Insulation detection method and terminal

Abstract

The invention discloses an insulation detection method of an energy storage system and a terminal, and the method comprises the steps: detecting the operation state of an energy storage converter, if the energy storage converter is in the operation state, controlling an insulation detection module to be closed, starting an electric leakage detection module at an AC side, and carrying out the insulation judgment through the electric leakage detection module; and if the energy storage converter is in the shutdown state, controlling the electric leakage detection module to be closed, starting the insulation detection module on the direct current side, and performing insulation judgment by using the insulation detection module. Under the TN power distribution system, the electric leakage detection module is arranged on the alternating current side to perform insulation detection on the energy storage system under the condition that the energy storage converter is switched on, and meanwhile, the insulation detection module is arranged on the direct current side to perform insulation detection on the energy storage system when the energy storage converter is shut down, so that an isolation transformer does not need to be newly added to convert the TN system into an IT system; therefore, the insulation detection of the energy storage system can be realized, and the safety of the energy storage system is maintained while the cost is saved.

Description

[0001] This case is a divisional application based on the invention patent with application date of 2023-10-24, application number 202311377998.2, and name “An insulation detection method and terminal for energy storage system” as the parent case. Technical Field

[0002] The present invention relates to the field of energy storage, and in particular to an insulation detection method and a terminal for an energy storage system. Background Art

[0003] With the development of the energy storage industry, various power generation side, user side, large charging power stations, small energy storage power stations, and energy storage modules have sprung up everywhere. In order to ensure the safety of electrochemical energy storage systems, the system insulation monitoring function has also been increasingly valued.

[0004] Especially in the energy storage system on the user side, since it generally adopts the TN grounding system (the neutral point of the power supply is directly grounded), the neutral line of the system is biased from the ground. In this case, the resistance of the phase line to the ground is 0, which makes it difficult for the current bridge method or the AC signal injection method to detect the resistance value of the phase line to the ground. In order to make these methods effective, it is necessary to add an isolation transformer to the front end of the system to change the circuit connection from the TN system to the IT system (the neutral point of the power supply is not grounded). This method brings a series of problems, including increased costs, more equipment space requirements, and reduced overall system efficiency. Especially for small industrial and commercial storage systems, this method is extremely low cost-effective. 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, so as to realize insulation detection of a TN circuit system without an isolation transformer.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] An insulation detection method for an energy storage system comprises the following steps:

[0008] S1, detecting the operating state of the energy storage converter, if the energy storage converter is in the operating state, proceeding to step S2; if the energy storage converter is in the shutdown state, proceeding to step S3;

[0009] S2, controlling the insulation detection module on the DC side to turn off, starting the leakage detection module on the AC side, and using the leakage detection module to perform insulation judgment;

[0010] S3, controlling the leakage detection module on the AC side to turn off, starting the insulation detection module on the DC side, and using the insulation detection module to perform insulation judgment.

[0011] In order to solve the above technical problems, another technical solution adopted by the present invention is:

[0012] An insulation detection terminal for an energy storage system comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, any step of an insulation detection method for an energy storage system is completed.

[0013] The beneficial effects of the present invention are as follows: providing an insulation detection method and terminal for an energy storage system, in a TN power distribution system, by arranging a leakage detection module on the AC side to perform insulation detection on the energy storage system when the energy storage converter is turned on, and at the same time arranging an insulation detection module on the DC side to perform insulation detection on the energy storage system when the energy storage converter is shut down, without adding an isolation transformer to convert the TN system into an IT system, insulation detection of the energy storage system can be achieved, saving costs while maintaining the safety of the energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a flow chart of an insulation detection method for an energy storage system in an embodiment of the present invention;

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

[0016] Description of labels:

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

[0018] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in conjunction with the implementation modes and the accompanying drawings.

[0019] Please refer to Figure 1 , an insulation detection method for an energy storage system, comprising the steps of:

[0020] S1, detecting the operating state of the energy storage converter, if the energy storage converter is in the operating state, proceeding to step S2; if the energy storage converter is in the shutdown state, proceeding to step S3;

[0021] S2, controlling the insulation detection module on the DC side to turn off, starting the leakage detection module on the AC side, and using the leakage detection module to perform insulation judgment;

[0022] S3, controlling the leakage detection module on the AC side to turn off, starting the insulation detection module on the DC side, and using the insulation detection module to perform insulation judgment.

[0023] From the above description, it can be seen that the beneficial effects of the present invention are: providing an insulation detection method and terminal for an energy storage system, in a TN power distribution system, by arranging a leakage detection module on the AC side to perform insulation detection on the energy storage system when the energy storage converter is turned on, and at the same time arranging an insulation detection module on the DC side to perform insulation detection on the energy storage system when the energy storage converter is shut down, without adding an isolation transformer to convert the TN system into an IT system, insulation detection of the energy storage system can be achieved, saving costs while maintaining the safety of the energy storage system.

[0024] Furthermore, the step S3 is specifically as follows:

[0025] S31, controlling the leakage detection module on the AC side to be turned off, and starting the insulation detection module on the DC side;

[0026] S32, using the insulation detection module to monitor the test value of the DC bus in real time, and connecting 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.

[0027] From the above description, it can be seen that when the energy storage converter is in the shutdown state, that is, 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 occurs by real-time detection of the test value of the DC bus.

[0028] Specifically, in the embodiment of the present invention, since each functional module is connected in parallel to 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] Furthermore, the step S32 is specifically as follows:

[0030] S321, using the insulation detection module to monitor the test value of the DC bus in real time, and connecting to the DC side of the energy storage converter;

[0031] S322, within the first preset sampling period, calculating the actual comprehensive test value of the DC bus and recording it as the first test value, if the first test value is higher than the preset first test value, determining that there is an insulation fault and reporting the fault location as the energy storage converter; otherwise, proceeding to the next step;

[0032] S323, connecting the energy storage battery, calculating the actual comprehensive test value of the DC bus within the second preset sampling period and recording it as the second test value, if the second test value is higher than the preset second test value, determining that the insulation fault is occurring and reporting that the fault location is the energy storage battery; otherwise, proceeding to the next step;

[0033] S324, connect the nth functional module, calculate the actual test value of the DC bus within the nth preset sampling period and record it as the nth test value, if the nth test value is higher than the preset nth test value, determine that there is an insulation fault and report the fault location as the currently connected functional module; n is an integer greater than 2.

[0034] From the above description, it can be seen that in order to determine the fault location of the insulation detection, when monitoring the test value of the DC bus, first connect to the DC side of the energy storage converter, detect the test value after connection within the first preset sampling period and record it as the first test value, if the first test value is higher than the preset first test value, it is considered that the energy storage converter has an insulation fault;

[0035] Then, the energy storage battery is connected, and the test value after the 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, it is considered that the energy storage battery has an insulation fault; at this time, the energy storage converter and the energy storage battery are both connected to the DC bus;

[0036] Secondly, on the premise that the insulation tests of the energy storage inverter and the energy storage battery are normal, other functional modules, such as DC photovoltaic modules, charging piles, DC loads, etc., are connected. Each time a functional module is connected, the insulation test of the currently connected module is performed within the corresponding preset sampling period; it should be noted that each time other functional modules are connected, insulation test is performed when the functional modules in the above steps have been entered, and the DC bus is not connected separately for testing.

[0037] Furthermore, the calculation formula of the nth test value is:

[0038]

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

[0040] R0 is the standard insulation resistance 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 detected by the insulation detection module after the nth functional module is connected to the DC bus.

[0044] From the above description, it can be seen that the calculation formula of 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 nis the actual insulation resistance of each functional module; that is, when the actual insulation resistance of a functional module is lower than its preset insulation resistance, the DC bus test value detected will be higher than the preset test value, which indicates that an insulation fault occurs in the currently connected functional module.

[0045] Specifically, in the embodiment of the present 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 module.

[0046] Furthermore, the calculation formula of the nth preset sampling period is:

[0047]

[0048] Among them, T n is 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 after the energy storage converter is connected to the DC bus;

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

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

[0054] From the above description, it can be seen that since the insulation sampling period needs to take into account the pre-charge time constant (i.e., RC time), based on the above-mentioned calculated test value, the calculation formula for the nth preset sampling period is the product of the inverse 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 of k is as follows: before the insulation test is performed, charging time needs to be reserved for the capacitors of each functional module. According to experimental tests, generally at least 3 RCs are 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] Furthermore, the step S2 is specifically as follows:

[0057] S21, controlling the insulation detection module on the DC side to be turned off, and starting the leakage detection module on the AC side;

[0058] S22, using the leakage detection module to monitor the leakage current value of the energy storage system in real time, and connecting to the functional modules on the AC side and the DC side, if the actual leakage current value is higher than the preset leakage current value, it is determined that the insulation fault occurs.

[0059] From the above description, it can be seen that when the energy storage converter is in working state, that is, 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 TN system phase line is conductive to the ground, the insulation detection module on the DC side cannot operate, and the leakage detection module on the AC side is used to determine whether an insulation fault occurs by real-time detection of the leakage value of the energy storage system.

[0060] Furthermore, the step S22 is specifically as follows:

[0061] S221, using the leakage detection module to monitor the leakage current value of the energy storage system in real time, and conducting the DC side and AC side of the energy storage converter;

[0062] S222, calculating the actual comprehensive leakage value of the energy storage system and recording it as the first leakage value. If the first leakage value is higher than the preset first leakage value, determining that the insulation fault is faulty and reporting the fault location as the energy storage converter; otherwise, proceeding to the next step;

[0063] S323, connecting the energy storage battery, calculating the actual comprehensive leakage value of the energy storage system and recording it as the second leakage value, if the second leakage value is higher than the preset second leakage value, determining that the insulation fault is and reporting the fault location as the energy storage battery; otherwise, proceeding to the next step;

[0064] S324, connect the nth functional module, calculate the actual leakage value of the energy storage system within the nth preset sampling period and record it as the nth leakage value, if the nth leakage value is higher than the preset nth leakage value, determine that there is an insulation fault and report the fault location as the currently connected functional module; n is an integer greater than 2.

[0065] From the above description, it can be seen that in order to determine the fault location of the insulation detection, when monitoring the leakage value of the energy storage system, the energy storage converter is first connected, and the leakage value after connection is recorded as the first leakage value. If the first leakage value is higher than the preset first leakage value, it is considered that the energy storage converter has 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, it is considered that the energy storage battery insulation fault occurs. At this time, the energy storage converter and the energy storage battery are both connected to the DC bus.

[0067] Secondly, under the premise that the insulation tests of the energy storage inverter and the energy storage battery are normal, other functional modules (including functional modules on the AC side), such as DC photovoltaic modules, charging piles, DC loads, AC loads, AC photovoltaics, etc., are connected. Each time a functional module is connected, an insulation test is performed on the currently connected module; it should be noted that each time other functional modules are connected, insulation tests are performed when the functional modules in the above steps have been entered, and the energy storage system is not connected separately for testing.

[0068] Please refer to Figure 2 , an insulation detection terminal for an energy storage system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor completes any step in an insulation detection method for an energy storage system when executing the computer program.

[0069] The present invention provides an insulation detection method and terminal for an energy storage system, which are mainly used for insulation monitoring of a user-side energy storage system, and are specifically described below in conjunction with 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 steps of:

[0071] S1, detecting the operating state of the energy storage converter, if the energy storage converter is in the operating state, proceeding to step S2; if the energy storage converter is in the shutdown state, proceeding to step S3;

[0072] S2, control the insulation detection module on the DC side to turn off, start the leakage detection module on the AC side, and use the leakage detection module to perform insulation judgment;

[0073] S3, controlling the leakage detection module on the AC side to turn off, starting the insulation detection module on the DC side, and using the insulation detection module to perform insulation judgment.

[0074] That is, in this embodiment, an insulation detection method for an energy storage system is provided. In a TN power distribution system, a leakage detection module is arranged 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 arranged on the DC side to perform insulation detection on the energy storage system when the energy storage converter is shut down. Insulation detection of the energy storage system can be achieved without adding an isolation transformer to convert the TN system into an IT system, thereby saving costs while maintaining the safety of the energy storage system.

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

[0076] S31, controlling the leakage detection module on the AC side to be turned off, and starting the insulation detection module on the DC side;

[0077] S32, using the insulation detection module to monitor the test value of the DC bus in real time, and connecting 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.

[0078] That is, in this embodiment, when the energy storage converter is in shutdown state, that is, 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 occurs by detecting the test value of the DC bus in real time.

[0079] Specifically, S32 is divided into the following steps:

[0080] S321, using the insulation detection module to monitor the test value of the DC bus in real time, and connecting to the DC side of the energy storage converter;

[0081] S322, within the first preset sampling period, calculating the actual comprehensive test value of the DC bus and recording it as the first test value, if the first test value is higher than the preset first test value, determining that there is an insulation fault and reporting the fault location as the energy storage converter; otherwise, proceeding to the next step;

[0082] S323, connecting the energy storage battery, calculating the actual comprehensive test value of the DC bus within the second preset sampling period and recording it as the second test value, if the second test value is higher than the preset second test value, determining that the insulation fault is occurring and reporting that the fault location is the energy storage battery; otherwise, proceeding to the next step;

[0083] S324, connect the nth functional module, calculate the actual test value of the DC bus within the nth preset sampling period and record it as the nth test value, if the nth test value is higher than the preset nth test value, determine that there is an insulation fault and report the fault location as the currently connected functional module; n is an integer greater than 2.

[0084] That is, in order to determine the fault location of the insulation detection, when monitoring the test value of the DC bus, first connect to the DC side of the energy storage converter, detect the test value after connection within the first preset sampling period and record it as the first test value, if the first test value is higher than the preset first test value, it is considered that the energy storage converter has an insulation fault;

[0085] Then, the energy storage battery is connected, and the test value after the 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, it is considered that the energy storage battery has an insulation fault; at this time, the energy storage converter and the energy storage battery are both connected to the DC bus;

[0086] Secondly, on the premise that the insulation tests of the energy storage inverter and the energy storage battery are normal, other functional modules, such as DC photovoltaic modules, charging piles, DC loads, etc., are connected. Each time a functional module is connected, the insulation test of the currently connected module is performed within the corresponding preset sampling period; it should be noted that each time other functional modules are connected, insulation test is performed when the functional modules in the above steps have been entered, and the DC bus is not connected separately for testing.

[0087] In this embodiment, the calculation formula of the nth test value is:

[0088]

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

[0090] R0 is the standard insulation resistance 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 detected by the insulation detection module after the nth functional module is connected to the DC bus.

[0094] That is, the calculation formula of 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 is the actual insulation resistance 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 DC bus test value detected will be higher than the preset test value, which indicates that an insulation fault occurs in the currently connected functional module.

[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 module.

[0097] At the same time, in this embodiment, the calculation formula of the nth preset sampling period is:

[0098]

[0099] Among them, T n is 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 after the energy storage converter is connected to the DC bus;

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

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

[0105] From the above description, it can be seen that since the insulation sampling cycle 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 cycle is the product of the inverse 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 of k is as follows: before the insulation test is performed, charging time needs to be reserved for the capacitors of each functional module. According to experimental tests, generally at least 3 RCs are 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: Based on Embodiment 1, step S2 is specifically as follows:

[0108] S21, controlling the insulation detection module on the DC side to be turned off, and starting the leakage detection module on the AC side;

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

[0110] That is, in this embodiment, when the energy storage converter is in working state, that is, 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 TN system phase line is conductive to the ground, the insulation detection module on the DC side cannot operate, and the leakage detection module on the AC side is used to determine whether an insulation fault occurs by real-time detection of the leakage value of the energy storage system.

[0111] Specifically, step S22 is divided into the following steps:

[0112] S221, using the leakage detection module to monitor the leakage current value of the energy storage system in real time, and conducting the DC side and AC side of the energy storage converter;

[0113] S222, calculating the actual comprehensive leakage value of the energy storage system and recording it as the first leakage value. If the first leakage value is higher than the preset first leakage value, determining that the insulation fault is faulty and reporting the fault location as the energy storage converter; otherwise, proceeding to the next step;

[0114] That is, in order to determine the fault location of the insulation detection, 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, it is considered that the energy storage converter has 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, it is considered that the energy storage battery insulation fault occurs. At this time, the energy storage converter and the energy storage battery are both connected to the DC bus.

[0116] Secondly, under the premise that the insulation tests of the energy storage inverter and the energy storage battery are normal, other functional modules (including functional modules on the AC side), such as DC photovoltaic modules, charging piles, DC loads, AC loads, AC photovoltaics, etc., are connected. Each time a functional module is connected, an insulation test is performed on the currently connected module; it should be noted that each time other functional modules are connected, insulation tests are performed when the functional modules in the above steps have been entered, and the energy storage system is not connected separately for testing.

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

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

[0119]

[0120]

[0121] When the energy storage converter is shut down, the AC injection method is used to detect the test value on the DC side. A contactor switch is set on each module circuit. When an insulation fault occurs, the contactor switch is disconnected to stop the current module from connecting to the energy storage system.

[0122] The first power-on detection steps are as follows:

[0123] 1. All modules are disconnected;

[0124] 2. The insulation detection module detects that there is no problem with the DC bus test value;

[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 repeated for three consecutive cycles and the average value of the test results is taken. In the actual comparison process, if the actual insulation resistance R1 is greater than the allowable value R 1预 , it means that the insulation of the DC side of the energy storage converter is normal at this time; at the same time, because each functional module is connected in parallel to the DC bus, it is more convenient to use the test value in statistical calculation, that is, if the first test value is lower than the preset first test value (W1 <W 1预 ), it means that the insulation is normal at this time, and the actual insulation resistance R1 is calculated in reverse; if the test result is W1>W 1预, it means that the insulation fault occurs at this time, and it occurs on the DC side of the currently connected energy storage converter)

[0128] 3. Close the battery switch / contactor, apply high voltage to the DC, and the insulation detection module detects the DC bus test value;

[0129] (Same as above step, 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 reversely calculate the actual insulation resistance R2 at this time. If the test result is W2>W 2预 , it means that the insulation fault occurs at this time, and it occurs in the currently connected energy storage battery)

[0130] 4. Connect other functional modules and use the same detection method as above. If a fault occurs, it means 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 detection module.

[0132] The detection method refers to the detection method on the DC side mentioned above.

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

[0134] I 7预 =I0+I 1预 +…+I 7预

[0135] The actual leakage current value is:

[0136] I7=I0+I1+…+I7

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

[0138] Please refer to Figure 2 The fourth embodiment of the present invention is: an insulation detection terminal 1 for an energy storage system, comprising a memory 2, a processor 3, and a computer program stored in the memory 2 and executable on the processor 3, wherein the steps of the insulation detection method for an energy storage system in any one of the above-mentioned embodiments 1 to 3 are completed when the processor 3 executes the computer program.

[0139] In summary, the present invention provides an insulation detection method and terminal for an energy storage system. In a TN power distribution system, a leakage detection module is arranged 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 arranged on the DC side to perform insulation detection on the energy storage system when the energy storage converter is shut down. Insulation detection of the energy storage system can be achieved without adding an isolation transformer to convert the TN system into an IT system, thereby saving costs while maintaining the safety of the energy storage system.

[0140] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An insulation detection method, characterized in that: Includes steps: S1, detecting the operating state of the energy storage converter, if the energy storage converter is in the operating state, proceeding to step S2; S2, controlling the insulation detection module on the DC side to turn off, starting the leakage detection module on the AC side, and using the leakage detection module to perform insulation judgment; The step S2 is specifically as follows: S21, controlling the insulation detection module on the DC side to be turned off, and starting the leakage detection module on the AC side; S22, using the leakage detection module to monitor the test value of the DC bus in real time, and connecting 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, it is determined that an insulation fault occurs; The step S22 is specifically as follows: S221, using the leakage detection module to monitor the leakage current value of the energy storage system in real time, and conducting the DC side and AC side of the energy storage converter; S222, calculating the actual comprehensive leakage value of the energy storage system and recording it as the first leakage value. If the first leakage value is higher than the preset first leakage value, determining that the insulation fault is faulty and reporting the fault location as the energy storage converter; otherwise, proceeding to the next step; S223, connecting the energy storage battery, calculating the actual comprehensive leakage value of the energy storage system and recording it as the second leakage value, if the second leakage value is higher than the preset second leakage value, determining that the insulation fault is and reporting the fault location as the energy storage battery; otherwise, proceeding to the next step; S224, connect the nth functional module, calculate the actual leakage value of the energy storage system within the nth preset sampling period and record it as the nth leakage value, if the nth leakage value is higher than the preset nth leakage value, determine that there is an insulation fault and report the fault location as the currently connected functional module; n is an integer greater than 2.

2. An insulation detection method according to claim 1, characterized in that: The step S1 further comprises the steps of: If the energy storage converter is in a shutdown state, proceed to step S3; The step S3 specifically comprises the following steps: The leakage detection module on the AC side is controlled to be turned off, the insulation detection module on the DC side is started, and the insulation detection module is used to perform insulation judgment.

3. An insulation detection method according to claim 2, characterized in that: The step S3 is specifically as follows: S31, controlling the leakage detection module on the AC side to be turned off, and starting the insulation detection module on the DC side; S32, using the insulation detection module to monitor the actual test value of the DC bus in real time, and connecting 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.

4. An insulation detection method according to claim 3, characterized in that: The step S32 is specifically as follows: S321, using the insulation detection module to monitor the actual test value of the DC bus in real time, and connecting to the DC side of the energy storage converter; S322, within the first preset sampling period, calculating the actual comprehensive test value of the DC bus and recording it as the first test value, if the first test value is higher than the preset first test value, determining that there is an insulation fault and reporting the fault location as the energy storage converter; otherwise, proceeding to the next step; S323, connecting the energy storage battery, calculating the actual comprehensive test value of the DC bus within the second preset sampling period and recording it as the second test value, if the second test value is higher than the preset second test value, determining that the insulation fault is occurring and reporting that the fault location is the energy storage battery; otherwise, proceeding to the next step; S324, connect the nth functional module, calculate the actual test value of the DC bus within the nth preset sampling period and record it as the nth test value, if the nth test value is higher than the preset nth test value, determine that there is an insulation fault and report the fault location as the currently connected functional module; n is an integer greater than 2.

5. An insulation detection method according to claim 4, characterized in that: The calculation formula of the nth test value is: Among them, W n is the nth test value; R0 is the standard insulation resistance of the DC bus; R1 is the actual insulation resistance value detected by the insulation detection module after the energy storage converter is connected to the DC bus; R2 is the actual insulation resistance value detected by the insulation detection module after the energy storage battery is connected to the DC bus; R n The insulation resistance value detected by the insulation detection module after the nth functional module is connected to the DC bus; The calculation formula of the nth preset sampling period is: Among them, T n is the nth preset sampling period; k is an integer ranging from 3 to 5; C0 is the capacitance value of the DC bus; C1 is the capacitance value after the energy storage converter is connected to the DC bus; C2 is the capacitance value after the energy storage battery is connected to the DC bus; C n It is the capacitance value after the nth functional module is connected to the DC bus.

6. An insulation detection method according to claim 5, characterized in that: The value of k is 5.

7. An insulation detection terminal, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor completes the steps of an insulation detection method as claimed in any one of claims 1 to 6 when executing the computer program.

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