A micro-grid source and load collaborative control method and system for load voltage management

Abstract

The application discloses a load voltage management-oriented distribution area micro-grid source-load collaborative control method and system, and belongs to the technical field of power system control; the load voltage management-oriented distribution area micro-grid source-load collaborative control method comprises the following steps: combining a droop control structure and theory to construct an input-output simplified regulation and control model of a distributed power supply; based on graph theory, a communication topology architecture between distributed power supply nodes in the distribution area micro-grid is constructed; based on the input-output simplified regulation and control model of the distributed power supply and the communication topology architecture between the distributed power supply nodes in the distribution area micro-grid, a load voltage driven power distributed collaborative control strategy is constructed and executed, so that each distributed power supply cooperatively operates and tracks the expected voltage value of a selected load node; and thus the voltage control precision and dynamic response capability are improved, and the power supply quality is effectively guaranteed.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of power system control, and particularly relates to a feeder micro-grid source-load collaborative control method and system for load voltage management and control. BACKGROUND

[0002] With large-scale access of high-proportion renewable energy to power systems, the penetration rate of distributed power sources in distribution networks continues to increase, and the traditional feeder voltage control mode based on centralized scheduling faces structural challenges. On the one hand, the strong uncertainty and spatial and temporal dispersion characteristics of distributed power output cause significant aggravation of load node voltage fluctuations; on the other hand, sensitive industrial production lines, medical facilities and data centers and other key loads have higher requirements for power supply quality.

[0003] The existing voltage control technology mainly has two defects: the local correction strategy is easy to cause control conflicts due to the lack of global coordination, and the hierarchical centralized control is difficult to meet the real-time response demand due to the restriction of communication delay. In the power mutation or fault condition, the above-mentioned methods cannot realize the rapid and accurate tracking of the load voltage, not only causing the deterioration of power quality, but also endangering the power supply stability of important loads and causing economic losses. Therefore, a feeder micro-grid source-load collaborative control method for load voltage management and control is urgently needed to ensure the safe and reliable operation of the new power system. SUMMARY

[0004] In view of the deficiencies of the prior art, the purpose of the present application is to provide a feeder micro-grid source-load collaborative control method and system for load voltage management and control, which solves the problems in the prior art.

[0005] The purpose of the present application can be achieved by the following technical solutions:

[0006] The feeder micro-grid source-load collaborative control method for load voltage management and control comprises the following steps:

[0007] A simplified input-output regulation model of the distributed power source is constructed in combination with the droop control structure and theory;

[0008] A communication topology architecture between the distributed power source nodes in the feeder micro-grid is constructed based on the graph theory;

[0009] Based on the simplified input-output regulation model of the distributed power source and the communication topology architecture between the distributed power source nodes in the feeder micro-grid, a power distributed collaborative control strategy based on load voltage driving is constructed and executed, so that each distributed power source tracks the expected voltage value of the selected load node through collaborative operation.

[0010] Further, the simplified input-output regulation model of the distributed power source is:

[0011]

[0012]

[0013] wherein subscript i denotes the i th droop-controlled distributed generator in the microgrid, is the differential state of the output voltage of the distributed generator, is a virtual control input for simplifying the regulation model; is the reactive-voltage droop coefficient, is the reactive power reference instruction, is the rated operating voltage, is the output reactive power of the distributed generator, is the output voltage of the distributed generator, is the filter time constant of the low-pass filter.

[0014] Further, the microgrid comprises: N one droop-controlled distributed generator and one load; N one droop-controlled distributed generator as a follower and the load as a leader, and a directed graph characterizes the distributed communication topology of each controlled unit; in the directed graph, denotes the set of follower droop-controlled distributed generator agents, denotes the edge set of the agent, is the adjacency matrix.

[0015] Further, the execution process of the power distributed collaborative control strategy based on the load voltage driving comprises:

[0016] each power source collects the local voltage in real time;

[0017] transmits its own voltage state through the communication network and obtains the voltage state information of the adjacent distributed power source and the leader load node;

[0018] based on the dynamic consistency algorithm, the local and adjacent distributed power source voltage data are fused to generate a reactive power adjustment instruction reference and issued to the inverter of the local distributed power source for execution.

[0019] Further, the control form of the power distributed collaborative control strategy based on the load voltage driving is:

[0020]

[0021] wherein, is a virtual control input for simplifying the regulation model, denotes the i th droop-controlled distributed generator voltage tracking error, and a control gain of the distributed cooperative control strategy.

[0022] Further, an energy function-based verification equation is adopted to verify the stability of the distributed cooperative control strategy of the load voltage driven power supply, and the energy function-based verification equation is:

[0023]

[0024] wherein, an energy function suitable for the distributed cooperative control strategy of the load voltage driven power supply, is a voltage tracking error of the overall substation micro-grid.

[0025] The substation micro-grid source-load cooperative control system for load voltage management and control comprises:

[0026] A regulation model construction module: a simplified regulation model of input and output of the distributed power supply is constructed in combination with the droop control structure and theory.

[0027] A topological architecture construction module: a communication topological architecture among the distributed power supply nodes in the substation micro-grid is constructed based on the graph theory.

[0028] A coordination control module: a distributed cooperative control strategy based on the load voltage driven power supply is constructed and executed based on the simplified regulation model of input and output of the distributed power supply and the communication topological architecture among the distributed power supply nodes in the substation micro-grid, so that each distributed power supply tracks the expected voltage value of the selected load node through cooperative operation.

[0029] A computer storage medium storing a readable program, when the program is executed, the program can instruct a computing device to execute the substation micro-grid source-load cooperative control method for load voltage management and control as described above.

[0030] An electronic device comprising a processor, a memory, a communication interface and a communication bus, the processor, the memory and the communication interface complete the communication among each other through the communication bus.

[0031] The memory is used to store at least one executable instruction, and the executable instruction makes the processor execute the operation corresponding to the substation micro-grid source-load cooperative control method for load voltage management and control as described above.

[0032] A computer program product comprising computer instructions, the computer instructions instruct a computing device to execute the operation corresponding to the substation micro-grid source-load cooperative control method for load voltage management and control as described above.

[0033] The beneficial effects of the present application are:

[0034] 1. Through the proposed distributed cooperative control strategy, multiple distributed power sources work cooperatively, which can accurately and quickly track the expected voltage value of the selected load node, improve the voltage control accuracy and dynamic response ability, and effectively guarantee the power supply quality.

[0035] 2. The application designs a communication topology based on graph theory, and only needs to interact with limited information between adjacent power nodes to realize the autonomous cooperative regulation of the power source. The distributed architecture does not need a central controller, enhances the flexibility, scalability and reliability of the system, and facilitates the plug-and-play of the distributed power source.

[0036] 3. The control process is analyzed by constructing a simplified power source model, and strict stability theory analysis is carried out based on energy function, which provides a solid guarantee for the effectiveness and robustness of the control strategy, simplifies the control design, and improves the engineering practicability and reliability of the method. DETAILED DESCRIPTION

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0038] Figure 1 is the micro-grid architecture diagram of the transformer area of the present application;

[0039] Figure 2 is the micro-grid source-load cooperative control method flow chart of the transformer area of the present application facing load voltage management and control;

[0040] Figure 3 is the micro-grid test simulation system diagram of the present application;

[0041] Figure 4 is the voltage response curve of the four distributed power nodes and one load node of the present application;

[0042] Figure 5 is the control effect comparison diagram of the load node voltage in the micro-grid of the transformer area before and after using the method of the present application. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0044] Embodiment 1

[0045] As Figure 1 shown, a micro-grid in a transformer area is deployed with N a plurality of distributed power sources (1~N) interconnected through a distributed communication topology. Each power source is equipped with a distributed controller to realize on-site instruction calculation and regulation. The controllers of each distributed power source interact with adjacent nodes relying on the communication topology to form a collaborative control network. A critical load node (marked as a leader node) is provided in the micro-grid, which has the following characteristics: as a leader node of the distributed communication network; a voltage collector is configured to collect the local voltage state of the load node in real time; and the voltage data is transmitted to the designated distributed power source controller through the communication link. When the load switching or new energy power fluctuation occurs in the transformer area micro-grid, the critical load node is prone to voltage deviation, which leads to the decline of power quality and endangers the reliability of power supply. The control method provided in the embodiment is designed to solve this problem.

[0046] As Figure 2 shown, the transformer area micro-grid source-load collaborative control method for load voltage management includes the following steps:

[0047] S1, combining the droop control structure and theory, an input-output simplified regulation model of the distributed power source is constructed to realize accurate mapping from the control instruction to the output voltage;

[0048] The droop control distributed power source can realize autonomous voltage regulation through the reactive power-voltage droop characteristic: when the output reactive power increases, the output voltage amplitude decreases according to the preset droop coefficient, and vice versa. This characteristic enables it to have dynamic reactive power compensation capability, which can suppress line voltage drop and support critical node voltage stability. This step constructs a simplified voltage regulation model to reveal the dynamic response relationship from the reactive power regulation instruction to the output voltage amplitude, providing a quantitative basis for multi-source collaborative voltage control.

[0049] Considering that the time scale of the transformer area micro-grid voltage secondary control is seconds, the invention ignores the millisecond transient process of the internal double loop of the distributed power source when modeling, and only retains the first-order low-pass filter dynamics of the power measurement. Therefore, for the first N of the i distributed power sources among the assumed distributed power sources in the micro-grid, the input-output simplified regulation model of the droop control distributed power source can be represented as:

[0050] (1)

[0051] Wherein, is the reactive power-voltage droop coefficient, is the reactive power reference instruction, is the rated operating voltage, The output reactive power of the distributed power source. The output voltage of the distributed power source. The filtering time constant of the low-pass filter. It is the Laplace operator.

[0052] To facilitate the design of state feedback, the first i The simplified input-output control model of a droop-controlled distributed power source can be represented in the form of a first-order differential:

[0053] (2)

[0054] in, This represents the differential state of the output voltage of the distributed power source. To simplify the virtual control input of the control model, it will be obtained through a locally deployed distributed secondary controller. The reactive power output of the distributed power source will be provided by Calculated.

[0055] S2, based on graph theory, constructs the communication topology architecture between distributed power generation nodes in the distribution microgrid to clarify the communication relationships between distributed power generation;

[0056] Based on graph theory, an undirected connected communication network is constructed. The node adjacency matrix and edge weight allocation rules are defined to realize the distributed dynamic interaction of voltage / power states between power nodes, forming a decentralized cyber-physical fusion architecture. This ensures data accessibility and supports the real-time and robust requirements of distributed decision-making.

[0057] For the microgrid in the distribution area proposed in this invention, such as Figure 1 As shown, including N One droop-controlled distributed power source and one load that needs to be accurately controlled. Among them, N One drooping control distributed source acts as a follower, and one load that needs to be accurately controlled acts as the leader, using an undirected graph. This represents the distributed communication topology of each controlled unit. In an undirected graph, This represents a set of distributed power supply intelligent agents that follow the drooping control. The edge set representing the agent, An undirected graph G The adjacency matrix, where Represents the first in the adjacency matrix i OK j The coefficient of the column. When there exists a first... i The distributed power source to the first j When the information flow of a distributed power source is... ;otherwise Undirected graph GThe Laplacian matrix of the graph G is defined as whose elements satisfy:

[0058] (3)

[0059] The leader matrix is adopted to describe the connection relationship between the distributed power and the leader load. When , it indicates that there is information flow from the leader node to the i-th distributed power. i

[0060] S3, based on the regulation model constructed by S1 and the communication topology architecture constructed by S2, constructs and executes the power distributed collaborative control strategy based on the load voltage driving, so that each distributed power cooperates through collaborative operation to track the expected voltage value of the selected load node.

[0061] The power distributed collaborative control strategy based on the load voltage driving designed in this embodiment includes three specific execution processes:

[0062] First, each power source collects the local voltage in real time.

[0063] Second, the voltage state of itself is transmitted through the communication network, and the voltage state information of the adjacent distributed power and the leader load node is obtained.

[0064] Finally, based on the dynamic consistency algorithm, the local and adjacent distributed power voltage data are fused to generate a reactive power regulation instruction reference and issued to the inverter of the local distributed power for execution.

[0065] In the controlled console area microgrid, assuming that the expected value of the node voltage of the leader load is , the voltage deviation of the leader load node can be expressed as:

[0066] (4)

[0067] wherein, is the node voltage measurement state of the leader load, is the voltage deviation state of the leader load node.

[0068] Further, the global instruction reference transmitted by the leader load node to the distributed power through the distributed communication topology can be designed as:

[0069] (5)

[0070] wherein, is the global instruction reference, and are gain coefficients in the calculation of the global instruction reference. ​

[0071] Based on the global reference instruction and the droop control input and output of the distributed power supply, the input and output of the distributed power supply are simplified, and the distributed collaborative control strategy of the load voltage driven power supply is designed as follows:

[0072] (6)

[0073] (7)

[0074] wherein, represents the voltage tracking error of the mth droop control distributed power supply, i and is the control gain of the distributed collaborative control strategy

[0075] Based on the above formula, the final reactive power reference instruction of the droop control distributed power supply can be expressed as:

[0076] (8)

[0077] wherein, is the reactive power reference instruction of the droop control distributed power supply.

[0078] In this embodiment, the stability theory analysis of the proposed control strategy is carried out, the strategy verification equation based on the energy function is designed, and the effectiveness of the method is verified through simulation;

[0079] In order to prove the stability of the control method and the whole extraction microgrid control system, combined with the graph theory basis of the above steps and the tracking error and method of single power supply, this embodiment expresses the distributed tracking error of the whole system form of the microgrid as:

[0080] (9)

[0081] wherein, is the voltage tracking error of the whole microgrid, expressed as , the voltage state of the whole microgrid, expressed as .

[0082] Further, the distributed virtual control input of the whole system form of the microgrid is expressed as:

[0083] (10)

[0084] wherein, is a diagonal matrix defined, is the global form of the distributed control collaborative input of the whole system form of the microgrid, expressed as: ​

[0085] ;

[0086] In combination with the above definitions, the stability analysis adopts the Lyapunov function method, and the energy function of the overall distribution micro-grid distributed control system is constructed as follows:

[0087] (11)

[0088] wherein, is the energy function suitable for the power distributed collaborative control strategy based on the load voltage driving, is the voltage tracking error of the overall distribution micro-grid;

[0089] The differential form with respect to time is expressed as:

[0090] (12)

[0091] Because, since is a positive definite matrix, when the control gain of the distributed collaborative control strategy and are negative numbers, the result is: This result proves the stability of the overall control system, that is, the distribution micro-grid distributed control system can be stably controlled and operated.

[0092] Based on the similar inventive concept, the embodiment of the present application also provides a computer storage medium, which stores a readable program, when the program is run by a processor, the program can execute the above-mentioned load voltage-oriented management and control distribution micro-grid source-load collaborative control method.

[0093] Based on the similar inventive concept, the embodiment of the present application provides an electronic device, which comprises a processor, a memory, a communication interface and a communication bus, the processor, the memory and the communication interface complete the communication among each other through the communication bus;

[0094] The memory is used to store at least one executable instruction, and the executable instruction makes the processor execute the operation corresponding to the above-mentioned load voltage-oriented management and control distribution micro-grid source-load collaborative control method.

[0095] Based on the similar inventive concept, the embodiment of the present application also provides a computer program product, which comprises computer instructions, and the computer instructions instruct a computing device to execute the operation corresponding to the above-mentioned load voltage-oriented management and control distribution micro-grid source-load collaborative control method.

[0096] Embodiment 2

[0097] In order to verify the effect of the control method of the present application, a distribution micro-grid system as shown in FIG. 1 is built in this embodiment. Figure 3The shown substation micro-grid test simulation system contains 4 distributed power sources using droop control, 3 operating loads and 1 load requiring key power supply;

[0098] Figure 4 The voltage response curves of the 4 distributed power source nodes and 1 load node in the system are shown. From the results, it can be observed that when the power fluctuation caused by the switching of other loads causes the voltage of the load node to deviate, the control method of the application can quickly control the voltage of the node to the rated value (400V) through the coordinated action of the 4 distributed power sources. In addition, the 4 distributed power sources also achieve stable distributed consistent voltage coordination.

[0099] Figure 5 The control effects of the load node voltage in the substation micro-grid before and after using the method of the application are shown. The observation results can be seen. Under the same simulation test scene, without precise control of load voltage, the load voltage deviates from the expected rated value by about 20V, and the power supply quality is low. However, using the method of the application, the load voltage can be stably tracked around the expected rated value of 400V, and the power supply quality is high.

[0100] Embodiment 3

[0101] In this embodiment, a substation micro-grid source-load collaborative control system for load voltage control is proposed, which specifically includes:

[0102] The regulation model construction module: combining the droop control structure and theory, a simplified input-output regulation model of the distributed power source is constructed;

[0103] The topology architecture construction module: based on graph theory, the communication topology architecture between the distributed power source nodes in the substation micro-grid is constructed;

[0104] The coordination control module: based on the regulation model and the communication topology architecture, a power distributed collaborative control strategy based on load voltage driving is constructed and executed, so that each distributed power source tracks the expected voltage value of the selected load node through collaborative operation.

[0105] The methods of the present application can be implemented in hardware, firmware, or software, or any combination thereof, and can be stored in or implemented with the aid of software or computer code stored in a recording medium as a computer program product without departing from the scope of the present application. The computer program product includes a computer readable medium, such as but not limited to the non-transitory machine-readable medium described above. The computer program product can also include packaging housing the computer-readable medium. The computer readable medium having stored thereon the software or computer code, which software or computer code, when executed by a computer, processor, or hardware, causes the computer, processor, or hardware to implement the methods described herein. The software or computer code can be stored in a computer readable medium, which is non-transitory, operable to store the software or computer code. Examples of the computer- readable medium include a hard disk, a CD-ROM, an optical disk, a DVD, a Blu-ray disk, a magnetic tape, a flash memory, a PROM, RAM, ROM, and the like. The computer readable medium can be portable, non-portable, or built-in (i.e., non-removable) with the computer or processor. The computer readable medium can be a recording medium, a memory device, or a combination thereof. The software or computer code can be stored in the computer readable medium, which is non-transitory, operable to store the software or computer code. Examples of the computer-readable medium include a hard disk, a CD-ROM, an optical disk, a DVD, a Blu-ray disk, a magnetic tape, a flash memory, a PROM, RAM, ROM, and the like. The computer readable medium can be portable, non-portable, or built-in (i.e., non-removable) with the computer or processor. The computer readable medium can be a recording medium, a memory device, or a combination thereof.

[0106] The foregoing is considered as illustrative only of the principles of the application. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the application to the exact construction and practice described. Accordingly, all such variations and modifications are intended to be included within the scope of the present application as defined in the following claims.

Claims

1. A source-load coordinated control method for distribution transformer microgrids oriented towards load voltage management, characterized in that, Includes the following steps: By combining droop control structure and theory, a simplified input-output control model for distributed power sources is constructed. Based on graph theory, a communication topology architecture between distributed power generation nodes in a transformer microgrid is constructed. Based on the simplified input-output control model of the distributed power source and the communication topology between distributed power source nodes in the distribution microgrid, a distributed power source cooperative control strategy based on load voltage drive is constructed and executed, so that each distributed power source can track the expected voltage value of the selected load node through cooperative operation. The simplified input-output control model of the distributed power source is as follows: Among them, subscript i Indicates the first i Distributed power source serial numbers in each microgrid area. This represents the differential state of the output voltage of the distributed power source. To simplify the virtual control input of the control model; This is the reactive power-voltage droop factor. This is a reactive power reference command. Rated operating voltage, The output reactive power of the distributed power source. The output voltage of the distributed power source. This is the filtering time constant of the low-pass filter; The microgrid in the distribution area includes: N One droop-controlled distributed power source and one load; N A drooping control distributed power source acts as a follower, and the load acts as the leader, using an undirected graph. Characterize the distributed communication topology of each controlled unit; in an undirected graph, This represents a set of distributed power supply intelligent agents that follow the drooping control. The edge set representing the agent, It is an adjacency matrix; The execution process of the load voltage-driven distributed power supply cooperative control strategy includes: Each power source collects local voltage data in real time; It transmits its own voltage status through the communication network and obtains the voltage status information of adjacent distributed power sources and leader load nodes. Based on the dynamic consensus algorithm, the voltage data of local and adjacent distributed power sources are integrated to generate reactive power regulation command references and send them to the inverters of local distributed power sources for execution. The control form of the power distributed cooperative control strategy based on load voltage drive is as follows: in, To simplify the virtual control input of the control model, Indicates the first i A droop control of the voltage tracking error of a distributed power source. and The control gain is for the distributed collaborative control strategy.

2. The source-load coordinated control method for distribution microgrids oriented towards load voltage management according to claim 1, characterized in that, The stability of the load voltage-driven distributed power supply cooperative control strategy is verified using a verification equation based on an energy function. The verification equation based on the energy function is as follows: in, The energy function is suitable for a distributed power supply cooperative control strategy based on load voltage drive. It is the voltage tracking error of the entire distribution area microgrid.

3. A source-load coordinated control system for a distribution microgrid oriented towards load voltage management, executing the control method described in claim 1 or 2, characterized in that, include: Regulation model construction module: Combining droop control structure and theory, a simplified input-output regulation model for distributed power sources is constructed; Topology architecture construction module: Based on graph theory, construct the communication topology architecture between distributed power generation nodes in the transformer substation microgrid; Coordination and control module: Based on the simplified input and output control model of the distributed power source and the communication topology between distributed power source nodes in the distribution microgrid, it constructs and executes a distributed power source cooperative control strategy driven by load voltage, so that each distributed power source can track the expected voltage value of the selected load node through cooperative operation.

4. A computer storage medium storing a readable program, characterized in that, When the program runs, it can instruct the computing device to execute the source-load coordinated control method for distribution microgrids oriented towards load voltage management as described in any one of claims 1-2.

5. An electronic device, characterized in that, include: The processor, memory, communication interface, and communication bus are provided, wherein the processor, memory, and communication interface communicate with each other via the communication bus. The memory is used to store at least one executable instruction, which causes the processor to perform the operation corresponding to the source-load coordinated control method for distribution microgrids oriented towards load voltage management as described in any one of claims 1-2.

6. A computer program product comprising computer instructions, characterized in that, The computer instructions instruct the computing device to perform the operations corresponding to the source-load coordinated control method for distribution microgrids oriented towards load voltage management as described in any of claims 1-2.

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