A master / slave station optimized switching method under fault of a flexible interconnected power distribution system based on multi-factor comprehensive evaluation
By using a multi-factor comprehensive evaluation method for master/slave station optimization switching, the problem of insufficient autonomous reconfiguration capability of multi-terminal flexible interconnected power distribution systems after master station failure is solved. This method enables steady-state operation and loss optimization under fault conditions, thereby improving the system's self-healing capability and operating efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HEFEI UNIV OF TECH
- Filing Date
- 2026-04-21
- Publication Date
- 2026-07-07
AI Technical Summary
Existing multi-terminal flexible interconnected power distribution systems lack the ability to autonomously reconfigure after a main station failure. In particular, they are prone to phase-locked loop (PLL) loss of synchronization, parameter mismatch, and current surges in weak grid environments. They also lack a comprehensive assessment of stability and economy, resulting in unstable system operation and high losses.
A master/slave station optimization switching method based on multi-factor comprehensive evaluation is adopted. By calculating the short-circuit ratio and controller parameters of each slave station, a power stability limit curve is constructed. The station with the minimum loss in the entire network is selected as the new master station, and a smooth switching is performed under fault conditions to ensure the steady-state operation of the system under fault conditions.
It improves the system's self-healing success rate after a fault, reduces operational losses after reconfiguration, ensures the safety of power electronic devices, shortens the recovery cycle, and achieves deep coupling optimization of stability and economy.
Smart Images
Figure CN122348487A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of operation control of multi-terminal flexible interconnected power distribution systems, specifically to a master / slave station optimized switching method under fault conditions in flexible interconnected power distribution systems based on multi-factor comprehensive evaluation. Background Technology
[0002] Currently, power distribution networks are facing challenges from the large-scale integration of distributed renewable energy sources (photovoltaics, wind power) and DC loads (data centers, charging stations), resulting in complex power flow, voltage fluctuations, and insufficient power transfer capacity. Therefore, multi-terminal flexible interconnected distribution systems based on power electronics technology have become crucial for the construction of new power systems.
[0003] Flexible interconnection systems replace traditional tie switches with flexible multi-state switches (Soft Open Point, SOP), power electronic transformers (PET), or voltage source converters (VSC), achieving flexible connections and precise power distribution between feeders. Compared to physical contact switches, flexible interconnection devices can achieve continuous, bidirectional, and proactive power flow regulation, and provide millisecond-level response support under fault conditions. In the control architecture of multi-terminal flexible interconnection systems, "master-slave control" is the most widely used strategy. In this mode, the system uses a master converter station with constant DC voltage control to act as a "balance node" to maintain the stability of the DC bus voltage; the remaining converter stations act as slave stations, performing constant active / reactive power control to achieve power balance and optimized scheduling.
[0004] However, while master-slave control architecture enhances system flexibility, it also introduces significant reliability risks. Since the stability of the system's DC-side voltage is highly dependent on the master station's regulation capability, if the master station is forced to shut down due to internal component failure, AC grid disturbances, or communication interruptions, the DC bus will lose voltage support. If the system cannot select and switch to the optimal alternative master station from the remaining slave stations within a very short time (typically milliseconds), it will rapidly lead to DC-side charge imbalance, inducing a significant drop or surge in DC voltage, ultimately triggering network-wide protection lockout and causing a severe power outage. Therefore, "optimized master / slave station switching methods under fault conditions" has become a key technology for ensuring the safe operation of flexible interconnected systems.
[0005] Existing technologies and research findings still have limitations in solving this problem in the following three aspects: First, there is insufficient attention paid to the grid strength ratio (SCR) at the connection point. With the increase of distributed generation at the end of the distribution network, some converter stations may be connected to weak grid environments, resulting in lower short-circuit ratios (SCRs). Traditional switching strategies often select based solely on the remaining capacity or geographical location of alternative stations, neglecting the interaction between the converter station and the system impedance under weak grid conditions. In weak grid environments, the phase-locked loop (PLL) and current control loop of the converter station are highly susceptible to resonant coupling. Blindly switching the weak grid port to the master station can easily trigger low-frequency oscillations, leading to switching attempts failing.
[0006] Secondly, the dynamic mismatch between controller parameters (such as PI parameters) and the physical system is ignored. The control parameters of a converter station are typically optimized for a specific topology and operating point. When a system fault reconfiguration occurs, the equivalent impedance, power flow distribution, and dynamic characteristics of the entire network change drastically. Most existing methods use fixed control parameters for switching, failing to consider that during strong / weak grid switching, the original PI parameters may no longer satisfy the Lyapunov stability criterion, leading to huge current surges or voltage overshoots at the moment of switching, seriously threatening the safety of the converter devices.
[0007] Finally, there is a lack of a multi-dimensional trade-off mechanism between "stability" and "economic efficiency." Existing switching logic is mostly single-objective, either solely pursuing stability (e.g., selecting the strongest grid port) or solely pursuing economic efficiency (e.g., selecting the port with the lowest losses). In actual operation, the optimal switching point is often the result of multiple coupled factors. For example, a site connected to a strong grid may be far from the load center, and switching to the master station would significantly increase the overall network's operating losses; while a site with good economic efficiency may be on the edge of the stable operating domain. How to balance network loss optimization and power expansion potential while ensuring "stability first" has not yet been established as a comprehensive, hierarchical evaluation system.
[0008] In summary, existing self-healing and reconfiguration technologies for multi-terminal flexible interconnected systems are ill-suited to the demands of modern power distribution networks with increasingly complex structures and variable operating conditions. Summary of the Invention
[0009] To address the issue of insufficient autonomous reconfiguration capability of existing flexible interconnection systems after master station failure, this invention proposes a master / slave station optimized switching method based on multi-factor comprehensive evaluation. This method aims to reduce system losses and improve operating efficiency, thereby effectively resolving the bottlenecks of parameter mismatch and power limitation during strong / weak grid switching and significantly enhancing the system's self-healing reconfiguration and steady-state operation capabilities under fault conditions.
[0010] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: This invention discloses a master / slave station optimization switching method under fault conditions in a flexible interconnected power distribution system based on multi-factor comprehensive evaluation. The method is characterized in that the multi-terminal flexible interconnected power distribution system is composed of equivalent loads on the AC side and the DC side; wherein, the AC side is composed of M groups of "AC power supply-transformer-load" branches connected in parallel to the DC bus via an AC-DC converter. In the multi-terminal flexible interconnected power distribution system, any one of the following can be selected: k One AC-DC converter is the master station, and the remaining AC-DC converters are slave stations. During normal operation of the flexible interconnected power distribution system, the master station uses constant DC voltage control, and the slave stations use constant active-reactive power control. The optimized master / slave station switching method under fault conditions in the flexible interconnected power distribution system includes the following steps: S1: When a power outage fault is detected at the master station in the flexible interconnected power distribution system, the master station automatically switches to voltage and frequency control to support the AC load, and uses equation (1) to obtain the load power on the master station side. : (1) In equation (1), For the first u The transmission power of each slave station N This indicates the total number of stations. The total load on the DC side, This represents the total network loss of a flexible interconnected power distribution system. S2: Calculate the equivalent short-circuit ratio from each slave station to the AC side, and determine the power grid environment of the flexible interconnected distribution system based on the short-circuit ratio: If the flexible interconnected power distribution system is in a strong grid environment, then proceed to step S3; If the flexible interconnected power distribution system is in a weak network environment, then proceed to step S4; S3: Construct three types of power stability limit curves for a single AC-DC converter under a strong grid environment; and compare and screen the phase-locked loop parameters and controller PI parameters of each slave station, finally selecting the station with the lowest loss in the entire network as the new master station, and execute step S5; S4: Set a power transmission range deviation threshold. By comparing the power limit differences of each slave station, the station with the lowest loss in the entire network is finally selected as the new master station. S5: The flexible interconnected power distribution system sends a control mode switching command to the new master station, causing it to switch from constant active-reactive power control to constant DC voltage control. The other slave stations and the faulty original master station maintain constant active-reactive power control, so as to achieve optimized switching between master and slave stations in the fault state.
[0011] The method for optimized master / slave station switching under fault conditions in a flexible interconnected power distribution system based on multi-factor comprehensive evaluation, as described in this invention, is characterized in that S3 includes the following steps: S3.1: Power command value for a given operating point The steady-state voltage at the operating point is obtained using equation (2). With steady-state work angle : (2) In equation (2), This represents the equivalent impedance of a single AC-DC converter. This represents the impedance angle of a single AC-DC converter; For a given operating point, the active power input to a single AC-DC converter is... For a given operating point, the reactive power input to a single AC-DC converter is... , Two nonlinear mapping functions characterize the power grid parameters to the operating point, and we have: (3) In equation (3), For the voltage of a multi-terminal flexible interconnected power distribution system, The equivalent resistance of a single AC-DC converter. The equivalent inductance of a single AC-DC converter; S3.2: Constructing three types of power stability limit curves for a single AC-DC converter under strong grid conditions: S3.2.1: The static power limit boundary equation of a single AC-DC converter is constructed using equation (4) to fit the static stability limit curve. : (4) S3.2.2: Using equation (5), construct the thermal capacity limit boundary equation for a single AC-DC converter under the apparent power rating condition, and use it to fit the thermal capacity limit curve. : (5) In equation (5), The rated power of a single AC-DC converter; S3.2.3: Based on the dynamic parameters of the phase-locked loops of each slave station, using... Reaching the critical angle Power boundary fitting PLL stability limit curve ; S3.3: In and Under the constraints, by comparing the phase-locked loop parameters of each slave station with the controller PI parameters, the problems caused by the master station switching process are eliminated. Sites with inward-shrinking boundaries; and based on the stable operating region SOR enclosed by three types of power stability limit curves and the power circle, with the goal of maximizing the SOR, selecting sites with a smaller impact on the SOR to form a candidate slave site set; S3.4: Calculate the total network line loss for each candidate slave station as the candidate master station, and select the candidate slave station with the lowest total network line loss as the new master station: Using equation (6), we obtain the first... Injection current of each candidate slave station : (6) In equation (6), Represents any number of The voltage of each candidate slave station, Represents any number of The candidate slave station and any first Admittance between candidate stations m Indicates the number of candidate slave stations; Using equation (7), we obtain the first... Injection power of each candidate slave station : (7) Assume the first a Each candidate slave station is used as a candidate master station, and the total network line loss of the candidate master station is obtained using equation (8). : (8) In equation (8), The voltage of the candidate master station. For the remaining candidate sites besides the main site i The voltage of each candidate slave station.
[0012] Furthermore, S4 includes the following steps: S4.1: Calculate the first using equations (9) and (10) u The maximum apparent power of each slave station With the upper limit of the active range and lower limit : (9) (10) In equations (9) and (10), For the first u The active power of each slave station For the first u The rated apparent power of each station, For the first uThe reverse rated apparent power of each slave station; For the first u The equivalent impedance of each slave station, For the first u The impedance angle of each slave station; S4.2: Select all slave stations whose stability limit of the phase-locked loop (PLL) precedes its own thermal capacity limit to reach instability as candidate slave stations, and then determine the steady-state power angle based on the... With the critical stability angle of the phase-locked loop The intersection point is excluded from the candidate stations. The candidate slave station with the largest shrinkage is selected to obtain the candidate slave stations after the initial screening; S4.3: Obtain the active power transmission limit of each candidate slave station after initial screening under reactive power assistance, and select the candidate slave station corresponding to the maximum active power transmission limit as the target station. If the power limit deviation of the target site is greater than or equal to the preset power transmission range deviation threshold, then the corresponding target site is set as the new master site; otherwise, the total network line loss of each candidate slave site after initial screening is calculated, and the candidate slave site with the smallest total network line loss is selected as the new master site.
[0013] The present invention provides an electronic device, including a memory and a processor, characterized in that: the memory is used to store instructions supporting the processor in executing a computer program, and the processor is configured to run the computer program to perform the steps in the optimized switching method.
[0014] The present invention discloses a computer-readable storage medium storing a computer program, characterized in that: when the computer program is executed by a processor, it implements the steps in the optimization switching method.
[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention addresses the instability problem of master-slave switching under complex power grid conditions by designing a combined decision-making mechanism based on SCR classification and stable operating domain assessment. This overcomes the limitations of traditional methods that rely solely on remaining capacity as the switching criterion, effectively solving the risks of phase-locked loop out-of-step and parameter mismatch caused by switching at converter stations in weak power grid environments, and significantly improving the system's self-healing success rate after a fault.
[0016] 2. The optimized switching method proposed in this invention achieves a deep coupling of "stability priority" and "economic priority." By introducing secondary optimization logic for network losses in a strong power grid environment, it minimizes the operating losses after system reconfiguration while ensuring robust DC voltage support. Simultaneously, through real-time quantification of the power expansion potential index, it directly provides the dynamic stability boundary of the alternative substation, offering a more intuitive and accurate scientific basis for the operation and control of multi-terminal flexible interconnection systems.
[0017] 3. This invention introduces smooth switching control based on transient voltage feedforward. Compared with conventional direct switching methods, this method can effectively suppress inrush current and voltage overshoot generated during switching, ensuring the safe operation of power electronic devices during reconfiguration and shortening the adjustment period for the system to recover from the fault state to the steady state. Attached Figure Description
[0018] Figure 1 This is a topology diagram of a multi-terminal flexible interconnected power distribution system. Figure 2 Equivalent topology diagram of a multi-terminal flexible interconnected power distribution system; Figure 3 Dynamic stability limit diagram of PLL for multi-terminal flexible interconnected power distribution system; Figure 4 This is a graph showing the maximum transmission power of the converter. Figure 5 This is a graph showing the maximum transmission power of the converter under reactive power auxiliary control. Figure 6 This is the stable operating domain for a multi-terminal flexible interconnected power distribution system under normal conditions. Figure 7 For the stable operating domain under fault reconfiguration of multi-terminal flexible interconnected power distribution systems; Figure 8 This is for the stable operation domain under the restoration and optimization of multi-terminal flexible interconnected power distribution systems. Detailed Implementation
[0019] In this embodiment, for multi-factor coupled operating conditions, a master / slave station optimized switching method under fault conditions of a multi-terminal flexible interconnected distribution system based on multi-factor comprehensive evaluation is proposed. This method is a master / slave station optimized switching method that can accurately identify the system stability margin, quantify the impact of grid intensity, and take into account the operational economy, and includes the following steps: like Figure 1 As shown, the multi-terminal flexible interconnected power distribution system consists of equivalent loads on both the AC and DC sides; the AC side is formed by connecting M sets of "AC power supply-transformer-load" branches in parallel to the DC bus via an AC-DC converter.
[0020] like Figure 2 As shown, during the analysis, the open-circuit voltage is obtained by disconnecting the connection point between the converter and the AC side, and the equivalent impedance is calculated after short-circuiting the AC power supply, thus simplifying the complex AC side network into a standard Thevenin equivalent model. Figure 3 As shown, this is the stable operating domain under the initial conditions.
[0021] S1: When a power outage fault is detected at the master station in the flexible interconnected power distribution system, the master station automatically switches to voltage and frequency control to support the AC load, and uses equation (1) to obtain the load power on the master station side. : (1) In equation (1), For the first u The transmission power of each slave station N This indicates the total number of stations. The total load on the DC side, This represents the total network loss of a flexible interconnected power distribution system. For example... Figure 4 The image shows the stable operating domain after fault reconstruction. For the remaining slave stations, a master control optimization and handover assessment is initiated.
[0022] S2: Calculate the equivalent short-circuit ratio from each slave station to the AC side, and determine the power grid environment of the flexible interconnected distribution system based on the short-circuit ratio: If the flexible interconnected power distribution system is in a strong grid environment, then proceed to step S3; If the flexible interconnected power distribution system is in a weak network environment, then proceed to step S4.
[0023] S3: If there is at least one slave station in the system The system is determined to be in a strong network environment. Three types of power stability limit curves for a single AC-DC converter under strong network environment are constructed; and the phase-locked loop parameters of each slave station are compared and screened with the controller PI parameters. Finally, the station with the lowest line loss in the entire network is selected as the new master station, and step S5 is executed. S3.1: Power command value for a given operating point The steady-state voltage at the operating point is obtained using equation (2). With steady-state work angle : (2) In equation (2), This represents the equivalent impedance of a single AC-DC converter. This represents the impedance angle of a single AC-DC converter; For a given operating point, the active power input to a single AC-DC converter is... For a given operating point, the reactive power input to a single AC-DC converter is... , Two nonlinear mapping functions characterize the power grid parameters to the operating point, and we have: (7) In equation (3), For the voltage of a multi-terminal flexible interconnected power distribution system, The equivalent resistance of a single AC-DC converter. This is the equivalent inductance of a single AC-DC converter.
[0024] S3.2: Using the derived state variables, define the three types of power stability limit curves of the converter under strong grid conditions. Limit curves) Figure 5 As shown: S3.2.1: The static power limit boundary equation of a single AC-DC converter is constructed using equation (4) to fit the static stability limit curve. : (4) S3.2.2: Using equation (5), construct the thermal capacity limit boundary equation for a single AC-DC converter under the apparent power rating condition, and use it to fit the thermal capacity limit curve. : (5) In equation (5), The rated power of a single AC-DC converter; S3.2.3: Based on the dynamic parameters of the phase-locked loops of each slave station, using... Reaching the critical angle Power boundary fitting PLL stability limit curve .
[0025] S3.3: In and Under the constraints, by comparing the phase-locked loop parameters of each slave station with the controller PI parameters, the problems caused by the master station switching process are eliminated. Sites with inward-shrinking boundaries; and based on the stable operating region SOR enclosed by three types of power stability limit curves and the power circle, with the goal of maximizing the SOR, selecting sites with a smaller impact on the SOR to form a candidate slave site set.
[0026] S3.4: Calculate the total network line loss when each candidate slave station is set as a candidate master station, and determine the candidate slave station with the smallest total network line loss as the new master station: Using equation (6), we obtain the first... Injection current of each candidate slave station : (6) In equation (6), Represents any number of The voltage of each candidate slave station, Represents any number of The candidate slave station and any first Admittance between candidate stations m Indicates the number of candidate slave stations; Using equation (7), we obtain the first... Injection power of each candidate slave station : (7) Assume the first a Each candidate slave station is used as a candidate master station, and the total network line loss of the candidate master station is obtained using equation (8). : (8) In equation (8), The voltage of the candidate master station. The voltage of all stations other than the candidate master station; Compare the total network line loss corresponding to each of the candidate sites when they are selected as candidate master sites. Select the option that minimizes the overall network line loss. The smallest candidate station is designated as the new master station, and an instruction to switch to constant DC voltage control mode is issued to it.
[0027] S4: If all slave stations The system is determined to be in a weak network environment. In this case, it is necessary to comprehensively draw the SOR, including the dynamic boundary of the PLL introduced by the PI parameter.
[0028] S4.1: Calculate the first using equations (9) and (10) u The maximum apparent power of each slave station With the upper limit of the active range and lower limit The graph of the maximum apparent power can be drawn according to equation (9), as shown below. Figure 6 As shown, Figure 4 The two intersections of the parabola with the P-axis represent the range of active power transmitted on each converter side.
[0029] (9) (10) In equations (9) and (10), For the first u The active power of each slave station For the first u The rated apparent power of each station, For the first u The reverse rated apparent power of each station, For the first u The equivalent impedance of each slave station, For the first u The impedance angle of each slave station.
[0030] S4.2: Select all slave stations whose stability limit of the phase-locked loop (PLL) precedes its own thermal capacity limit to reach instability as candidate slave stations, and then determine the steady-state power angle based on the... With the critical stability angle of the phase-locked loop The intersection point is excluded from the candidate stations. The candidate slave station with the largest shrinkage is selected to obtain the candidate slave stations after the initial screening.
[0031] S4.3: Set the power transmission range deviation threshold (e.g., If a certain station is operating under reactive power assistance, its active power range is... Significantly superior to other sites (i.e., SCR relative maximum or impedance angle) If the best option is found, then that station will be selected as the main station. For example... Figure 7 As shown, the goal is to retain sites with high power expansion potential as PQ slaves to maximize the overall network power transmission capacity. If the power limit deviation of each site is less than the threshold, then proceed to S4.5.
[0032] S4.4: Conduct line loss analysis on the candidate stations after initial screening and select the scheme with the lowest line loss across the entire network. If the line loss difference is also extremely small (deviation)... If the target station is selected, it will be selected according to the system's preset fixed priority sequence or randomly.
[0033] S5: Based on the previous decision results, the optimal master station switching target is identified. The system issues a control mode switching command, and the selected station smoothly switches to constant DC voltage. The system is controlled by a single control unit (PQ), while other stations use PQ control to complete the system's self-healing reconfiguration under fault conditions. For example... Figure 8 As shown, this is the stable operating domain after recovery and optimization.
[0034] In this embodiment, an electronic device includes a memory and a processor. The memory stores a program that supports the processor in executing the above-described method, and the processor is configured to execute the program stored in the memory.
[0035] In this embodiment, a computer-readable storage medium stores a computer program, which is executed by a processor to perform the steps of the above method.
Claims
1. A method for optimized master / slave station switching under fault conditions in a flexible interconnected power distribution system based on multi-factor comprehensive evaluation, characterized in that, The multi-terminal flexible interconnected power distribution system consists of equivalent loads on both the AC and DC sides; wherein, the AC side is formed by connecting M sets of "AC power supply-transformer-load" branches in parallel to the DC bus via an AC-DC converter; In the multi-terminal flexible interconnected power distribution system, any one of the following can be selected: k One AC-DC converter is the master station, and the remaining AC-DC converters are slave stations. During normal operation of the flexible interconnected power distribution system, the master station uses constant DC voltage control, and the slave stations use constant active-reactive power control. The optimized master / slave station switching method under fault conditions in the flexible interconnected power distribution system includes the following steps: S1: When a power outage fault is detected at the master station in the flexible interconnected power distribution system, the master station automatically switches to voltage and frequency control to support the AC load, and uses equation (1) to obtain the load power on the master station side. : (1) In equation (1), For the first u The transmission power of each slave station N This indicates the total number of stations. The total load on the DC side, This represents the total network loss of a flexible interconnected power distribution system. S2: Calculate the equivalent short-circuit ratio from each slave station to the AC side, and determine the power grid environment of the flexible interconnected distribution system based on the short-circuit ratio: If the flexible interconnected power distribution system is in a strong grid environment, then proceed to step S3; If the flexible interconnected power distribution system is in a weak network environment, then proceed to step S4; S3: Construct three types of power stability limit curves for a single AC-DC converter under a strong grid environment; and compare and screen the phase-locked loop parameters and controller PI parameters of each slave station, finally selecting the station with the lowest loss in the entire network as the new master station, and execute step S5; S4: Set a power transmission range deviation threshold. By comparing the power limit differences of each slave station, the station with the lowest loss in the entire network is finally selected as the new master station. S5: The flexible interconnected power distribution system sends a control mode switching command to the new master station, causing it to switch from constant active-reactive power control to constant DC voltage control. The other slave stations and the faulty original master station maintain constant active-reactive power control, so as to achieve optimized switching between master and slave stations in the fault state.
2. The method for optimized master / slave station switching under fault conditions in a flexible interconnected power distribution system based on multi-factor comprehensive evaluation as described in claim 1, characterized in that, S3 includes the following steps: S3.1: Power command value for a given operating point The steady-state voltage at the operating point is obtained using equation (2). With steady-state work angle : (2) In equation (2), This represents the equivalent impedance of a single AC-DC converter. This represents the impedance angle of a single AC-DC converter; For a given operating point, the active power input to a single AC-DC converter is... For a given operating point, the reactive power input to a single AC-DC converter is... , Two nonlinear mapping functions characterize the power grid parameters to the operating point, and we have: (3) In equation (3), For the voltage of a multi-terminal flexible interconnected power distribution system, The equivalent resistance of a single AC-DC converter. The equivalent inductance of a single AC-DC converter; S3.2: Constructing three types of power stability limit curves for a single AC-DC converter under strong grid conditions: S3.2.1: The static power limit boundary equation of a single AC-DC converter is constructed using equation (4) to fit the static stability limit curve. : (4) S3.2.2: Using equation (5), construct the thermal capacity limit boundary equation for a single AC-DC converter under the apparent power rating condition, and use it to fit the thermal capacity limit curve. : (5) In equation (5), The rated power of a single AC-DC converter; S3.2.3: Based on the dynamic parameters of the phase-locked loops of each slave station, using... Reaching the critical angle Power boundary fitting PLL stability limit curve ; S3.3: In and Under the constraints, by comparing the phase-locked loop parameters of each slave station with the controller PI parameters, the problems caused by the master station switching process are eliminated. Sites with inward-shrinking boundaries; and based on the stable operating region SOR enclosed by three types of power stability limit curves and the power circle, with the goal of maximizing the SOR, selecting sites with a smaller impact on the SOR to form a candidate slave site set; S3.4: Calculate the total network line loss for each candidate slave station as the candidate master station, and select the candidate slave station with the lowest total network line loss as the new master station: Using equation (6), we obtain the first... Injection current of each candidate slave station : (6) In equation (6), Represents any number of The voltage of each candidate slave station, Represents any number of The candidate slave station and any first Admittance between candidate stations m Indicates the number of candidate slave stations; Using equation (7), we obtain the first... Injection power of each candidate slave station : (7) Assume the first a Each candidate slave station is used as a candidate master station, and the total network line loss of the candidate master station is obtained using equation (8). : (8) In equation (8), The voltage of the candidate master station. For the remaining candidate sites besides the main site i The voltage of each candidate slave station.
3. The master / slave optimized switching method for flexible interconnected power distribution systems under fault conditions based on multi-factor comprehensive evaluation as described in claim 2, characterized in that, S4 includes the following steps: S4.1: Calculate the first using equations (9) and (10) u The maximum apparent power of each slave station With the upper limit of the active range and lower limit : (9) (10) In equations (9) and (10), For the first u The active power of each slave station For the first u The rated apparent power of each station, For the first u The reverse rated apparent power of each slave station; For the first u The equivalent impedance of each slave station, For the first u The impedance angle of each slave station; S4.2: Select all slave stations whose stability limit of the phase-locked loop (PLL) precedes its own thermal capacity limit to reach instability as candidate slave stations, and then determine the steady-state power angle based on the... With the critical stability angle of the phase-locked loop The intersection point is excluded from the candidate stations. The candidate slave station with the largest shrinkage is selected to obtain the candidate slave stations after the initial screening; S4.3: Obtain the active power transmission limit of each candidate slave station after initial screening under reactive power assistance, and select the candidate slave station corresponding to the maximum active power transmission limit as the target station. If the power limit deviation of the target site is greater than or equal to the preset power transmission range deviation threshold, then the corresponding target site is set as the new master site; otherwise, the total network line loss of each candidate slave site after initial screening is calculated, and the candidate slave site with the smallest total network line loss is selected as the new master site.
4. An electronic device, comprising a memory and a processor, characterized in that: The memory is used to store instructions that enable the processor to execute a computer program, the processor being configured to run the computer program to perform the steps of the optimized switching method as described in any one of claims 1-3.
5. A computer-readable storage medium storing a computer program thereon, characterized in that: When the computer program is run by the processor, it implements the steps in the optimized switching method as described in any one of claims 1-3.