An insulation testing method and terminal

Abstract

This invention discloses an insulation detection method and terminal for an energy storage system. The method detects the operating status of the energy storage converter. If the energy storage converter is running, the insulation detection module is shut down, and the leakage current detection module on the AC side is activated for insulation assessment. If the energy storage converter is shut down, the leakage current detection module is shut down, and the insulation detection module on the DC side is activated for insulation assessment. In a TN power distribution system, this invention performs insulation detection on the energy storage system by setting a leakage current detection module on the AC side when the energy storage converter is conducting, and simultaneously setting an insulation detection module on the DC side when the energy storage converter is shut down. This eliminates the need for an additional isolation transformer to convert the TN system to an IT system, achieving insulation detection of the energy storage system while saving costs and maintaining its safety.

Description

[0001] This case is a divisional application based on the invention patent filed on October 24, 2023, with application number 202311377998.2 and titled "An Insulation Detection Method and Terminal for an Energy Storage System". Technical Field

[0002] This invention relates to the field of energy storage, and more particularly to an insulation testing method and terminal for an energy storage system. Background Technology

[0003] With the development of the energy storage industry, various power generation-side and user-side systems, large charging stations, small energy storage stations, and energy storage modules are springing up everywhere. To ensure the safety of electrochemical energy storage systems, the system insulation monitoring function is receiving increasing attention.

[0004] Especially in user-side energy storage systems, which typically employ a TN grounding system (directly grounded neutral point), the neutral wire is biased to ground. In this case, the phase wire resistance to ground is zero, making it difficult to detect the phase wire resistance using current bridge methods or AC signal injection methods. To make these methods effective, an isolation transformer needs to be added at the system front end, changing the circuit connection from a TN system to an IT system (ungrounded neutral point). This approach introduces a series of problems, including increased costs, the need for more equipment space, and reduced overall system efficiency. This method is particularly inefficient for small-scale commercial and industrial energy storage systems. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an insulation detection method and terminal for an energy storage system, which can realize insulation detection of TN circuit system without the need for isolation transformer.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] An insulation testing method for an energy storage system includes the following steps:

[0008] S1. Detect the operating status of the energy storage converter. If the energy storage converter is in operation, proceed to step S2; if the energy storage converter is in shutdown, proceed to step S3.

[0009] S2. Control the DC side insulation detection module to shut down, start the AC side leakage detection module, and use the leakage detection module to perform insulation judgment;

[0010] S3. The leakage detection module on the AC side is turned off, the insulation detection module on the DC side is turned on, and the insulation detection module is used to determine the insulation.

[0011] To solve the above-mentioned technical problems, another technical solution adopted by the present invention is as follows:

[0012] An insulation testing terminal for an energy storage system includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it completes any step of an insulation testing method for an energy storage system.

[0013] The beneficial effects of this invention are as follows: It provides an insulation detection method and terminal for an energy storage system. In a TN power distribution system, by setting a leakage current detection module on the AC side to perform insulation detection on the energy storage system when the energy storage converter is turned on, and simultaneously setting an insulation detection module on the DC side to perform insulation detection on the energy storage system when the energy storage converter is turned off, the insulation detection of the energy storage system can be realized without adding an isolation transformer to convert the TN system into an IT system, thus saving costs while maintaining the safety of the energy storage system. Attached Figure Description

[0014] Figure 1 This is a flowchart of an insulation detection method for an energy storage system according to an embodiment of the present invention;

[0015] Figure 2 This is a schematic diagram of an insulation detection terminal for an energy storage system according to an embodiment of the present invention;

[0016] Label Explanation:

[0017] 1. An insulation detection terminal for an energy storage system; 2. A memory; 3. A processor. Detailed Implementation

[0018] To explain in detail the technical content, objectives, and effects of the present invention, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0019] Please refer to Figure 1 An insulation testing method for an energy storage system includes the following steps:

[0020] S1. Detect the operating status of the energy storage converter. If the energy storage converter is in operation, proceed to step S2; if the energy storage converter is in shutdown, proceed to step S3.

[0021] S2. Control the DC side insulation detection module to shut down, start the AC side leakage detection module, and use the leakage detection module to perform insulation judgment;

[0022] S3. The leakage detection module on the AC side is turned off, the insulation detection module on the DC side is turned on, and the insulation detection module is used to determine the insulation.

[0023] As can be seen from the above description, the beneficial effects of the present invention are as follows: It provides an insulation detection method and terminal for an energy storage system. In a TN power distribution system, by setting a leakage current detection module on the AC side to perform insulation detection on the energy storage system when the energy storage converter is turned on, and simultaneously setting an insulation detection module on the DC side to perform insulation detection on the energy storage system when the energy storage converter is turned off, the insulation detection of the energy storage system can be realized without adding an isolation transformer to convert the TN system into an IT system, thus saving costs while maintaining the safety of the energy storage system.

[0024] Further, step S3 specifically includes:

[0025] S31. Control the AC side leakage detection module to shut down and start the DC side insulation detection module;

[0026] S32. The insulation detection module is used to monitor the test value of the DC bus in real time and connect to various functional modules on the DC side. If the actual test value is higher than the preset test value associated with the connected functional module, an insulation fault is determined.

[0027] As can be seen from the above description, when the energy storage converter is in a shutdown state, that is, when the energy storage battery of the energy storage system is supplying DC power, the insulation detection module on the DC side determines whether an insulation fault has occurred by detecting the test value of the DC bus in real time.

[0028] Specifically, in the embodiments of the present invention, since each functional module is connected in parallel with the DC bus, for the convenience of statistics, the test value is the sum of the reciprocals of the actual insulation resistance values ​​of each functional module connected to the DC bus.

[0029] Further, step S32 specifically includes:

[0030] S321. The insulation detection module is used to monitor the test value of the DC bus in real time and connected to the DC side of the energy storage converter;

[0031] S322. Within the first preset sampling period, calculate the actual comprehensive test value of the DC bus and record it as the first test value. If the first test value is higher than the preset first test value, determine the insulation fault and report the fault location as the energy storage converter; otherwise, proceed to the next step.

[0032] S323. Connect the energy storage battery. Within the second preset sampling period, calculate the actual comprehensive test value of the DC bus and record it as the second test value. If the second test value is higher than the preset second test value, determine the insulation fault and report the fault location as the energy storage battery; otherwise, proceed to the next step.

[0033] S324. When the nth functional module is connected, the actual test value of the DC bus is calculated and recorded as the nth test value within the nth preset sampling period. If the nth test value is higher than the preset nth test value, an insulation fault is determined and the fault location is reported as the currently connected functional module; n is an integer greater than 2.

[0034] As can be seen from the above description, in order to determine the location of the insulation fault, when monitoring the test value of the DC bus, the DC side of the energy storage converter is first connected, and the test value after connection is detected within the first preset sampling period and recorded as the first test value. If the first test value is higher than the preset first test value, the energy storage converter is considered to have an insulation fault.

[0035] Then, the energy storage battery is connected, and the test value after connection is detected within the second preset sampling period and recorded as the second test value. If the second test value is higher than the preset second test value, the energy storage battery is considered to have an insulation fault. At this time, both the energy storage converter and the energy storage battery are connected to the DC bus.

[0036] Secondly, assuming that the insulation tests of the energy storage converter and the energy storage battery are normal, other functional modules, such as DC photovoltaic modules, charging piles, and DC loads, are then connected. Each time a functional module is connected, the insulation of the currently connected module is tested within the corresponding preset sampling period. It should be noted that each time another functional module is connected, the insulation test is performed after the functional module in the above steps has been connected, and it is not tested by connecting the DC bus separately.

[0037] Furthermore, the formula for calculating the nth test value is as follows:

[0038]

[0039] Among them, W n This is the nth test value;

[0040] R0 is the standard insulation resistance value of the DC bus;

[0041] R1 is the actual insulation resistance value detected by the insulation detection module after the energy storage converter is connected to the DC bus.

[0042] R2 is the actual insulation resistance value detected by the insulation detection module after the energy storage battery is connected to the DC bus.

[0043] R n The insulation resistance value is obtained by the insulation detection module after the nth functional module is connected to the DC bus.

[0044] As described above, the formula for calculating the test value is the sum of the reciprocals of the insulation resistance values ​​of each functional module, where R0 is the standard insulation resistance value of the DC bus; and R1-R nThis refers to the actual insulation resistance value of each functional module; that is, when the actual insulation resistance value of a certain functional module is lower than its preset insulation resistance value, the detected DC bus test value will be higher than the preset test value, indicating that the currently connected functional module has an insulation fault.

[0045] Specifically, in this embodiment of the invention, the preset nth test value is the sum of the reciprocals of the standard test values ​​of the currently accessed functional module and the previously accessed functional modules.

[0046] Furthermore, the formula for calculating the nth preset sampling period is:

[0047]

[0048] Among them, T n The nth preset sampling period;

[0049] k is an integer ranging from 3 to 5;

[0050] C0 is the capacitance value of the DC bus;

[0051] C1 is the capacitance value of the energy storage converter after it is connected to the DC bus;

[0052] C2 is the capacitance value of the energy storage battery after it is connected to the DC bus;

[0053] C n This is the capacitance value after the nth functional module is connected to the DC bus.

[0054] As can be seen from the above description, since the insulation sampling period needs to take into account the pre-charge time constant (i.e. RC time), based on the above calculated test values, the calculation formula for the nth preset sampling period is the product of the reciprocal of the actual test value of the currently connected functional module and the sum of the capacitance values ​​of all currently connected functional modules.

[0055] The principle behind the value of k is as follows: Before insulation testing, charging time needs to be reserved for the capacitors of each functional module. According to experimental tests, at least 3 RC cycles are generally required for the corresponding capacitance value to reach 0.9 times the stable capacitance value. When k is 5, the corresponding capacitance value can reach 0.99 times the stable capacitance value. Preferably, k is 5.

[0056] Further, step S2 specifically includes:

[0057] S21. Control the DC side insulation detection module to shut down and start the AC side leakage detection module;

[0058] S22. The leakage current detection module is used to monitor the leakage current value of the energy storage system in real time and is connected to the functional modules on the AC side and DC side. If the actual leakage current value is higher than the preset leakage current value, an insulation fault is determined.

[0059] As can be seen from the above description, when the energy storage converter is in operation, that is, the power transmission between the external power grid and the energy storage battery is converted through the energy storage converter, the DC side insulation detection module cannot operate because the phase line of the TN system is connected to ground. The AC side leakage detection module is used to determine whether an insulation fault has occurred by detecting the leakage current value of the energy storage system in real time.

[0060] Further, step S22 specifically includes:

[0061] S221. The leakage current detection module is used to monitor the leakage current value of the energy storage system in real time, and the DC side and AC side of the energy storage converter are connected.

[0062] S222. Calculate the actual comprehensive leakage current value of the energy storage system and record it as the first leakage current value. If the first leakage current value is higher than the preset first leakage current value, then determine the insulation fault and report the fault location as the energy storage converter; otherwise, proceed to the next step.

[0063] S323. Connect the energy storage battery, calculate the actual comprehensive leakage current value of the energy storage system and record it as the second leakage current value. If the second leakage current value is higher than the preset second leakage current value, then determine the insulation fault and report the fault location as the energy storage battery; otherwise, proceed to the next step.

[0064] S324. When the nth functional module is connected, the actual leakage current value of the energy storage system is calculated within the nth preset sampling period and recorded as the nth leakage current value. If the nth leakage current value is higher than the preset nth leakage current value, an insulation fault is determined and the fault location is reported as the currently connected functional module; n is an integer greater than 2.

[0065] As can be seen from the above description, in order to determine the location of the insulation fault, when monitoring the leakage current value of the energy storage system, the energy storage converter is first connected, and the leakage current value after connection is recorded as the first leakage current value. If the first leakage current value is higher than the preset first leakage current value, the energy storage converter is considered to have an insulation fault.

[0066] Then, the energy storage battery is connected, and the leakage current value after connection is detected and recorded as the second leakage current value. If the second leakage current value is higher than the preset second leakage current value, the energy storage battery is considered to have an insulation fault. At this time, both the energy storage converter and the energy storage battery are connected to the DC bus.

[0067] Secondly, assuming that the insulation tests of the energy storage converter and the energy storage battery are normal, other functional modules (including AC-side functional modules) are then connected, such as DC photovoltaic modules, charging piles, DC loads, AC loads, AC photovoltaics, etc. Insulation tests are performed on the currently connected modules each time they are connected. It should be noted that insulation tests are performed on the other functional modules only after the functional modules in the above steps have been connected, and not on the energy storage system alone.

[0068] Please refer to Figure 2 An insulation testing terminal for an energy storage system includes a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor executes the computer program to complete any step in an insulation testing method for an energy storage system.

[0069] This invention provides an insulation detection method and terminal for an energy storage system, which is mainly applied to insulation monitoring of user-side energy storage systems. The following is a detailed description with reference to embodiments.

[0070] Please refer to Figure 1 Embodiment 1 of the present invention is: an insulation detection method for an energy storage system, comprising the following steps:

[0071] S1. Detect the operating status of the energy storage converter. If the energy storage converter is in operation, proceed to step S2; if the energy storage converter is in shutdown, proceed to step S3.

[0072] S2. Control the DC side insulation detection module to shut down, start the AC side leakage detection module, and use the leakage detection module to perform insulation judgment;

[0073] S3. The leakage detection module on the AC side is turned off, the insulation detection module on the DC side is turned on, and the insulation detection module is used to determine the insulation.

[0074] In this embodiment, an insulation detection method for an energy storage system is provided. In a TN power distribution system, a leakage current detection module is set on the AC side to perform insulation detection on the energy storage system when the energy storage converter is turned on. At the same time, an insulation detection module is set on the DC side to perform insulation detection on the energy storage system when the energy storage converter is turned off. This eliminates the need to add an isolation transformer to convert the TN system to an IT system, thereby achieving insulation detection of the energy storage system, saving costs while maintaining the safety of the energy storage system.

[0075] Please refer to Figure 1 Embodiment 2 of the present invention is as follows: Based on Embodiment 1, step S3 specifically includes:

[0076] S31. Control the AC side leakage detection module to shut down and start the DC side insulation detection module;

[0077] S32. The insulation detection module is used to monitor the test value of the DC bus in real time and connect to various functional modules on the DC side. If the actual test value is higher than the preset test value associated with the connected functional module, an insulation fault is determined.

[0078] In this embodiment, when the energy storage converter is in a shutdown state, i.e., the energy storage battery of the energy storage system is supplying DC power, the insulation detection module on the DC side determines whether an insulation fault has occurred by detecting the test value of the DC bus in real time.

[0079] Specifically, S32 consists of the following steps:

[0080] S321. Use an insulation detection module to monitor the test value of the DC bus in real time and connect it to the DC side of the energy storage converter;

[0081] S322. Within the first preset sampling period, calculate the actual comprehensive test value of the DC bus and record it as the first test value. If the first test value is higher than the preset first test value, determine the insulation fault and report the fault location as the energy storage converter; otherwise, proceed to the next step.

[0082] S323. Connect the energy storage battery. Within the second preset sampling period, calculate the actual comprehensive test value of the DC bus and record it as the second test value. If the second test value is higher than the preset second test value, determine the insulation fault and report the fault location as the energy storage battery; otherwise, proceed to the next step.

[0083] S324. When the nth functional module is connected, the actual test value of the DC bus is calculated and recorded as the nth test value within the nth preset sampling period. If the nth test value is higher than the preset nth test value, an insulation fault is determined and the fault location is reported as the currently connected functional module; n is an integer greater than 2.

[0084] In order to determine the location of the insulation fault, when monitoring the test value of the DC bus, the DC side of the energy storage converter is first connected. The test value after connection is detected within the first preset sampling period and recorded as the first test value. If the first test value is higher than the preset first test value, the energy storage converter is considered to have an insulation fault.

[0085] Then, the energy storage battery is connected, and the test value after connection is detected within the second preset sampling period and recorded as the second test value. If the second test value is higher than the preset second test value, the energy storage battery is considered to have an insulation fault. At this time, both the energy storage converter and the energy storage battery are connected to the DC bus.

[0086] Secondly, assuming that the insulation tests of the energy storage converter and the energy storage battery are normal, other functional modules, such as DC photovoltaic modules, charging piles, and DC loads, are then connected. Each time a functional module is connected, the insulation of the currently connected module is tested within the corresponding preset sampling period. It should be noted that each time another functional module is connected, the insulation test is performed after the functional module in the above steps has been connected, and it is not tested by connecting the DC bus separately.

[0087] In this embodiment, the formula for calculating the nth test value is:

[0088]

[0089] Among them, W n This is the nth test value;

[0090] R0 is the standard insulation resistance value of the DC bus;

[0091] R1 is the actual insulation resistance value detected by the insulation detection module after the energy storage converter is connected to the DC bus.

[0092] R2 is the actual insulation resistance value detected by the insulation detection module after the energy storage battery is connected to the DC bus.

[0093] R n The insulation resistance value is obtained by the insulation detection module after the nth functional module is connected to the DC bus.

[0094] The formula for calculating the test value is the sum of the reciprocals of the insulation resistance values ​​of each functional module, where R0 is the standard insulation resistance value of the DC bus; and R1-R... n The actual insulation resistance value of each functional module;

[0095] That is, when the actual insulation resistance of a certain functional module is lower than its preset insulation resistance, the detected DC bus test value will be higher than the preset test value, indicating that the currently connected functional module has an insulation fault.

[0096] Specifically, in this embodiment, the preset nth test value is the sum of the reciprocals of the standard test values ​​of the currently accessed functional module and the previously accessed functional modules.

[0097] Meanwhile, in this embodiment, the formula for calculating the nth preset sampling period is:

[0098]

[0099] Among them, T n The nth preset sampling period;

[0100] k is an integer ranging from 3 to 5;

[0101] C0 is the capacitance value of the DC bus;

[0102] C1 is the capacitance value of the energy storage converter after it is connected to the DC bus;

[0103] C2 is the capacitance value of the energy storage battery after it is connected to the DC bus;

[0104] C n This is the capacitance value after the nth functional module is connected to the DC bus.

[0105] As can be seen from the above description, since the insulation sampling period needs to take into account the pre-charge time constant, based on the above calculated test value, the calculation formula for the nth preset sampling period is the product of the reciprocal of the actual test value of the currently connected functional module and the sum of the capacitance values ​​of all currently connected functional modules.

[0106] The principle behind the value of k is as follows: Before insulation testing, charging time needs to be reserved for the capacitors of each functional module. According to experimental tests, at least 3 RC cycles are generally required for the corresponding capacitance value to reach 0.9 times the stable capacitance value. When k is 5, the corresponding capacitance value can reach 0.99 times the stable capacitance value. Preferably, k is 5.

[0107] Please refer to Figure 1 Embodiment 3 of the present invention is as follows: Based on Embodiment 1, step S2 specifically includes:

[0108] S21. Control the DC side insulation detection module to shut down and start the AC side leakage detection module;

[0109] S22. Use a leakage current detection module to monitor the leakage current value of the energy storage system in real time, and connect it to the functional modules on the AC side and DC side. If the actual leakage current value is higher than the preset leakage current value, an insulation fault is determined.

[0110] In this embodiment, when the energy storage converter is in operation, the power transmission between the external power grid and the energy storage battery is converted through the energy storage converter. At this time, since the phase line of the TN system is connected to ground, the insulation detection module on the DC side cannot operate. The leakage detection module on the AC side is used to determine whether an insulation fault has occurred by detecting the leakage current value of the energy storage system in real time.

[0111] Specifically, step S22 consists of the following steps:

[0112] S221. Use a leakage current detection module to monitor the leakage current value of the energy storage system in real time, and connect the DC side and AC side of the energy storage converter.

[0113] S222. Calculate the actual comprehensive leakage current value of the energy storage system and record it as the first leakage current value. If the first leakage current value is higher than the preset first leakage current value, then determine the insulation fault and report the fault location as the energy storage converter; otherwise, proceed to the next step.

[0114] In order to determine the location of the insulation fault, when monitoring the leakage current value of the energy storage system, the energy storage converter is first connected, and the leakage current value after connection is recorded as the first leakage current value. If the first leakage current value is higher than the preset first leakage current value, the energy storage converter is considered to have an insulation fault.

[0115] Then, the energy storage battery is connected, and the leakage current value after connection is detected and recorded as the second leakage current value. If the second leakage current value is higher than the preset second leakage current value, the energy storage battery is considered to have an insulation fault. At this time, both the energy storage converter and the energy storage battery are connected to the DC bus.

[0116] Secondly, assuming that the insulation tests of the energy storage converter and the energy storage battery are normal, other functional modules (including AC-side functional modules) are then connected, such as DC photovoltaic modules, charging piles, DC loads, AC loads, AC photovoltaics, etc. Insulation tests are performed on the currently connected modules each time they are connected. It should be noted that insulation tests are performed on the other functional modules only after the functional modules in the above steps have been connected, and not on the energy storage system alone.

[0117] An example of the application of an insulation testing method for an energy storage system in this embodiment is as follows:

[0118] The data statistics for each functional module within the energy storage system are as follows:

[0119]

[0120]

[0121] When the energy storage converter is shut down, the test value on the DC side is detected by the AC injection method. Each module circuit is equipped with a contactor switch. When an insulation fault occurs, the contactor switch is opened, stopping the current module from connecting to the energy storage system.

[0122] The initial power-on test steps are as follows:

[0123] 1. All modules are disconnected;

[0124] 2. The insulation detection module detected no problems with the DC bus test values;

[0125] (At this time, the DC bus only has the DC side of the energy storage converter, the DC power line, and the copper busbar.)

[0126]

[0127] The test is performed for three consecutive cycles, and the average value of the results is taken. During the actual comparison, if the actual insulation resistance R1 is greater than the allowable value R... 1预 This indicates that the DC side insulation of the energy storage converter is normal at this time; at the same time, since each functional module is connected in parallel to the DC bus, it is more convenient to use test values ​​for statistical calculations, that is, if the first test value is lower than the preset first test value (W1) <W 1预 If the result is W1 > W, it indicates that the insulation is normal, and the actual insulation resistance R1 is calculated in reverse. 1预This indicates that an insulation fault has occurred, and it is happening on the DC side of the currently connected energy storage converter.

[0128] 3. Engage the battery switch / contaminator to apply high voltage to DC, and the insulation detection module checks the DC bus test value;

[0129] (Same as above, use the insulation detection module to obtain the second test value and compare it with the preset second test value. If W2) <W 2预 Then, calculate the actual insulation resistance value R2 in reverse. If the test result is W2>W 2预 This indicates an insulation fault at this time, and it occurs in the currently connected energy storage battery.

[0130] 4. When connecting other functional modules, the detection method is the same as above. If a fault occurs, it indicates that the fault location is the currently connected functional module.

[0131] When the energy storage converter is in operation, the leakage current value of the energy storage system is detected by the leakage current detection module.

[0132] The detection method is the same as the DC side detection method described above.

[0133] For example, if the currently connected functional module is AC photovoltaic, the allowed leakage current value is:

[0134] I 7预 =I0+I 1预 +…+I 7预

[0135] Actual leakage value:

[0136] I7 = I0 + I1 + ... + I7

[0137] If the actual leakage current value is greater than the allowable leakage current value, it indicates that there is an insulation fault and the fault location is the currently connected functional module.

[0138] Please refer to Figure 2 Embodiment 4 of the present invention is: an insulation detection terminal 1 for an energy storage system, including a memory 2, a processor 3, and a computer program stored on the memory 2 and executable on the processor 3. When the processor 3 executes the computer program, it performs the steps in any of the insulation detection methods of the energy storage system described in Embodiments 1 to 3 above.

[0139] In summary, this invention provides an insulation detection method and terminal for an energy storage system. In a TN power distribution system, by setting a leakage current detection module on the AC side to perform insulation detection on the energy storage system when the energy storage converter is turned on, and simultaneously setting an insulation detection module on the DC side to perform insulation detection on the energy storage system when the energy storage converter is turned off, the insulation detection of the energy storage system can be achieved without adding an isolation transformer to convert the TN system to an IT system, thus saving costs while maintaining the safety of the energy storage system.

[0140] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification and drawings, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. An insulation testing method, characterized in that: Including the following steps: S1. Detect the operating status of the energy storage converter. If the energy storage converter is in operation, proceed to step S2. S2. Control the DC side insulation detection module to shut down, start the AC side leakage detection module, and use the leakage detection module to perform insulation judgment; Step S2 specifically involves: S21. Control the DC side insulation detection module to shut down and start the AC side leakage detection module; S22. The leakage current detection module is used to monitor the test value of the DC bus in real time and connect to each functional module on the DC side. If the actual test value is higher than the preset test value associated with the connected functional module, an insulation fault is determined. Step S22 specifically involves: S221. The leakage current detection module is used to monitor the leakage current value of the energy storage system in real time, and the DC side and AC side of the energy storage converter are connected. S222. Calculate the actual comprehensive leakage current value of the energy storage system and record it as the first leakage current value. If the first leakage current value is higher than the preset first leakage current value, then determine the insulation fault and report the fault location as the energy storage converter; otherwise, proceed to the next step. S223. Connect the energy storage battery, calculate the actual comprehensive leakage current value of the energy storage system and record it as the second leakage current value. If the second leakage current value is higher than the preset second leakage current value, then determine the insulation fault and report the fault location as the energy storage battery; otherwise, proceed to the next step. S224. When the nth functional module is connected, the actual leakage current value of the energy storage system is calculated within the nth preset sampling period and recorded as the nth leakage current value. If the nth leakage current value is higher than the preset nth leakage current value, an insulation fault is determined and the fault location is reported as the currently connected functional module; n is an integer greater than 2. The functional modules include a DC photovoltaic module, a charging pile, and a DC load; Each time the nth functional module is connected, insulation testing is performed after the previous n-1 functional modules have been connected, rather than testing is performed by connecting the DC bus separately.

2. An insulation testing terminal, characterized in that: It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to perform the steps in the insulation detection method of claim 1.

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