RLC load general control modeling method for anti-islanding protection test of energy storage converter

Abstract

According to the RLC load general control modeling method for the anti-islanding protection test of the energy storage converter, an RLC parameter configuration integrated modeling and per-unit calculation module and a bus constant voltage control unit are arranged. The RLC load general control modeling method for the anti-islanding protection test of the energy storage converter comprises RLC parameter per-unit calculation, can be suitable for anti-islanding protection simulation tests of energy storage converters with different rated capacities, can reuse and transplant a simulation model, shortens the simulation modeling period, improves the test efficiency, and is suitable for the anti-islanding protection simulation tests of the energy storage converters with different rated capacities. The method further comprises integrated modeling of RLC parameter calculation of the anti-islanding protection test working condition and Bpcc bus constant voltage control, so that configuration of the anti-islanding protection test working condition can be rapidly and accurately completed, RLC parameter calculation is not needed, the misoperation risk is reduced, and the user experience is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of simulation testing of new energy power generation equipment, and in particular to a general control modeling method for an RLC load of an energy storage converter anti-islanding protection test. Background Art

[0002] The anti-islanding protection test is based on the relevant provisions of GB / T 34120-2023 "Technical Requirements for Energy Storage Converters of Electrochemical Energy Storage Systems". The energy storage converter connected to the distribution network should have anti-islanding protection function. The anti-islanding test condition table of the test items required in the "Anti-Islanding Protection" chapter of GB / T 34133-2023 "Technical Regulations for Energy Storage Converter Testing" includes 32 to 47 of the anti-islanding test condition table for the extended test table under rated conditions. From the test item table, it can be seen that the typical items of the anti-islanding protection test of the energy storage converter include 47 items.

[0003] During the anti-islanding test, the parameter value of the RLC load needs to be adjusted to ensure that the working state of the load matches the working condition of the test item. When the rated capacity of the energy storage converter under test is different, the parameter value of the RLC load is also different under the working condition of the same test item. RLC load simulation model Figure 1 As shown in the figure, there are mainly load bus (BL), adjustable resistance load (R), adjustable capacitance load (C), adjustable reactance load (L), load bus voltage transformer (UpLoad), RLC branch current transformer (IpLoadR, IpLoadL, IpLoadC) and RCL load given value instruction (Zref R 、Zref C 、Zref cR 、Zref L 、Zref LR ). When the voltage of the load bus (BL) is fixed, the required RLC load command value (Zref R 、Zref C 、Zref CR 、Zref L 、Zref LR ). The active power consumed by the RLC load is defined as P load , the capacitive reactive power consumed by the RLC load is defined as Q Cload , the inductive reactive power consumed by the RLC load is defined as Q Lload .

[0004] The active power, capacitive reactive power, and inductive reactive power of the RLC load are calculated by the following formula:

[0005]

[0006] The current pain points of anti-islanding protection testing are: (1) The RLC load parameter configuration is complex: First, according to the rated voltage and rated frequency of the energy storage converter under test, calculate the theoretical calculated value of the RLC parameter corresponding to each anti-islanding protection test condition. There are 47 typical anti-islanding protection test items, which need to be calculated 47 times. (2) The RLC parameters need to be corrected: When the AC equivalent power supply remains unchanged, the operating conditions of the energy storage converter are different, and the equivalent impedance voltage drop of the AC equivalent power supply is also different, resulting in a deviation between the voltage at the Bpcc bus and the rated value, which further causes a deviation between the RLC load power and the theoretical calculated value, affecting the simulation accuracy of the test condition. The RLC parameters need to be adjusted dynamically to ensure that the accuracy of the test condition meets the requirements. (3) The RLC parameter configuration cannot be reused: When a new test is carried out again, if the rated capacity and rated voltage of the energy storage converter under test change, it is necessary to repeat the contents described in (1) and (2), which is a lot of work. The conventional test steps of anti-islanding test are as follows: Figure 2 As shown, according to the rated parameters (rated voltage, rated power) of the energy storage converter under test, combined with the various working conditions described in "Table 1 Anti-islanding Detection Conditions Table", the theoretical value of the RLC parameter is calculated. Configure the RLC parameter given value and check whether it meets the test condition requirements. If not, adjust the RLC parameter given value; if it meets, trigger the test. After the test is completed, carry out the next anti-islanding test until the 47 items are completed.

[0007] At present, the anti-islanding protection test of energy storage converters is mainly carried out based on the "power test platform" of energy storage converters. This test platform needs to output the DC side power supply with real voltage level and power, the AC side power supply with real voltage level and power, access to the energy storage converter device, and access to the RLC load equal to the rated power of the energy storage converter under test. However, the "power test platform" has serious shortcomings, including: the difficulty in setting up the test environment of the "power test platform", the high construction cost, and the incomplete assessment, which leaves safety hazards. This is because the overall capacity of the energy storage converter device is growing rapidly at present, and the power of the "RLC load" of the existing "power test platform" cannot cover the test requirements of the large-capacity energy storage converter device, so the "RLC load" needs to be expanded, and the larger capacity "RLC load" needs to occupy a larger physical space and has a high investment cost. In other words, due to the limitation of funds or physical space, it becomes impractical to significantly increase the capacity of the "RLC load". For example, the industry currently has a wide range of energy storage inverters with a rated capacity of 3.75MW, and high-voltage direct-mounted energy storage inverters with a capacity of tens of MW have been launched one after another. The relevant technical requirements of the industry standard require anti-islanding tests to be carried out under full-load operation. At this time, the energy storage inverter power test platform is required to provide resistive loads (R), inductive loads (L) and capacitive loads (C) with a rated power of tens of MW. At present, there is no energy storage inverter power test platform in the industry that can provide an RLC load test environment of tens of MW, making it difficult to comprehensively carry out anti-islanding protection tests on energy storage inverters, leaving safety risks.

[0008] Therefore, in view of the shortcomings of the existing technology, it is necessary to provide a general control modeling method for RLC load of anti-islanding protection test of energy storage converter to solve the shortcomings of the existing technology. Summary of the invention

[0009] The purpose of the present invention is to avoid the shortcomings of the prior art and provide a universal control modeling method for RLC load of anti-islanding protection test of energy storage converter. The universal control modeling method for RLC load of anti-islanding protection test of energy storage converter can be applied to anti-islanding protection simulation test of energy storage converters with different rated capacities, and the simulation model is reusable and portable, which shortens the simulation modeling cycle and improves the test efficiency.

[0010] The above-mentioned purpose of the present invention is achieved by the following technical measures:

[0011] A general control modeling method for RLC load of anti-islanding protection test of energy storage converter is provided, which is provided with:

[0012] RLC parameter configuration integrated modeling and per-unit calculation module - collect the rated parameters of the energy storage converter under test; then calculate the reference impedance value Z for RLC parameter per-unit calculation based on the rated parameters B ;Finally, according to the reference impedance value ZB and rated parameters, calculate the RLC load parameter given value instruction, and complete the configuration of the anti-islanding protection test condition;

[0013] Bus constant voltage control unit: drives the AC equivalent power supply according to the instantaneous value of the three-phase voltage of the power supply Bs bus, so that the AC equivalent power supply has a constant output voltage, thereby avoiding the RLC parameter correction of the RLC parameter configuration integrated modeling and per-unit calculation module.

[0014] Preferably, the above RLC parameter configuration integrated modeling and per-unit calculation module is provided with:

[0015] Input module - collects the rated parameters of the energy storage converter under test;

[0016] RLC parameter calculation module - calculates RLC load parameter given value instructions according to the rated parameters;

[0017] Output module: outputs the RLC load parameter given value instruction obtained by the RLC parameter calculation module to the RLC load simulation model.

[0018] Preferably, the above-mentioned input module inputs rated parameters of the energy storage converter under test, wherein the rated parameters are rated voltage UN, rated capacity SN, load power type TypLoad and test serial number TestNum.

[0019] Preferably, the RLC parameter calculation module parses the value according to the load power type TypLoad and the test number TestNum of the input module, and finds the corresponding reference capacity multiple nSN and the percentage errorP of the load active power nominal value in the anti-islanding detection item comparison table according to the load power type TypLoad and the test number TestNum parsed value. R , and the percentage of the load reactive power nominal value errorQ L The sum is the percentage of the load reactive power nominal value errorQ C .

[0020] Preferably, the RLC parameter calculation module is also based on the rated voltage U N and rated capacity S N , and get the reference impedance value Z B .

[0021] Preferably, the RLC parameter calculation module further calculates the impedance value Z according to the reference impedance value Z. B , the reference capacity multiple nSN, and the percentage errorP of the nominal value of the load active power R , and the percentage of the load reactive power nominal value errorQ L, and the percentage errorQ of the load reactive power nominal value C , get the RCL load given value instruction.

[0022] Preferably, the above RLC parameter calculation module is provided with a preconfiguration unit, a reference impedance calculation unit and an RLC calculation unit.

[0023] Preferably, the pre-configuration unit collects the load power type TypLoad and the test number TestNum according to the input module to parse the value, and finds the corresponding reference capacity multiple nSN and the percentage errorP of the load active power nominal value in the anti-islanding detection item comparison table according to the load power type TypLoad and the test number TestNum parsed value. R , and the percentage of the load reactive power nominal value errorQ L The sum is the percentage of the load reactive power nominal value errorQ C .

[0024] Preferably, the reference impedance calculation unit calculates the rated voltage U according to the rated voltage U collected by the input module. N and rated capacity S N , and get the reference impedance value Z B .

[0025] Preferably, the RLC calculation unit is based on the reference impedance value Z B , the reference capacity multiple nSN, and the percentage errorP of the nominal value of the load active power R , and the percentage of the load reactive power nominal value errorQ L , and the percentage errorQ of the load reactive power nominal value C , get the RCL load given value instruction Z refR , RCL load given value instruction Z refC , RCL load given value instruction Z refCR , RCL load given value instruction Z refL and RCL load given value instruction Z refLR .

[0026] Preferably, the above RCL load given value instruction Z refR , the RCL load given value instruction Z refC , the RCL load given value instruction Z refCR , the RCL load given value instruction Z refL and the RCL load given value instruction Z refLR From formula (1), we can get:

[0027]

[0028] in, is the impedance tangent of the capacitor branch in RLC, is the impedance angle cotangent value of the capacitor branch in RLC, tan δ is the impedance tangent of the inductor branch in RLC, cos δ is the cotangent value of the impedance angle of the inductor branch in RLC.

[0029] Preferably, the bus constant voltage control unit calculates the collected instantaneous value of the three-phase voltage of the Bs bus through the root mean square RMS to obtain the standard value Us of the effective value of the three-phase voltage mea ; Then the per unit value Us mea and expected voltage value Us ref Subtract and get the difference u err , the difference u err Output u through PI control module add , and then u add With bus voltage given value Un ref Added output Us Mag , driving the external AC equivalent power supply S1 to produce a constant output voltage.

[0030] Preferably, the expected voltage value Us ref Configured as 1.0pu.

[0031] Preferably, the above bus voltage given value Un ref Configured as the rated voltage value of the Bpcc bus.

[0032] The present invention provides a general control modeling method for RLC load of anti-islanding protection test of energy storage converter, which comprises: RLC parameter configuration integrated modeling and per-unit calculation module to collect rated parameters of tested energy storage converter; and then calculate the reference impedance value Z for RLC parameter per-unit calculation according to the rated parameters. B ;Finally, according to the reference impedance value Z Band rated parameters, calculate the RLC load parameter given value instruction, and complete the configuration of the anti-islanding protection test condition; the bus constant voltage control unit drives the AC equivalent power supply according to the instantaneous value of the three-phase voltage of the power supply Bs bus, so that the AC equivalent power supply outputs a constant voltage, thereby avoiding the RLC parameter correction of the integrated modeling and per-unit calculation module of the RLC parameter configuration. The RLC load universal control modeling method for the anti-islanding protection test of the energy storage converter of the present invention includes RLC parameter per-unit calculation, which can be applied to the anti-islanding protection simulation test of energy storage converters with different rated capacities, and the simulation model is reusable and portable, shortening the simulation modeling cycle and improving the test efficiency. The present invention also includes the integrated modeling of the RLC parameter calculation of the anti-islanding protection test condition and the Bpcc bus constant voltage control, so that the configuration of the anti-islanding protection test condition can be completed quickly and accurately without the need to perform RLC parameter calculation, reducing the risk of misoperation and improving the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention is further described with reference to the accompanying drawings, but the contents in the accompanying drawings do not constitute any limitation to the present invention.

[0034] Figure 1 Schematic diagram of the existing RLC load simulation model.

[0035] Figure 2 Flow chart of the current routine test steps for anti-islanding testing.

[0036] Figure 3 It is a schematic diagram of an energy storage converter anti-islanding protection simulation test system corresponding to the RLC load universal control modeling method for energy storage converter anti-islanding protection test of the present invention.

[0037] Figure 4 Schematic diagram of the integrated modeling and per-unit calculation module for RLC parameter configuration.

[0038] Figure 5 This is a schematic diagram of the busbar constant voltage control unit.

[0039] Figure 6 The figure is a flow chart of the improved anti-islanding test steps of the present invention. Figure 7 This is the waveform recording of the 41st extended detection item in Example 2. DETAILED DESCRIPTION

[0040] The technical solution of the present invention is further described in conjunction with the following embodiments. Among them, the energy storage converter power test platform: a test platform for an AC / DC power supply capable of outputting a real voltage level and power, connected to an energy storage converter device, and capable of simulating a variety of power grid operating conditions to assess the performance of the connected energy storage converter. The energy storage converter semi-physical simulation test platform: a digital and physical hybrid simulation test platform, that is, the mathematical modeling of the power system is completed on a real-time digital simulator device and runs in real time, and a real energy storage converter controller device is connected through a high-speed IO interface. The power grid system is simulated to fail or run in an abnormal state through a digital simulation method, and the performance of the connected energy storage converter controller device is assessed. Island operation of the energy storage system: When the energy storage power station is in normal discharge operation, the main power grid and the energy storage system jointly supply power to the load. After the main power grid system is disconnected, the energy storage system and the local load together form a small isolated power grid, called an island. Islands can be divided into planned islands and unplanned islands. Planned islands are pre-demarcated island areas. After the main power grid is disconnected, the island can operate stably. Unplanned islanding refers to a situation where the energy storage station continues to supply power to the surrounding area due to a fault trip on the main grid system side, becoming a self-sufficient power supply island that cannot be controlled by the main grid. Islanding protection: Islanding protection refers to a protection mechanism that prevents power generation equipment (including energy storage systems) from supplying power to the load as an isolated power source when the grid loses pressure or is disconnected (unplanned islanding), thereby forming a power supply island. This phenomenon usually occurs when the grid fails or is under maintenance. If not handled in time, it may cause damage to power equipment and even cause safety problems. RLC load: resistive load (R), inductive load (L) and capacitive load (C).

[0041] Example 1

[0042] A general control modeling method for RLC load of energy storage converter anti-islanding protection test is provided, which comprises:

[0043] RLC parameter configuration integrated modeling and per-unit calculation module - collect the rated parameters of the energy storage converter under test; then calculate the reference impedance value Z for RLC parameter per-unit calculation based on the rated parameters B ;Finally, according to the reference impedance value Z B and rated parameters, calculate the RLC load parameter given value instruction, and complete the configuration of the anti-islanding protection test condition;

[0044] Bus constant voltage control unit: drives the AC equivalent power supply according to the instantaneous value of the three-phase voltage of the power supply Bs bus, so that the AC equivalent power supply has a constant output voltage, thereby avoiding the RLC parameter correction of the RLC parameter configuration integrated modeling and per-unit calculation module.

[0045] It should be noted that the energy storage converter anti-islanding protection simulation test system corresponding to the RLC load general control modeling method for the energy storage converter anti-islanding protection test of the present invention is applied. Figure 3 shown.

[0046] exist Figure 3 The dashed part in RTDS is the RLC parameter configuration integrated modeling and per-unit calculation module and bus constant voltage control unit modeled by the present invention. The energy storage converter anti-islanding protection simulation test system mainly consists of RTDS real-time digital simulator, energy storage converter controller and IO interface. The RTDS is provided with a primary system and a secondary measurement control system, wherein the primary system is provided with an infinite power source S1, an AC equivalent impedance Zs, an AC circuit breaker K1, an RCL load (also called an RLC load simulation model), a box transformer T1, an energy storage converter PCS, a bus Bs, a bus Bg, a bus Bpcc, an AC equivalent grid-side current transformer IpSourse, a current transformer IpGrid of a grid-connected switch K2, a current transformer IpPcc at the Bpcc bus, an AC-side current transformer IpEut of the energy storage converter, an AC-side switch K3 of the energy storage converter, a voltage transformer UpSourse at the Bs bus, a voltage transformer UpGrid at the Bg bus, a voltage transformer UpPcc at the Bpcc bus, a voltage transformer UpEut at the Be bus, a current transformer IpLoad at the RLC load branch, etc. The secondary measurement control system is provided with simulation modeling of AC power supply control and RLC control. The IO interface includes GTAO (Gigabit transceiver analog output card), GTDI (Gigabit transceiver digital input card), and GTDO (Gigabit transceiver digital output card), which realizes low-latency transmission of AC and DC voltage, current signals, switch quantity signals, and PWM pulse signals between the RTDS real-time digital simulation system and the energy storage converter controller. The dotted line part in the RTDS of the present invention is the focus of the present invention. The IO interface and the energy storage converter controller are physical devices and conventional technologies.

[0047] The anti-islanding test condition table of the test items required by the "Anti-islanding Protection" chapter of GB / T 34133-2023 "Technical Specifications for Energy Storage Inverter Testing" is shown in Table 1. The typical items of the anti-islanding protection test of the energy storage inverter include 47 items.

[0048] Table 1. Anti-islanding detection conditions

[0049]

[0050]

[0051] like Figure 4 As shown, the RLC parameter configuration integrated modeling and per-unit calculation module settings are:

[0052] Input module - collects the rated parameters of the energy storage converter under test; the rated parameters are rated voltage UN, rated capacity SN, load power type

[0053] Type TypLoad and test number TestNum.

[0054] RLC parameter calculation module - calculates RLC load parameter given value instructions based on the rated parameters.

[0055] Output module: outputs the RLC load parameter given value instruction obtained by the RLC parameter calculation module to the RLC load simulation model.

[0056] The RLC parameter calculation module parses the value according to the load power type TypLoad and the test number TestNum of the input module, and finds the corresponding reference capacity multiple nSN and the percentage errorP of the load active power nominal value in the anti-islanding detection item comparison table according to the parsed value of the load power type TypLoad and the test number TestNum. R , and the percentage of the load reactive power nominal value errorQ L The sum is the percentage of the load reactive power nominal value errorQ C The RLC parameter calculation module also calculates the rated voltage U of the input module. N and rated capacity S N , and get the reference impedance value Z B The RLC parameter calculation module also calculates the reference impedance value Z B , the reference capacity multiple nSN, and the percentage errorP of the nominal value of the load active power R , and the percentage of the load reactive power nominal value errorQ L , and the percentage of the load reactive power nominal value errorQC, to obtain the RCL load given value instruction.

[0057] It should be noted that, among them, the value of the reference capacity multiple nSN is equal to the value of TypLoad, and the comparison relationship between the load power type TypLoa and the anti-islanding protection test items is shown in Table 2. For example, when the load reactive power is 100% Pn, the load power type (TypLoad = 1.0); when the load reactive power is 66% Pn, the load power type (TypLoad = 0.66); when the load reactive power is 33% Pn, the load power type (TypLoad = 0.33). The test number TestNum is the anti-islanding test number, which is used to indicate the test conditions of "percentage of the load active power nominal value" and "percentage of the load reactive power nominal value".

[0058] Table 2 Anti-islanding detection items comparison table

[0059]

[0060]

[0061] The RLC parameter calculation module is provided with a preconfiguration unit, a reference impedance calculation unit and an RLC calculation unit.

[0062] The pre-configuration unit collects the load power type TypLoad and the test number TestNum according to the input module, and finds the corresponding reference capacity multiple nSN and the percentage errorP of the load active power nominal value in the anti-islanding detection item comparison table according to the load power type TypLoad and the test number TestNum. R , and the percentage of the load reactive power nominal value errorQ L The sum is the percentage of the load reactive power nominal value errorQ C .

[0063] The reference impedance calculation unit calculates the rated voltage U according to the input module. N and rated capacity S N , get the reference impedance value Z B .

[0064] The RLC calculation unit calculates the reference impedance value Z B , the reference capacity multiple nSN, and the percentage errorP of the nominal value of the load active power R , and the percentage of the load reactive power nominal value errorQ L , and the percentage errorQ of the load reactive power nominal value C , get the RCL load given value instruction Z refR , RCL load given value instruction Z refC , RCL load given value instruction Z refCR , RCL load given value instruction Z refL and RCL load given value instruction Z refLR .

[0065] The RCL load given value instruction Z of the present invention refR , RCL load given value instruction Z refC , RCL load given value instruction Z refCR , RCL load given value instruction Z refL and RCL load given value instruction Z refLR From formula (1), we can get:

[0066]

[0067] in, is the impedance tangent of the capacitor branch in RLC, is the impedance angle cotangent value of the capacitor branch in RLC, tan δ is the impedance tangent of the inductor branch in RLC, cos δ is the cotangent value of the impedance angle of the inductor branch in RLC.

[0068] like Figure 5 As shown in the figure, the bus constant voltage control unit calculates the collected instantaneous value of the three-phase voltage of the Bs bus through the root mean square RMS to obtain the standard value Us of the effective value of the three-phase voltage mea ; Then the per unit value Us mea and expected voltage value Us ref Subtract and get the difference u err , the difference u err Output u through PI control module add , and then u add With bus voltage given value Un ref Added output Us Mag , driving the external AC equivalent power supply S1 to output a constant voltage. The expected voltage value Us ref The bus voltage setting value is Un. ref Configured as the rated voltage value of the Bpcc bus.

[0069] It should be noted that, since the power bus (Bs), the grid-connected bus (Bg) and the grid-connected point bus (Bpcc) are connected through AC circuit breakers (K1, K2), when the AC circuit breaker is closed, the voltages of the three buses Bs, Bg and Bpcc are consistent, that is, the voltage of the Bs bus is kept constant at the rated voltage value during the anti-islanding protection test, and the voltage of the Bpcc bus can be kept constant at the rated voltage value, thereby ensuring the active power and reactive power corresponding to the RLC impedance consumption obtained by theoretical calculation. When the output of the RLC load or energy storage converter changes, causing the Bpcc bus voltage to shift, the Bpcc bus constant voltage control module of the present invention can automatically adjust the voltage amplitude of the AC equivalent power supply (S1), ensuring that the Bpcc bus voltage remains at the rated value, thereby ensuring that the RLC load output meets the theoretical calculation value. It should also be pointed out that the PI control module is a common pid control module in the control field, which is used for closed-loop regulation of the amplitude of the AC equivalent power supply. The AC equivalent power source S1 is a controlled voltage source, and the amplitude of the AC equivalent power source S1 is Us Mag .

[0070] The anti-islanding test steps after the improved RLC load general control modeling method of the energy storage converter anti-islanding protection test of the present invention are as follows: Figure 6 As shown in the figure, the test phase only needs to enter the rated parameters once, select the load power (TypLoad) and test number (TestNum) corresponding to the anti-islanding detection condition table as needed, and the test can be triggered. The improved test method eliminates the manual calculation of RLC parameters, the adjustment of RLC parameter deviation, and the repeated calculation steps for different capacities of the energy storage converter under test, simplifies the test steps, and improves the efficiency of anti-islanding protection testing.

[0071] The universal control modeling method for RLC load of the anti-islanding protection test of the energy storage converter includes RLC parameter normalization calculation, which can be applicable to the anti-islanding protection simulation test of energy storage converters with different rated capacities. The simulation model is reusable and portable, which shortens the simulation modeling cycle and improves the test efficiency. The present invention also includes integrated modeling of RLC parameter calculation of anti-islanding protection test conditions and Bpcc bus constant voltage control, so that the configuration of the anti-islanding protection test conditions can be completed quickly and accurately without the need to perform RLC parameter calculation, thereby reducing the risk of misoperation and improving user experience.

[0072] Example 2

[0073] An application of the RLC load universal control modeling method for anti-islanding protection test of an energy storage converter as in Example 1 is described by taking an anti-islanding protection application case of an energy storage converter of a certain manufacturer as an example.

[0074] The basic information of the energy storage converter under test is: rated power 2MW, rated voltage on the AC side 690V.

[0075] The anti-islanding protection test case is the 41st extended detection item in Table 1: the percentage of the nominal value of the load active power = 5%, the percentage of the nominal value of the load reactive power = 10%, and the RLC load active power is 1.05pu, and the RLC load reactive power is 0.1pu.

[0076] The waveform of the 41st extended detection item is as follows Figure 7 As shown, the interval of -100.0ms to 0.0ms is the stable state of the test system, and the interval of 0.0ms to 150.0ms is the state of triggering the island test condition. From the waveform recording diagram, it can be seen that the anti-islanding protection action time of the energy storage converter under test is 67.8ms. The method proposed in the present invention is used during the test process to accurately and conveniently carry out the anti-islanding protection test.

[0077] exist Figure 7 The definitions of each recording channel are as follows:

[0078] UpPccA, UpPccB, and UpPccC are the instantaneous values ​​of the three-phase voltage of the Bpcc bus (in kV).

[0079] IpPccA, IpPccB, and IpPccC are the instantaneous values ​​of the three-phase currents of the energy storage converter flowing into the Bpcc bus (in kA).

[0080] IpLoadA, IpLoadB, and IpLoadC are the instantaneous values ​​of the three-phase currents of the RLC load branch (in kA).

[0081] IpGridA, IpGridB, and IpGridC are the instantaneous values ​​of the three-phase currents (in kA) of the AC equivalent power flowing into the Bpcc bus.

[0082] Pcc_U1p is the effective value of the three-phase voltage of the Bpcc bus (unit: pu).

[0083] PLoad and QLoad are the active power and reactive power consumed by the RLC load (unit: pu).

[0084] Pcc_freq is the frequency measurement value of the Bpcc bus (in Hz).

[0085] IslandStart and IslandStop are the start flags of the anti-islanding protection test and the anti-islanding protection action flags of the energy storage converter under test.

[0086] Ctrl Source Figure 3 The closing position status flag of the circuit breaker (K1) on the power grid side (high level indicates closing, low level indicates opening).

[0087] Moreover, the RLC load universal control modeling method for the energy storage converter anti-islanding protection test of the present invention has been applied to the energy storage converter anti-islanding protection simulation test with a rated capacity of 3.45MW and the energy storage converter anti-islanding protection simulation test with a rated capacity of 2.00MW.

[0088] The above application proves that the invented RLC load universal control modeling method for anti-islanding protection test of energy storage converter can be applied to anti-islanding protection simulation test of energy storage converters with different rated capacities. The simulation model is reusable and portable, shortening the simulation modeling cycle and improving the test efficiency. It can also quickly and accurately complete the configuration of the anti-islanding protection test conditions without the need for RLC parameter calculation, reducing the risk of misoperation and improving user experience.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A general control modeling method for RLC load of energy storage converter anti-islanding protection test, characterized in that , the settings are: RLC parameter configuration integrated modeling and per-unit calculation module - collect the rated parameters of the energy storage converter under test; then calculate the reference impedance value Z for RLC parameter per-unit calculation based on the rated parameters B ;Finally, according to the reference impedance value Z B and rated parameters, calculate the RLC load parameter given value instruction, and complete the configuration of the anti-islanding protection test condition; Bus constant voltage control unit: drives the AC equivalent power supply according to the instantaneous value of the three-phase voltage of the power supply Bs bus, so that the AC equivalent power supply has a constant output voltage, thereby avoiding the RLC parameter correction of the RLC parameter configuration integrated modeling and per-unit calculation module.

2. The RLC load universal control modeling method for anti-islanding protection test of energy storage converter according to claim 1 is characterized in that: The RLC parameter configuration integrated modeling and per-unit calculation module is provided with: Input module - collects the rated parameters of the energy storage converter under test; RLC parameter calculation module - calculates RLC load parameter given value instructions according to the rated parameters; Output module: outputs the RLC load parameter given value instruction obtained by the RLC parameter calculation module to the RLC load simulation model.

3. The RLC load universal control modeling method for anti-islanding protection test of energy storage converter according to claim 2 is characterized in that: The rated parameters are rated voltage UN, rated capacity SN, load power type TypLoad and test serial number TestNum.

4. The RLC load universal control modeling method for anti-islanding protection test of energy storage converter according to claim 3 is characterized in that: The RLC parameter calculation module parses the value according to the load power type TypLoad and the test number TestNum of the input module, and finds the corresponding reference capacity multiple nSN and the percentage errorP of the load active power nominal value in the anti-islanding detection item comparison table according to the parsed value of the load power type TypLoad and the test number TestNum. R , and the percentage of the load reactive power nominal value errorQ L The sum is the percentage of the load reactive power nominal value errorQ C ; The RLC parameter calculation module also calculates the rated voltage U of the input module according to the rated voltage U N and rated capacity S N , get the reference impedance value Z B ; The RLC parameter calculation module also calculates the reference impedance value Z B , the reference capacity multiple nSN, and the percentage errorP of the nominal value of the load active power R , and the percentage of the load reactive power nominal value errorQ L , and the percentage errorQ of the load reactive power nominal value C , get the RCL load given value instruction.

5. The RLC load universal control modeling method for anti-islanding protection test of energy storage converter according to claim 4 is characterized in that: The RLC parameter calculation module is provided with a preconfiguration unit, a reference impedance calculation unit and an RLC calculation unit.

6. The RLC load universal control modeling method for anti-islanding protection test of energy storage converter according to claim 5 is characterized in that: The pre-configuration unit parses the values ​​of the load power type TypLoad and the test number TestNum collected by the input module, and finds the corresponding reference capacity multiple nSN and the percentage errorP of the load active power nominal value in the anti-islanding detection item comparison table according to the values ​​after parsing the load power type TypLoad and the test number TestNum. R , and the percentage of the load reactive power nominal value errorQ L The sum is the percentage of the load reactive power nominal value errorQ C .

7. The RLC load universal control modeling method for anti-islanding protection test of energy storage converter according to claim 6 is characterized in that: The reference impedance calculation unit calculates the rated voltage U collected by the input module. N and rated capacity S N , get the reference impedance value Z B .

8. The RLC load universal control modeling method for anti-islanding protection test of energy storage converter according to claim 7 is characterized in that: The RLC calculation unit calculates the reference impedance value Z B , the reference capacity multiple nSN, and the percentage errorP of the nominal value of the load active power R , and the percentage of the load reactive power nominal value errorQ L , and the percentage errorQ of the load reactive power nominal value C , get the RCL load given value instruction Z refR , RCL load given value instruction Z refC , RCL load given value instruction Z refCR , RCL load given value instruction Z refL and RCL load given value instruction Z refLR ; The RCL load given value instruction Z refR , the RCL load given value instruction Z refC , RCL load given value instruction Z refCR , the RCL load given value instruction Z refL and the RCL load given value instruction Z refLR From formula (1), we can get: in, is the impedance tangent of the capacitor branch in RLC, is the impedance angle cotangent value of the capacitor branch in RLC, tan δ is the impedance tangent of the inductor branch in RLC, cot δ is the cotangent value of the impedance angle of the inductor branch in RLC.

9. The RLC load universal control modeling method for anti-islanding protection test of energy storage converter according to any one of claims 1 to 8, characterized in that: The bus constant voltage control unit calculates the collected instantaneous value of the three-phase voltage of the Bs bus through the root mean square RMS to obtain the per unit value Us of the three-phase voltage effective value mea ; Then the per unit value Us mea and expected voltage value Us ref Subtract and get the difference u err , the difference u err Output u through PI control module add , and then u add With bus voltage given value Un ref Added output Us Mag , driving the external AC equivalent power supply S1 to produce a constant output voltage.

10. The RLC load universal control modeling method for anti-islanding protection test of energy storage converter according to claim 9 is characterized in that: The expected voltage value Us ref Configured as 1.0pu; The bus voltage given value Un ref Configured as the rated voltage value of the Bpcc bus.

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