Distributed cooperative control system of power distribution network

Abstract

The invention relates to the technical field of power distribution network control, and particularly discloses a power distribution network distributed cooperative control system, which comprises a sensing acquisition module, a state judgment module, a communication interaction module, a main node setting module, a consensus control module, a control execution module and an exception handling module. According to the scheme, a dynamic main node selection method is adopted, the main nodes are dynamically arranged in each control period, the multiple main nodes can guide different local sub-graphs respectively, partition cooperative adjustment is achieved, the efficient response capacity and robustness of the system are improved, and rapid convergence of the system is facilitated through target-driven reactive power adjustment; state convergence among PV nodes is achieved through a consensus control method, it is guaranteed that all PV nodes output reactive power in equal proportion according to the capacities of the PV nodes through node identification and command transmission, overload or idle of some PV nodes is avoided, system-level reactive synchronous control is achieved, the self-adaptive capacity of the system is effectively improved, and network topology changes are flexibly coped with.

Description

Technical Field

[0001] The present invention relates to the technical field of power distribution network control, and in particular to a distributed collaborative control system for a power distribution network. Background Art

[0002] With the widespread deployment of distributed photovoltaic (PV) systems in modern distribution networks, voltage excursions have become a significant bottleneck restricting the integration of high-proportion PV systems, particularly in low-voltage distribution networks. Traditional centralized control strategies rely on a central controller for unified scheduling, but suffer from poor robustness and limited scalability in the face of PV (photovoltaic inverter) node communication interruptions, topology changes, or system disturbances. Existing distributed approaches rely on fixed leader nodes, which are unable to adapt to dynamic changes in key nodes and make it difficult to ensure voltage stability and fair reactive power distribution in the distribution network. Summary of the Invention

[0003] In response to the above situation and to overcome the shortcomings of the prior art, the present invention provides a distributed collaborative control system for a distribution network. This solution addresses the problem that some existing distributed methods rely on fixed leader nodes, cannot adapt to dynamic changes in key nodes, and have difficulty ensuring voltage stability and fair distribution of reactive power in the distribution network. This solution adopts a dynamic master node selection method to dynamically set a master node within each control cycle. Multiple master nodes can guide different local subgraphs, respectively, to achieve partitioned collaborative regulation, improve the system's efficient responsiveness and robustness, and facilitate rapid system convergence through target-driven reactive power regulation. Traditional centralized control strategies rely on a central controller for unified scheduling, but suffer from poor robustness and limited scalability in the face of PV node communication interruptions, topology changes, or system disturbances. This solution achieves state convergence among PV nodes through a consensus control method. Through node identification and command transmission, it ensures that all PV nodes output reactive power in proportion to their capacity, avoids overload or idleness of some PV nodes, and achieves system-level reactive synchronous control, effectively improving the system's adaptability and flexibly responding to network topology changes.

[0004] The present invention provides a distributed collaborative control system for a power distribution network, comprising a sensing and acquisition module, a state judgment module, a communication interaction module, a master node setting module, a consensus control module, a control execution module, and an exception handling module;

[0005] The sensing and acquisition module periodically samples the operating parameters of the PV node, including voltage, current, active power, reactive power and inverter rated capacity, and sends the operating parameters of the PV node to the status judgment module and the consensus control module;

[0006] The state judgment module judges the node operation state according to the voltage value of the PV node, calculates the reactive power utilization rate, and generates an abnormal state flag as a communication broadcast content to be sent to the communication interaction module;

[0007] The communication interaction module builds a point-to-point communication link to realize information interaction between PV nodes;

[0008] The master node setting module periodically determines the master node and generates a guide value to be broadcasted to the non-master nodes;

[0009] The consensus control module coordinates the tracking response of the non-master nodes to the master node's guidance value, and outputs the reactive power ratio adjustment value of the PV node to the control execution module;

[0010] The control execution module drives the inverter to output actual reactive power according to the reactive power ratio adjustment amount of the PV node;

[0011] The exception handling module triggers the fault tolerance mechanism when an abnormal condition occurs in the distribution network.

[0012] Furthermore, the state judgment module obtains the normal operating voltage range, judges the node operation state according to the voltage value of the PV node, calculates the reactive power utilization of the PV node in intervals, and generates the abnormal state flag of the PV node according to the calculation result of the reactive power utilization: abnormal is 1 and normal is 0.

[0013] Furthermore, the master node setting module periodically determines the master node and generates a guide value to be broadcasted to the non-master nodes, specifically including the following steps:

[0014] Step S1: Master node determination. A control cycle is set. During each control cycle, the PV node obtains the reactive power utilization of its neighboring nodes through a point-to-point communication link and compares them. If the absolute value of the reactive power utilization of the current PV node is the largest, it is considered to have the most serious voltage deviation in the local area and is set as the master node of this control cycle. The node ID is 1. All other neighboring nodes are non-master nodes and their node IDs are set to 0.

[0015] Step S2: Command graph construction: construct one or more unidirectional directed graphs as command graphs based on the node identifiers. The directed edges in the command graphs are from the primary node to the adjacent non-primary nodes.

[0016] Step S3: Guide value broadcasting: the master node broadcasts its reactive power utilization as a guide value to adjacent non-master nodes through the command graph.

[0017] Furthermore, the consensus control module coordinates the tracking response of the non-master nodes to the master node's guidance value, so that the reactive power ratios output by all PV nodes gradually converge, and outputs the reactive power ratio adjustment value of the PV node. The formula used is as follows: ;

[0018] Where, Indicates PV node The reactive power ratio adjustment amount, is the control gain coefficient, Indicates PV node The set of neighbor nodes of represents neighbor nodes, Indicates the command transmission coefficient for determining whether the PV node receives information from neighboring nodes. The communication weight indicating whether there is a communication connection between PV nodes, Indicates PV node The reactive power, Indicates PV node The maximum reactive power output value, Indicates PV node The reactive power ratio, Represents neighbor nodes The reactive power ratio, Indicates the node ID, Indicates the boot value of the master node.

[0019] Furthermore, the control execution module calculates a reactive current component reference value based on the reactive power ratio adjustment of the PV node, which serves as the input of the current controller inside the inverter. The current controller drives the inverter to output actual reactive power, while constraining the PV node to meet the inverter capacity limit condition at any time to prevent the inverter from overloading. The formula used is as follows: ; ;

[0020] Where, Indicates PV node The reference value of the reactive current component, Indicates PV node The rated capacity of the inverter, Indicates PV node The voltage, represents the control function that converts the reactive power ratio adjustment into the reactive current component reference value, Indicates PV node active power.

[0021] The beneficial effects achieved by the present invention using the above scheme are as follows:

[0022] (1) In response to the problem that some existing distributed methods rely on fixed leader nodes and cannot adapt to the dynamic changes of key nodes, making it difficult to ensure the voltage stability of the distribution network and the fair distribution of reactive power, this scheme adopts a dynamic master node selection method to dynamically set the master node in each control cycle. Multiple master nodes can guide different local subgraphs respectively to achieve partitioned collaborative regulation, improve the system's efficient response capability and robustness, and help the system converge quickly through target-driven reactive power regulation.

[0023] (2) In response to the problem that traditional centralized control strategies rely on a central controller for unified scheduling, but have poor robustness and limited scalability when facing PV node communication interruptions, topology changes, or system disturbances, this scheme uses a consensus control method to achieve state convergence among PV nodes. Through node identification and command transmission, it ensures that all PV nodes output reactive power in proportion to their capacity, avoids overload or idleness of some PV nodes, realizes system-level reactive power synchronization control, effectively improves the system's adaptability, and flexibly responds to changes in network topology. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of a distributed collaborative control system for a power distribution network proposed by the present invention;

[0025] Figure 2 This is a schematic diagram of the process in Example 4.

[0026] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0028] Example 1, see Figure 1 , a distributed collaborative control system for a distribution network provided by the present invention includes a perception and acquisition module, a state judgment module, a communication interaction module, a master node setting module, a consensus control module, a control execution module and an exception handling module;

[0029] The sensing and acquisition module periodically samples the operating parameters of the PV node, including voltage, current, active power, reactive power and inverter rated capacity, and sends the operating parameters of the PV node to the status judgment module and the consensus control module;

[0030] The state judgment module judges the node operation state according to the voltage value of the PV node, calculates the reactive power utilization rate, and generates an abnormal state flag as a communication broadcast content to be sent to the communication interaction module;

[0031] The communication interaction module builds a point-to-point communication link to realize information interaction between PV nodes;

[0032] The master node setting module periodically determines the master node and generates a guide value to be broadcasted to the non-master nodes;

[0033] The consensus control module coordinates the tracking response of the non-master nodes to the master node's guidance value, and outputs the reactive power ratio adjustment value of the PV node to the control execution module;

[0034] The control execution module drives the inverter to output actual reactive power according to the reactive power ratio adjustment amount of the PV node;

[0035] The exception handling module triggers the fault tolerance mechanism when an abnormal condition occurs in the distribution network.

[0036] Example 2, see Figure 1 This embodiment is based on the above embodiment. The state judgment module obtains the normal operating voltage range of 0.9-1.1pu, judges the node operation state according to the voltage value of the PV node, and calculates the reactive power utilization rate of the PV node according to the corresponding interval. Specifically,

[0037] When the PV node is in normal working condition, the reactive power utilization rate is calculated as follows: ;

[0038] Where, Indicates the index of the PV node, Indicates the Reactive power utilization of each PV node, Indicates the The voltage value of each PV node;

[0039] When the PV node is in abnormal working conditions, the reactive power utilization is calculated using a piecewise nonlinear function. The formula used is as follows: ;

[0040] Where, Indicates abnormal working conditions The maximum reactive power that a PV node can output, Indicates the Rated capacity of each inverter;

[0041] The abnormal status flag of the PV node is generated according to the reactive power utilization calculation result: abnormal is 1 and normal is 0.

[0042] Example 3, see Figure 1 This embodiment is based on the above embodiment. The communication interaction module builds a point-to-point communication link to implement information interaction between PV nodes, including the following steps:

[0043] Step A1: Bidirectional neighbor status exchange: each PV node establishes a point-to-point communication link with its neighbor node and initializes the neighbor node set and status table;

[0044] Step A2: Data synchronization. The synchronization period is set to 1 second. The PV node broadcasts a data packet once in each synchronization period. The data packet contains the PV node's reactive power utilization, abnormal status flag, and the set and status table of neighbor nodes received in the previous synchronization period. The data packet is sent to all neighbor nodes simultaneously through the point-to-point communication link.

[0045] Step A3: Neighbor status update. After the PV node receives the data packet from the neighbor node, it automatically updates the neighbor node set and status table.

[0046] Example 4, see Figure 1 and Figure 2 This embodiment is based on the above embodiment. The master node setting module periodically determines the master node and generates a guidance value to be broadcast to the non-master nodes. Specifically, the following steps are included:

[0047] Step S1: Master node determination. A control cycle is set. During each control cycle, the PV node obtains the reactive power utilization of its neighboring nodes through a point-to-point communication link and compares them. If the absolute value of the reactive power utilization of the current PV node is the largest, it is considered to have the most serious voltage deviation in the local area and is set as the master node of this control cycle. The node ID is 1. All other neighboring nodes are non-master nodes and their node IDs are set to 0.

[0048] Step S2: Command graph construction: construct a unidirectional directed graph as the command graph based on the node identifiers. The directed edges in the command graph are from the primary node to the adjacent non-primary node.

[0049] Step S3: Guide value broadcasting: the master node broadcasts its reactive power utilization rate as a guide value to adjacent non-master nodes through the command graph. The non-master nodes receive the guide value from the master node and perform follow-up control based on the guide value.

[0050] By performing the above operations, in order to address the problem that some existing distributed methods rely on fixed leader nodes, cannot adapt to the dynamic changes of key nodes, and have difficulty in ensuring the voltage stability of the distribution network and the fair distribution of reactive power, this solution adopts a dynamic master node selection method to dynamically set the master node in each control cycle. Multiple master nodes can respectively guide different local subgraphs to achieve partitioned collaborative regulation, improve the system's efficient responsiveness and robustness, and help the system converge quickly through target-driven reactive power regulation.

[0051] Example 5, see Figure 1 This embodiment is based on the above embodiment. The consensus control module coordinates the tracking response of the non-master nodes to the master node's guidance value, so that the reactive power ratios output by all PV nodes gradually converge, and outputs the reactive power ratio adjustment value of the PV node. The formula used is as follows: ;

[0052] Where, Indicates PV node The reactive power ratio adjustment amount, is the control gain coefficient, Indicates PV node The set of neighbor nodes of represents neighbor nodes, Indicates the command transmission coefficient for determining whether the PV node receives information from neighboring nodes. The communication weight indicating whether there is a communication connection between PV nodes, Indicates PV node The reactive power, Indicates PV node The maximum reactive power output value, Indicates PV node The reactive power ratio, Represents neighbor nodes The reactive power ratio, Indicates the node ID, Indicates the boot value of the master node.

[0053] By executing the above operations, the traditional centralized control strategy relies on a central controller for unified scheduling, but has poor robustness and limited scalability when facing PV node communication interruptions, topology changes or system disturbances. This solution uses a consensus control method to achieve state convergence among PV nodes. Through node identification and command transmission, it ensures that all PV nodes output reactive power in proportion to their capacity, avoids overload or idleness of some PV nodes, realizes system-level reactive power synchronization control, effectively improves the system's adaptability, and flexibly responds to changes in network topology.

[0054] Example 6, see Figure 1 This embodiment is based on the above embodiment. The control execution module calculates the reactive current component reference value based on the reactive power ratio adjustment value of the PV node as the input of the current controller inside the inverter. The current controller drives the inverter to output actual reactive power. At the same time, the PV node is constrained to meet the inverter capacity limit condition at any time to prevent the inverter from overloading. The formula used is as follows: ; ;

[0055] Where, Indicates PV node The reference value of the reactive current component, Indicates PV node The rated capacity of the inverter, Indicates PV node The voltage, represents the control function that converts the reactive power ratio adjustment into the reactive current component reference value, Indicates PV node active power.

[0056] Example 7, see Figure 1 This embodiment is based on the above embodiment. The abnormality handling module triggers the fault tolerance mechanism when an abnormal condition occurs in the distribution network. The abnormal conditions include node voltage out of range, communication interruption, and neighbor node disconnection. The fault tolerance mechanism is: when the communication link between PV nodes is disconnected or the node is offline, the neighbor node re-broadcasts the node status; if the master node is offline, the remaining nodes re-evaluate the election process and complete the master node switching; if the abnormal status flag of the neighbor node is 1, it enters the abnormal synchronous response mode, expands the reactive power utilization range, improves the response sensitivity, and gives priority to protecting voltage stability.

[0057] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0058] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

[0059] The present invention and its embodiments are described above. This description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if a person skilled in the art is inspired by this and, without departing from the purpose of the present invention, designs structures and embodiments similar to this technical solution without inventiveness, they shall fall within the scope of protection of the present invention.

Claims

1. A distributed collaborative control system for a distribution network, characterized by: It includes perception and acquisition module, status judgment module, communication interaction module, master node setting module, consensus control module, control execution module and exception handling module; The sensing and acquisition module periodically samples the operating parameters of the PV node, including voltage, current, active power, reactive power and inverter rated capacity, and sends the operating parameters of the PV node to the status judgment module and the consensus control module; The state judgment module judges the node operation state according to the voltage value of the PV node, calculates the reactive power utilization rate, and generates an abnormal state flag as a communication broadcast content to be sent to the communication interaction module; The communication interaction module builds a point-to-point communication link to realize information interaction between PV nodes; The master node setting module periodically determines the master node and generates a guide value to be broadcasted to the non-master nodes; The consensus control module coordinates the tracking response of the non-master nodes to the master node's guidance value, and outputs the reactive power ratio adjustment value of the PV node to the control execution module; The control execution module drives the inverter to output actual reactive power according to the reactive power ratio adjustment amount of the PV node; The exception handling module triggers the fault tolerance mechanism when an abnormal condition occurs in the distribution network.

2. A distributed collaborative control system for a power distribution network according to claim 1, characterized in that: The state judgment module obtains the normal operating voltage range, judges the node operation state according to the voltage value of the PV node, calculates the reactive power utilization rate of the PV node by interval, and generates the abnormal state flag of the PV node according to the reactive power utilization calculation result: abnormal is 1 and normal is 0.

3. The distributed coordinated control system for a power distribution network according to claim 1, characterized in that: The master node setting module periodically determines the master node and generates a guide value to be broadcast to the non-master nodes, specifically including the following steps: Step S1: Master node determination. A control cycle is set. During each control cycle, the PV node obtains the reactive power utilization of its neighboring nodes through a point-to-point communication link and compares them. If the absolute value of the reactive power utilization of the current PV node is the largest, it is considered to have the most serious voltage deviation in the local area and is set as the master node of this control cycle. The node ID is 1. All other neighboring nodes are non-master nodes and their node IDs are set to 0. Step S2: Command graph construction: construct one or more unidirectional directed graphs as command graphs based on the node identifiers. The directed edges in the command graphs are from the primary node to the adjacent non-primary nodes. Step S3: Guide value broadcasting: the master node broadcasts its reactive power utilization as a guide value to adjacent non-master nodes through the command graph.

4. A distributed coordinated control system for a power distribution network according to claim 1, characterized in that: The consensus control module coordinates the tracking response of non-master nodes to the master node's guidance value, so that the reactive power ratios output by all PV nodes gradually converge, and outputs the reactive power ratio adjustment value of the PV node. The formula used is as follows: ； Where, Indicates PV node The reactive power ratio adjustment amount, is the control gain coefficient, Indicates PV node The set of neighbor nodes of represents neighbor nodes, Indicates the command transmission coefficient for determining whether the PV node receives information from neighboring nodes. The communication weight indicating whether there is a communication connection between PV nodes, Indicates PV node The reactive power, Indicates PV node The maximum reactive power output value, Indicates PV node The reactive power ratio, Represents neighbor nodes The reactive power ratio, Indicates the node ID, Indicates the boot value of the master node.

5. The distributed collaborative control system for a power distribution network according to claim 1, characterized in that: The control execution module calculates a reactive current component reference value based on the reactive power ratio adjustment of the PV node as the input of the current controller inside the inverter, and drives the inverter to output actual reactive power through the current controller. At the same time, it constrains the PV node to meet the inverter capacity limit conditions at any time to prevent the inverter from overloading.

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