CN115800411A - Independent micro-grid multi-source self-adaptive reactive power distribution method and device without interconnection lines - Google Patents
Independent micro-grid multi-source self-adaptive reactive power distribution method and device without interconnection lines Download PDFInfo
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Abstract
The invention relates to a multi-source self-adaptive reactive power distribution method and a device for an independent microgrid without interconnection lines, wherein the method comprises the following steps: a reactive power distribution stage: calculating respective reactive power distribution coefficients according to the residual reactive capacity of each micro power supply in the independent micro grid, obtaining a reactive power instruction value through the voltage of a grid connection point of the distributed power supply, and calculating the voltage compensation quantity of droop control based on the reactive power instruction value; and a reactive power control stage: the reactive power distribution coefficient is adjusted in a self-adaptive mode, a voltage reference value of a droop control strategy is given, when the reactive power distribution coefficient is adjusted, the influence of equivalent output reactance on reactive power output is eliminated by adding active output quantity, and reactive power distribution precision among multiple sources of the microgrid is improved by adding reactive output quantity. The invention can improve the reactive power utilization rate and improve the reactive power distribution rate.
Description
Technical Field
The invention relates to the technical field of reactive power distribution of independent micro-grids, in particular to a multi-source adaptive reactive power distribution method and device of an independent micro-grid without interconnection lines.
Background
The control of the microgrid mainly comprises control of a grid-connected controller at the bottom layer and overall coordination control at the upper layer, and no matter what coordination control mode is adopted by the microgrid, voltage control and reactive power distribution are difficult and important. The overall coordination control strategy of the micro-grid can be divided into two categories: centralized control and decentralized control. The centralized control is that the microgrid has a microgrid centralized controller (MGCC), the MGCC collects the information of all the microgrid controllers and the load controllers, the information is processed in real time and then sends out a control command, and the control signal is transmitted to each unit of the microgrid through a fast and reliable communication network. And a micro-grid reactive power control strategy of secondary control is adopted, and the MGCC performs centralized adjustment on the no-load output voltage of each distributed power supply according to the control strategy, so that the aim of improving reactive power output distribution can be fulfilled. However, the distribution network global reactive power optimization scheduling needs to be coordinated, the distribution network global reactive power optimization scheduling needs to be wide in distribution and large in quantity, the problems of wide-area communication delay, equipment adjustment characteristic difference and the like exist, the dependence on system communication is strong, the optimization solving process is complex, and the response speed is low.
Distributed control, namely the micro-grid only calculates instructions to control local micro-sources according to local information or other micro-source controller information, all control functions are arranged in each sub-module, and the sub-modules are correlated with each other but have weak dependence on communication, so that the reliability is high, but the control precision is easily influenced by physical parameters, and thus multi-micro-source coordination control based on improved droop control is widely concerned. The distributed control method is mainly used in an equivalent control mode, and is improved aiming at the problem of line impedance mismatching between the traditional droop control and the low-voltage microgrid. And the decoupling control of the output power of the micro source can be realized by adopting a virtual power control strategy of coordinate rotation. A droop control strategy is improved through the reactive power sharing of the micro-grid based on the synchronous idea, a reactive power compensation and voltage recovery strategy is introduced on the basis of the traditional droop control, and a droop characteristic curve is modified by using a low-bandwidth signal sent by the MGCC, so that the reactive power output distribution precision is improved. According to the droop control strategy of weak communication and virtual impedance, good reactive distribution can be realized between micro-sources under the conditions of normal work and communication damage. However, under the influence of physical parameters, the current sharing effect is poor, the reactive power output by each micro power supply is not distributed in proportion according to the reactive power capacity of the micro power supply, and the overall reactive power utilization rate is low.
Disclosure of Invention
The invention aims to solve the technical problem of providing a multi-source adaptive reactive power distribution method and device for an independent micro-grid without interconnection lines, which can improve the reactive power utilization rate and improve the reactive power distribution rate.
The technical scheme adopted by the invention for solving the technical problem is as follows: the utility model provides a do not have independent little electric wire netting multiple source self-adaptation reactive power distribution method of interconnection line, includes the following step:
a reactive power distribution stage: calculating respective reactive power distribution coefficients according to the residual reactive capacity of each micro power supply in the independent micro grid, obtaining a reactive power instruction value through the voltage of a grid connection point of the distributed power supply, and calculating the voltage compensation quantity of droop control based on the reactive power instruction value;
and a reactive power control stage: the reactive power distribution coefficient is adjusted in a self-adaptive mode, a voltage reference value of a droop control strategy is given, when the reactive power distribution coefficient is adjusted, the influence of equivalent output reactance on reactive power output is eliminated by adding active output, and reactive power distribution precision among multiple sources of the micro-grid is improved by adding reactive output.
The reactive power distribution phase comprises the following steps:
calculating the residual reactive capacity of the micro power supplies at different positions and capacities according to the real-time operation data of each micro power supply in the micro grid;
calculating the reactive power distribution coefficient of the micro power source according to the initial reactive power dispatching instruction;
calculating a reactive power instruction value of the micro power supply based on the voltage value of the grid-connected point of the micro power supply by adopting a reactive-voltage droop control method;
a voltage compensation amount for droop control is calculated based on the reactive power instruction value.
The residual reactive capacity is passed
Is calculated to obtain, wherein S i Current transformer capacity, P, representing the ith micropower i,t The converter output of the ith micro power supply has active power, n is the number of the micro power supplies, Q si,t The residual reactive capacity of the ith micro power supply at the moment t.
The micro power supply has no power distribution coefficient passing
Is calculated to obtain, wherein R t Global distribution coefficient, R, for micro-grids i,t For the reactive power distribution coefficient of the ith micro power supply at the moment t,
for the reactive scheduling instruction per unit value based on the remaining capacity,
for the reactive scheduling instruction value of the ith micro power supply at the moment t, i Vat the lower end of the normal range of voltage, V low_TW The minimum voltage value of the off-grid micro-grid is obtained.
Reactive command value pass of the micro power supply
Is calculated to obtain, wherein Q ref,i For the reactive output instruction of the ith micro power supply at the moment t,
a reactive scheduling instruction value R of the ith micro power supply at the time t t Global distribution coefficient, Q, for micro-grids si,t For the remaining reactive capacity of the ith micro power supply at time t, i Vis the lower limit of the normal range of the voltage,
at the upper limit of the normal range of voltage, V it The voltage is real-time voltage of a grid-connected point of the micro-power supply.
The voltage compensation amount is defined by Δ E = (Q) ref,i -Q i )(k vp +k vi Is calculated, wherein, delta E is a voltage compensation quantity, Q ref,i For the reactive output command of the ith micro-power at time t, Q i Outputting a reactive real-time value, k, for a distributed power supply vp And k vi S represents the laplacian for the PI parameter of the voltage compensation loop.
The reactive power distribution coefficient passes f (P) i ,Q i )＝K Q +k pi P i +k qi Q i Make an adjustment which satisfies
Constraint where f (P) i ,Q i ) For adjusted reactive power distribution coefficient, P i And Q i Respectively outputting an active real-time value and a reactive real-time value for the ith micro power supply, K Q Is a reactive droop reference coefficient, k pi And k qi Respectively the active proportionality coefficient and the reactive proportionality coefficient of the ith micro power supply, wherein delta U is voltage drop, Q max To the maximum reactive output value, Δ U max Maximum voltage drop, X, for independent microgrid i Is the reactance value, P, of the ith micro-power-supply connection line i_max Maximum active output of ith micro power supply, C pi Representing the active power distribution coefficient.
The voltage reference value of the droop control strategy passes through U refi ＝E 0i +ΔE+f(P i ,Q i )(Q 0 -Q i ) Is calculated to obtain, wherein, U refi Voltage reference value of ith micro power supply obtained for droop strategy, delta E is voltage compensation quantity, Q o As a reactive reference value, E 0i Representing a no-load potential.
The technical scheme adopted by the invention for solving the technical problems is as follows: provided is an independent micro-grid multi-source adaptive reactive power distribution device without interconnection lines, comprising:
the reactive power distribution module is used for calculating respective reactive power distribution coefficients according to the residual reactive capacity of each micro power supply in the independent microgrid, obtaining a reactive power instruction value through the voltage of a grid-connected point of the distributed power supplies and calculating the voltage compensation quantity of droop control on the basis of the reactive power instruction value;
and the reactive power control module is used for adjusting the reactive power distribution coefficient in a self-adaptive mode and providing a voltage reference value of a droop control strategy, the reactive power distribution coefficient eliminates the influence of equivalent output reactance on reactive power output by adding active output when being adjusted, and the reactive power distribution precision among multiple sources of the micro-grid is improved by adding reactive output.
The technical scheme adopted by the invention for solving the technical problems is as follows: there is provided an electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the steps of the above interconnection-line-free independent microgrid multi-source adaptive reactive power distribution method when executing the computer program.
The technical scheme adopted by the invention for solving the technical problem is as follows: there is provided a computer readable storage medium having stored thereon a computer program which, when being executed by a processor, carries out the steps of the above-mentioned interconnection-line-less independent microgrid multi-source adaptive reactive power distribution method.
Advantageous effects
Due to the adoption of the technical scheme, compared with the prior art, the invention has the following advantages and positive effects: according to the method, respective reactive power distribution coefficients are calculated according to the residual reactive capacity of each power supply in the independent microgrid, reactive power output instructions are obtained through the voltage of the grid-connected points of the distributed power supplies, and then voltage compensation quantity of droop control is calculated, so that the effect that the reactive power output is in direct proportion to the respective residual reactive capacity is achieved, the influence of reactive power distribution caused by output power change is eliminated through self-adaptive distribution of the droop coefficients, the influence of equivalent output reactance on the reactive power output is eliminated, the reactive power distribution precision among multiple micro sources is improved, and the redundancy and the plug-and-play characteristic of the system are realized. The invention can realize the reactive high-precision distribution of multiple power supplies in the independent micro-grid under the condition of no interconnection line, thereby improving the reactive utilization rate of the system and stabilizing the operating voltage of the independent micro-grid. The method ensures that each micro power supply outputs reactive power according to the proportion of the residual reactive capacity of the micro power supply, and has high reactive power distribution precision and high system reliability because of not depending on communication.
Drawings
Fig. 1 is a flowchart of a multi-source adaptive reactive power distribution method for an independent microgrid without interconnection lines according to a first embodiment of the present invention;
fig. 2 is a block diagram of a multi-source adaptive reactive power distribution strategy of the independent microgrid in the first embodiment of the invention;
fig. 3 is a block diagram of a second embodiment of the invention, a self-contained microgrid multi-source adaptive reactive power distribution system without interconnection lines.
Detailed Description
The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.
The first embodiment of the invention relates to a multi-source adaptive reactive power distribution method for an independent micro-grid without interconnection lines, which is suitable for safe and stable operation of a new energy micro-grid. As shown in fig. 1, the method is mainly composed of two parts: a micro power source reactive power distribution stage based on residual reactive power capacity and a high-precision reactive power control stage based on a self-adaptive droop coefficient.
The distributed power supply reactive power distribution stage based on the residual reactive capacity means that respective reactive power distribution coefficients are calculated according to the residual reactive capacity of each power supply in the independent microgrid, a reactive power output instruction is obtained through the voltage of a grid-connected point of the distributed power supply, and then the voltage compensation quantity of droop control is calculated, so that the effect that the reactive power output is in direct proportion to the respective residual reactive capacity is achieved. The high-precision reactive power control stage based on the self-adaptive droop coefficient is characterized in that the influence of reactive power distribution caused by output power change is eliminated through the self-adaptive droop coefficient, the influence of equivalent output reactance on reactive power output is eliminated, the reactive power distribution precision among multiple micro sources is improved, and the redundancy and plug-and-play characteristics of a system are realized.
In the embodiment, two links of reactive power distribution and high-precision reactive power control are added in the traditional droop control, and the following improved self-adaptive droop control strategy is designed:
in the formula of U refi The voltage reference value of the ith micro power supply obtained for the droop strategy, delta E is the closed-loop voltage compensation quantity, f (P) i ,Q i ) The reactive power distribution coefficient after self-adaptive adjustment is obtained; p i ，Q i For the output real and reactive values of the ith micro-power supply, Q o For a reactive reference value, Q ref Calculating a reactive instruction value for a reactive distribution link; k Q Is a reactive droop reference coefficient, k pi ，k qi Is the active and reactive proportionality coefficient, k vp ，k vi For the voltage compensation loop PI parameter, s represents the laplacian operator.
In the reactive power distribution link, a reactive power output instruction Q is obtained through the voltage of a grid-connected point ref And comparing the instruction with the actual reactive output, and obtaining the closed-loop voltage compensation quantity through the reactive deviation by the PI controller, thereby changing the stable operation point of the droop controller of the distributed power supply and achieving the effect of outputting the reactive quick tracking reactive instruction. The high-precision reactive power control link adopts a self-adaptive distribution coefficient f (P) i ,Q i ) The influence of reactive power distribution caused by output power change is eliminated, and the reactive power distribution precision among multiple micro sources can be well improved.
The reactive power distribution link provides compensation voltage for the improved droop control, each inverter only carries out reactive power instruction calculation according to the local voltage situation and the residual reactive power capacity of the inverter, and the reactive power distribution link comprises the following steps:
the method comprises the following steps: according to the real-time operation data of each power supply in the microgrid, calculating the residual reactive capacity of the microgrid sources at different positions and capacities:
in the formula, S i Current transformer capacity, P, representing the ith micropower i,t Representing the output of the ith micro-power converter is active, n is the total micro-power number in the micro-grid, Q si,t The residual reactive capacity of the ith micro power supply at the moment t.
Step two: each micro power source calculates the reactive power distribution coefficient of the micro power source according to the initial reactive power dispatching instruction:
in the formula (I), the compound is shown in the specification,
for the reactive scheduling instruction value of the ith micro power supply at the moment t,
is a reactive scheduling instruction per unit value based on the residual capacity. R is i,t The reactive power distribution coefficient R of the ith micro power supply at the moment t t And distributing coefficients for the microgrid globally, wherein all the micro power supplies are the same. i VAt the lower end of the normal range of voltage, V low_TW The minimum voltage value of the off-grid of the microgrid is obtained.
Step three: and calculating the reactive instruction value of each micro power supply according to the following formula based on the voltage value of the grid-connected point of each micro power supply by adopting a reactive-voltage droop control method:
in the formula, V i,t Is the real-time voltage of the grid-connected point of the micro power supply,
at the upper limit of the normal range of voltage, Q ref,i And outputting a reactive power instruction of the ith micro power supply at the moment t. Because the global reactive power distribution coefficients of all the distributed power supplies in the microgrid are the same, the reactive power instruction output by all the converters is in direct proportion to the respective residual reactive capacity.
In the high-precision reactive power control link, an adaptive distribution coefficient f (P) is provided for the improved droop control i ,Q i ) The method is used for eliminating the influence of reactive power distribution caused by output power change, and the self-adaptive distribution coefficient is calculated by the following formula:
f(P i ,Q i )＝K Q +k pi P i +k qi Q i (6)
wherein, P i_max For maximum active output, Q max To the maximum reactive output value, Q i The reactive output is obtained; Δ U is the voltage drop, Δ U max Maximum voltage drop, X, for independent microgrid i Is the reactance value of the micro-power supply connection line, C q Represents a constant, C pi Representing the active power distribution coefficient.
Finally, in combination with the above control links, the method adopted in this embodiment may utilize a voltage-current dual-loop controller to realize fast tracking of the reactive instruction, the dual-loop controller performs decoupling control on the voltage-current dq axis components respectively, the composite virtual impedance is used to further reduce the reactive power distribution error of each distributed power supply, and finally, high-precision reactive power control is realized, and the control structure thereof is shown in fig. 2.
In the figure, P o 、Q o 、f o 、E o Rated active and reactive power of the inverter respectivelyConstant frequency and voltage, U ref 、U md 、U mq Respectively outputting a voltage reference value and a dq-axis component reference value, U for a grid-connected point of a grid-connected converter nd 、U nq And respectively grid-connected point voltage dq axis components of the grid-connected converter. i.e. i dref 、i qref Reference values, i, for the components of the inductor current dq axes, respectively Ld 、i Lq Are respectively dq-axis components, u, of the inductor current Ldref 、u Lqref Reference values for dq-axis components of the inverter output voltage, respectively; PI is a proportional-integral controller, and L is a reactance of an output filter of the grid-connected converter; r is vr And L vr Respectively compounding the virtual resistance and the virtual reactance value of the impedance.
The invention can realize the reactive high-precision distribution of multiple power supplies in the independent micro-grid under the condition of no interconnection line, thereby improving the reactive utilization rate of the system and stabilizing the operating voltage of the independent micro-grid. The method ensures that each micro power supply outputs reactive power according to the proportion of the residual reactive capacity of the micro power supply, and has high reactive power distribution precision and high system reliability because of not depending on communication.
A second embodiment of the present invention relates to an independent microgrid multi-source adaptive reactive power distribution device without interconnection lines, as shown in fig. 3, including:
the reactive power distribution module is used for calculating respective reactive power distribution coefficients according to the residual reactive capacity of each micro power supply in the independent microgrid, obtaining a reactive power instruction value through the voltage of a grid-connected point of the distributed power supplies and calculating the voltage compensation quantity of droop control based on the reactive power instruction value;
and the reactive power control module is used for adjusting the reactive power distribution coefficient in a self-adaptive mode and providing a voltage reference value of a droop control strategy, and when the reactive power distribution coefficient is adjusted, the influence of an equivalent output reactance on reactive power output is eliminated by adding an active output quantity, and the reactive power distribution precision among multiple sources of the microgrid is improved by adding a reactive output quantity.
The reactive power distribution module includes:
the first calculation unit is used for calculating the residual reactive capacity of the micro power supplies at different positions and capacities according to the real-time operation data of each micro power supply in the micro power grid;
the second calculation unit is used for calculating the reactive power distribution coefficient of the micro power source according to the initial reactive power dispatching instruction;
the third calculation unit is used for calculating a reactive instruction value of the micro power supply based on the voltage value of the grid-connected point of the micro power supply by adopting a reactive-voltage droop control method;
and the fourth calculating unit is used for calculating the voltage compensation amount of the droop control based on the reactive power instruction value.
The first computing unit is connected to the first network
Calculating to obtain the residual reactive capacity, wherein S i Representing the converter capacity, P, of the ith micro-source i,t The converter output of the ith micro power supply has active power, n is the number of the micro power supplies, Q si,t The residual reactive capacity of the ith micro power supply at the time t.
The second computing unit passes
Calculating to obtain the reactive distribution coefficient, wherein R t Global distribution coefficient, R, for micro-grids i,t For the reactive power distribution coefficient of the ith micro power supply at the time t,
for the per unit value of the reactive scheduling instruction based on the remaining capacity,
for the reactive scheduling instruction value of the ith micro power supply at the moment t, i Vat the lower end of the normal range of voltage, V low_TW The minimum voltage value of the off-grid of the microgrid is obtained.
The third computing unit passes
Calculating to obtain a reactive instruction value of the micro power supply, wherein Q ref,i For the reactive output instruction of the ith micro power supply at the moment t,
for the reactive scheduling instruction value R of the ith micro power supply at the moment t t Global distribution coefficient, Q, for micro-grids si,t For the remaining reactive capacity of the ith micro power supply at time t, i Vis the lower limit of the normal range of the voltage,
upper limit of the normal range of voltage, V i,t The voltage is the real-time voltage of the grid-connected point of the micro power supply.
The fourth calculation unit passes Δ E = (Q) ref,i -Q i )(k vp +k vi /s) calculating to obtain voltage compensation amount, wherein delta E is the voltage compensation amount, Q ref,i For the reactive output command of the ith micro-power at time t, Q i Outputting a reactive real-time value, k, for a distributed power supply vp And k vi For the PI parameter of the voltage compensation loop, s represents the laplacian operator.
The reactive power control module passes f (P) i ,Q i )＝K Q +k pi P i +k qi Q i Adjusting the reactive power distribution coefficient, wherein the adjusted reactive power distribution coefficient meets the requirement
Constraint, where f (P) i ,Q i ) For adjusted reactive power distribution coefficient, P i And Q i Respectively outputting an active real-time value and a reactive real-time value, K, for the ith micro power supply Q Is a reactive droop reference coefficient, k pi And k qi The active proportionality coefficient and the reactive proportionality coefficient of the ith micro power supply respectively, wherein delta U is voltage drop and Q max To the maximum reactive output value, Δ U max Maximum voltage drop, X, for independent microgrid i Is the reactance value, P, of the ith micro-power-supply connection line i_max Is a firstMaximum active output of i micro-power supplies, C pi The active power distribution coefficient is shown.
The reactive power control module passes through U refi ＝E 0i +ΔE+f(P i ,Q i )(Q 0 -Q i ) Calculating a voltage reference value of a droop control strategy, wherein U refi Voltage reference value of ith micro power supply obtained for droop strategy, delta E is voltage compensation quantity, Q o As a reactive reference value, E 0i Representing a no-load potential.
A third embodiment of the present invention relates to an electronic device, which includes a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor implements the steps of the interconnection-line-less independent microgrid multi-source adaptive reactive power distribution method of the first embodiment when executing the computer program.
A fourth embodiment of the invention relates to a computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements the steps of the interconnection-line-less independent microgrid multi-source adaptive reactive power distribution method of the first embodiment.
As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein. The scheme in the embodiment of the invention can be realized by adopting various computer languages, such as object-oriented programming language Java and transliterated scripting language JavaScript.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (11)
1. A multi-source adaptive reactive power distribution method for an independent micro-grid without interconnection lines is characterized by comprising the following steps:
a reactive power distribution stage: calculating respective reactive power distribution coefficients according to the residual reactive capacity of each micro power supply in the independent microgrid, obtaining a reactive power instruction value through the voltage of a grid-connected point of the distributed power supplies, and calculating the voltage compensation quantity of droop control on the basis of the reactive power instruction value;
and a reactive power control stage: the reactive power distribution coefficient is adjusted in a self-adaptive mode, a voltage reference value of a droop control strategy is given, when the reactive power distribution coefficient is adjusted, the influence of equivalent output reactance on reactive power output is eliminated by adding active output, and reactive power distribution precision among multiple sources of the micro-grid is improved by adding reactive output.
2. The interconnection-line-free independent microgrid multi-source adaptive reactive power distribution method according to claim 1, characterized in that the reactive power distribution phase comprises:
calculating the residual reactive capacity of the micro power supplies at different positions and capacities according to the real-time operation data of each micro power supply in the micro power grid;
calculating the reactive power distribution coefficient of the micro power source according to the initial reactive power dispatching instruction;
calculating a reactive instruction value of the micro power supply based on the voltage value of the grid-connected point of the micro power supply by adopting a reactive-voltage droop control method;
and calculating the voltage compensation amount of the droop control based on the reactive power instruction value.
3. The interconnection-line-free standalone microgrid multi-source adaptive reactive power distribution method of claim 2, characterized in that the residual reactive capacity is passed through
Is calculated to obtain, wherein S i Current transformer capacity, P, representing the ith micropower i,t The converter output of the ith micro power supply is active, n is the number of the micro power supplies, Q si,t Is the remaining none of the ith micro power supply at time tWork capacity.
4. The interconnection-line-free standalone microgrid multi-source adaptive reactive power distribution method of claim 2, characterized in that the microgrid reactive power distribution coefficients pass through
Is calculated to obtain, wherein R t Global distribution coefficient, R, for micro-grids i,t For the reactive power distribution coefficient of the ith micro power supply at the moment t,
for the reactive scheduling instruction per unit value based on the remaining capacity,
for the reactive scheduling instruction value, V, of the ith micro power supply at the time t i At the lower end of the normal range of voltage, V low_TW The minimum voltage value of the off-grid of the microgrid is obtained.
5. The interconnection-line-free independent microgrid multi-source adaptive reactive power distribution method of claim 2, characterized in that reactive command values of the micro power sources are passed through
Is calculated to obtain, wherein Q ref,i For the reactive output instruction of the ith micro power supply at the moment t,
for the reactive scheduling instruction value R of the ith micro power supply at the moment t t Global distribution coefficient, Q, for micro-grids si,t Is the residual reactive capacity, V, of the ith micro power supply at time t i Is the lower limit of the normal range of the voltage,
at the upper limit of the normal range of voltage, V i,t The voltage is the real-time voltage of the grid-connected point of the micro power supply.
6. The interconnection-line-free standalone microgrid multi-source adaptive reactive power distribution method of claim 2, characterized in that the voltage compensation amount is by Δ E = (Q) ref,i -Q i )(k vp +k vi Is calculated, wherein, delta E is a voltage compensation quantity, Q ref,i For the reactive output command of the ith micro-power at time t, Q i Outputting a reactive real-time value, k, for a distributed power supply vp And k vi For the PI parameter of the voltage compensation loop, s represents the laplacian operator.
7. The interconnection-line-free standalone microgrid multi-source adaptive reactive power distribution method of claim 1, characterized in that the reactive power distribution coefficient passes f (P) i ,Q i )＝K Q +k pi P i +k qi Q i Make an adjustment which satisfies
Constraint where f (P) i ,Q i ) For the adjusted reactive power distribution coefficient, P i And Q i Respectively outputting an active real-time value and a reactive real-time value, K, for the ith micro power supply Q Is a reactive droop reference coefficient, k pi And k qi The active proportionality coefficient and the reactive proportionality coefficient of the ith micro power supply respectively, wherein delta U is voltage drop and Q max To maximum reactive output value, Δ U max Maximum voltage drop, X, for independent microgrid i Is the reactance value, P, of the ith micro-power supply connection line i_max Maximum active output of ith micro power supply, C pi Representing the active power distribution coefficient.
8. The interconnection-line-free standalone microgrid of claim 7 a multi-source adaptive reactive power distribution method,wherein the voltage reference value of the droop control strategy is U refi ＝E 0i +ΔE+f(P i ,Q i )(Q 0 -Q i ) Is calculated to obtain, wherein, U refi Voltage reference value of ith micro power supply obtained for droop strategy, delta E is voltage compensation quantity, Q o As a reactive reference value, E 0i Representing a no-load potential.
9. An independent microgrid multi-source adaptive reactive power distribution device without interconnection lines, comprising:
the reactive power distribution module is used for calculating respective reactive power distribution coefficients according to the residual reactive capacity of each micro power supply in the independent microgrid, obtaining a reactive power instruction value through the voltage of a grid-connected point of the distributed power supplies and calculating the voltage compensation quantity of droop control based on the reactive power instruction value;
and the reactive power control module is used for adjusting the reactive power distribution coefficient in a self-adaptive mode and providing a voltage reference value of a droop control strategy, and when the reactive power distribution coefficient is adjusted, the influence of an equivalent output reactance on reactive power output is eliminated by adding an active output quantity, and the reactive power distribution precision among multiple sources of the microgrid is improved by adding a reactive output quantity.
10. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor when executing the computer program implements the steps of the interconnection-line-less standalone microgrid multi-source adaptive reactive power distribution method according to any one of claims 1 to 8.
11. A computer-readable storage medium, having stored thereon a computer program, which, when being executed by a processor, carries out the steps of the interconnection-line-less independent microgrid multi-source adaptive reactive power distribution method according to any one of claims 1 to 8.
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