Load voltage management and control-oriented source-load cooperative control method and system for district micro-grid

Abstract

The invention discloses a transformer area micro-grid source load cooperative control method and system for load voltage control, and belongs to the technical field of power system control. The load voltage control-oriented district micro-grid source load cooperative control method comprises the following steps of: constructing an input and output simplified regulation and control model of a distributed power supply by combining a droop control structure and a droop control theory; based on a graph theory, constructing a communication topology architecture among distributed power supply nodes in the district micro-grid; constructing and executing a power supply distributed cooperative control strategy based on load voltage driving based on the input and output simplified regulation and control model of the distributed power supplies and the communication topology architecture among the distributed power supply nodes in the transformer area micro-grid, and enabling each distributed power supply to track an expected voltage value of a selected load node through cooperative operation; therefore, the voltage control precision and the dynamic response capability are improved, and the power supply quality is effectively guaranteed.

Description

Technical Field

[0001] The present invention belongs to the technical field of power system control, and specifically relates to a method and system for coordinated source-load control of a microgrid in an area for load voltage control. Background Art

[0002] With the large-scale integration of high-proportion renewable energy into the power system, the penetration of distributed generation (DGs) in the distribution network continues to increase. Traditional centralized dispatch-based substation voltage control models face structural challenges. On the one hand, the high uncertainty and spatiotemporal dispersion of DG output significantly exacerbate voltage fluctuations at load nodes. On the other hand, critical loads such as sensitive industrial production lines, medical facilities, and data centers place higher demands on power supply quality.

[0003] Existing voltage control technologies suffer from two main flaws: local correction strategies are prone to control conflicts due to a lack of global coordination, while hierarchical centralized control is constrained by communication delays and cannot meet real-time response requirements. Under power surges or fault conditions, these methods are unable to quickly and accurately track load voltages, which not only degrades power quality but also endangers the power supply stability of critical loads and causes economic losses. Therefore, a coordinated source-load control method for microgrids in substations is urgently needed for load voltage control to ensure the safe and reliable operation of new power systems. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a method and system for coordinated source-load control of a substation microgrid for load voltage control, thereby solving the problems in the prior art.

[0005] The purpose of the present invention can be achieved through the following technical solutions: The source-load coordinated control method of the microgrid in the substation area for load voltage control includes the following steps: Combining droop control structure and theory, a simplified input and output control model of distributed power supply is constructed; Based on graph theory, a communication topology architecture between distributed power generation nodes in the substation microgrid is constructed; Based on the simplified input and output control model of the distributed power source and the communication topology architecture between the distributed power source nodes in the substation microgrid, a power source distributed collaborative control strategy driven by load voltage is constructed and executed, so that each distributed power source can track the expected voltage value of the selected load node through collaborative operation.

[0006] Furthermore, the simplified input and output control model of the distributed power supply is: Among them, the subscript i Indicates the iThe serial number of distributed power sources in each area microgrid, is the differential state of the output voltage of the distributed power supply, To simplify the regulation model, virtual control input is used; is the reactive-voltage droop coefficient, is the reactive power reference instruction, is the rated operating voltage, is the output reactive power of distributed power generation, is the output voltage of the distributed power supply, is the filtering time constant of the low-pass filter.

[0007] Furthermore, the substation microgrid includes: N A droop-controlled distributed generation and a load; N The droop control distributed generation is used as a follower and the load is used as a leader. Characterize the distributed communication topology of each controlled unit; in an undirected graph, represents the set of distributed power generation agents following droop control, represents the edge set of the agent, is the adjacency matrix.

[0008] Furthermore, the execution process of the load voltage-driven distributed collaborative control strategy for power supplies includes: Each power supply collects local voltage in real time; Transmit its own voltage status through the communication network and obtain the status information of the voltage of adjacent distributed power sources and leading load nodes; Based on the dynamic consistency algorithm, the local and adjacent distributed power supply voltage data are integrated to generate reactive power regulation instruction reference and send it to the inverter of the local distributed power supply for execution.

[0009] Furthermore, the control form of the power supply distributed collaborative control strategy based on load voltage drive is: in, In order to simplify the virtual control input of the control model, Indicates the i The voltage tracking error of the distributed power supply under droop control is and is the control gain of the distributed cooperative control strategy.

[0010] Furthermore, a verification equation based on an energy function is used to verify the stability of the distributed collaborative control strategy of the power supply based on load voltage drive; the verification equation based on the energy function is: in, is the energy function applicable to the distributed cooperative control strategy of power supply based on load voltage drive, is the voltage tracking error of the entire substation microgrid.

[0011] The microgrid source-load collaborative control system for load voltage control in the substation area includes: Control model construction module: Combines droop control structure and theory to build a simplified input and output control model for distributed power sources; Topology architecture building module: Based on graph theory, it builds the communication topology architecture between distributed power nodes in the substation microgrid; Coordination control module: Based on the simplified input and output control model of the distributed power supply and the communication topology architecture between the distributed power supply nodes in the substation microgrid, a power supply distributed collaborative control strategy driven by load voltage is constructed and executed, so that each distributed power supply can track the expected voltage value of the selected load node through collaborative operation.

[0012] A computer storage medium stores a readable program. When the program is run, the program can instruct a computing device to execute the above-mentioned substation microgrid source-load coordinated control method for load voltage control.

[0013] An electronic device comprising: a processor, a memory, a communication interface, and a communication bus, wherein the processor, the memory, and the communication interface communicate with each other via the communication bus; The memory is used to store at least one executable instruction, and the executable instruction enables the processor to perform operations corresponding to the above-mentioned substation microgrid source-load coordinated control method for load voltage control.

[0014] A computer program product includes computer instructions, which instruct a computing device to perform operations corresponding to the above-mentioned method for source-load coordinated control of a substation microgrid for load voltage control.

[0015] Beneficial effects of the present invention: 1. Through the proposed distributed collaborative control strategy, multiple distributed power sources can work together to accurately and quickly track the expected voltage value of the selected load node, improve the voltage control accuracy and dynamic response capability, and effectively ensure the power supply quality.

[0016] 2. This invention utilizes a graph-theoretic communication topology to achieve autonomous and coordinated power supply regulation, requiring only limited information exchange between adjacent power supply nodes. This distributed architecture eliminates the need for a central controller, enhancing system flexibility, scalability, and reliability, and facilitating plug-and-play distributed power supply deployment.

[0017] 3. By constructing a simplified power supply model to analyze the control process and conducting rigorous stability theory analysis based on the energy function, a solid guarantee is provided for the effectiveness and robustness of the control strategy. At the same time, the control design is simplified and the engineering practicality and credibility of the method are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0019] Figure 1 This is a diagram of the microgrid architecture of the substation area of ​​the present invention; Figure 2 This is a flow chart of the method for coordinated source-load control of a microgrid in an area for load voltage control according to the present invention; Figure 3 This is a diagram of the test simulation system of the substation microgrid of the present invention; Figure 4 is the voltage response curve of four distributed power supply nodes and one load node of the present invention; Figure 5 The figure is a comparison diagram of the control effect of the load node voltage in the substation microgrid before and after adopting the method of the present invention. DETAILED DESCRIPTION

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0021] Example 1 like Figure 1 As shown in the figure, the microgrid in the substation area is deployed with N A distributed power source interconnected by a distributed communication topology ( ~ ), each power source is equipped with a distributed controller to realize local command calculation and regulation. The controller of each distributed power source relies on the communication topology to interact with the adjacent nodes to form a collaborative control network. A key load node (marked as a leader node) is provided in the microgrid. The node has the following characteristics: serving as the leader node of the distributed communication network; configuring a voltage collector to collect the local voltage status of this load node in real time; and transmitting voltage data to the designated distributed power source controller through a communication link. When load switching or new energy power fluctuations occur in the substation microgrid, key load nodes are prone to voltage deviations, resulting in a decline in power quality and endangering power supply reliability. The control method provided in this embodiment is designed to solve this problem.

[0022] like Figure 2 As shown in FIG, the source-load coordinated control method of the substation microgrid for load voltage control includes the following steps: S1, combining droop control structure and theory, constructs a simplified input-output control model of distributed power supply to achieve accurate mapping from control instructions to output voltage; Droop-controlled distributed power sources can achieve autonomous voltage regulation through the reactive-voltage droop characteristic: when the output reactive power increases, the output voltage amplitude is reduced by a preset droop factor, and vice versa. This characteristic enables dynamic reactive power compensation, suppressing line voltage drops and supporting voltage stability at key nodes. This step constructs a simplified voltage regulation model, revealing the dynamic response relationship from reactive power regulation commands to output voltage amplitude, providing a quantitative basis for coordinated voltage control of multiple power sources.

[0023] Considering that the time scale of the secondary control of the voltage in the microgrid is in the order of seconds, the present invention ignores the millisecond transient process of the dual loop inside the distributed power supply when modeling, and only retains the first-order low-pass filter dynamics of the power measurement. N The first distributed power source i The simplified control model of the input and output of the distributed power supply with droop control can be expressed as: (1) in, is the reactive-voltage droop coefficient, is the reactive power reference instruction, is the rated operating voltage, is the output reactive power of distributed power generation, is the output voltage of the distributed power supply, is the filtering time constant of the low-pass filter, is the Laplace operator.

[0024] To facilitate the design of state feedback, iThe simplified input-output control model of a droop-controlled distributed power supply is expressed in the form of first-order differential: (2) in, is the differential state of the output voltage of the distributed power supply, To simplify the control model virtual control input, it will be obtained through the locally deployed distributed secondary controller. is the output reactive power of distributed power generation, which will be Calculated.

[0025] S2, based on graph theory, constructs the communication topology architecture between distributed power nodes in the substation microgrid to clarify the communication relationship between distributed power sources; Based on graph theory, an undirected connected communication network is constructed, and the node adjacency matrix and edge weight distribution rules are defined to realize the distributed dynamic interaction of voltage / power status between power nodes, forming a decentralized information-physical fusion architecture to ensure data accessibility and support the real-time and robustness requirements of distributed decision-making.

[0026] For the microgrid in the substation area proposed in the present invention, Figure 1 Shown, including N A droop-controlled distributed power source and a load that needs to be accurately controlled. N The droop control distributed power source is used as a follower, and the load that needs to be accurately controlled is used as a leader. Characterizes the distributed communication topology of each controlled unit. In an undirected graph, represents the set of distributed power generation agents following droop control, represents the edge set of the agent, is an undirected graph G The adjacency matrix of Represents the first i OK j The coefficient of the column. i Distributed power supply to j When the information flow of a distributed power source is ;otherwise Undirected graph G The Laplace matrix of , whose elements satisfy: (3) Adopting a leadership matrix Describe the connection relationship between distributed power sources and leading loads. When , it means there is a leader node to the i The information flow of a distributed power source.

[0027] S3, based on the control model constructed in S1 and the communication topology architecture constructed in S2, constructs and executes a distributed collaborative control strategy for power sources driven by load voltage, so that each distributed power source can track the expected voltage value of the selected load node through collaborative operation; The distributed coordinated control strategy for power sources based on load voltage drive designed in this embodiment includes three specific execution processes: First, each power supply collects local voltage in real time; Secondly, it transmits its own voltage status through the communication network and obtains the status information of the voltage of the adjacent distributed power sources and the leading load node; Finally, the local and adjacent distributed power supply voltage data are fused based on the dynamic consistency algorithm to generate a reactive power regulation instruction reference and send it to the inverter of the local distributed power supply for execution.

[0028] In the controlled microgrid, it is assumed that the node voltage expectation of the leading load is , then the voltage deviation of the leading load node can be expressed as: (4) in, is the node voltage measurement status of the leading load, It is the voltage deviation state of the leading load node.

[0029] Furthermore, the global instruction reference transmitted from the leading load node to the distributed power source through the distributed communication topology can be designed as: (5) in, For global instruction reference, and It is the gain coefficient in the global instruction reference calculation.

[0030] Based on the simplified input-output control model of the global reference command and droop control distributed power supply, the following distributed tracking error and virtual control input are designed for the distributed coordinated control strategy of the load voltage-driven power supply: (6) (7) in, Indicates the i The voltage tracking error of the distributed power supply under droop control is and is the control gain of the distributed cooperative control strategy Based on the above formula, the reactive power reference instruction of the final droop control distributed power supply can be expressed as: (8) in, Reactive power reference command for droop control of distributed generation.

[0031] 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; To demonstrate the stability of all control methods and the overall extraction of the microgrid control system, combined with the graph theory foundation of the above steps and the tracking error and method of a single power source, this embodiment expresses the distributed tracking error of the entire system as: (9) in, is the voltage tracking error of the entire microgrid, expressed as , The voltage state of the entire microgrid is expressed as .

[0032] Furthermore, the distributed virtual control input of the entire system of the substation microgrid is expressed as: (10) in, is a diagonal matrix defined as is the distributed control coordination input of the whole system of the substation microgrid in the global form, which is expressed as: ; Combined with the above definitions, the stability analysis adopts the Lyapunov function method to construct the following energy function for the entire substation microgrid distributed control system: (11) in, is the energy function applicable to the distributed cooperative control strategy of power supply based on load voltage drive, is the voltage tracking error of the entire substation microgrid; The differential form with respect to time is expressed as: (12) Because, due to is a positive definite matrix, so when the control gain of the distributed cooperative control strategy is and When it is a negative number, you can get the result: This result proves the stability of the overall control system, that is, the distributed control system of the substation microgrid can be stably controlled and operated.

[0033] Based on similar inventive concepts, an embodiment of the present invention also provides a computer storage medium storing a readable program. When the program is run by a processor, it can execute the above-mentioned substation microgrid source-load coordinated control method for load voltage control.

[0034] Based on similar inventive concepts, an embodiment of the present invention provides an electronic device, comprising: a processor, a memory, a communication interface, and a communication bus, wherein the processor, the memory, and the communication interface communicate with each other via the communication bus; The memory is used to store at least one executable instruction, and the executable instruction enables the processor to perform operations corresponding to the above-mentioned substation microgrid source-load collaborative control method for load voltage control.

[0035] Based on similar inventive concepts, an embodiment of the present invention also provides a computer program product, including computer instructions, which instruct a computing device to perform operations corresponding to the above-mentioned substation microgrid source-load collaborative control method for load voltage control.

[0036] Example 2 In order to verify the effect of the control method of the present invention, the following Figure 3 The substation microgrid test simulation system shown includes four distributed generation units using droop control, three operating loads, and one load that requires critical power supply. Figure 4 The voltage response curves for four distributed power generation (DG) nodes and one load node within the system are shown. The results show that when the load node voltage deviates due to power fluctuations caused by the switching of other loads, the control method of the present invention can quickly control the node voltage to the rated value (400V) by leveraging the coordinated action of the four DGs. Furthermore, the four DGs achieve stable, distributed, and consistent voltage coordination.

[0037] Figure 5 The control effect of the load node voltage in the substation microgrid before and after the implementation of the method of the present invention is demonstrated. The observation results show that under the same simulation test scenario, without precise load voltage control, the load voltage deviates from the expected rated value by approximately 20V, resulting in low power supply quality. However, using the method of the present invention, the load voltage can be stably tracked to the expected rated value of around 400V, with high power supply quality.

[0038] Example 3 In this embodiment, a microgrid source-load collaborative control system for load voltage control in a substation area is proposed, specifically including: Control model construction module: Combines droop control structure and theory to build a simplified input and output control model for distributed power sources; Topology architecture building module: Based on graph theory, it builds the communication topology architecture between distributed power nodes in the substation microgrid; Coordination control module: Based on the regulation model and the communication topology architecture, construct and execute a distributed coordinated control strategy of power sources driven by load voltage, so that each distributed power source can track the expected voltage value of the selected load node through coordinated operation.

[0039] The method of the present invention can be implemented in hardware, firmware, or as software or computer code that can be stored in a recording medium (such as a CDROM, RAM, floppy disk, hard disk or magneto-optical disk), or as computer code that is originally stored in a remote recording medium or a non-temporary machine-readable medium downloaded over a network and will be stored in a local recording medium, so that the method described herein can be stored in such software processing on a recording medium using a general-purpose computer, a special-purpose processor or programmable or special-purpose hardware (such as an ASIC or FPGA). It will be understood that a computer, a processor, a microprocessor controller or programmable hardware includes a storage component (e.g., RAM, ROM, flash memory, etc.) that can store or receive software or computer code, and when the software or computer code is accessed and executed by a computer, a processor or hardware, the method described herein is implemented. In addition, when a general-purpose computer accesses the code for implementing the method shown here, the execution of the code converts the general-purpose computer into a special-purpose computer for executing the method shown here.

[0040] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the invention as claimed.

Claims

1. A source-load coordinated control method for a microgrid in a substation for load voltage control, characterized by: The following steps are involved: Combining droop control structure and theory, a simplified input and output control model of distributed power supply is constructed; Based on graph theory, a communication topology architecture between distributed power generation nodes in the substation microgrid is constructed; Based on the simplified input and output control model of the distributed power source and the communication topology architecture between the distributed power source nodes in the substation microgrid, a power source distributed collaborative control strategy driven by load voltage is constructed and executed, so that each distributed power source can track the expected voltage value of the selected load node through collaborative operation.

2. The method for source-load coordinated control of a microgrid in a substation area for load voltage control according to claim 1 is characterized in that: The simplified input and output control model of the distributed power supply is: Among them, the subscript i Indicates the i The serial number of distributed power sources in each area microgrid, is the differential state of the output voltage of the distributed power supply, To simplify the regulation model, virtual control input is used; is the reactive-voltage droop coefficient, is the reactive power reference instruction, is the rated operating voltage, is the output reactive power of distributed power generation, is the output voltage of the distributed power supply, is the filtering time constant of the low-pass filter.

3. The method for source-load coordinated control of a microgrid in a substation area for load voltage control according to claim 1 is characterized in that: The substation microgrid includes: N A droop-controlled distributed generation and a load; N The droop control distributed generation is used as a follower and the load is used as a leader. Characterize the distributed communication topology of each controlled unit; in an undirected graph, represents the set of distributed power generation agents following droop control, represents the edge set of the agent, is the adjacency matrix.

4. The method for source-load coordinated control of a microgrid in a substation area for load voltage control according to claim 3 is characterized in that: The execution process of the power supply distributed collaborative control strategy based on load voltage drive includes: Each power supply collects local voltage in real time; Transmit its own voltage status through the communication network and obtain the status information of the voltage of adjacent distributed power sources and leading load nodes; Based on the dynamic consistency algorithm, the local and adjacent distributed power supply voltage data are integrated to generate reactive power regulation instruction reference and send it to the inverter of the local distributed power supply for execution.

5. The method for source-load coordinated control of a microgrid in an area for load voltage control according to claim 3 or 4, characterized in that: The control form of the power supply distributed collaborative control strategy based on load voltage drive is: in, In order to simplify the virtual control input of the control model, Indicates the i The voltage tracking error of the distributed power supply under droop control is and is the control gain of the distributed cooperative control strategy.

6. The method for source-load coordinated control of a microgrid in an area for load voltage control according to claim 5 is characterized in that: The energy function-based verification equation is used to verify the stability of the load voltage-driven distributed power supply cooperative control strategy; the energy function-based verification equation is: in, is the energy function applicable to the distributed cooperative control strategy of power supply based on load voltage drive, is the voltage tracking error of the entire substation microgrid.

7. The microgrid source-load collaborative control system for load voltage control in the substation area is characterized by: include: Control model construction module: Combines droop control structure and theory to build a simplified input and output control model for distributed power sources; Topology architecture building module: Based on graph theory, it builds the communication topology architecture between distributed power nodes in the substation microgrid; Coordination control module: Based on the simplified input and output control model of the distributed power supply and the communication topology architecture between the distributed power supply nodes in the substation microgrid, a power supply distributed collaborative control strategy driven by load voltage is constructed and executed, so that each distributed power supply can track the expected voltage value of the selected load node through collaborative operation.

8. A computer storage medium storing a readable program, characterized in that: When the program is running, the program can instruct the computing device to execute the substation microgrid source-load collaborative control method for load voltage control as described in any one of claims 1-6.

9. An electronic device, characterized in that: include: A processor, a memory, a communication interface, and a communication bus, wherein the processor, the memory, and the communication interface communicate with each other via the communication bus; The memory is used to store at least one executable instruction, and the executable instruction enables the processor to perform operations corresponding to the substation microgrid source-load collaborative control method for load voltage control as described in any one of claims 1-6.

10. A computer program product comprising computer instructions, characterized in that The computer instructions instruct the computing device to perform operations corresponding to the substation microgrid source-load collaborative control method for load voltage control as described in any one of claims 1-6.

Images