A power grid backup automatic switching coordination control method fusing distributed power supply

Abstract

This application relates to a grid backup automatic transfer coordination control method integrating distributed power sources, comprising a housing, a control module fixedly mounted at one end of the housing, a communication module fixedly mounted inside the housing, a communication interface fixedly mounted at one end of the communication module, a data acquisition module fixedly mounted inside the housing near the communication module, an input terminal fixedly mounted at one end of the data acquisition module, and a relay output module fixedly mounted inside the housing near the data acquisition module, an output module interface fixedly mounted at one end of the relay output module. This application, by setting an input terminal, solves the problem of requiring power outages for maintenance operations and the risk of open circuits in the current transformer (CT) due to manual plugging and unplugging, thereby achieving online uninterrupted maintenance, ensuring the safety of maintenance personnel and equipment, and improving power supply continuity.

Description

Technical Field

[0001] This invention relates to the field of automatic power grid switching, and in particular to a coordinated control method for automatic power grid switching that integrates distributed generation. Background Technology

[0002] Traditional automatic transfer switches (ATS) are mainly used in conventional dual-power or bus tie systems. After detecting a loss of power to the main power supply, they automatically switch on the backup power supply according to preset logic. Their core functions include bus tie backup switching, incoming line backup switching, and self-recovery modes, and they also have control components such as charging condition judgment, interlocking logic, and delayed tripping and closing.

[0003] However, with the large-scale integration of distributed power sources (such as photovoltaic, wind power, and energy storage) into microgrids, the system power structure has changed from a simple dual-power source to a multi-power source operating in parallel, and the power flow direction may be bidirectional. Traditional automatic transfer switch (ATS) devices rely solely on bus voltage and incoming line voltage as criteria, facing the following challenges when distributed power sources are connected: When the main power source fails, if a distributed power source connected to the bus is still generating electricity, the bus voltage may remain in a "voltaged" state, causing the ATS charging conditions to be unmet or the operation logic to be blocked, preventing the timely activation of the backup power source and affecting power supply reliability. Furthermore, maintenance or replacement of the device itself usually requires a power outage. Although the device backplane provides terminal connections, manual plugging and unplugging may open the CT secondary circuit, generating dangerous high voltages, and the process is cumbersome, affecting power supply continuity. Summary of the Invention

[0004] The purpose of this application is to provide a grid backup automatic transfer coordination control method that integrates distributed power sources to solve the problems mentioned in the background art.

[0005] This application provides a grid backup automatic transfer coordination control method integrating distributed generation, including the following stages: Distributed power source status perception and pre-judgment stage; The distributed power source status perception and pre-judgment stage involves the control module monitoring the output of the distributed power source and the grid connection switch status in real time. The stage of comprehensive assessment of investment conditions and selection of investment model; The comprehensive judgment and mode selection stage of the backup power supply conditions is to add the distributed power supply coordination status ready condition, that is, the communication module needs to receive the control module's allow switching or shutdown signal, and the acquisition module needs to detect that the output of the distributed power supply is lower than the set threshold. After all conditions are met, the backup automatic charging is completed. Maintenance mode safety coordination and control phase; The maintenance mode safety coordination control phase is when the fault detection chip of the control module detects that the panel maintenance plug-in button is triggered, or when a remote maintenance command is received through the communication module, the control module sends a device maintenance request to the microgrid central controller or dispatch system through the communication module.

[0006] Preferably, in the distributed power supply status perception and pre-judgment stage, when the acquisition module detects a loss of working power supply voltage, the control module does not immediately trigger the traditional backup power supply logic. Instead, it first uses the bus voltage sampling data to determine whether the bus is truly without voltage. If the bus has voltage, the controller calls the islanding detection algorithm in the storage chip and combines it with the distributed power supply output data to confirm whether it is islanding operation supported by the distributed power supply. If it is determined to be islanding operation, the control module decides to maintain the islanding, cut off part of the load, or initiate backup power supply switching based on the acquired islanding system frequency and voltage stability data, combined with the load and output balance and the islanding operation allowable time setting.

[0007] Preferably, during the comprehensive judgment and mode selection stage of backup power conditions, when the acquisition module detects residual voltage generated by distributed power sources on the bus side, it starts high-precision crystal oscillator, sample-and-hold circuit and phasor measurement dedicated chip to perform high-precision phase angle difference measurement on the bus. Only after confirming that the amplitude, frequency and phase angle difference of the backup power source and the residual voltage of the bus meet the synchronous closing set value is closing allowed. Based on the operating mode before the fault, the location of the power source that lost power, and the distribution data of the distributed power sources, the control module dynamically selects the optimal backup mode. For example, when a section of the bus loses power and the distributed power source connected to that bus can maintain islanding, the bus tie backup mode is selected first, and the power source of another section of the bus is supported. If the support capacity is insufficient, non-critical loads are cut off or the incoming line backup mode is switched. The control module outputs trip and close commands through the driver chip of the relay output module and executes the operation in the sequence of trip delay, synchronization check, and close delay.

[0008] Preferably, during the maintenance mode safety coordination control phase, after the control module receives and confirms the coordination command from the dispatch system, it drives the miniature electric push rod installed on the input terminal to extend and retract, thereby causing the connecting frame to slide along the guide groove, which in turn moves the insulating plate, preventing the insulating plate from contacting the shorting spring, and allowing the shorting spring to contact the conductive contact, thus achieving a reliable short circuit of the CT secondary circuit. Afterwards, the miniature electric push rod sends a feedback signal to the control module. Upon receiving the feedback signal indicating that the short circuit is complete, the control module issues a physical disconnection permission indication, then removes the end cover. After the device maintenance is completed, the end cover is inserted back into the base of the input terminal, allowing the plug to be inserted into the socket. Then, the control module controls the miniature electric push rod to reset, thereby moving the insulating plate and causing the shorting spring to deform, thus preventing it from contacting the conductive contact, releasing the short circuit of the CT secondary circuit, and restoring the current sampling function of the acquisition module. Afterwards, the communication module reports the device's ready status to the dispatch system, and then the relay output module resumes normal control signal output. Throughout the entire process, the CT circuit remains in a safe state and does not affect the operation of the microgrid.

[0009] In summary, this application includes at least one of the following beneficial technical effects: This invention provides a grid backup automatic transfer coordination control method integrating distributed power sources. The control module monitors the output of the distributed power sources and the status of the grid-connected switches in real time. When the acquisition module detects a loss of voltage in the working power supply (UL1 without voltage), if the bus is still under voltage, the control module activates an islanding detection algorithm to determine whether the voltage is a false signal supported by the distributed power source. If islanding is confirmed, the control module decides whether to maintain islanding, cut off non-critical loads, or initiate backup transfer switching based on islanding stability and load balance. This solves the problem of backup automatic transfer blocking caused by false voltage on the bus, improves the accuracy of backup automatic transfer in microgrids containing distributed power sources, avoids false trips and failures, and enhances power supply reliability.

[0010] This invention provides a coordinated control method for grid backup automatic transfer (RTG) integrating distributed power sources. By using shorting springs and miniature electric actuators, when a maintenance command is received, the control module first sends a maintenance request to the dispatch system via the communication module. After confirmation by the dispatch system, the controller's miniature electric actuator extends or retracts, thereby moving the insulating plate via the connecting frame. This prevents the insulating plate from contacting the shorting spring, allowing the shorting spring to contact the conductive contact, thus completing a reliable short circuit in the CT secondary circuit. Afterward, the miniature electric actuator sends a feedback signal to the control module, which receives the short circuit completion feedback signal. Afterwards, a physical disconnection instruction is issued, and then the end cover is removed. After the device maintenance is completed, the end cover is inserted back into the base of the input terminal, so that the plug is inserted into the socket. Then, the control module controls the micro electric push rod to reset, which in turn moves the insulating plate and causes the shorting spring to deform, so that it is no longer in contact with the conductive parts, thus releasing the short circuit of the CT secondary circuit and restoring the current sampling function of the acquisition module. This solves the problem that maintenance requires power outage operation and that manual plugging and unplugging can easily cause the CT to open circuit, thereby realizing online maintenance without power interruption, ensuring the safety of maintenance personnel and equipment, and improving the continuity of power supply. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the overall structure of the automatic switching device of the present invention; Figure 2 This is a schematic diagram of the internal structure of the outer shell of the present invention; Figure 3 This is a schematic diagram showing the position and structure of the end cap and base of the present invention; Figure 4 This is a schematic diagram of the plug mounting structure of the present invention; Figure 5 for Figure 4 Enlarged view of the structure at point A in the middle; Figure 6 for Figure 3 Enlarged view of the structure at point B in the middle.

[0012] The components are as follows: 1. Outer shell; 2. Control module; 3. Communication module; 4. Communication interface; 5. Data acquisition module; 6. Input terminal; 7. Relay output module; 8. Output module interface; 9. Plug; 10. End cap; 11. Mounting base; 12. Conductive contact; 13. Conductive tube; 14. Socket; 15. Bolt; 16. Wire clamp; 17. Shorting spring; 18. Insulating plate; 19. Connecting frame; 20. Guide groove; 21. Fixing base; 22. Miniature electric actuator; 23. Base. Detailed Implementation

[0013] The following is in conjunction with the appendix Figure 1 - Appendix Figure 6 This application will be described in further detail below.

[0014] Example 1: A grid backup automatic transfer coordination control method integrating distributed power sources. This control method is implemented through a grid backup automatic transfer coordination control device integrating distributed power sources. The device includes a housing 1, a control module 2 fixedly installed at one end of the housing 1, a communication module 3 fixedly installed inside the housing 1, a communication interface 4 fixedly installed at one end of the communication module 3, a data acquisition module 5 fixedly installed inside the housing 1 near the communication module 3, an input terminal 6 fixedly installed at one end of the data acquisition module 5, and a relay output module 7 fixedly installed inside the housing 1 near the data acquisition module 5, an output module interface 8 fixedly installed at one end of the relay output module 7. The communication module 3, the data acquisition module 5, and the relay output module 7 are all electrically connected to the control module 2. The input terminal 6 includes a base 23 and an end cover 10. Two sets of plugs 9 are fixed inside the base 23 by screws. The end cover 10 is inserted into the outside of the base 23. Two sets of mounting seats 11 are fixedly mounted on the upper end of the end cover 10. Bolts 15 are threaded inside each mounting seat 11, and wire clamps 16 are slidably mounted outside the bolts 15. Conductive contacts 12 are fixedly mounted on the surface of each mounting seat 11. Both ends of the conductive contacts 12 extend into the end cover 10. A conductive tube 13 is fixedly mounted on one end of the conductive contact 12, and a socket 14 corresponding to the plug 9 is fixedly mounted on the lower end of the conductive tube 13. The socket 14 contacts the plug 9. During use, the wire terminal is placed inside the wire clamp 16, and then the bolts 15 are tightened to clamp the wire terminal. Then, the end cover 10 is inserted into the base 23. During insertion, the plug 9 mounted on the base 23 will insert into the mounting seat 11 on the end cover 10 and contact the inner wall of the mounting seat 11, thereby transferring current from the end cover 10 to the end. Mounting base 11 is connected to plug 9. One end of each set of conductive contact 12 is fixedly provided with shorting spring 17. Shorting spring 17 is in contact with one end of another set of conductive contact 12. Both sides of end cover 10 are provided with guide grooves 20. Connecting frame 19 is slidably arranged inside the two guide grooves 20. Insulating plate 18 is fixedly arranged between the two connecting frames 19. Fixing base 21 is fixedly arranged on both sides of end cover 10. Mini electric push rod 22 is fixedly arranged on the surface of the two fixing bases 21. The telescopic end of mini electric push rod 22 is fixedly connected to the connecting frame 19. Mini electric push rod 22 is electrically connected to control module 2. When in use, the mini electric push rod 22 is activated to extend and retract, thereby driving the connecting frame 19 to slide along the guide groove 20, thereby driving the insulating plate 18 to move, so that the insulating plate 18 is no longer in contact with the shorting spring 17, thereby making the shorting spring 17 contact with the conductive contact 12, thereby realizing the reliable shorting of the CT secondary circuit. Control module 2 includes a motherboard, and a dual-core controller, fault detection chip, memory, filter capacitors, Zener diodes, and fuses soldered onto the motherboard. Power supply and signal interconnection are achieved through copper foil circuitry on the motherboard. The dual-core controller is used to run the backup automatic transfer core logic, distributed power supply coordination control algorithm, and maintenance control program, while ensuring control reliability. The fault detection chip is used to detect the device's operating status and maintenance trigger commands. The memory pre-stores parameters such as the islanding detection allowance time, distributed power supply output lockout threshold, and synchronous closing phase difference angle setting, and can also store operating data, supporting parameter modification to adapt to the operating requirements of different microgrids. The filter capacitor is used to filter out noise in the power supply, providing a stable power input to the dual-core controller and reducing the impact of power fluctuations on the controller. The Zener diode provides voltage regulation protection to prevent damage to the dual-core controller due to excessive power supply voltage. The fuse is an overcurrent protection component; when an overcurrent fault occurs in the circuit, the fuse will melt, cutting off the circuit and preventing damage to the core components of the device. Communication module 3 includes... The motherboard, along with the communication main control chip, dedicated protocol parsing chip, signal amplification chip, opto-isolation chip, power surge protector, and electrostatic protection diode soldered onto it, achieves power supply and signal interconnection through the motherboard's copper foil circuitry. The communication main control chip is used for overall control of data transmission and reception, and is electrically connected to the dual-core controller, receiving maintenance requests sent by the dual-core controller. The dedicated protocol parsing chip has a built-in communication protocol parsing program, used to parse instructions sent by the scheduling system and communication data transmitted by the distributed power supply. The signal amplification chip is used to amplify communication signals and solve the attenuation problem during communication signal transmission. The opto-isolation chip is used for electrical isolation of communication signals to prevent external interference or high voltage damage to the internal chips of the device. The surge protector is connected in parallel between communication interface 4 and the opto-isolation chip to prevent instantaneous high voltage damage to communication module components caused by lightning strikes. The electrostatic protection diode prevents electrostatic breakdown of the chip and ensures the long-term stable operation of the communication module. The communication module realizes the transmission of data and scheduling system instructions through the communication interface. The acquisition module 5 includes a motherboard, and on the motherboard are a high-speed ADC sampling chip, a signal amplifier, a resistor voltage transformer, a current transformer, a filter circuit, an optocoupler, pull-up resistors, a communication transceiver chip, an input expansion board, a data buffer chip, a communication interface, a surge protector, a phasor measurement chip, a high-precision crystal oscillator, and a sample-and-hold circuit. Power supply and signal interconnection are achieved through copper foil circuitry on the motherboard. The outputs of the resistor voltage transformer and the current transformer are connected to the input pins of the signal amplifier to amplify the weak voltage and current analog signals acquired. The high-speed ADC sampling chip converts the amplified analog signals into digital signals for analysis by the dual-core controller in control module 2. The filter circuit filters out high-frequency interference noise in the sampled signal, and the optocoupler is used for... Electrical isolation of the current switching signals prevents external interference from affecting the controller's operation. Pull-up resistors ensure the stability of the switching signal level and prevent signal distortion. Communication transceiver chips, input expansion boards, data buffer chips, and communication interface surge protectors can acquire the switching status, output, frequency, and voltage data of the distributed power grid connection point through expanded inputs or communication. The data buffer chip is used to temporarily store the acquired distributed power data. The communication interface surge protector protects the communication interface of the acquisition unit. The sampling input pin of the phasor measurement chip is connected to the output pin of the high-speed ADC sampling chip to acquire converted voltage and current digital sampling data. A high-precision crystal oscillator provides a stable clock signal for the phasor measurement chip, and a sample-and-hold circuit is used to maintain the stability of the sampled data. The relay output module 7 includes a main board, and on the main board are a relay driver chip, a current-limiting resistor, a freewheeling diode, an optocoupler isolation chip, a multi-channel electromagnetic relay, a photoelectric sensor, and a feedback resistor. Power supply and signal interconnection are achieved through copper foil circuitry on the main board. The optocoupler isolation chip provides electrical isolation for control signals. The relay driver chip amplifies the control signals to ensure reliable relay operation. The current-limiting resistor limits the drive current to prevent excessive current from damaging the relay driver chip and the multi-channel electromagnetic relay. The multi-channel electromagnetic relay receives the drive signal and opens / closes the contacts, then outputs control signals such as switch tripping / closing, alarms, and device status. The freewheeling diode is used for… The reverse electromotive force generated when the absorption coil is de-energized prevents the reverse electromotive force from damaging the relay driver chip. The photoelectric sensor is used to detect the contact operation status of multiple electromagnetic relays and converts the operation status into an electrical signal to feed back to the dual-core controller. The feedback resistor is used to stabilize the output level of the photoelectric sensor and prevent the feedback signal from being distorted. The dual-core controller is used to run the backup automatic transfer core logic, the distributed power supply coordination control algorithm and the maintenance control program. It supports online replacement of functional modules without affecting the operation of the core logic. The memory pre-stores parameters such as the islanding detection allowable time, the distributed power supply output lockout threshold, and the synchronous closing phase difference angle setting. The fault detection chip is used to detect the device's operating status and maintenance trigger commands. The grid backup automatic transfer coordination control method integrating distributed generation includes the following stages: Distributed power source status perception and pre-judgment: Control module 2 monitors the output of distributed power sources and the status of grid-connected switches in real time. When the acquisition module 5 detects that the working power supply UL1 is out of voltage, control module 2 does not immediately trigger the traditional backup logic. Instead, it first uses the bus voltage sampling data to determine whether the bus is truly out of voltage. If the bus is under voltage, the controller calls the islanding detection algorithm in the storage chip, which is an active frequency disturbance method / impedance measurement method. Combined with the output data of the distributed power source, it confirms whether the islanding operation is supported by the distributed power source. If it is determined to be islanding operation, control module 2 decides to maintain the islanding, cut off part of the load, or start the backup switching based on the collected islanding system frequency and voltage stability data, combined with the load and output balance and the islanding operation allowable time setting. Comprehensive judgment and mode selection of backup power supply conditions: Add a condition for the coordinated state of distributed power supply, that is, the communication module 3 needs to receive the signal of permission to switch or shutdown from the control module 2, and the acquisition module 5 needs to detect that the output of the distributed power supply is lower than the set threshold. After all conditions are met, the backup automatic transfer charging is completed. When the acquisition module 5 detects that there is residual voltage generated by the distributed power supply on the bus side, it starts the high-precision crystal oscillator, sample and hold circuit and phasor measurement dedicated chip to perform high-precision phase angle difference measurement on the bus. Only after confirming that the amplitude, frequency and phase angle difference of the backup power supply and the residual voltage of the bus meet the synchronous closing set value can closing be allowed. Based on the operating mode before the fault, the location of the power source that lost power, and the distribution data of the distributed power sources, the control module 2 dynamically selects the optimal backup mode: bus tie backup, incoming line backup, or main backup power supply backup. For example, if a section of the bus loses power and the distributed power source connected to that bus can maintain islanding, the bus tie backup is selected first, and the power source of another section of the bus is supported. If the support capacity is insufficient, non-critical loads are cut off or the incoming line backup is switched. The control module 2 outputs trip and close commands through the driver chip of the relay output module 7 and performs the operation in the sequence of trip delay, synchronization check, and close delay. Maintenance mode safety coordination control: When the fault detection chip of control module 2 detects that the panel maintenance plug-in button is triggered, or when a remote maintenance command is received through communication module 3, control module 2 sends a device maintenance request to the microgrid central controller or dispatch system through communication module 3. After control module 2 receives and confirms the coordination command from the dispatch system, it drives the miniature electric push rod 22 installed on input terminal 6 to extend and retract, thereby causing the connecting frame 19 to slide along the guide groove 20, which in turn causes the insulating plate 18 to move, so that the insulating plate 18 is no longer in contact with the shorting spring 17, and thus the shorting spring 17 contacts the conductive contact 12, thereby achieving a reliable short circuit of the CT secondary circuit. Afterwards, the miniature electric push rod 22 sends a feedback signal to the control module. After receiving the feedback signal indicating that the short circuit is complete, the control module 2 issues a physical disconnection instruction and then pulls out the end cover 10. After the device is repaired, the end cover 10 is inserted back into the base 23 of the input terminal 6, so that the plug 9 is inserted into the socket 14. Then, the control module 2 controls the micro electric push rod 22 to reset, which in turn drives the insulating plate 18 to move, thereby causing the short-circuit spring 17 to deform and no longer contact the conductive contact 12, thus releasing the short circuit of the CT secondary circuit and restoring the current sampling function of the acquisition module 5. Then, the communication module 3 reports the device ready status to the dispatch system. After that, the relay output module 7 resumes normal control signal output. Throughout the entire process, the CT circuit is always in a safe state and does not affect the operation of the microgrid.

Claims

1. A method for coordinating control of a grid backup automatic switching device with a distributed power supply, characterized in that: Includes the following stages: Distributed power source status perception and pre-judgment stage; The distributed power source status perception and pre-judgment stage is the control module (2) which monitors the output of the distributed power source and the grid connection switch status in real time. The stage of comprehensive assessment of investment conditions and selection of investment model; The standby power supply condition comprehensive judgment and mode selection stage is to add the distributed power supply coordination state ready condition, that is, it is necessary to receive the allow switching or shutdown signal from the control module (2) through the communication module (3) and the acquisition module (5) detect that the output of the distributed power supply is lower than the set threshold. After all conditions are met, the standby power supply charging is completed. Maintenance mode safety coordination and control phase; The maintenance mode safety coordination control stage is when the fault detection chip of the control module (2) detects that the panel maintenance plug-in button is triggered, or when the remote maintenance instruction is received through the communication module (3), the control module (2) sends a device maintenance request to the microgrid central controller or dispatch system through the communication module (3). 2.The grid automatic switching coordination control method of the integrated distributed power supply according to claim 1, characterized in that: In the distributed power supply status perception and pre-judgment stage, when the acquisition module (5) detects that the working power supply is out of voltage, the control module (2) does not immediately trigger the traditional backup logic. Instead, it first uses the bus voltage sampling data to determine whether the bus is truly out of voltage. If the bus is under voltage, the controller calls the island detection algorithm in the storage chip and combines the distributed power supply output data to confirm whether it is an island operation supported by the distributed power supply. If it is determined to be an island operation, the control module (2) decides to maintain the island, cut off part of the load or start the backup switching based on the collected island system frequency and voltage stability data, combined with the load and output balance and the island operation allowable time setting. 3.The grid automatic switching coordination control method of the integrated distributed power supply according to claim 1, characterized in that: In the stage of comprehensive judgment of standby conditions and mode selection, when the acquisition module (5) detects the residual voltage generated by the distributed power supply on the bus side, it starts the high-precision crystal oscillator, sample and hold circuit and phasor measurement dedicated chip to perform high-precision phase angle difference measurement on the bus. Only after confirming that the amplitude, frequency and phase angle difference of the standby power supply and the residual voltage of the bus meet the synchronous closing setting value can the closing be allowed. The control module (2) dynamically selects the optimal backup mode based on the operating mode before the fault, the location of the power supply that lost power, and the distribution data of the distributed power supply. For example, when a section of the bus loses power and the distributed power supply connected to the bus can maintain the island, the bus tie backup mode is selected first, and the power supply of another section of the bus is supported. If the support capacity is insufficient, non-critical loads are cut off or the incoming line backup mode is switched. The control module (2) outputs trip and close commands through the drive chip of the relay output module (7) and performs the operation in the order of trip delay, synchronization check, and close delay.

4. The method of claim 1, wherein the method further comprises: During the maintenance mode safety coordination control phase, after the control module (2) receives and confirms the coordination command from the scheduling system, it drives the miniature electric push rod (22) installed on the input terminal (6) to extend and retract, thereby causing the connecting frame (19) to slide along the guide groove (20), which in turn causes the insulating plate (18) to move, so that the insulating plate (18) no longer contacts the shorting spring (17), and then the shorting spring (17) contacts the conductive contact (12), thereby achieving a reliable short circuit of the CT secondary circuit. After that, the miniature electric push rod (22) sends a feedback signal to the control module. After receiving the feedback signal that the short circuit is completed, the control module (2) issues an indication that physical disconnection is allowed, and then pulls out the end. After the device is repaired, the end cover (10) is inserted back into the base (23) of the input terminal (6), so that the plug (9) is inserted into the socket (14). Then the control module (2) controls the micro electric push rod (22) to reset, thereby driving the insulating plate (18) to move, thereby causing the shorting spring (17) to deform and no longer contact the conductive contact (12), thus releasing the short circuit of the CT secondary circuit, thereby restoring the current sampling function of the acquisition module (5). Then the communication module (3) reports the device ready status to the dispatching system. Then the relay output module (7) resumes normal control signal output. Throughout the process, the CT circuit is always in a safe state and does not affect the operation of the microgrid.

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