Distributed power flow control device cluster optimization coordination control method

Abstract

A distributed power flow control device cluster optimization coordination control method is characterized by comprising the following steps: step 1, calculating the operation efficiency of a DPFC device; step 2, calculating the reliability of the DPFC cluster; 3, constructing a DPFC device output model with the highest reliability and working efficiency of the DPFC cluster as a target; and step 4, designing a control strategy between DPFC clusters. The technical problem to be solved by the invention is to provide a distributed power flow control device cluster optimization coordination control method, and provides a control strategy for improving the working efficiency of a DPFC cluster for the working efficiency and the reliability of the DPFC in each cluster based on DPFC structural characteristics and cluster control characteristics. Therefore, high-efficiency operation of the DPFC and high-efficiency regulation and control of a power network are realized.

Description

Technical Field

[0001] The present invention relates to the field of AC power transmission device control, and in particular to a cluster optimization and coordinated control method for distributed power flow control devices. Background Art

[0002] Distributed Power Flow Controllers (DPFCs) are small-capacity, low-voltage, distributed series compensation devices deployed dispersed along the power lines, resulting in relatively low cost. Each DPFC has an independent controller that can coordinate operations in batches based on different objectives, greatly improving the flexibility and stability of power system power flow control. However, when large numbers of DPFCs are deployed in modern power grids, the continued use of traditional centralized control decision-making systems will face challenges with control flexibility, system reliability, and massive communication. Consequently, DPFCs may be unable to effectively meet the power flow control requirements of the power grid, thereby impacting the normal operation of the power system.

[0003] Traditional cluster control approaches fail to consider the operating status and characteristics of DPFC units when allocating tasks. This simplistic, idealized allocation of tasks often results in the entire DPFC cluster being constantly operating during the control process, resulting in wasted resources and reduced system reliability. Furthermore, DPFC units are deployed along the controlled lines, and their operating status is significantly affected by communication methods and unexpected factors. This can often lead to deviations in control performance or even failures among several DPFC units within a DPFC cluster.

[0004] Cluster control primarily addresses the issue of consistency, leveraging distributed coordination algorithms to achieve a certain consistency in the states or outputs of individual entities within a network. Distributed coordination algorithms employ simple local rules to coordinate global behavior. Cluster control has broad application in large-scale clusters of devices or in scenarios where multiple entities operate collaboratively. This present invention provides a method for cluster control of DPFC devices using a distributed coordination algorithm, laying the foundation for large-scale DPFC applications in power grids. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a distributed power flow control device cluster optimization and coordinated control method. Based on the DPFC structural characteristics and cluster control characteristics, a control strategy for improving the DPFC cluster working efficiency and reliability in each cluster is proposed, thereby achieving efficient operation of the DPFC and efficient regulation of the power network.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is: a distributed power flow control device cluster optimization coordinated control method, comprising the following steps: Step 1, calculation of DPFC device operating efficiency; Step 2, DPFC cluster reliability calculation; Step 3: constructing a DPFC device output model with the goal of maximizing DPFC cluster reliability and efficiency; Step 4: Design the DPFC inter-cluster control strategy.

[0007] Preferably, the DPFC device comprises a single-phase converter, a DC capacitor, and a filter, and is directly connected in series to the circuit without passing through a coupling transformer.

[0008] Under normal working conditions, the DPFC single-phase converter operates approximately in the saturation region, and the loss equivalent resistance has nothing to do with the line current and the regulation voltage. That is, the active loss equivalent resistance within the normal regulation range of the DPFC is The size of remains unchanged; Assume that the injection voltage of a single DPFC is , considering the loss of DPFC filtering link, the working efficiency of a single DPFC is: ; (1) Where b represents the harmonic order, Indicates fundamental current (50Hz), is the filter inductance (including transformer leakage inductance), is the filter capacitor, is the active loss equivalent resistance.

[0009] Preferably, a non-negative random variable X is used to describe the component life. The core energy device of DPFC is the converter, and its service life obeys the exponential function distribution. If the failure rate of each DPFC device unit is λ, then the mean failure-free working time of each DPFC device is 1 / λ, and its failure probability F(t) conforms to the exponential distribution: ; (2) Where, t The working hours of the device; For multi-component system reliability can be utilized Model to analyze, The reliability of the entire system under the model is: ; (3) Where P is the reliability of each module and q is the unreliability; Assume that there is DPFC devices, only If all DPFC devices are in working condition, the reliability of the whole system is ; (4) Where λ is the failure rate of each DPFC device unit; When the number of DPFC output in the system is When , the system reliability is: ; (5) By comparison, we can get: ; (6) Under the condition of meeting the regulation requirements, the fewer DPFCs put into operation, the greater the system redundancy, the higher the reliability of the entire DPFC cluster, and the lower the probability of system occurrence.

[0010] Preferably, step 3 comprises the following steps: Step 3.1: Based on cluster reliability, divide the feasible output combinations; Step 3.2: Find the feasible combination that satisfies the minimum number of units and the highest efficiency; Preferably, the step 3.1 is as follows: According to each DPFC state, set n corresponding variables, including its rated capacity , operational efficiency ; Among them, the rated capacity is a preset fixed value; The objective function is to minimize the number of output units, as shown in the following formula: ; (7) in, is the decision vector of DPFC working state, , n is the number of DPFCs, ; The control demand constraint is as follows: ; (8) For the The output of each converter, It is the DPFC cluster regulation target; The device efficiency constraint is as follows: ; (9).

[0011] Preferably, the step 3.2 is specifically as follows: Calculate from step 3.1 feasible combinations , is the working efficiency of the DPFC with the smallest rated capacity in each combination, and is expressed as follows: ; (10) by The larger one is taken as the optimal solution.

[0012] Based on the improved output distribution mathematical model mentioned above, a DPFC cluster control strategy is proposed to achieve high-efficiency regulation of the DPFC cluster through efficient output distribution and output device replacement.

[0013] Preferably, step 4 comprises the following steps: Step 4.1: Classify the DPFC device; Step 4.2: Determine the DPFC cluster output; Step 4.3: Calculate the output distribution within the DPFC cluster; Step 4.4: Replace output within the cluster.

[0014] Preferably, step 4.1 divides the DPFCs in the cluster into two states according to the current working state of the DPFC: normal operating state and fault state; the DPFCs in the normal operating state enter the control instruction requirements of this cycle, while the DPFCs in the fault state send an early warning to the dispatch center to eliminate the fault as soon as possible; The step 4.2 is to make a control judgment based on the DPFC grouping status in the cluster to determine whether it is capable of meeting the cluster scheduling requirements; the DPFC cluster regulation capacity is the sum of the regulation ranges of the DPFC devices in the normal operating state, that is, ; (11) Where, Indicates the maximum output voltage of the DPFC device, For the The output of each converter, is the number of DPFC devices in operation.

[0015] Preferably, the step 4.3 is as follows: ① The rated output of the DPFC devices in the cluster Get the collection in order from largest to smallest , and form a corresponding working state variable set , assuming the number of system output units is ; ② Under the premise of meeting the cluster output control target, find the minimum number of output units. The solution is as follows: The superior regulatory indicators First with Compare and get the deviation value ,Right now ; (12) when season , At this time, only the first DPFC unit is put into regulation; when season , and and For comparison, that is ; (13) same Similar to Compare with 0 and Modify and so on, by comparing the deviation value with each DPFC device until At this time, DPFC devices are put into operation, and the number of cluster output units at this time is recorded The value of ③ Traverse all DPFC output combinations that meet the DPFC control target and obtain the output number as follows: All combinations of , that is, to obtain the corresponding working state set ; ④ Regarding the above The working efficiency of the last DPFC device in the processing combination is sorted, and the set with the highest working efficiency is selected as the output allocation instruction.

[0016] Preferably, the step 4.4 is specifically as follows: The time stamp of each DPFC unit is a function of the converter operating time. ; (14) in, is the failure probability of the DPFC unit; Under the constraints of this function, the time stamp of each DPFC device gradually decreases as the operating time increases. According to the actual control requirements of the line and the characteristics of the DPFC device itself, the critical value is set to ; When the DPFC output distribution is completed, the DPFC time stamp is judged. when When the DPFC is put into operation according to the output allocation; when When , the DPFC device does not perform any regulation action; at this time, the output of the device is judged and distributed by the remaining DPFC devices in the cluster, and a suitable DPFC device is selected to replace the DPFC device to meet the regulation requirements and realize output replacement.

[0017] This invention provides a method for optimizing and coordinating the control of a cluster of distributed power flow control devices. The improved control strategy flexibly allocates the output of DPFC units in the cluster according to demand, significantly improving both the operating efficiency of the input units and the reliability of the cluster. The DPFC cluster reliability achieved under the improved control strategy surpasses both the output allocation results obtained under the equal-sharing and proportional methods, and the DPFC unit operating efficiency exceeds 80%, meeting the converter efficiency constraints. This strategy flexibly allocates DPFC unit output, avoiding waste of control resources and energy. Furthermore, this control strategy reduces the operating time of some DPFC units by replacing their output, thereby improving the reliability of the DPFC units and the DPFC cluster. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 It is a structural schematic diagram of the present invention; Figure 2 Schematic diagram of the structure of the DPFC of the present invention; Figure 3 This is a flow chart of the method for step 4 of the present invention; Figure 4 This is a structural diagram of the system under test of the present invention; Figure 5 This is a simulation model diagram of the tested system containing four groups of DPFC devices according to the present invention; Figure 6 This is the output diagram of four groups of DPFC devices under the improved allocation strategy of the present invention. DETAILED DESCRIPTION

[0019] like Figure 1 As shown, a distributed power flow control device cluster optimization coordinated control method includes the following steps: Step 1, calculation of DPFC device operating efficiency; Step 2, DPFC cluster reliability calculation; Step 3: constructing a DPFC device output model with the goal of maximizing DPFC cluster reliability and efficiency; Step 4: Design the DPFC inter-cluster control strategy.

[0020] Preferably, the DPFC device comprises a single-phase converter, a DC capacitor, and a filter, and is directly connected in series to the circuit without a coupling transformer. As one of the important members of the D-FACTS family, the core energy conversion device of DPFC is a single-phase voltage source converter. Figure 2 As shown, the single-turn coupling transformer is ignored here. is the filter inductance (including transformer leakage inductance), is the filter capacitor, is the active loss equivalent resistance, is the parallel DC capacitor.

[0021] Under normal working conditions, the DPFC single-phase converter operates approximately in the saturation region, and the loss equivalent resistance has nothing to do with the line current and the regulation voltage. That is, the active loss equivalent resistance within the normal regulation range of the DPFC is The size of remains unchanged; Assume that the injection voltage of a single DPFC is , considering the loss of DPFC filtering link, the working efficiency of a single DPFC is: ; (1) Where b represents the harmonic order, Indicates fundamental current (50Hz), is the filter inductance (including transformer leakage inductance), is the filter capacitor, is the active loss equivalent resistance.

[0022] In order to improve the working efficiency of each DPFC unit and avoid a large amount of power waste due to harmonics and DPFC's own switching losses, it is necessary to ensure that the inverter voltage of each DPFC unit is more than 80% of the rated voltage. The closer to the rated output, the higher the working efficiency of the device.

[0023] A DPFC cluster consists of several DPFC units. Failure or failure of any one component in the system can lead to failure of the entire system. Therefore, the reliability of the entire DPFC cluster is closely related to the reliability of each DPFC unit.

[0024] Reliability in power systems is mainly divided into component reliability research and system reliability research. For component reliability research, a non-negative random variable X is used to describe the component life. The core energy device of DPFC is the converter, and its service life follows an exponential distribution. If the failure rate of each DPFC unit is λ, then the mean failure-free working time of each DPFC unit is 1 / λ, and its failure probability F(t) conforms to the exponential distribution: ; (2) Where, t The working hours of the device; For multi-component system reliability can be utilized Model to analyze, The reliability of the entire system under the model is: ; (3) Where P is the reliability of each module and q is the unreliability; Assume that there is DPFC devices, only If all DPFC devices are in working condition, the reliability of the whole system is ; (4) Where λ is the failure rate of each DPFC device unit; When the number of DPFC output in the system is When , the system reliability is: ; (5) By comparison, we can get: ; (6) Under the condition of meeting the regulation requirements, the fewer DPFCs put into operation, the greater the system redundancy, the higher the reliability of the entire DPFC cluster, and the lower the probability of system occurrence.

[0025] Based on the above analysis, this paper proposes a DPFC unit output model that targets maximizing DPFC cluster reliability and operating efficiency. This model consists of two steps. The first step, based on the DPFC cluster output target, divides feasible output combinations based on the number of units in the cluster—that is, cluster reliability—as the target. The second step, based on the combination divisions in the first step, calculates the operating efficiency of the unit with the smallest rated capacity within each feasible output combination. The combination with the highest operating efficiency is then determined as the optimal output combination.

[0026] Preferably, step 3 comprises the following steps: Step 3.1: Based on cluster reliability, divide the feasible output combinations; Step 3.2: Find the feasible combination that satisfies the minimum number of units and the highest efficiency; Preferably, the step 3.1 is as follows: According to each DPFC state, set n corresponding variables, including its rated capacity , operational efficiency ; Among them, the rated capacity is a preset fixed value; The objective function is to minimize the number of output units, as shown in the following formula: ; (7) in, is the decision vector of DPFC working state, , n is the number of DPFCs, , The control demand constraint is as follows: ; (8) For the The output of each converter, It is the DPFC cluster regulation target; The device efficiency constraint is as follows: ; (9).

[0027] Preferably, the step 3.2 is specifically as follows: Calculate from step 3.1 feasible combinations , is the working efficiency of the DPFC with the smallest rated capacity in each combination, and is expressed as follows: ; (10) by The larger one is taken as the optimal solution.

[0028] Based on the improved output distribution mathematical model mentioned above, a DPFC cluster control strategy is proposed to achieve high-efficiency regulation of the DPFC cluster through efficient output distribution and output device replacement.

[0029] Preferably, Figure 3 As shown, step 4 includes the following steps: Step 4.1: Classify the DPFC device; Step 4.2: Determine the DPFC cluster output; Step 4.3: Calculate the output distribution within the DPFC cluster; Step 4.4: Replace output within the cluster.

[0030] Preferably, the step 4.1 divides the DPFCs in the cluster into two states according to the current working state of the DPFCs: normal operating state and fault state; Table 1 DPFC device classification

[0031] Normal operating state class enters the current cycle control instruction demand, and fault state class sends an early warning to the dispatch center to eliminate the fault as soon as possible; The step 4.2 is to make a control judgment based on the DPFC grouping status in the cluster to determine whether it is capable of meeting the cluster scheduling requirements; the DPFC cluster regulation capacity is the sum of the regulation ranges of the DPFC devices in the normal operating state, that is, ; (11) Where, Indicates the maximum output voltage of the DPFC device, For the The output of each converter, is the number of DPFC devices in operation.

[0032] The output distribution is performed according to the improved output distribution model proposed above. This mathematical model is a simple finite number of selections, so it can be solved using the ergodic method. Preferably, the step 4.3 is as follows: ① The rated output of the DPFC devices in the cluster Get the collection in order from largest to smallest , and form a corresponding working state variable set , assuming the number of system output units is ; ② Under the premise of meeting the cluster output control target, find the minimum number of output units. The solution is as follows: The superior regulatory indicators First with Compare and get the deviation value ,Right now ; (12) when season , At this time, only the first DPFC unit is put into regulation; when season , and and For comparison, that is ; (13) same Similar to Compare with 0 and Modify and so on, by comparing the deviation value with each DPFC device until At this time, DPFC devices are put into operation, and the number of cluster output units at this time is recorded The value of ③ Traverse all DPFC output combinations that meet the DPFC control target and obtain the output number as follows: All combinations of , that is, to obtain the corresponding working state set ; ④ Regarding the above The working efficiency of the last DPFC device in the processing combination is sorted, and the set with the highest working efficiency is selected as the output allocation instruction.

[0033] Preferably, the step 4.4 is specifically as follows: DPFC reliability declines over time and under varying operating conditions. When reliability declines to a certain level, irreversible damage may occur. Therefore, to extend the lifespan and reliability of DPFC units within a cluster, regular output replacement is required to ensure full utilization of each DPFC within the cluster.

[0034] The output replacement process is based on mathematical statistical analysis, and each DPFC makes output replacement decisions based on the current working hours.

[0035] The time stamp of each DPFC unit is a function of the converter operating time. ; (14) in, is the failure probability of the DPFC unit; Under the constraints of this function, the time stamp of each DPFC device gradually decreases as the operating time increases. According to the actual control requirements of the line and the characteristics of the DPFC device itself, the critical value is set to ; When the DPFC output distribution is completed, the DPFC time stamp is judged. when When the DPFC is put into operation according to the output allocation; when When , the DPFC device does not perform any regulation action; at this time, the output of the device is judged and distributed by the remaining DPFC devices in the cluster, and a suitable DPFC device is selected to replace the DPFC device to meet the regulation requirements and realize output replacement.

[0036] The simulation test process is set as follows: The simulation system uses two three-phase AC voltage sources of 0.38 kV, located at the system's head and tail ends. The impedances of the system lines are set to Z1 = 0.001 + j0.314 Ω, Z2 = 0.001 + j0.072 Ω, Z3 = 0.004 + j0.047 Ω, and Z4 = 0.001 + j0.072 Ω, respectively. The system's sole load, Rload, is located at node III, with a resistance of 2.8 Ω. Transformers I and II are Y-△ type transformers, both rated at 0.6 MVA, with a transformation ratio of 0.38 / 0.38 kV and a short-circuit ratio of 10%. The rated outputs of the four DPFC units A, B, C, and D are shown in Figure 1. They are 80V, 60V, 45V, and 25V respectively. Set the cluster control system to issue a command at 0s, the target value is 100V, and the system output demand is changed to 150V at 4s. The simulation system structure and simulation model are as follows Figure 4 、 Figure 5 shown.

[0037] like Figure 6 As shown in the figure, under the improved control strategy, at 0s, the DPFC devices of groups B and C are put into operation, with group B outputting 60V and group C outputting 40V. At this time, group B is working at rated capacity, with an operating voltage utilization rate of 100%, and group C has an operating voltage utilization rate of 89%. The operating voltage utilization rates of both groups of devices reach above 80%, which meets the operating voltage utilization rate constraint of the improved control strategy. At this time, the reliability of the DPFC cluster is ; (15) At 2 seconds, the operating time of the DPFC units in groups A and D reached the threshold, and output was swapped within the cluster. After power redistribution, the output of groups B and C was reduced to 0, and groups A and D resumed operation. At this point, group A's output was 80V, and group D's output was 20V. Group A was operating at rated capacity, and group D's operating voltage utilization was 80%. Both groups' operating voltage utilization rates exceeded 80%, meeting the operating voltage utilization constraint of the improved control strategy.

[0038] At 4s, the cluster control target changes, and the output target is 150V. At this time, the DPFC group A maintains an output of 80V, the DPFC group D changes its output to 25V, and the DPFC group C starts working with an output of 45V. At this time, the DPFC groups A, C, and D3 are all working at rated capacity, and the operating voltage utilization rate is 100%, which meets the operating voltage utilization rate constraint of the improved control strategy mathematical model. At this time, the DPFC cluster reliability is ; (16) Simulation results show that the improved control strategy can flexibly allocate the output of DPFC devices in the cluster according to demand, and ensure the operating voltage utilization of the devices and the reliability of the cluster.

[0039] The above embodiments are merely preferred technical solutions of the present invention and should not be construed as limiting the present invention. The scope of protection of the present invention shall be the technical solutions set forth in the claims, including equivalent alternatives to the technical features of the technical solutions set forth in the claims. In other words, equivalent alternatives and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A distributed power flow control device cluster optimization coordination control method, characterized in that: The following steps are involved: Step 1, calculation of DPFC device operating efficiency; Step 2, DPFC cluster reliability calculation; Step 3: constructing a DPFC device output model with the goal of maximizing DPFC cluster reliability and efficiency; Step 4: Design the DPFC inter-cluster control strategy.

2. A distributed power flow control device cluster optimization and coordinated control method according to claim 1, characterized in that: The DPFC device comprises a single-phase converter, a DC capacitor, and a filter, and is directly connected in series to the circuit without a coupling transformer; Under normal working conditions, the DPFC single-phase converter operates approximately in the saturation region, and the loss equivalent resistance has nothing to do with the line current and the regulation voltage. That is, the active loss equivalent resistance within the normal regulation range of the DPFC is The size of remains unchanged; Assume that the injection voltage of a single DPFC is , considering the loss of DPFC filtering link, the working efficiency of a single DPFC is: ；（1） Where b represents the harmonic order, represents the fundamental current, is the filter inductor, is the filter capacitor, is the active loss equivalent resistance.

3. A distributed power flow control device cluster optimization and coordinated control method according to claim 2, characterized in that: The non-negative random variable X is used to describe the component life. The core energy device of DPFC is the converter, and its service life follows an exponential function distribution. If the failure rate of each DPFC device unit is λ, then the mean failure-free working time of each DPFC device is 1 / λ, and its failure probability F(t) conforms to the exponential distribution: ；（2） Where, t The working hours of the device; For multi-component system reliability can be utilized Model to analyze, The reliability of the entire system under the model is: ；（3） Where P is the reliability of each module and q is the unreliability; Assume that there is DPFC devices, only If all DPFC devices are in working condition, the reliability of the whole system is ；（4） Where, λ is the failure rate of each DPFC device unit; When the number of DPFC output in the system is When , the system reliability is: ；（5） By comparison, we can get: ；（6） Under the condition of meeting the regulation requirements, the fewer DPFCs put into operation, the greater the system redundancy, the higher the reliability of the entire DPFC cluster, and the lower the probability of system occurrence.

4. A distributed power flow control device cluster optimization and coordinated control method according to claim 1, characterized in that: The step 3 comprises the following steps: Step 3.1: Based on cluster reliability, divide the feasible output combinations; Step 3.2: Find the feasible combination that satisfies the minimum number of units and the highest efficiency.

5. A distributed power flow control device cluster optimization and coordinated control method according to claim 4, characterized in that: The step 3.1 is as follows: According to each DPFC state, set n corresponding variables, including its rated capacity , operational efficiency ; Among them, the rated capacity is a preset fixed value; The objective function is to minimize the number of output units, as shown in the following formula: ；（7） in, is the decision vector of DPFC working state, , n is the number of DPFCs, ; The control demand constraint is as follows: ；（8） For the The output of each converter, It is the DPFC cluster regulation target; The device efficiency constraint is as follows: ；（9）。 6. A distributed power flow control device cluster optimization and coordinated control method according to claim 5, characterized in that: The step 3.2 is as follows: Calculate from step 3.1 feasible combinations , is the working efficiency of the DPFC with the smallest rated capacity in each combination, and is expressed as follows: ； （10） by The larger one is taken as the optimal solution.

7. A distributed power flow control device cluster optimization and coordinated control method according to claim 1, characterized in that: The step 4 comprises the following steps: Step 4.1: Classify the DPFC device; Step 4.2: Determine the DPFC cluster output; Step 4.3: Calculate the output distribution within the DPFC cluster; Step 4.4: Replace output within the cluster.

8. A distributed power flow control device cluster optimization and coordinated control method according to claim 7, characterized in that: Step 4.1 divides the DPFCs in the cluster into two states based on their current working state: normal operation state and fault state. The DPFCs in the normal operation state will receive the control instruction requirements of this cycle, while the DPFCs in the fault state will issue an early warning to the dispatch center to eliminate the fault as soon as possible. The step 4.2 performs control judgment based on the DPFC grouping status within the cluster to determine whether it is capable of meeting the cluster scheduling requirements; The regulation capacity of the DPFC cluster is the sum of the regulation ranges of the DPFC units in normal operation, i.e. ；（11） Where, Indicates the maximum output voltage of the DPFC device, For the The output of each converter, is the number of DPFC devices in operation.

9. A distributed power flow control device cluster optimization and coordinated control method according to claim 8, characterized in that: The step 4.3 is as follows: ① The rated output of the DPFC devices in the cluster Get the collection in order from largest to smallest , and form a corresponding working state variable set , assuming the number of system output units is ; ② Under the premise of meeting the cluster output control target, find the minimum number of output units. The solution is as follows: The superior regulatory indicators First with Compare and get the deviation value ,Right now ； （12） when season , At this time, only the first DPFC unit is put into regulation; when season , and and For comparison, ； （13） same Similar to Compare with 0 and Modify and so on, by comparing the deviation value with each DPFC device until At this time, DPFC devices are put into operation, and the number of cluster output units at this time is recorded The value of ③ Traverse all DPFC output combinations that meet the DPFC control target and obtain the output number as follows: All combinations of , that is, to obtain the corresponding working state set ; ④ Regarding the above The working efficiency of the last DPFC device in the processing combination is sorted, and the set with the highest working efficiency is selected as the output allocation instruction.

10. A distributed power flow control device cluster optimization and coordinated control method according to claim 9, characterized in that: The step 4.4 is as follows: The time stamp of each DPFC unit is a function of the converter operating time. ； （14） in, is the failure probability of the DPFC unit; Under the constraints of this function, as the operating time of each DPFC device increases, its time mark gradually decreases; according to the actual control requirements of the line and the characteristics of the DPFC device itself, the critical value is set to ; When the DPFC output distribution is completed, the DPFC time stamp is judged. when When the DPFC is put into operation according to the output allocation; when When , the DPFC device does not perform any regulation action; at this time, the output of the device is judged and distributed by the remaining DPFC devices in the cluster, and a suitable DPFC device is selected to replace the DPFC device to meet the regulation requirements and realize output replacement.

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