed, when the leakage current is less than the second current threshold, a return action is executed to turn on the line;
[0071] In an example, the leakage current is generated by a line fault, the first current threshold may be 30 mA, and the second current threshold may be 100 uA.
[0072] The leakage protection acceleration module 2 is connected to the leakage protection action and return module 1, and the leakage protection acceleration module 2 is used to:
[0073] Calculate the leakage current;
[0074] It is determined whether the leakage current is greater than a first current threshold.
[0075] See also Figure 2 , the leakage protection action and return module 1 includes:
[0076] The device equivalent circuit is connected to the line, and the device equivalent circuit is used to mirror the current in the line;
[0077] The K1 leakage protection switch is connected to the line and the distribution transformer respectively. The K1 leakage protection switch is used to perform leakage protection action to disconnect or conduct the line;
[0078] The grounding module is connected to the device equivalent circuit and the line respectively;
[0079] The grounding module includes: a grounding resistor Z and a grounding switch S2.
[0080] The load module is connected to the line.
[0081] The device equivalent circuit includes:
[0082] The current transformer CT1 is used to collect leakage current, and the calculation module identifies the leakage fault according to the leakage current. The calculation module can be a chip or a comparator. The current detection range of the current transformer CT1 is 1-10000mA. The first end of the current transformer CT1 is connected to the distribution transformer.
[0083] The current limiting resistor R1 is connected to the current transformer CT1, and is used to limit the leakage current to ensure the safety of electric leakage. The first end of the current limiting resistor R1 is connected to the second end of the current transformer CT1.
[0084] The current transformer CT2 is connected to the current limiting resistor R1. The current transformer CT2 is used to detect the leakage current in the device equivalent circuit and identify whether the leakage fault disappears according to the leakage current; the current detection range of the current transformer CT2 is 0-2mA; the first end of the current transformer CT2 is connected to the second end of the current limiting resistor R1. The second end of the current transformer CT2 is grounded.
[0085] The grounding switch S1 is connected to the current transformer CT1 and the current transformer CT2 respectively. The grounding switch S1 is used to: connect the first end of the grounding switch S1 to the second end of the current transformer CT1. The second end of the grounding switch S1 is grounded. PE is the earth.
[0086] When the K1 leakage protection switch is closed, the neutral point of the transformer is directly grounded;
[0087] When the K1 leakage protection switch is disconnected, the main grounding circuit switches to the current limiting grounding circuit. The K1 leakage protection switch is connected to the distribution transformer and performs corresponding protection actions according to the two leakage current values monitored by the device equivalent circuit.
[0088] In an example, see Figure 2 , there is a distribution transformer on the line, the grounding resistor Z is used to simulate the human body electric shock resistance, and Z1, Z2 and Z3 are loads. The equivalent circuit of the device contains two grounding loops, the loop where the switch S1 is located is the main grounding loop, and the loop where R1 is located is the current limiting grounding loop. When the S1 switch of the main grounding loop is closed, the current limiting loop is short-circuited, and the role of the current limiting resistor R1 in the circuit is ignored.
[0089] The leakage protection acceleration module 2 includes:
[0090] The calculation module is used to calculate the current leakage current sampling point mutation value Δik in real time by using a window moving method; the window moving method specifically includes:
[0091] M points are sampled per cycle, the fixed window length is N, and the number of cycles is N / M.
[0092] See also Figure 3 The window moving mode is described by taking 12 sampling points per cycle as an example. The fixed length of the window is 36 (S1 to S36), that is, 3 cycles.
[0093] The basic working principle of the leakage protection acceleration module is to accelerate the leakage protection action by calculating the leakage current mutation amount.
[0094] The determination module is connected to the calculation module and is used to determine the mutation value Δi of three consecutive leakage current sampling points. k whether they are all greater than a first current threshold;
[0095] If so, the grounding switch S1 is controlled to be disconnected, the current limiting resistor R1 suppresses the leakage current to a safe current, and the leakage protection switch K1 is closed;
[0096] If not, the grounding switch S1 is controlled to be closed, the current limiting resistor R1 is short-circuited, and the leakage protection switch K1 is closed.
[0097] See also Figure 4 , the value of the sampling point is used to calculate the sampling point mutation amount Δi k The formula is:
[0098] Δi k =i k -i k-N ;
[0099] Δi k is the calculated value of the fault component at the K sampling time; i kis the leakage current sampling value at time K; i k-N It is the leakage current sampling value of one cycle before the K moment.
[0100] In one example, the actual application calculation formula is:
[0101] Δi k =||Δi k -i k-N |-|Δi k-N -i k-2N ||;
[0102] In order to ensure the anti-interference ability of the calculation process, the mutation value Δi of three consecutive leakage current sampling points is taken. k .
[0103] See also Figure 5 , take the mutation value Δi of three consecutive leakage current sampling points k The occurrence of leakage fault can be detected within a quarter of a cycle, greatly improving the speed of protection action.
[0104] The leakage protection acceleration module 2 also includes:
[0105] The fault determination unit is used to:
[0106] After the current limiting resistor R1 suppresses the leakage current to a safe current, if the leakage current detected by the current transformer CT2 is less than the first preset current threshold, and the leakage current duration T1 is greater than the first preset time threshold, the grounding switch S2 has been disconnected, the grounding switch S1 is closed, and the neutral point of the transformer is directly grounded, then the leakage fault is eliminated and it is determined to be a transient fault;
[0107] After the current limiting resistor R1 suppresses the leakage current to a safe current, if the leakage current detected by the current transformer CT2 is greater than or equal to the second preset current threshold, and the leakage current duration T2 is greater than the second preset time threshold, the grounding switch S2 is in a closed state, the grounding switch S1 is closed, the locking device is activated again to directly ground the neutral point of the transformer, and the K1 leakage protection switch is disconnected, and it is determined to be a permanent fault;
[0108] When the K1 leakage protection switch is disconnected, the leakage current disappears and the locking device is automatically released.
[0109] The action logic of leakage protection and return module 1 is:
[0110] Under normal circumstances, the K1 leakage protection switch is closed, S1 is closed, S2 is open, and the neutral point of the transformer is directly grounded.
[0111] Action process: When a leakage fault occurs, it is equivalent to S2 closing. At the moment S2 is closed, the current transformer CT1 monitors whether the leakage current exceeds the first preset current threshold (threshold value, such as 30 mA), and the device quickly disconnects S1. Specifically, through the above leakage protection acceleration module, the leakage current monitored by the current transformer CT1 is obtained in real time, and based on the leakage current, the current sampling point mutation amount Δi is calculated in real time using a window moving method. k , when there are three consecutive points of Δi k When both are greater than the threshold value, S1 is controlled to disconnect quickly, R1 is automatically switched on to quickly suppress the leakage current to a safe current, and the K1 leakage protection switch does not operate.
[0112] Return process: After R1 is put into operation, if the leakage current detected by the current transformer CT2 is less than the second preset current threshold (threshold value, such as 100 microamperes), and lasts for T1 time greater than the first preset time threshold (10 seconds), it means that S2 has been disconnected, the leakage fault is eliminated, and it is a transient fault. The device closes S1 to directly ground the neutral point of the transformer. If the leakage current detected by the current transformer CT2 is greater than or equal to the second preset current threshold (threshold value, such as 100 microamperes), and lasts for T2 time greater than the second preset time threshold (2 hours), it means that S2 is still in a closed state, which is a permanent fault. The device closes S1 and locks the leakage protection action system again, so that the neutral point of the transformer is directly grounded, forcing the K1 leakage protection switch installed on site to operate and cut off the line power supply. When the power is cut off and the leakage current disappears, the device lock is automatically released.
[0113] In summary, in the embodiment of the present invention, the leakage protection action and return module is used to perform a protection action and disconnect the line when leakage occurs in the line and the leakage current is greater than the first current threshold; perform a return action and conduct the line when the leakage current is less than the second current threshold after the protection action is performed; the leakage protection acceleration module is used to: calculate the magnitude of the leakage current; determine whether the leakage current is greater than the first current threshold. The application of the leakage protection acceleration module increases the speed of calculating the magnitude of the leakage current, so the protection action response speed is improved.
[0114] To achieve this, see Figure 6 , the embodiment of the present invention also provides the following solution:
[0115] Step 1: Obtain and calculate the leakage current; specifically including:
[0116] Step 11: Use the window moving method to calculate the current leakage current sampling point mutation value Δi in real time k ;
[0117] Step 2: Determine whether the leakage current is greater than a first current threshold;
[0118] If so, when leakage occurs in the line and the leakage current is greater than the first current threshold, a protection action is performed to disconnect the line;
[0119] After the protection action is executed, when the leakage current is less than the second current threshold, a return action is executed to turn on the line;
[0120] If not, keep the line connected.
[0121] Determining whether the leakage current is greater than the first current threshold specifically includes:
[0122] Step 21: Determine the mutation value Δi of three consecutive leakage current sampling points k whether they are all greater than a first current threshold;
[0123] If so, the grounding switch S1 is controlled to be disconnected, the current limiting resistor R1 suppresses the leakage current to a safe current, and the leakage protection switch K1 is closed;
[0124] If not, the grounding switch S1 is controlled to be closed, the current limiting resistor R1 is short-circuited, and the leakage protection switch K1 is closed;
[0125] Step 22: After the current limiting resistor R1 suppresses the leakage current to a safe current, if the leakage current detected by the current transformer CT2 is less than the first preset current threshold, and the leakage current duration T1 is greater than the first preset time threshold, the grounding switch S2 has been disconnected, the grounding switch S1 is closed, and the neutral point of the transformer is directly grounded, then the leakage fault is eliminated and it is determined to be a transient fault;
[0126] Step 23: After the current limiting resistor R1 suppresses the leakage current to a safe current, if the leakage current detected by the current transformer CT2 is greater than or equal to the second preset current threshold, and the leakage current duration T2 is greater than the second preset time threshold, the grounding switch S2 is in a closed state, the grounding switch S1 is closed, the locking device is activated again to directly ground the neutral point of the transformer, and the K1 leakage protection switch is disconnected, and it is determined to be a permanent fault;
[0127] When the K1 leakage protection switch is disconnected, the leakage current disappears and the locking device is automatically released.
[0128] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.
[0129] This article uses specific examples to illustrate the principles and implementation methods of the embodiments of the present invention. The description of the above embodiments is only used to help understand the methods and core ideas of the embodiments of the present invention. At the same time, for those skilled in the art, according to the ideas of the embodiments of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the embodiments of the present invention.
Claims
1. A leakage protection action system, characterized in that: include: Leakage protection action and return module, used for: When leakage occurs in the line and the leakage current is greater than a first current threshold, a protection action is executed to disconnect the line; After the protection action is performed, when the leakage current is less than the second current threshold, a return action is performed to conduct the circuit; The leakage protection acceleration module is connected to the leakage protection action and return module and is used to: Calculating the magnitude of the leakage current; It is determined whether the leakage current is greater than a first current threshold.
2. The leakage protection system according to claim 1, characterized in that: The leakage protection action and return module includes: An equivalent circuit of the device is connected to the circuit and is used to mirror the current in the circuit; K1 leakage protection switch, connected to the line and the distribution transformer respectively, for performing leakage protection action to disconnect or connect the line; A grounding module, connected to the device equivalent circuit and the circuit respectively; The load module is connected to the line.
3. The leakage protection system according to claim 2, characterized in that: The device equivalent circuit comprises: The current transformer CT1 is used to collect leakage current and identify leakage fault according to the leakage current; the current detection range of the current transformer CT1 is 1-10000mA; A current limiting resistor R1 is connected to the current transformer CT1 and is used to limit the leakage current; A current transformer CT2 is connected to the current limiting resistor R1 and is used to detect the leakage current in the equivalent circuit of the device and identify whether the leakage fault disappears according to the leakage current; the current detection range of the current transformer CT2 is 0-2mA; The grounding switch S1 is connected to the current transformer CT1 and the current transformer CT2 respectively, and is used for: When the K1 leakage protection switch is closed, the neutral point of the transformer is directly grounded; When the K1 leakage protection switch is disconnected, the main grounding circuit is switched to the current limiting grounding circuit.
4. The leakage protection action system according to claim 3, characterized in that: The leakage protection acceleration module comprises: The calculation module is used to calculate the current leakage current sampling point mutation value Δi in real time by using the window moving method k ; A determination module is connected to the calculation module and is used to determine the mutation amount Δi of three consecutive leakage current sampling points. k whether they are all greater than a first current threshold; If so, the grounding switch S1 is controlled to be disconnected, the current limiting resistor R1 suppresses the leakage current to a safe current, and the leakage protection switch K1 is closed; If not, the grounding switch S1 is controlled to be closed, the current limiting resistor R1 is short-circuited, and the leakage protection switch K1 is closed.
5. The leakage protection system according to claim 4, characterized in that: The grounding module comprises: Grounding resistor Z and grounding switch S2.
6. The leakage protection action system according to claim 5, characterized in that: The window moving method specifically includes: M points are sampled per cycle, the fixed window length is N, and the number of cycles is N / M.
7. The leakage protection system according to claim 4, characterized in that: The leakage protection acceleration module also includes: A fault determination unit is used for: After the current limiting resistor R1 suppresses the leakage current to a safe current, if the leakage current detected by the current transformer CT2 is less than the first preset current threshold, and the leakage current duration T1 is greater than the first preset time threshold, the grounding switch S2 has been disconnected, the grounding switch S1 is closed, and the neutral point of the transformer is directly grounded, then the leakage fault is eliminated and it is determined to be a transient fault; After the current limiting resistor R1 suppresses the leakage current to a safe current, if the leakage current detected by the current transformer CT2 is greater than or equal to the second preset current threshold, and the leakage current duration T2 is greater than the second preset time threshold, the grounding switch S2 is in a closed state, the grounding switch S1 is closed, the locking device is activated again to directly ground the neutral point of the transformer, and the K1 leakage protection switch is disconnected, and it is determined to be a permanent fault; When the K1 leakage protection switch is disconnected, the leakage current disappears and the locking device is automatically released.
8. A leakage protection action method, characterized in that: include: Obtain and calculate the magnitude of leakage current; Determining whether the leakage current is greater than a first current threshold; If so, when leakage occurs in the line and the leakage current is greater than the first current threshold, a protection action is performed to disconnect the line; After the protection action is performed, when the leakage current is less than the second current threshold, a return action is performed to conduct the circuit; If not, keep the line connected.
9. The leakage protection action method according to claim 8, characterized in that: The obtaining and calculating the magnitude of the leakage current specifically includes: The window moving method is used to calculate the current leakage current sampling point mutation value Δi in real time k .
10. The leakage protection action method according to claim 9, characterized in that: Determining whether the leakage current is greater than the first current threshold specifically includes: Determine the mutation value Δi of three consecutive leakage current sampling points k whether they are all greater than a first current threshold; If so, the grounding switch S1 is controlled to be disconnected, the current limiting resistor R1 suppresses the leakage current to a safe current, and the leakage protection switch K1 is closed; If not, the grounding switch S1 is controlled to be closed, the current limiting resistor R1 is short-circuited, and the leakage protection switch K1 is closed; After the current limiting resistor R1 suppresses the leakage current to a safe current, if the leakage current detected by the current transformer CT2 is less than the first preset current threshold, and the leakage current duration T1 is greater than the first preset time threshold, the grounding switch S2 has been disconnected, the grounding switch S1 is closed, and the neutral point of the transformer is directly grounded, then the leakage fault is eliminated and it is determined to be a transient fault; After the current limiting resistor R1 suppresses the leakage current to a safe current, if the leakage current detected by the current transformer CT2 is greater than or equal to the second preset current threshold, and the leakage current duration T2 is greater than the second preset time threshold, the grounding switch S2 is in a closed state, the grounding switch S1 is closed, the locking device is activated again to directly ground the neutral point of the transformer, and the K1 leakage protection switch is disconnected, and it is determined to be a permanent fault; When the K1 leakage protection switch is disconnected, the leakage current disappears and the locking device is automatically released.