Microgrid controller multifunctional comprehensive test system and method

Abstract

The present application relates to a kind of microgrid controller multifunctional comprehensive test system and method, wherein the method includes: scheduling and configuring each execution unit in microgrid;Adjust the response accuracy of microgrid controller to verify the working parameter of power grid;The operating parameters of energy storage system in microgrid are configured to simulate the working state of energy storage system under different scenarios;Multiple load operating scenarios are configured to microgrid;Simulate communication operating environment to evaluate the communication protection capability of microgrid controller;Simulate the process of energy storage system in microgrid grid-connected / off-grid state switching to induce microgrid controller switching operation mode;Collect instruction message in the operation process of microgrid controller to evaluate the control consistency of microgrid controller according to instruction response delay data.The present application can realize the functional detection of microgrid control in laboratory stage, and find the control logic defects of microgrid controller under complex working conditions in advance, to provide reliable test basis for engineering application of microgrid controller.

Description

Technical Field

[0001] This invention relates to the field of new energy power grid testing technology, and in particular to a multi-functional integrated testing system and method for microgrid controllers. Background Technology

[0002] As the core scheduling unit of a microgrid system, the correctness of the control logic and the stability of operation of the microgrid controller are directly related to the safe operation of the entire microgrid system. Therefore, functional testing of the microgrid controller is particularly important.

[0003] Existing testing methods for microgrid controllers have the following shortcomings: 1) Fragmented test scenarios: Most tests can only target a single scenario of power grid, energy storage or load, making it difficult to simulate multiple factors superimposed on the working conditions; 2) Lack of system-level collaborative verification: It is impossible to verify the overall behavior of the microgrid controller when multiple energy linkages, communication anomalies and mode switching occur simultaneously; 3) Lack of long-term operation testing capabilities: It is difficult to detect problems such as memory leaks, logic drift or policy failures that occur in the microgrid controller during long-term operation.

[0004] The shortcomings of these testing methods mean that performance defects of microgrid controllers can only be discovered during actual applications. At this point, it is difficult to debug, repair or replace them. Therefore, a new testing scheme is needed that can expose the potential risks of microgrid controllers in real operating environments in advance during the laboratory stage. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a multi-functional integrated testing system and method for microgrid controllers, which has the advantages of enabling simulation testing under various working conditions and improving testing reliability.

[0006] To achieve the above and other related objectives, the present invention provides the following technical solution:

[0007] The first aspect of the present invention discloses a multi-functional integrated testing method for a microgrid controller, comprising:

[0008] Scheduling and configuring each execution unit in the microgrid to build a microgrid controller test environment;

[0009] Adjust the power grid operating parameters to simulate various operating conditions of the microgrid in order to verify the response accuracy of the microgrid controller;

[0010] Configure the operating parameters of the energy storage system in the microgrid to simulate the working state of the energy storage system under different scenarios, and evaluate the timing coordination control capability through the response results of the microgrid controller;

[0011] The microgrid was configured with multiple load operating scenarios, including constant load, sudden load, and impact load, to evaluate the response and anti-interference capability of the microgrid controller.

[0012] Simulate communication operating environments including communication link jitter and packet attacks to evaluate the communication protection capabilities of the microgrid controller;

[0013] The process of switching between grid-connected and off-grid states of energy storage systems in microgrids is simulated to induce the microgrid controller to switch operating modes, and the control stability of the microgrid controller is evaluated based on the switching results.

[0014] The system collects command messages during the operation of the microgrid controller to evaluate the control consistency of the microgrid controller based on command response delay data.

[0015] As a preferred embodiment of the invention, when scheduling and configuring the execution units in the microgrid, the coordination control capability of the microgrid controller is detected, including:

[0016] Initial operating data is configured for each execution unit in the microgrid to form a test operation strategy, and a linkage control strategy is generated. The linkage control strategy is: when the grid voltage drops to a predetermined low voltage threshold, the energy storage system operation mode is forcibly switched.

[0017] The aforementioned operating strategy and linkage control strategy are converted into test script files for loading and execution.

[0018] Load the test script file and control the microgrid operation according to the linkage control strategy;

[0019] Obtain the command transmission time and mode switching timing difference of the microgrid controller to evaluate the linkage accuracy.

[0020] As a preferred embodiment of the invention, the adjustment of power grid operating parameters to simulate various operating conditions of the microgrid to verify the response accuracy of the microgrid controller specifically includes:

[0021] Configure voltage / frequency variation parameters for the microgrid, and determine the amplitude accuracy and ramp rate control capability of the output analog quantity based on the output voltage / output frequency data;

[0022] Overvoltage fault command, voltage flashover command and undervoltage protection cascade command are sequentially issued to the microgrid, and the accuracy of the response is evaluated based on the response results of the output voltage.

[0023] To simulate islanding, the microgrid is sequentially issued generation grid disconnection and grid restoration commands. The islanding response function is evaluated based on the voltage status of the microgrid's voltage output port.

[0024] As a preferred embodiment of the invention, configuring the operating parameters of the energy storage system in the microgrid to simulate the working state of the energy storage system under different scenarios, and evaluating the timing coordination control capability through the response results of the microgrid controller specifically includes:

[0025] The initial operating parameters of the energy storage system in the microgrid are configured and a steady-state operating condition is formed. The energy storage system includes a photovoltaic simulation unit, an energy storage simulation unit, and an adjustable power generation unit.

[0026] At the first test moment, the operating parameters of the photovoltaic simulation unit are adjusted to change abruptly, the decreasing trend of the bus voltage / frequency is detected, and the discharge power of the energy storage simulation unit is adjusted with a delay and the virtual three-phase current value is fed back to the microgrid controller to detect the energy storage output current establishment status.

[0027] At the second test moment, the power generation state of the adjustable power generation unit is adjusted, and after the adjustable power generation unit is connected to the grid, the SOC value of the energy storage simulation unit is adjusted to simulate the power alarm state, and the control command issuance status of the microgrid controller is detected.

[0028] At the third test moment, the energy storage system is adjusted to restore its initial steady-state operation, and a timing comparison diagram of the microgrid controller's command sequence and the energy storage system's response sequence is output.

[0029] As a preferred embodiment of the invention, the method of configuring the microgrid with multiple load operating scenarios including constant load, sudden load, and impulsive load to evaluate the response and anti-interference capability of the microgrid controller specifically includes:

[0030] Configure a constant load for the microgrid and ensure its stable operation;

[0031] The nonlinear load simulation unit is activated to inject harmonic current into the microgrid's point of common coupling to simulate grid noise;

[0032] The nonlinear load simulation unit reverses the phase of the harmonic current to cause a jump in the total harmonic distortion rate of the voltage, in order to simulate the change in line impedance caused by a fault at the far end of the power grid.

[0033] The output voltage waveform of the microgrid controller is detected and the response time of the waveform distortion suppression algorithm is recorded to evaluate the anti-interference capability of the response.

[0034] As a preferred embodiment of the invention, the method of configuring the microgrid with multiple load operating scenarios including constant load, sudden load and impact load to evaluate the response and anti-interference capability of the microgrid controller further includes:

[0035] Configure a constant load for the microgrid and ensure its stable operation, and control the energy storage system to operate in accordance with the initial preset parameters;

[0036] When a constant load is switched to a sudden load, the microgrid controller issues a photovoltaic power reduction command or a trip command to limit reverse power and records the time difference between the command issuance.

[0037] The load is switched back to a constant load, and the nonlinear load simulation unit is started to inject harmonic current into the microgrid's point of common coupling to calculate the total harmonic distortion rate. The host computer sends a photovoltaic output limiting command to the microgrid controller and obtains the active power decline curve of the energy storage system to determine the success rate of the microgrid controller's response.

[0038] Switch from a constant load to an impact load and check if the microgrid controller is misjudging.

[0039] As a preferred embodiment of the invention, the simulation includes communication link jitter and communication operating environments subjected to packet attacks to evaluate the communication protection capabilities of the microgrid controller, specifically including:

[0040] The microgrid is configured to operate at steady-state parameters, and the microgrid controller obtains sampled measurement values ​​to determine whether there are any communication anomalies.

[0041] When the system reaches the first test moment, a communication degradation instruction is triggered to improve communication latency and packet loss rate. Each sampled measurement value is timestamped and sent out with a delay. The microgrid controller receives the reported data to determine the communication status.

[0042] During the second test moment after communication deterioration, the GOOSE output message of the microgrid controller is detected, and the tripping intention is captured through the GOOSE output message to force the microgrid controller into a fault handling logic dead loop, thereby determining the control logic defect.

[0043] Normal communication is restored at the third test point after communication degradation, and the system detects whether false tripping occurs during the communication degradation period to assess communication robustness.

[0044] As a preferred embodiment of the invention, the process of simulating the grid-connected / off-grid switching of the energy storage system in a microgrid to induce the microgrid controller to switch operating modes, and evaluating the control stability of the microgrid controller based on the switching result, specifically includes:

[0045] Initialize the microgrid operating environment and simulate the steady-state operation of the large power grid in terms of voltage and frequency.

[0046] Simulates the issuance of power dispatch commands to control the energy storage system to adjust its power setpoint;

[0047] The control grid simulator disconnects the internal output relay to simulate a sudden power outage due to a large power grid failure.

[0048] Record the time difference between the grid voltage drop and the microgrid controller sending an islanding alarm signal;

[0049] Trigger the off-grid disconnection of the energy storage system and force a switch in the operating mode of the energy storage system. Evaluate the control stability based on the switching control status of the microgrid controller.

[0050] As a preferred embodiment of the invention, the step of collecting command messages during the operation of the microgrid controller to evaluate the control consistency of the microgrid controller based on command response delay data specifically includes:

[0051] Configure the microgrid with initial photovoltaic power output and initial load for steady-state operation;

[0052] The load mutation command is triggered at a predetermined mutation time to control the increase of load mutation.

[0053] The energy storage system responds to load change commands by controlling the actual output power to increase, and records the instantaneous values ​​of the three-phase voltage and current of the energy storage system;

[0054] The command delay is calculated based on the moment the load change command is issued and the moment the energy storage current begins to rise in order to determine the command response delay. The adjustment time when the voltage recovers to the steady state value is calculated to determine the consistency.

[0055] A second aspect of the present invention discloses a multi-functional integrated testing system for microgrid controllers, comprising:

[0056] The unified scheduling and control module is used to schedule and configure the various execution units in the microgrid system to build a microgrid controller test environment;

[0057] The power grid operating condition simulation module is used to adjust the power grid operating parameters to simulate various operating conditions of the microgrid in order to verify the response accuracy of the microgrid controller.

[0058] The multi-energy simulation module, along with the microgrid controller's closed-loop control, is used to configure the operating parameters of the energy storage system in the microgrid to simulate the working state of the energy storage system under different scenarios, and to evaluate the timing coordination control capability through the response results of the microgrid controller.

[0059] The load simulation control module is used to configure multiple load operation scenarios for microgrids, including constant load, sudden load and impact load, in order to evaluate the response and anti-interference capability of the microgrid controller.

[0060] The communication anomaly injection module is used to simulate communication operating environments, including communication link jitter and packet attacks, to evaluate the communication protection capabilities of the microgrid controller.

[0061] The mode strategy induction module is used to simulate the grid-connected / off-grid state switching process of the energy storage system in the microgrid to induce the microgrid controller to switch operating modes, and evaluate the control stability of the microgrid controller based on the switching results;

[0062] The data acquisition and analysis module is used to collect command messages during the operation of the microgrid controller in order to evaluate the control consistency of the microgrid controller based on command response delay data.

[0063] As described above, the present invention has the following beneficial effects:

[0064] This invention provides a multi-functional integrated testing system and method for microgrid controllers. The method includes: scheduling and configuring various execution units in a microgrid to construct a microgrid controller test environment; adjusting grid operating parameters to simulate various operating conditions of the microgrid to verify the response accuracy of the microgrid controller; configuring operating parameters of the energy storage system in the microgrid to simulate the operating state of the energy storage system under different scenarios, and evaluating the timing coordination control capability through the response results of the microgrid controller; configuring multi-load operating scenarios including constant load, sudden load, and impact load for the microgrid to evaluate the response anti-interference capability of the microgrid controller; simulating communication operating environments including communication link jitter and packet attacks to evaluate the communication protection capability of the microgrid controller; simulating the grid-connected / off-grid state switching process of the energy storage system in the microgrid to induce the microgrid controller to switch operating modes, and evaluating the control stability of the microgrid controller based on the switching results; and collecting command messages during the operation of the microgrid controller to evaluate the control consistency of the microgrid controller based on command response delay data. Through testing processes such as power grid operating condition simulation, multi-energy simulation, load switching simulation, communication anomaly simulation, and mode strategy induction, the microgrid control can be functionally tested in multiple aspects in the laboratory stage. This allows for verification of the overall stability of the microgrid controller under multiple superimposed conditions, and enables the early detection of control logic defects in the microgrid controller under complex operating conditions, providing a reliable test basis for the engineering application of the microgrid controller. Attached Figure Description

[0065] Figure 1 The diagram shown is a flowchart of a multi-functional integrated testing method for a microgrid controller in an embodiment of the present invention.

[0066] Figure 2 The diagram shown is a structural schematic of the multi-functional integrated test system for microgrid controllers in an embodiment of the present invention. Detailed Implementation

[0067] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0068] Please see Figure 1 The first aspect of this invention provides a multi-functional integrated testing method for a microgrid controller, comprising:

[0069] S100 schedules and configures each execution unit in the microgrid to build a microgrid controller test environment.

[0070] Specifically, when scheduling and configuring the various execution units in the microgrid, the coordinated control capability of the microgrid controller is tested, including:

[0071] S101. Configure initial operating data for each execution unit in the microgrid to form a test operation strategy, and generate a linkage control strategy. The linkage control strategy is: when the grid voltage drops to a predetermined low voltage threshold, forcibly switch the energy storage system operation mode.

[0072] This microgrid is designed to simulate a real large power grid and includes a grid simulator, an energy storage system, and a load simulator. The energy storage system comprises a photovoltaic simulation unit, an energy storage simulation unit, and an adjustable generation unit. Initial operating data can be configured as follows: the grid simulator outputs a rated voltage of 380V / 50Hz; the photovoltaic simulator operates in MPPT mode with an output power of 50kW; the energy storage simulator operates in PQ mode with a discharge power of 20kW; and the load simulator is configured as a resistive load of 100kW. A specific linkage control strategy can be set as follows: when the grid voltage drops to 20%Un, the photovoltaic simulator is forced to switch from MPPT mode to constant reactive power control mode, with the active current limited to 0.4pu.

[0073] S102. The running strategy and linkage control strategy are converted into test script files for loading and execution. This process is to facilitate reading and executing instructions.

[0074] S103. Load the test script file and control the microgrid operation according to the linkage control strategy. Based on the linkage control strategy, the specific execution process is as follows:

[0075] S1031. At time T0, the test script file is executed.

[0076] S1032. At time T0+500ms, the output of the power grid simulator drops sharply, and the microgrid controller detects that the power grid status register has changed to "fault state".

[0077] S1033. At time T0+500.5ms, the microgrid control bypasses the communication delay of the host computer and directly sends a mode switching command to the photovoltaic simulator and energy storage simulator through the underlying bus.

[0078] S1034. At time T0+1125ms, the microgrid controller detects that the grid simulator voltage has recovered and triggers the energy storage simulator and photovoltaic simulator to resume MPPT / PQ mode again.

[0079] S104. Obtain the instruction sending time and mode switching timing difference of the microgrid controller to evaluate the linkage accuracy. In this embodiment, the linkage accuracy of the microgrid controller can be evaluated by detecting whether the reactive power compensation instruction issued by the microgrid controller is issued within 30ms after the fault and whether the timing difference of mode switching is less than 1ms.

[0080] S200: Adjust the power grid operating parameters to simulate various operating conditions of the microgrid in order to verify the response accuracy of the microgrid controller.

[0081] Specifically, the S200 includes:

[0082] S201. Configure voltage / frequency variation parameters for the microgrid, and determine the amplitude accuracy and ramp rate control capability of the output analog quantity based on the output voltage / output frequency data.

[0083] In a specific instance, step S201 specifically includes:

[0084] S2011. Set the voltage reference value to 230V (1 pu) and the frequency to 50Hz. At this time, the PWM modulation unit in the microgrid starts and outputs a stable three-phase AC voltage. The reading can be detected by a high-precision power analyzer. The steady-state voltage error should be controlled to <±0.2% FS.

[0085] S2012. Control voltage: The voltage increases from 1 pu to 1.1 pu (253V) at a rate of 10 pu / s. At this time, the output voltage should increase smoothly and linearly without obvious steps or overshoot. This can be monitored by a waveform recorder. The actual rise rate deviation should be <±1%.

[0086] S2013. When the control frequency changes abruptly from 50Hz to 49.8Hz, the output frequency should be adjusted within 40ms, and the frequency change rate (df / dt) should meet the preset value.

[0087] S202. Issue overvoltage fault commands, voltage flashover commands, and undervoltage protection cascade commands to the microgrid in sequence, and evaluate the accuracy of the response based on the response results of the output voltage.

[0088] In a specific instance, step S202 specifically includes:

[0089] S2021. Issue an overvoltage fault command, adjust the trigger voltage to 1.3 pu for 500ms. During this process, the voltage instantly rises from 1.0 pu to 1.3 pu, then starts an internal timer and automatically recovers to 1.0 pu after 500ms. When the voltage recovery signal is detected, the high voltage protection alarm flag of the energy storage simulation unit is automatically unlocked.

[0090] S2022: Issue a voltage drop command to adjust the voltage drop to 0.1 pu and maintain it for 40ms to simulate the reclosing process. During this process, the voltage waveform is cut off at the zero crossing point. After 40ms ± 1ms, the voltage waveform recovers at the phase continuity point. Measure the drop duration width with an oscilloscope. The error should be less than the simulation step size setting value, which is usually set to < 10us.

[0091] S2023: Issue an undervoltage protection cascade command to adjust the voltage linearly to 0.7 pu. During this process, the output voltage drops to 161V, and the status register is set to "Under_Voltage_Flag". When this Flag is read, the "load switching module" should be automatically triggered to disconnect the three-level load. Verify whether the load disconnection action is completed before the voltage recovers to 0.85 pu.

[0092] This verifies whether the microgrid controller accurately records events and correctly exits after a specified duration when undervoltage, overvoltage, or intermittent power outages occur.

[0093] S203. Issue generation grid disconnection and grid restoration commands sequentially to the microgrid to simulate islanding, and evaluate the islanding response function based on the voltage status of the microgrid voltage output port.

[0094] In a specific instance, step S203 specifically includes:

[0095] S2031, when the power grid disconnection command is issued, the main grid circuit breaker is disconnected. At this time, the grid-connected contactor simulates the relay disconnection, and the output voltage port switches to a high impedance state to simulate grid loss. This can be measured with a multimeter. There is electrical isolation between the microgrid output terminal and the microgrid controller sampling terminal, and the resistance value is > 10MΩ.

[0096] S2032. Maintain the disconnected state for 5 seconds, monitor whether the microgrid controller reports "islanding" and trips. During this process, maintain a high impedance state and report the "Breaker_Open" status word through the auxiliary communication channel. Record the time when the microgrid controller sends the trip signal. If the microgrid controller does not act within 2 seconds, the system determines that the anti-islanding has failed, automatically terminates the test and alarms.

[0097] S2033, issue a power grid restoration command. During this process, first output a small voltage that is in phase and frequency with the current voltage of the microgrid. After a 100ms delay, close the internal simulated relay and then instantly raise the voltage to the rated value. The simulated surge current value at the moment of restoration should be less than the preset limit to verify whether the dispatch module has issued a soft start command.

[0098] S300: Configure the operating parameters of the energy storage system in the microgrid to simulate the working state of the energy storage system under different scenarios, and evaluate the timing coordination control capability through the response results of the microgrid controller.

[0099] Specifically, the S300 includes:

[0100] S301. Configure initial operating parameters for the energy storage system in the microgrid and establish a steady-state operating condition.

[0101] In a specific example, the photovoltaic simulation unit is set up with a standard illumination curve (1000W / m²) and a rated output power Ppv=100kW; the energy storage simulation unit is set up with an initial SOC=80%, operating in PQ mode, and a power command of 0; and the adjustable generator unit is set up with a diesel generator output Pgen=50kW.

[0102] During this process, the microgrid controller should detect that the system frequency is stable at 50Hz and the bus voltage is stable. It should determine whether to establish steady-state operation by judging whether the power command issued by the controller has zero error.

[0103] S302. At the first test moment, adjust the sudden change of the operating parameters of the photovoltaic simulation unit, detect the downward trend of the bus voltage / frequency, delay the adjustment of the discharge power of the energy storage simulation unit and feed back the virtual three-phase current value to the microgrid controller, and detect the establishment status of the energy storage output current.

[0104] In a specific instance, S302 specifically includes:

[0105] S3021. The photovoltaic simulation unit injects a "cloud shading" event at the first test moment (T1) and modifies the illumination curve parameters to make Ppv drop sharply from 100kW to 20kW within 200ms, simulating the rapid drop characteristics of real photovoltaics. During this process, the microgrid controller should detect a downward trend in the bus frequency / voltage. By observing whether the microgrid controller can fill the power gap using the rapid response capability of the energy storage simulation unit during the transient process of photovoltaic drop, the linkage test can be achieved.

[0106] S3022. The energy storage simulation unit responds to the microgrid controller's command. At time T1+10ms, it receives the "constant power discharge 80kW" command issued by the controller, updates the SOC value of the internal energy storage system, and feeds back the virtual three-phase current value to the energy storage controller. At this time, the microgrid controller should detect the establishment of the energy storage output current and the recovery of the system frequency. Timing verification is achieved by judging whether the response delay of the energy storage simulation unit (simulation communication + IGBT action time) causes the system to crash.

[0107] S303. At the second test moment, adjust the power generation state of the adjustable power generation unit, and after the adjustable power generation unit is connected to the grid, adjust the SOC value of the energy storage simulation unit to simulate the power alarm state, and detect the control command issuance status of the microgrid controller.

[0108] In a specific instance, S303 specifically includes:

[0109] S3031. At the second test moment (T2), the adjustable generator unit simulates the diesel engine startup process. It first outputs a "starting" status flag (no power output) for 5 seconds, and then establishes voltage grid connection. During this process, the microgrid controller should detect that the energy storage SOC is dropping rapidly and receive the diesel generator "ready" signal, thereby verifying whether the microgrid controller has the timing logic to wait for the diesel generator to start.

[0110] S3032. At T2+5s, after the adjustable generator unit is connected to the grid, the energy storage simulation unit simulates the SOC reaching the lower limit alarm state. The energy storage simulation unit automatically limits the maximum discharge power to 0, simulating BMS protection. During this process, the microgrid controller detects that the energy storage can no longer support the system and automatically issues a "energy storage shutdown, diesel generator increase" command, thereby verifying whether the microgrid controller can correctly handle the over-discharge limit flag reported by the energy storage simulation unit.

[0111] S3033, the adjustable generation unit responds to the microgrid controller's additional generation command, simulates the speed governor's action, and controls the power to climb from 0 to 130kW, with a ramp rate limit of 20kW / s. At this time, the microgrid frequency drops slightly when the energy storage simulation unit exits, and is then pulled back by the adjustable generation unit. During this process, the state variables of the photovoltaic simulation unit, the energy storage simulation unit, and the adjustable generation unit are captured and processed by the microgrid controller at the same timestamp.

[0112] S304. At the third test moment, adjust the energy storage system to restore the initial steady-state operation state and output a timing comparison diagram of the microgrid controller's instruction sequence and the energy storage system's response sequence.

[0113] In a specific instance, S304 specifically includes:

[0114] S3041. When the photovoltaic simulation unit is unshaded at the third test moment (T3), the Ppv recovers to 100kW, the adjustable power generation unit maintains output, and the energy storage simulation unit is set to too low SOC and cannot charge. At this time, the microgrid controller detects that the photovoltaic has recovered and the system power is excessive. The microgrid controller should issue a diesel power reduction command. If it is still excessive, the photovoltaic power limiting command is triggered.

[0115] S3042. Re-control the energy storage system to restore it to the initial steady-state operation. After the operation stabilizes, the test ends. At this time, output a timing comparison diagram of the microgrid controller's instruction sequence and the energy storage system's response sequence throughout the entire testing process.

[0116] This verifies the timing coordination control logic of the microgrid controller for the energy storage system (rapid support) and the adjustable generation unit (steady-state support) under the dual impact of a sudden drop in photovoltaic output and a sudden increase in load. It also verifies whether the microgrid controller can accurately identify the "energy storage SOC depletion" boundary condition simulated by the simulation module and correctly execute the tripping / load reduction strategy.

[0117] S400, to evaluate the microgrid controller's response and immunity to interference by configuring multiple load operation scenarios including constant load, sudden load and impact load for microgrids;

[0118] Specifically, the S400 includes:

[0119] S401. Configure a constant load for the microgrid and ensure stable operation, for example, it can be set to operate at 50% of the rated resistive load.

[0120] S402. Start the nonlinear load simulation unit to inject harmonic current into the microgrid's point of common coupling to simulate grid noise. The number of harmonic current injections can be, for example, 3rd, 5th, 7th, etc. During this process, the grid THDu is gradually pushed up to 2.0%.

[0121] S403, the nonlinear load simulation unit reverses the phase of the harmonic current to cause the total harmonic distortion rate of the voltage to jump, in order to simulate the change in line impedance caused by a fault at the far end of the power grid. During this process, the active power setpoint of the system is not changed. By triggering the phase remapping function of the nonlinear load simulation unit, the phase of the 5th harmonic is reversed by 120° within 10ms, causing THDu to jump to 8.5% instantaneously.

[0122] S404. Detect the output voltage waveform of the microgrid controller and record the response time of the waveform distortion suppression algorithm to evaluate the response anti-interference capability. The expected effect is usually set as the microgrid controller identifying and starting the harmonic suppression damping algorithm within 20ms.

[0123] This verifies whether the microgrid controller can maintain stable output and avoid accidental tripping when the total harmonic distortion (THDu) of the voltage suddenly increases from 2% to 8%.

[0124] Furthermore, the S400 also includes:

[0125] S405. Configure a constant load for the microgrid and ensure its stable operation, and control the energy storage system to operate in parallel with the grid according to the initial preset parameters. In this process, for example, the grid simulator can be set to output a rated voltage of 380V / 50Hz, the photovoltaic simulation unit can be set to work in MPPT mode with an output power of Ppv=50kW, and the constant load can be set to a 50kW pure resistive load. At this time, the microgrid is in a critical state of power balance, and the grid connection point current Ig≈0A.

[0126] S406. When switching from a constant load to a sudden load change, the microgrid controller issues a photovoltaic power reduction command or a tripping command to limit reverse power and records the time difference between the command issuance. For example, at T1=5.000s, a 100% load sudden unloading is performed, and the load power drops from 50kW to 0kW. During this process, due to the output inertia or scheduling delay of the photovoltaic simulation unit, excess power is fed back to the grid side, generating instantaneous reverse power. The grid connection point detects a current phase angle offset of 180°. By accessing the Modbus TCP register or GOOSE message of the microgrid controller, the time difference Δt1 from T1 to the microgrid controller issuing the photovoltaic power reduction command or tripping command is recorded. The qualified judgment condition is set as: Δt1≤200ms.

[0127] S407. Switch the load back to a constant load and start the nonlinear load simulation unit to inject harmonic current into the microgrid's point of common coupling to calculate the total harmonic distortion (THD). The host computer sends a photovoltaic (PV) output limiting command to the microgrid controller and obtains the active power decline curve of the energy storage system to determine the microgrid controller's response success rate. In a specific example, for instance, the control load is readjusted to a 30kW resistive load. At this time, the nonlinear load simulation unit is started to inject the 5th harmonic current into the microgrid's point of common coupling, with a THD of 15%. The host computer sends a PV output limiting command to the microgrid controller via Modbus TCP to "limit PV output to 20kW". By monitoring the active power decline curve output by the PV simulation unit, the adjustment time Δt2 from the issuance of the command to the power stabilizing within the range of 20kW ± 2% is recorded. The qualified judgment condition is set as follows: under the poor power quality background of THD = 15%, the response success rate of the microgrid controller's scheduling command should be 100%, and there should be no oscillation or instability during the adjustment process.

[0128] S408. Switch the constant load to an impulsive load and check whether the microgrid controller misjudges the load. In a specific example, the impulsive load is set to simulate the full-voltage start of a 100kVA squirrel-cage induction motor within 20ms. At this time, check whether the microgrid controller misjudges the load as a "short-circuit fault" and trips the circuit breaker, or whether it correctly utilizes the energy storage module for transient power support. During this process, ensure that when a 100kVA impulsive load occurs, the grid simulator, energy storage simulation unit, and load module respond synchronously within microseconds to realistically reproduce the voltage drop depth of the microgrid bus. This allows for accurate evaluation of the microgrid controller's fault diagnosis algorithm and enables quantitative detection of the microgrid controller's reverse current protection action time and the response delay of power dispatch commands.

[0129] S500 simulates communication operating environments including communication link jitter and packet attacks to evaluate the communication protection capabilities of the microgrid controller.

[0130] Specifically, the S500 includes:

[0131] S501. Configure the microgrid to operate in steady state with the specified parameters. The microgrid controller obtains sampled measurement values ​​to determine if there is any communication abnormality. In a specific example, the microgrid operating parameters are set as follows: PCC point voltage 380V, frequency 50Hz, load rate 60%, duration 120s. The microgrid enables the IEC 61850 MMS server and normally sends the PCC point sampled measurement value (SMV) message to the microgrid controller. The message interval is 1ms, there is no packet loss, and the delay is <1ms. If the microgrid controller is in a normal grid-connected operating state, it is considered qualified.

[0132] S502. When the system reaches the first test moment, a communication degradation instruction is triggered to increase communication latency and packet loss rate. Each sampled measurement value is timestamped and sent with a delay. The microgrid controller receives the reported data to determine the communication status. In a specific example, when the system reaches the 30th second, the "communication degradation" macro instruction in the test script execution unit is triggered. The instruction parameters are: latency increased to 500ms, packet loss rate increased to 15%, and duration 20 seconds. At this time, the communication latency, packet loss, and abnormal frame injection unit takes over the data transmission buffer, adds a high-precision timestamp to the header of each sent SMV message frame, and deliberately delays it for 500ms before sending it. Then, 15% of the TCP retransmission acknowledgment packets are randomly discarded. At this time, the microgrid controller should detect an alarm of "remote terminal offline" or "data not refreshed", but the physical voltage and current of the electrical circuit do not change.

[0133] S503. At the second test moment after communication deterioration, the GOOSE output message of the microgrid controller is detected, and the tripping intention is captured through the GOOSE output message to force the microgrid controller into a fault handling logic dead loop, thereby identifying control logic defects. In a specific example, when the system runs to the 40th second (10 seconds after communication deterioration), the GOOSE output message of the microgrid controller is monitored. If the microgrid controller misjudges "grid-side voltage loss" due to communication timeout, it will usually send a tripping GOOSE command. By parsing the SBow (selective execution) field in the GOOSE message, the tripping intention is captured. Once the tripping intention is captured, an error code of "circuit breaker position status inconsistency" is returned to the microgrid controller, forcing the microgrid controller into a fault handling logic dead loop, thereby exposing its control logic defects.

[0134] S504. After the communication deterioration, normal communication is restored at the third test moment. The system checks whether a false trip occurred during the communication deterioration period to evaluate the communication robustness. In a specific example, when the system runs for 50 seconds (20 seconds of communication deterioration), packet loss and delay are canceled, normal communication is restored, and it is recorded whether the microgrid controller has experienced a false trip during the 20-second communication deterioration period. If no trip occurs and data refresh monitoring is restored within 52 seconds, the anti-islanding protection communication interlocking logic is deemed qualified. If a trip occurs, the communication robustness is deemed unqualified.

[0135] S600 simulates the grid-connected / off-grid state switching process of energy storage systems in microgrids to induce the microgrid controller to switch operating modes, and evaluates the control stability of the microgrid controller based on the switching results;

[0136] Specifically, the S600 includes:

[0137] S601. Initialize the microgrid operating environment, simulating the steady-state operation of the mains grid voltage and frequency. During this process, for example, it can be configured to send commands to the grid simulator to control the output AC 380V / 50Hz, close the grid connection switch to simulate the signal, and send commands to the energy storage simulation unit to control it to set to PQ mode, with initial power settings P=0 and Q=0. During this process, the microgrid controller detects the grid connection signal and remains in grid-connected standby / operation state.

[0138] S602, simulates the issuance of power dispatch commands to control the energy storage system to adjust the power setpoint; during this process, the power setpoint of the energy storage simulator can be modified through Modbus TCP messages: P_set=+50kW (charging), Q_set=+10kVar (inductive). At this time, the microgrid controller executes the PQ control strategy, and the energy storage simulator displays an active power absorption of 50kW.

[0139] S603, control the power grid simulator to disconnect the internal output relay to simulate a sudden power outage of the large power grid; during this process, the power grid simulator can be controlled to perform: disconnect the internal output relay, and the output voltage amplitude drops to 0V, thereby simulating the occurrence of unplanned islanding.

[0140] S604. Record the time difference between the grid voltage drop and the microgrid controller sending the islanding alarm signal. Specifically, record the time difference Δt from the start of the grid voltage drop in step S603 to the microgrid controller sending the "islanding alarm" signal. During this process, the microgrid controller should close the grid-connected switch trip signal within 2 seconds and start the off-grid logic.

[0141] S605 triggers the energy storage system to go off-grid and forces a switch in the operating mode of the energy storage system. The control stability is evaluated based on the switching control status of the microgrid controller. In a specific example, after detecting that the microgrid controller has entered the off-grid state, a forced mode switching command is sent to the energy storage simulator: switching from PQ mode to VF mode (constant voltage and constant frequency), with the voltage reference value set to 220V / 50Hz. During this process, the microgrid controller takes over the bus voltage, and the local load is not interrupted, completing seamless switching or short-term power outage switching.

[0142] This verifies whether the microgrid controller can correctly respond to dispatch instructions (PQ control) in grid-connected mode, and whether it can detect the islanding state and trigger the off-grid switching logic within the time specified by national standards (such as less than 2 seconds as specified in GB / T 33589) when the main grid loses power.

[0143] S700 collects command messages during the operation of the microgrid controller to evaluate the control consistency of the microgrid controller based on command response delay data.

[0144] Specifically, the S700 includes:

[0145] S701. Configure the initial photovoltaic output power and initial load for steady-state operation of the microgrid. In a specific example, the initial photovoltaic output power can be set to 50kW and the initial load to 30kW. When the event injection time is T=5.0s, a 50kW resistive load is suddenly added. After confirming that the photovoltaic simulation unit, energy storage simulation unit, and load simulator are all ready, the system enters the island steady state. At this time, capture the flag bits of the micro-hole controller: Mode = Island, V_ref = 220V.

[0146] S702. At a predetermined sudden change time, a load sudden change command is triggered to control the load sudden increase. Specifically, at T=5.0s, a sudden increase command is sent to the load simulator, and at the same time, at T=5.001s, the power adjustment command message sent by the microgrid controller to the energy storage converter is intercepted, in which the expected command is to increase the output by 50kW.

[0147] S703, the energy storage system responds to the load change command to control the actual output power to increase, and records the instantaneous values ​​of the three-phase voltage and current of the energy storage system; during this process, the energy storage converter responds to the command, the actual output power begins to climb, the system voltage Vrms experiences a transient drop, and the instantaneous values ​​of the three-phase voltage and current at the energy storage simulator port are recorded at a sampling rate of 10kHz.

[0148] S704. Calculate the command delay based on the issuance time of the load surge command and the start of the energy storage current rise to determine the command response delay, and calculate the adjustment time when the voltage recovers to the steady-state value to determine consistency. During this process, the command tracking error can also be determined based on the dynamic time warping distance between the command power curve and the actual output power curve. When determining consistency, the adjustment time within ±5% of the steady-state value can also be calculated. In this embodiment, the command response delay of the microgrid controller is set to 15ms under islanded sudden load surge conditions, which is less than the threshold of 20ms. However, the voltage drop depth exceeds the preset protection boundary, indicating a high risk of transient characteristic consistency issues for the microgrid controller.

[0149] like Figure 2 As shown, a second aspect of this invention provides a multi-functional integrated testing system for a microgrid controller, comprising: a unified scheduling and control module for scheduling and configuring various execution units in a microgrid system to construct a microgrid controller test environment; a power grid operating condition simulation module for adjusting power grid operating parameters to simulate various operating conditions of the microgrid to verify the response accuracy of the microgrid controller; a multi-energy simulation module, which, in conjunction with the microgrid controller's closed-loop control, configures the operating parameters of the energy storage system in the microgrid to simulate the working state of the energy storage system under different scenarios, and evaluates the timing coordination control capability through the response results of the microgrid controller; and a load simulation control module for controlling the microgrid... The system includes multiple load operation scenarios such as constant load, sudden load, and impact load to evaluate the microgrid controller's response and anti-interference capabilities; a communication anomaly injection module to simulate communication operating environments including communication link jitter and packet attacks to evaluate the microgrid controller's communication protection capabilities; a mode policy induction module to simulate the grid-connected / off-grid state switching process of the energy storage system in the microgrid to induce the microgrid controller to switch operating modes and evaluate the control stability of the microgrid controller based on the switching results; and a data acquisition and analysis module to collect command messages during the operation of the microgrid controller to evaluate the control consistency of the microgrid controller based on command response delay data.

[0150] This invention enables multi-faceted functional testing of microgrid control in the laboratory stage through testing processes such as power grid operating condition simulation, multi-energy simulation, load switching simulation, communication anomaly simulation, and mode strategy induction. This allows for the verification of the overall stability of the microgrid controller under multiple superimposed conditions, thereby identifying control logic defects of the microgrid controller under complex operating conditions in advance and providing a reliable test basis for the engineering application of the microgrid controller.

[0151] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A multi-functional integrated testing method for microgrid controllers, characterized in that, include: Scheduling and configuring each execution unit in the microgrid to build a microgrid controller test environment; Adjust the power grid operating parameters to simulate various operating conditions of the microgrid in order to verify the response accuracy of the microgrid controller; Configure the operating parameters of the energy storage system in the microgrid to simulate the working state of the energy storage system under different scenarios, and evaluate the timing coordination control capability through the response results of the microgrid controller; The microgrid was configured with multiple load operating scenarios, including constant load, sudden load, and impact load, to evaluate the response and anti-interference capability of the microgrid controller. Simulate communication operating environments including communication link jitter and packet attacks to evaluate the communication protection capabilities of the microgrid controller; The process of switching between grid-connected and off-grid states of energy storage systems in microgrids is simulated to induce the microgrid controller to switch operating modes, and the control stability of the microgrid controller is evaluated based on the switching results. The system collects command messages during the operation of the microgrid controller to evaluate the control consistency of the microgrid controller based on command response delay data.

2. The multi-functional integrated test method for microgrid controllers according to claim 1, characterized in that, When scheduling and configuring the execution units in the microgrid, the coordination and control capabilities of the microgrid controller are tested, including: Initial operating data is configured for each execution unit in the microgrid to form a test operation strategy, and a linkage control strategy is generated. The linkage control strategy is: when the grid voltage drops to a predetermined low voltage threshold, the energy storage system operation mode is forcibly switched. The aforementioned operating strategy and linkage control strategy are converted into test script files for loading and execution. Load the test script file and control the microgrid operation according to the linkage control strategy; Obtain the command transmission time and mode switching timing difference of the microgrid controller to evaluate the linkage accuracy.

3. The multi-functional integrated testing method for microgrid controllers according to claim 1, characterized in that, The adjustment of power grid operating parameters to simulate various operating conditions of the microgrid and to verify the response accuracy of the microgrid controller specifically includes: Configure voltage / frequency variation parameters for the microgrid, and determine the amplitude accuracy and ramp rate control capability of the output analog quantity based on the output voltage / output frequency data; Overvoltage fault command, voltage flashover command and undervoltage protection cascade command are sequentially issued to the microgrid, and the accuracy of the response is evaluated based on the response results of the output voltage. To simulate islanding, the microgrid is sequentially issued generation grid disconnection and grid restoration commands. The islanding response function is evaluated based on the voltage status of the microgrid's voltage output port.

4. The multi-functional integrated testing method for microgrid controllers according to claim 1, characterized in that, The configuration of operating parameters for the energy storage system in the microgrid to simulate the operating state of the energy storage system under different scenarios, and the evaluation of timing coordination control capabilities through the response results of the microgrid controller, specifically includes: The initial operating parameters of the energy storage system in the microgrid are configured and a steady-state operating condition is formed. The energy storage system includes a photovoltaic simulation unit, an energy storage simulation unit, and an adjustable power generation unit. At the first test moment, the operating parameters of the photovoltaic simulation unit are adjusted to change abruptly, the decreasing trend of the bus voltage / frequency is detected, and the discharge power of the energy storage simulation unit is adjusted with a delay and the virtual three-phase current value is fed back to the microgrid controller to detect the energy storage output current establishment status. At the second test moment, the power generation state of the adjustable power generation unit is adjusted, and after the adjustable power generation unit is connected to the grid, the SOC value of the energy storage simulation unit is adjusted to simulate the power alarm state, and the control command issuance status of the microgrid controller is detected. At the third test moment, the energy storage system is adjusted to restore its initial steady-state operation, and a timing comparison diagram of the microgrid controller's command sequence and the energy storage system's response sequence is output.

5. The multi-functional integrated testing method for microgrid controllers according to claim 1, characterized in that, The microgrid configuration includes multiple load operation scenarios such as constant load, sudden load, and impact load to evaluate the microgrid controller's response and anti-interference capability. Specifically, this includes: Configure a constant load for the microgrid and ensure its stable operation; The nonlinear load simulation unit is activated to inject harmonic current into the microgrid's point of common coupling to simulate grid noise; The nonlinear load simulation unit reverses the phase of the harmonic current to cause a jump in the total harmonic distortion rate of the voltage, in order to simulate the change in line impedance caused by a fault at the far end of the power grid. The output voltage waveform of the microgrid controller is detected and the response time of the waveform distortion suppression algorithm is recorded to evaluate the anti-interference capability of the response.

6. The multi-functional integrated testing method for microgrid controllers according to claim 5, characterized in that, The method for evaluating the microgrid controller's response and anti-interference capabilities by configuring microgrids with multiple load operating scenarios, including constant load, sudden load, and impact load, also includes: Configure a constant load for the microgrid and ensure its stable operation, and control the energy storage system to operate in accordance with the initial preset parameters; When a constant load is switched to a sudden load, the microgrid controller issues a photovoltaic power reduction command or a trip command to limit reverse power and records the time difference between the command issuance. The load is switched back to a constant load, and the nonlinear load simulation unit is started to inject harmonic current into the microgrid's point of common coupling to calculate the total harmonic distortion rate. The host computer sends a photovoltaic output limiting command to the microgrid controller and obtains the active power decline curve of the energy storage system to determine the success rate of the microgrid controller's response. Switch from a constant load to an impact load and check if the microgrid controller is misjudging.

7. The multi-functional integrated test method for microgrid controllers according to claim 1, characterized in that, The simulation includes communication link jitter and communication operating environments subjected to packet attacks to evaluate the communication protection capabilities of the microgrid controller. Specifically, it includes: The microgrid is configured to operate at steady-state parameters, and the microgrid controller obtains sampled measurement values ​​to determine whether there are any communication anomalies. When the system reaches the first test moment, a communication degradation instruction is triggered to improve communication latency and packet loss rate. Each sampled measurement value is timestamped and sent out with a delay. The microgrid controller receives the reported data to determine the communication status. During the second test moment after communication deterioration, the GOOSE output message of the microgrid controller is detected, and the tripping intention is captured through the GOOSE output message to force the microgrid controller into a fault handling logic dead loop, thereby determining the control logic defect. Normal communication is restored at the third test point after communication degradation to detect whether false tripping occurs during the communication degradation period in order to assess communication robustness.

8. The multi-functional integrated testing method for microgrid controllers according to claim 1, characterized in that, The simulated grid-connected / off-grid switching process of the energy storage system in the microgrid to induce the microgrid controller to switch operating modes, and the evaluation of the control stability of the microgrid controller based on the switching results, specifically includes: Initialize the microgrid operating environment and simulate the steady-state operation of the large power grid in terms of voltage and frequency. Simulate issuing power dispatch commands to control the energy storage system to adjust the power setpoint; The control grid simulator disconnects the internal output relay to simulate a sudden power outage due to a large power grid failure. Record the time difference between the grid voltage drop and the microgrid controller sending an islanding alarm signal; Trigger the off-grid disconnection of the energy storage system and force a switch in the operating mode of the energy storage system. Evaluate the control stability based on the switching control status of the microgrid controller.

9. The multi-functional integrated testing method for microgrid controllers according to claim 1, characterized in that, The process of collecting command messages during the operation of the microgrid controller to evaluate the control consistency of the microgrid controller based on command response delay data specifically includes: Configure the microgrid with initial photovoltaic power output and initial load for steady-state operation; The load mutation command is triggered at a predetermined mutation time to control the increase of load mutation. The energy storage system responds to load change commands by controlling the actual output power to increase, and records the instantaneous values ​​of the three-phase voltage and current of the energy storage system; The command delay is calculated based on the moment the load change command is issued and the moment the energy storage current begins to rise in order to determine the command response delay. The adjustment time when the voltage recovers to the steady state value is calculated to determine the consistency.

10. A multi-functional integrated testing system for microgrid controllers, characterized in that, include: The unified scheduling and control module is used to schedule and configure the various execution units in the microgrid system to build a microgrid controller test environment; The power grid operating condition simulation module is used to adjust the power grid operating parameters to simulate various operating conditions of the microgrid in order to verify the response accuracy of the microgrid controller. The multi-energy simulation module, along with the microgrid controller's closed-loop control, is used to configure the operating parameters of the energy storage system in the microgrid to simulate the working state of the energy storage system under different scenarios, and to evaluate the timing coordination control capability through the response results of the microgrid controller. The load simulation control module is used to configure multiple load operation scenarios for microgrids, including constant load, sudden load and impact load, in order to evaluate the response and anti-interference capability of the microgrid controller. The communication anomaly injection module is used to simulate communication operating environments, including communication link jitter and packet attacks, to evaluate the communication protection capabilities of the microgrid controller. The mode strategy induction module is used to simulate the grid-connected / off-grid state switching process of the energy storage system in the microgrid to induce the microgrid controller to switch operating modes, and evaluate the control stability of the microgrid controller based on the switching results; The data acquisition and analysis module is used to collect command messages during the operation of the microgrid controller in order to evaluate the control consistency of the microgrid controller based on command response delay data.

Images