Multi-source Adaptive Reactive Power Distribution Method and Device for Independent Microgrid without Interconnection Lines

Abstract

The present invention relates to a method and device for multi-source adaptive reactive power distribution of an independent microgrid without interconnection lines. The method includes: a reactive power distribution stage: calculating respective reactive power distribution coefficients according to the remaining reactive power capacity of each micro-source in the independent microgrid, obtaining a reactive power command value through the voltage at the connection point of the distributed power source, and calculating the voltage compensation amount of droop control based on the reactive power command value; a reactive power control stage: adaptively adjusting the reactive power distribution coefficients and giving the voltage reference value of the droop control strategy. When adjusting the reactive power distribution coefficients, the influence of the equivalent output reactance on the reactive power output is eliminated by adding the active power output, and the reactive power distribution accuracy among multiple sources in the microgrid is improved by adding the reactive power output. The present invention can improve the reactive power utilization rate and solve the problem of improving the reactive power distribution rate.

Description

Technical Field

[0001] The present invention relates to the technical field of reactive power distribution of independent microgrids, and particularly to a multi-source adaptive reactive power distribution method and device for an independent microgrid without interconnection lines. Background Art

[0002] The control of a microgrid mainly includes the control of the grid-connected controller at the bottom layer and the overall coordinated control at the upper layer. Regardless of the coordinated control method adopted by the microgrid, voltage control and reactive power distribution are both difficult points and key points. The overall coordinated control strategy of the microgrid can be divided into two categories: centralized control and decentralized control. Centralized control means that the microgrid is equipped with a Microgrid Central Controler (MGCC). The MGCC collects the information of all micro-source controllers and load controllers, processes it in real time and issues control instructions. The control signals are transmitted to each unit of the microgrid through a fast and reliable communication network. For the reactive power control strategy of a microgrid adopting secondary control, the MGCC centrally adjusts the no-load output voltage of each distributed power source according to the control strategy, and the purpose of improving the distribution of reactive power output can be achieved. However, for the global reactive power optimal dispatch of the distribution network, the equipment to be coordinated is widely distributed, with a large number, and has problems such as wide-area communication delay and differences in equipment regulation characteristics. It has a strong dependence on system communication, a complex optimization solution process, and a slow response speed.

[0003] Decentralized control means that the microgrid calculates instructions to control local micro-sources only based on local information or the information of other micro-source controllers. All control functions are set in each sub-module. Although the sub-modules are interconnected, they have a weak dependence on communication, so the reliability is very high. However, the control accuracy is easily affected by physical parameters. Therefore, the multi-micro-source coordinated control based on improved droop control has received extensive attention. The decentralized control method is mainly used in the peer-to-peer control mode to improve the problem of mismatch between the traditional droop control and the line impedance in a low-voltage microgrid. By adopting a virtual power control strategy of coordinate rotation, decoupled control of the micro-source output power can be realized. Through the improved droop control strategy of reactive power equalization in the microgrid based on the synchronization idea, a reactive power compensation and voltage restoration strategy is introduced on the basis of the traditional droop control. The droop characteristic curve is modified by using the low-bandwidth signal sent by the MGCC, thereby improving the distribution accuracy of reactive power output. According to the droop control strategy of weak communication and virtual impedance, good reactive power distribution can be achieved among micro-sources under normal working conditions and communication failures. However, affected by physical parameters, the current sharing effect is not good, and the reactive power output of each micro-power supply is not distributed in proportion to its own reactive power capacity, resulting in a low global reactive power utilization rate. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a multi-source adaptive reactive power distribution method and device for an independent microgrid without interconnection lines, which can improve the reactive power utilization rate and the reactive power distribution rate.

[0005] The technical solution adopted by the present invention to solve its technical problems is to provide a multi-source adaptive reactive power distribution method for an independent microgrid without interconnection lines, including the following steps:

[0006] Reactive power distribution stage: According to the remaining reactive power capacity of each micro-source in the independent microgrid, calculate their respective reactive power distribution coefficients, and obtain the reactive power command value through the voltage at the connection point of the distributed power source, and calculate the voltage compensation amount of droop control based on the reactive power command value;

[0007] Reactive power control stage: Adjust the reactive power droop coefficient in an adaptive manner and give the voltage reference value of the droop control strategy. When adjusting the reactive power droop coefficient, eliminate the influence of the equivalent output reactance on the reactive power output by adding the active power output, and improve the reactive power distribution accuracy among multiple sources in the microgrid by adding the reactive power output.

[0008] The reactive power distribution stage includes:

[0009] Calculate the remaining reactive power capacity of micro-sources at different positions and capacities according to the real-time operation data of each micro-source in the microgrid;

[0010] Calculate the reactive power distribution coefficient of the micro-source according to the initial reactive power scheduling instruction;

[0011] Adopt the reactive power-voltage droop control method and calculate the reactive power command value of the micro-source based on the voltage value at the connection point of the micro-source;

[0012] Calculate the voltage compensation amount of droop control based on the reactive power command value.

[0013] The remaining reactive power capacity is obtained through calculation, where S i represents the converter capacity of the i-th micro-source, P i,t represents the active power output by the converter of the i-th micro-source, n is the number of micro-sources, and Q si,t is the remaining reactive power capacity of the i-th micro-source at time t.

[0014] The reactive power distribution coefficient of the micro-source is obtained through calculation, where R t is the global distribution coefficient of the microgrid, R i,t is the reactive power distribution coefficient of the i-th micro-source at time t, is the per-unit value of the reactive power scheduling instruction based on the remaining capacity, is the reactive power scheduling instruction value of the i-th micro-source at time t, V i is the lower limit of the normal voltage range, and V low_TW is the minimum voltage value for the microgrid to go off-grid.

[0015] The reactive power command value of the micro-power supply is obtained through calculation, where Q ref,i is the reactive power output command of the i-th micro-power supply at time t, is the reactive power scheduling command value of the i-th micro-power supply at time t, R t is the global distribution coefficient of the microgrid, Q si,t is the remaining reactive power capacity of the i-th micro-power supply at time t, V i is the lower limit of the normal voltage range, is the upper limit of the normal voltage range, V i,t is the real-time voltage at the connection point of the micro-power supply.

[0016] The voltage compensation amount is calculated by ΔE=(Q ref,i -Q i )(k vp +k vi / s), where ΔE is the voltage compensation amount, Q ref,i is the reactive power output command of the i-th micro-power supply at time t, Q i is the real-time value of the reactive power output of the distributed power supply, k vp and k vi are the PI parameters of the voltage compensation loop, and s represents the Laplace operator.

[0017] The reactive power droop coefficient is adjusted by f(P i ,Q i )=K Q +k pi P i +k qi Q i and it satisfies constraints, where f(P i ,Q i ) is the adjusted reactive power droop coefficient, P i and Q i are respectively the real-time active power output value and the real-time reactive power output value of the i-th micro-power supply, K Q is the reactive power droop reference coefficient, k pi and k qi are respectively the active power proportion coefficient and the reactive power proportion coefficient of the i-th micro-power supply, ΔU is the voltage drop, Q max is the maximum reactive power output value, ΔU max is the maximum voltage drop of the independent microgrid, X i is the reactance value of the connection line of the i-th micro-power supply, P i_max is the maximum value of the active power output of the i-th micro-power supply, C pi represents the active power distribution coefficient.

[0018] The voltage reference value of the droop control strategy is through Urefi = E 0i + ΔE + f(P i , Q i )(Q0 - Q i ) is calculated, where U refi is the voltage reference value of the i-th micro-source obtained by the droop strategy, ΔE is the voltage compensation amount, Q o is the reactive power reference value, and E 0i represents the no-load electromotive force.

[0019] The technical solution adopted by the present invention to solve its technical problems is: to provide a multi-source adaptive reactive power distribution device for an islanded microgrid without interconnection lines, including:

[0020] A reactive power distribution module, which is used to calculate the respective reactive power distribution coefficients according to the remaining reactive power capacities of the micro-sources in the islanded microgrid, obtain the reactive power command value through the voltage at the distributed power grid connection point, and calculate the voltage compensation amount for droop control based on the reactive power command value;

[0021] A reactive power control module, which is used to adjust the reactive power droop coefficient in an adaptive manner and give the voltage reference value of the droop control strategy. When adjusting the reactive power droop coefficient, the influence of the equivalent output reactance on the reactive power output is eliminated by adding the active power output, and the reactive power distribution accuracy among multiple sources in the microgrid is improved by adding the reactive power output.

[0022] The technical solution adopted by the present invention to solve its technical problems is: to provide an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the steps of the above-mentioned multi-source adaptive reactive power distribution method for an islanded microgrid without interconnection lines are implemented.

[0023] The technical solution adopted by the present invention to solve its technical problems is: to provide a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the above-mentioned multi-source adaptive reactive power distribution method for an islanded microgrid without interconnection lines are implemented.

[0024] Beneficial effects

[0025] Due to the adoption of the above technical solution, compared with the prior art, the present invention has the following advantages and positive effects: According to the remaining reactive power capacity of each power source in the independent microgrid, the present invention calculates the respective reactive power distribution coefficients, obtains the reactive power output command through the voltage at the connection point of the distributed power source, and then calculates the voltage compensation amount of the droop control, so as to achieve the effect that the reactive power output is proportional to the respective remaining reactive power capacity. By adaptively distributing the droop coefficient, the influence of the change in output power on reactive power distribution is eliminated, the influence of the equivalent output reactance on reactive power output is eliminated, the reactive power distribution accuracy among multiple micro-sources is improved, and the redundancy and plug-and-play characteristics of the system are realized. The present invention can achieve high-precision reactive power distribution of multiple power sources in an independent microgrid without interconnection lines, thereby improving the reactive power utilization rate of the system and stabilizing the operating voltage of the independent microgrid. This method ensures that each micro-power source outputs reactive power according to the proportion of its own remaining reactive power capacity, and the reactive power distribution accuracy is high. Since it does not rely on communication, the reliability of the system is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a flowchart of the multi-source adaptive reactive power distribution method for an independent microgrid without interconnection lines according to the first embodiment of the present invention;

[0027] Figure 2 is a block diagram of the multi-source adaptive reactive power distribution strategy in the independent microgrid according to the first embodiment of the present invention;

[0028] Figure 3 is a block diagram of the multi-source adaptive reactive power distribution device for an independent microgrid without interconnection lines according to the second embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The following will further elaborate on the present invention in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0030] The first embodiment of the present invention relates to a multi-source adaptive reactive power distribution method for an independent microgrid without interconnection lines, which is applicable to the safe and stable operation of a new energy microgrid. As Figure 1 shown, this method mainly consists of two parts: the micro-source reactive power distribution stage based on the remaining reactive power capacity and the high-precision reactive power control stage based on the adaptive droop coefficient.

[0031] The reactive power distribution stage based on the remaining reactive power capacity means that, according to the remaining reactive power capacity of each power source in the independent microgrid, the respective reactive power distribution coefficients are calculated, and the reactive power output instructions are obtained through the voltage at the connection point of the distributed power source, and then the voltage compensation amount of the droop control is calculated, so as to achieve the effect that the reactive power output is proportional to the respective remaining reactive power capacity. The high-precision reactive power control stage based on the adaptive droop coefficient means that by adaptively distributing the droop coefficient, the influence of the change in output power on reactive power distribution is eliminated, the influence of the equivalent output reactance on reactive power output is eliminated, the reactive power distribution accuracy between multiple micro-sources is improved, and the redundancy and plug-and-play characteristics of the system are realized.

[0032] This embodiment adds two links of reactive power distribution and high-precision reactive power control to the traditional droop control, and designs the following improved adaptive droop control strategy:

[0033]

[0034] In the formula, U refi is the voltage reference value of the i-th micro-source obtained by the droop strategy, ΔE is the closed-loop voltage compensation amount, f(P i , Q i ) is the adaptively adjusted reactive power droop coefficient; P i , Q i are the real-time values of the active and reactive power output of the i-th micro-source, Q o is the reactive power reference value, Q ref is the reactive power instruction value calculated by the reactive power distribution link; K Q is the reactive power droop reference coefficient, k pi , k qi are the active and reactive power ratio coefficients, k vp , k vi are the PI parameters of the voltage compensation loop, and s represents the Laplace operator.

[0035] In the reactive power distribution link, the reactive power output instruction Q ref is obtained through the voltage at the connection point. This instruction is compared with the actual reactive power output. The reactive power deviation passes through the PI controller to obtain the closed-loop voltage compensation amount, thereby changing the stable operating point of the distributed power source droop controller and achieving the effect of quickly tracking the reactive power instruction for the output reactive power. The high-precision reactive power control link uses the adaptive distribution coefficient f(P i , Q i ) to eliminate the influence of the change in output power on reactive power distribution and can well improve the reactive power distribution accuracy between multiple micro-sources.

[0036] The reactive power distribution link provides a compensation voltage for the above improved droop control. Each inverter calculates the reactive power instruction only according to the local voltage situation and its own remaining reactive power capacity, including the following steps:

[0037] Step 1: Calculate the remaining reactive power capacity of micro - sources with different positions and capacities according to the real - time operation data of each power source in the micro - grid:

[0038]

[0039] In the formula, S i represents the converter capacity of the i - th micro - source, P i,t represents the active power output by the converter of the i - th micro - source, n is the total number of micro - sources in the micro - grid, Q si,t is the remaining reactive power capacity of the i - th micro - source at time t.

[0040] Step 2: Each micro - source calculates the reactive power distribution coefficient according to the initial reactive power dispatch instruction:

[0041]

[0042]

[0043] In the formula, is the reactive power dispatch instruction value of the i - th micro - source at time t, is the per - unit value of the reactive power dispatch instruction based on the remaining capacity. R i,t is the reactive power distribution coefficient of the i - th micro - source at time t, R t is the global distribution coefficient of the micro - grid, which is the same for each micro - source. V i is the lower limit of the normal voltage range, V low_TW is the minimum voltage value for the micro - grid to operate in islanding mode.

[0044] Step 3: Adopt the reactive - voltage droop control method. Based on the voltage values at the connection points of each micro - source, calculate the reactive power instruction value of each micro - source according to the following formula:

[0045]

[0046] In the formula, V i,t is the real - time voltage at the connection point of the micro - source, is the upper limit of the normal voltage range, Q ref,i is the reactive power output instruction of the i - th micro - source at time t. Since the global reactive power distribution coefficients of each distributed power source in the micro - grid are the same, the reactive power instructions output by each converter are proportional to their respective remaining reactive power capacities.

[0047] In the high - precision reactive power control link, an adaptive distribution coefficient is provided for the above - mentioned improved droop control. The adaptive droop coefficient f(P i ,Q i ) is used to eliminate the influence of the change in output power on reactive power distribution. The adaptive droop coefficient is calculated by the following formula:

[0048] f(P i ,Q i ) = K Q + k pi P i + k qi Q i (6)

[0049]

[0050] where P i_max is the maximum value of the active power output, Q max is the maximum reactive power output value, and Q i is the reactive power output; ΔU is the voltage drop, and ΔU max is the maximum voltage drop of the independent microgrid. X i is the reactance value of the micro-source connection line, C q represents a constant, and C pi represents the active power distribution coefficient.

[0051] Finally, combining the above control links, the method adopted in this embodiment can use a voltage-current double-loop controller to achieve fast tracking of the reactive power command. The double-loop controller decouples and controls the dq-axis components of the voltage and current respectively. The composite virtual impedance is used to further reduce the reactive power distribution error of each distributed power source, and finally achieve high-precision reactive power control. Its control structure is as Figure 2 shown.

[0052] In the figure, P o , Q o , f o , and E o are the rated active power, reactive power, rated frequency, and voltage of the inverter respectively. U ref , U md , and U mq are the reference values of the output voltage at the grid connection point of the grid-connected converter and the reference values of the dq-axis components respectively. U nd , and U nq are the dq-axis components of the voltage at the grid connection point of the grid-connected converter respectively. i dref , and i qref are the reference values of the dq-axis components of the inductor current respectively. i Ld , and i Lq are the dq-axis components of the inductor current respectively. u Ldref , and u Lqref are the reference values of the dq-axis components of the inverter output voltage respectively; PI is a proportional-integral controller, and L is the reactance of the output filter of the grid-connected converter; R vr and L vr are the virtual resistance and virtual reactance values of the composite impedance respectively.

[0053] It is not difficult to find that the present invention can achieve high-precision reactive power distribution of multiple power sources in an independent microgrid without interconnection lines, thereby improving the reactive power utilization rate of the system and stabilizing the operating voltage of the independent microgrid. This method ensures that each micro-source outputs reactive power according to the proportion of its remaining reactive power capacity, and has a high reactive power distribution accuracy. Since it does not rely on communication, the reliability of the system is high.

[0054] The second embodiment of the present invention relates to a multi-source adaptive reactive power distribution device for an independent microgrid without interconnection lines, such as Figure 3 shown, including:

[0055] A reactive power distribution module, configured to calculate respective reactive power distribution coefficients according to the remaining reactive power capacities of each micro-source in the independent microgrid, obtain a reactive power command value through the voltage at the connection point of the distributed power source, and calculate the voltage compensation amount of the droop control based on the reactive power command value;

[0056] A reactive power control module, configured to adjust the reactive power droop coefficient in an adaptive manner and give a voltage reference value for the droop control strategy. When adjusting the reactive power droop coefficient, the influence of the equivalent output reactance on the reactive power output is eliminated by adding the active power output amount, and the reactive power distribution accuracy among multiple sources in the microgrid is improved by adding the reactive power output amount.

[0057] The reactive power distribution module includes:

[0058] A first calculation unit, configured to calculate the remaining reactive power capacity of micro-sources at different positions and capacities according to the real-time operation data of each micro-source in the microgrid;

[0059] A second calculation unit, configured to calculate the reactive power distribution coefficient of the micro-source according to the initial reactive power scheduling instruction;

[0060] A third calculation unit, configured to calculate the reactive power command value of the micro-source based on the voltage value at the connection point of the micro-source by using the reactive power-voltage droop control method;

[0061] A fourth calculation unit, configured to calculate the voltage compensation amount of the droop control based on the reactive power command value.

[0062] The first calculation unit obtains the remaining reactive power capacity through calculation, where S i represents the converter capacity of the i-th micro-source, P i,t represents the active power output by the converter of the i-th micro-source, n is the number of micro-sources, and Q si,t is the remaining reactive power capacity of the i-th micro-source at time t.

[0063] The second calculation unit obtains the reactive power distribution coefficient through calculation, where R t is the global distribution coefficient of the microgrid, Ri,t is the reactive power distribution coefficient of the i-th micro-source at time t, is the per-unit value of the reactive power scheduling instruction based on the remaining capacity, is the reactive power scheduling instruction value of the i-th micro-source at time t, V i is the lower limit of the normal voltage range, V low_TW is the minimum voltage value for the microgrid to go off-grid.

[0064] The third calculation unit calculates the reactive power instruction value of the micro-source through where Q ref,i is the reactive power output instruction of the i-th micro-source at time t, is the reactive power scheduling instruction value of the i-th micro-source at time t, R t is the global distribution coefficient of the microgrid, Q si,t is the remaining reactive power capacity of the i-th micro-source at time t, V i is the lower limit of the normal voltage range, is the upper limit of the normal voltage range, V i,t is the real-time voltage at the connection point of the micro-source.

[0065] The fourth calculation unit calculates the voltage compensation amount through ΔE = (Q ref,i -Q i )(k vp +k vi / s), where ΔE is the voltage compensation amount, Q ref,i is the reactive power output instruction of the i-th micro-source at time t, Q i is the real-time value of the reactive power output by the distributed power source, k vp and k vi are the PI parameters of the voltage compensation loop, and s represents the Laplace operator.

[0066] The reactive power control module adjusts the reactive power droop coefficient through f(P i ,Q i ) = K Q +k pi P i +k qi Q i The adjusted reactive power droop coefficient satisfies constraint, where f(P i ,Q i ) is the adjusted reactive power droop coefficient, P i and Q i are the real-time active power output value and the real-time reactive power output value of the i-th micro-source respectively, K Q is the reactive power droop reference coefficient, k pi and k qiThe active power proportion coefficient and reactive power proportion coefficient of the i-th micro-power supply respectively, ΔU is the voltage drop, and Q max is the maximum reactive power output value, and ΔU max is the maximum voltage drop of the independent microgrid, X i is the reactance value of the connection line of the i-th micro-power supply, P i_max is the maximum active power output of the i-th micro-power supply, C pi represents the active power distribution coefficient.

[0067] The reactive power control module calculates the voltage reference value of the droop control strategy through U refi = E 0i + ΔE + f(P i , Q i )(Q0 - Q i ), where U refi is the voltage reference value of the i-th micro-power supply obtained by the droop strategy, ΔE is the voltage compensation amount, Q o is the reactive power reference value, and E 0i represents the no-load electromotive force.

[0068] The third embodiment of the present invention relates to an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the steps of the multi-source adaptive reactive power distribution method for an independent microgrid without interconnection lines in the first embodiment are implemented.

[0069] The fourth embodiment of the present invention relates to a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the multi-source adaptive reactive power distribution method for an independent microgrid without interconnection lines in the first embodiment are implemented.

[0070] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing computer-usable program codes. The solutions in the embodiments of the present invention can be implemented in various computer languages. For example, object-oriented programming languages such as Java and interpreted scripting languages such as JavaScript.

[0071] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and combinations of flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to the processors of general purpose computers, special purpose computers, embedded processors, or other programmable data processing devices to produce a machine, such that the instructions executed by the processors of the computer or other programmable data processing devices generate means for implementing the functions specified in the Figure 1 one or more flows and / or blocks Figure 1 one or more blocks.

[0072] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a particular manner, such that the instructions stored in the computer-readable memory produce a manufacture including instruction means that implement the functions specified in the Figure 1 one or more flows and / or blocks Figure 1 one or more blocks.

[0073] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operational steps are performed on the computer or other programmable device to produce a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in the Figure 1 one or more flows and / or blocks Figure 1 one or more blocks.

[0074] Although the preferred embodiments of the present invention have been described, additional changes and modifications can be made to these embodiments by those skilled in the art once they learn of the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications that fall within the scope of the present invention.

[0075] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. An adaptive reactive power distribution method for a multi-source independent microgrid without interconnection lines, characterized in that It includes the following steps: Reactive power distribution stage: According to the remaining reactive power capacity of each micro-source in the independent microgrid, calculate their respective reactive power distribution coefficients, obtain the reactive power command value through the voltage at the connection point of the distributed power source, and calculate the voltage compensation amount of droop control based on the reactive power command value. Specifically, it includes: Calculate the remaining reactive power capacity of micro-sources at different positions and with different capacities according to the real-time operation data of each micro-source in the microgrid; According to the initial reactive power dispatch instruction, calculate the reactive power distribution coefficient of the micro-source; wherein, the reactive power distribution coefficient of the micro-source is obtained by Calculated, where R t Is the global distribution coefficient of the microgrid, R i,t Is the reactive power distribution coefficient of the i-th micro-source at time t, Is the per-unit value of the reactive power dispatch instruction based on the remaining capacity, is the reactive power dispatch command value of the i-th micro-source at time t, V i is the lower limit of the normal voltage range, V low_TW is the minimum voltage value for the microgrid to go off-grid; Adopt the reactive power-voltage droop control method to calculate the reactive power command value of the micro-source based on the voltage value at the connection point of the micro-source; Calculate the voltage compensation amount of droop control based on the reactive power command value; Reactive power control stage: Adjust the reactive power droop coefficient in an adaptive manner and give the voltage reference value of the droop control strategy. When adjusting the reactive power droop coefficient, eliminate the influence of the equivalent output reactance on the reactive power output by adding the active power output, and improve the reactive power distribution accuracy among multiple sources in the microgrid by adding the reactive power output.

2. The multi-source adaptive reactive power distribution method for an independent microgrid without interconnection lines according to claim 1, characterized in that, The remaining reactive power capacity is obtained through calculation, where S i represents the converter capacity of the i-th micro-source, P i,t represents the active power output by the converter of the i-th micro-source, n is the number of micro-sources, and Q si,t is the remaining reactive power capacity of the i-th micro-source at time t.

3. The multi-source adaptive reactive power distribution method for an independent microgrid without interconnection lines according to claim 1, characterized in that, The reactive power command value of the micro - power supply is obtained through calculation. Among them, Q ref,i is the reactive power output command of the i - th micro - power supply at time t, is the reactive power scheduling command value of the i - th micro - power supply at time t, R t is the global distribution coefficient of the micro - grid, Q si,t is the remaining reactive power capacity of the i - th micro - power supply at time t, V i is the lower limit of the normal voltage range, is the upper limit of the normal voltage range, V i,t is the real - time voltage at the connection point of the micro - power supply.

4. The multi-source adaptive reactive power distribution method for an independent microgrid without interconnection lines according to claim 1, characterized in that, The voltage compensation amount is calculated by ΔE=(Q ref,i -Q i )(k vp +k vi / s), where ΔE is the voltage compensation amount, Q ref,i is the reactive power output command of the i-th micro-source at time t, Q i is the real-time value of the reactive power output by the distributed power source, k vp and k vi are the PI parameters of the voltage compensation loop, and s represents the Laplace operator.

5. The multi-source adaptive reactive power distribution method for an independent microgrid without interconnection lines according to claim 1, characterized in that, The reactive droop coefficient is adjusted through f(P i , Q i ) = K Q + k pi P i + k qi Q i for adjustment, and it satisfies constraints. Among them, f(P i , Q i ) is the adjusted reactive droop coefficient, P i and Q i are respectively the real-time active power output value and the real-time reactive power output value of the i-th micro-source, K Q is the reactive droop reference coefficient, k pi and k qi are respectively the active power proportion coefficient and the reactive power proportion coefficient of the i-th micro-source, ΔU is the voltage drop, Q max is the maximum reactive power output value, ΔU max is the maximum voltage drop of the independent microgrid, X i is the reactance value of the connection line of the i-th micro-source, P i_max is the maximum value of the active power output of the i-th micro-source, and C pi represents the active power distribution coefficient.

6. The multi-source adaptive reactive power distribution method for an independent microgrid without interconnection lines according to claim 5, characterized in that, The voltage reference value of the droop control strategy is obtained through U refi = E 0i + ΔE + f(P i , Q i )(Q0 - Q i ), where U refi is the voltage reference value of the i-th micro-source obtained by the droop strategy, ΔE is the voltage compensation amount, Q o is the reactive power reference value, and E 0i represents the no-load electromotive force.

7. An independent microgrid multi-source adaptive reactive power distribution device without interconnection lines, characterized in that, It includes: A reactive power distribution module, which is used to calculate their respective reactive power distribution coefficients according to the remaining reactive power capacity of each micro-source in the independent microgrid, obtain the reactive power command value through the voltage at the connection point of the distributed power source, and calculate the voltage compensation amount of droop control based on the reactive power command value; The reactive power distribution module includes: A first calculation unit, which is used to calculate the remaining reactive power capacity of micro-sources at different positions and with different capacities according to the real-time operation data of each micro-source in the microgrid; A second calculation unit for calculating a reactive power distribution coefficient of a micro-source according to an initial reactive power dispatch instruction; the second calculation unit calculates the reactive power distribution coefficient through The reactive power distribution coefficient is calculated, where R t is the global distribution coefficient of the microgrid, and R i,t is the reactive power distribution coefficient of the i-th micro-source at time t, is the per-unit value of the reactive power dispatch instruction based on the remaining capacity, is the reactive power dispatch instruction value of the i-th micro-source at time t, V i is the lower limit of the normal voltage range, and V low_TW is the minimum voltage value for the microgrid to go off-grid; A third calculation unit, which is used to adopt the reactive power-voltage droop control method to calculate the reactive power command value of the micro-source based on the voltage value at the connection point of the micro-source; A fourth calculation unit, which is used to calculate the voltage compensation amount of droop control based on the reactive power command value; A reactive power control module, which is used to adjust the reactive power droop coefficient in an adaptive manner and give the voltage reference value of the droop control strategy. When adjusting the reactive power droop coefficient, eliminate the influence of the equivalent output reactance on the reactive power output by adding the active power output, and improve the reactive power distribution accuracy among multiple sources in the microgrid by adding the reactive power output.

8. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the computer program, it realizes the steps of the multi-source adaptive reactive power distribution method for the wire-free independent microgrid as described in any one of claims 1-6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it realizes the steps of the multi-source adaptive reactive power distribution method for the wire-free independent microgrid as described in any one of claims 1-6.

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