Distributed wind storage system fault load flow calculation method based on droop control

Abstract

The invention discloses a distributed wind storage system fault load flow calculation method based on droop control. The method comprises the following steps: S1, constructing a droop control model considering characteristics of a distributed wind storage system: (1) active-frequency and reactive-voltage droop characteristics of a synchronous generator; (2) obtaining active power and reactive power of a wind storage node; (3) obtaining an output equation of the actual active power and the actual reactive power of the wind storage node; s2, fault load flow calculation: establishing a power balance equation of a balance node, a PQ node and a PV node; the power balance equation of the introduced WS node is composed of an output equation of actual active power and an output equation of actual reactive power; performing power correction on the WS nodes to obtain a WS node model; and a final load flow calculation model is obtained in combination with a WS node model. The problem that in the prior art, the calculation result and the actual operation state deviate remarkably is solved.

Description

Technical Field

[0001] This invention relates to the field of fault power flow calculation technology for distributed wind and storage systems, and specifically to a fault power flow calculation method for distributed wind and storage systems based on droop control. Background Technology

[0002] Driven by the goals of "carbon peaking and carbon neutrality," distributed wind and energy storage systems have become a core component of distributed energy systems in industrial parks, remote rural areas, and islands due to their core advantages of "proximity to load absorption, smoothing wind power fluctuations, and improving power supply reliability." Their operational stability highly depends on droop control technology—by simulating the active-frequency and reactive-voltage regulation characteristics of traditional synchronous generators, droop control enables autonomous power allocation among multiple wind and energy storage units, adapting to scenarios without large power grid support, such as off-grid or weak grids. Simultaneously, it meets the voltage and frequency stability requirements of distribution network standards, serving as a key support for upgrading distributed wind and energy storage from "single energy devices" to "actively regulating nodes." However, the planning, design, operation optimization, and fault diagnosis of distributed wind and energy storage systems are all based on power flow calculations. As a core tool for power system analysis, power flow calculations require solving key parameters such as voltage amplitude and phase angle at each node, and branch power distribution, providing data support for system capacity configuration, scheduling strategy formulation, and grid compatibility verification. Traditional power flow calculations are based on the core assumptions of "constant frequency (e.g., 50Hz) and fixed node type (PQ / PV / balance node)," which are suitable for the characteristics of "large grid support and controllable power output" in centralized power systems. However, in the droop control scenario, this assumption is completely broken, making it difficult for traditional methods to adapt to the dynamic operating characteristics of distributed wind and energy storage systems, resulting in a significant contradiction between "technical requirements" and "computing tools."

[0003] From the perspective of system operation characteristics, the three core changes introduced by droop control directly exacerbate the complexity of power flow calculation: First, the output of wind and energy storage units is deeply coupled with voltage and frequency. Active power fluctuates with frequency, and reactive power changes with voltage, causing the node type to change from "static and fixed" to "dynamic and fuzzy," making it impossible to classify them as traditional PQ / PV nodes. Second, in off-grid or weak grid scenarios, there are no ideal balancing nodes, and the frequency changes from a "known constant" to an "unknown variable that needs to be solved in conjunction with active power balance." The power flow calculation dimension expands from "voltage-phase angle two-dimensional" to "voltage-phase angle-frequency three-dimensional." Third, when multiple wind and energy storage units are running in parallel, the difference in droop coefficients causes mutual interference between power distribution and branch power flow. Coupled with the intermittency of wind power output and the time-varying nature of energy storage SOC (state of charge), the system parameters exhibit strong uncertainty, further amplifying the nonlinearity and convergence difficulty of power flow calculation in distributed wind and energy storage systems.

[0004] Currently, distributed wind and energy storage systems are developing towards "multi-energy complementarity, large-scale grid connection, and intelligent operation," with their installed capacity and application scenarios continuously expanding—for example, 10-50MW-level wind and energy storage microgrids in industrial parks and off-grid integrated wind and energy storage projects on islands. This places higher demands on the accuracy and adaptability of power flow calculations. If traditional power flow calculation methods are still used, the calculation results will deviate significantly from the actual operating state, potentially leading to unreasonable capacity allocation, ineffective scheduling strategies, and even system voltage / frequency instability. Therefore, addressing the droop control characteristics and breaking through the assumptions of traditional power flow calculations, constructing power flow calculation methods adapted to the dynamic coupling, multi-variable collaboration, and time-varying parameter characteristics of distributed wind and energy storage systems has become a key research direction supporting the large-scale application of distributed wind and energy storage and ensuring the safe and efficient operation of power systems. This has significant theoretical and engineering value. Summary of the Invention

[0005] The purpose of this invention is to provide a fault power flow calculation method for distributed wind and energy storage systems based on droop control. First, a droop control model considering the characteristics of distributed wind and energy storage systems is constructed to achieve a comprehensive description of the power output characteristics of distributed wind and energy storage systems. Then, a fault power flow calculation method for distributed wind and energy storage systems based on droop control is proposed to solve the problem that the calculation results of existing technologies deviate significantly from the actual operating conditions, which may lead to unreasonable capacity configuration, failure of scheduling strategies, and even system voltage / frequency instability.

[0006] This invention provides a fault power flow calculation method for a distributed wind-storage system based on droop control, and the specific implementation steps are as follows: S1. Construct a droop control model that considers the characteristics of a distributed wind storage system: (1) The droop control is achieved by simulating the primary frequency regulation characteristics of the generator and the active-frequency and reactive-voltage droop characteristics of the synchronous generator. (2) Based on the active power-frequency droop control characteristics, the active power of the wind-storage node is obtained; based on the reactive power-voltage droop control characteristics, the reactive power of the wind-storage node is obtained. (3) In actual grid connection, a low-pass filter will be added to the front end of the droop control to filter out high-order harmonics; based on the transfer function of the low-pass filter and the active-frequency droop control characteristics, the output equation of the actual active power of the wind-storage node is obtained; based on the transfer function of the low-pass filter and the reactive-voltage droop control characteristics, the output equation of the actual reactive power of the wind-storage node is obtained. S2, Fault Power Flow Calculation: Establish balance nodes, PQ Nodes and PV Power balance equations for nodes; For distributed wind and storage systems, the introduction of wind and storage nodes is... WSThe nodes are used to describe their internal droop control characteristics. WS The power balance equations of a node consist of the output equations for actual active power and actual reactive power; based on the fundamental principles of the Newton-Raphson method, the following steps are performed: WS Node power correction obtained WS Node model; Combination WS Node models and traditional power flow calculation methods PV Nodes and PQ The node is used to summarize the power flow calculation model of the entire distributed wind and storage system to obtain the final power flow calculation model; by inputting the system grid structure, wind and storage system control parameters, and load size into the power flow calculation model, the power flow parameters such as voltage amplitude and voltage phase angle of each node can be obtained.

[0007] Furthermore, in step S1, the active-frequency and reactive-voltage droop characteristics of the synchronous generator are specifically as follows: (1); in, ω 0 , V 0 These are the rated values ​​for angular frequency and voltage amplitude, respectively. ω , V These are the actual output values ​​of angular frequency and voltage amplitude, respectively. P n , Q n These represent the actual active power and reactive power output of the wind power storage system, respectively. K p , K q These are the droop control coefficients for active power frequency and reactive power voltage, respectively.

[0008] Further, in step S1, the active power output of the wind-storage node is obtained based on the active power-frequency droop control characteristics as follows: (2); Based on the reactive power-voltage droop control characteristics, the reactive power output of the wind-storage node is obtained as follows: (3); in, ω 0 , V 0 These are the rated values ​​for angular frequency and voltage amplitude, respectively. ω , V These are the actual output values ​​of angular frequency and voltage amplitude, respectively. P n , Qn These represent the actual active power and reactive power output of the wind power storage system, respectively. K p , K q These are the droop control coefficients for active power frequency and reactive power voltage, respectively.

[0009] Furthermore, the transfer function of the low-pass filter is: (4); in, K This is the scaling factor for the low-pass filter. ω a This is the cutoff angular frequency of the low-pass filter; s For the Laplace operator.

[0010] Furthermore, the output equation for the actual active power of the wind-storage node is obtained, specifically: (5); in, ω p The cutoff angular frequency of the low-pass filter in the active-frequency control branch; Based on the low-pass filter transfer function and reactive-voltage droop control characteristics, the output equation for the actual reactive power at the wind-storage node is obtained, specifically as follows: (6); in, ω q This is the cutoff angular frequency of the low-pass filter in the reactive power-voltage control branch.

[0011] Furthermore, establish balancing nodes, PQ Nodes and PV The power balance equations for the nodes are as follows: (7); in, S i for PQ Complex power of a node, P i for PV The active power of the node, Represents the given PV Node voltage amplitude, This represents the setpoint voltage at the slack node. Y ik The ()th node admittance matrix i , k ) elements.

[0012] Furthermore, the aforementioned WSThe power balance equations for the nodes are as follows: (8); Furthermore, based on the fundamental principles of the Newton-Raphson method, the power correction equation for the WS node is: (9); (10); in, P is , Q is These represent the given active power and given reactive power of the corresponding node, respectively. S base This is a power reference value. V base This is the voltage reference value.

[0013] Furthermore, in step 2, combined with WS Node models and traditional power flow calculation methods PV Nodes and PQ The nodes summarize the power flow calculation model of the entire distributed wind-storage system to obtain the final power flow calculation model, which is as follows: (11); (12); (13); Among them, P n Q n These are the active power reference value and reactive power reference value for the corresponding node, respectively. The specific calculation formula is as follows: (14); (15); in, a For admittance angle, b , c They are nodes n ,node m voltage phase angle, Y nm For nodes n and nodes m Mutual admittance between them N for PQ Nodes and PV Total number of nodes.

[0014] The working principle of this invention is as follows: 1. Droop control modeling The essence of droop control is to enable the inverter of the wind-storage system to simulate the primary frequency and voltage regulation response characteristics of a traditional synchronous generator. This invention is based on the active power-frequency droop control coefficient. K p Reactive power-voltage droop control coefficient K q Establish active power of wind storage nodes P n reactive power Q n With system angular frequency ω Voltage amplitude V The fundamental coupling relationship is established, clarifying the dynamic response law of power output as a function of system frequency and voltage fluctuations. Simultaneously, to address the interference of high-order harmonics on power output in actual grid-connected scenarios, a low-pass filter is introduced. Its transfer function is used to correct the power output of the active-frequency control branch and the reactive-voltage control branch. The actual active power output equation and the actual reactive power output equation, taking into account harmonic filtering, are derived respectively, thus achieving an accurate characterization of the true power output characteristics of the wind-storage unit and laying the model foundation for subsequent power flow calculations.

[0015] 2. Fault power flow calculation Traditional power flow calculation only supports balancing nodes. PQ node, PV Static power balance solutions for nodes cannot adapt to the power-frequency-voltage coupling characteristics of wind-storage units. This invention breaks through this framework: first, it establishes the power balance equations for traditional nodes, constructs a basic calculation system, and innovatively introduces... WS (Wind-Storage) node, using the above actual active and reactive power output equations as... WS The power balance constraint of the nodes solves the problem that traditional node types cannot describe the active voltage and frequency regulation characteristics of wind-storage units. Combining the iterative convergence principle of the Newton-Raphson method, the power correction equation for the WS node is derived, which... WS Nodes and Tradition PQ , PV The computational models of the nodes are integrated to form a complete fault power flow calculation model. The input system grid structure, wind and storage system control parameters, and load size are iteratively solved to output power flow parameters such as voltage amplitude and voltage phase angle of each node, so as to achieve accurate mapping of fault power flow in the distributed wind and storage system.

[0016] Compared with the prior art, the beneficial effects of the present invention are: This invention employs a fault power flow calculation method for distributed wind and energy storage systems based on droop control. It considers the impact of active-frequency and reactive-voltage control characteristics in droop control on the distributed wind and energy storage system. The power output equation is corrected by introducing a low-pass filter in actual grid connection to eliminate the influence of higher harmonics. Simultaneously, it innovatively… WSThe nodes represent the power-frequency-voltage coupling relationship of the wind-storage unit, effectively eliminating calculation errors caused by harmonic interference and lack of dynamic characteristics. Finally, the wind-storage node model established by the Newton-Raphson method is used to calculate the specific power flow distribution of the distributed wind-storage system, which has high practical value in the fault power flow calculation of new power systems containing distributed wind-storage systems. Attached Figure Description

[0017] The accompanying drawings of this invention are described below.

[0018] Figure 1 This is the droop control diagram of the decentralized wind storage system of the present invention; Figure 2 This is a topology diagram of the distributed wind storage system with droop control in this invention; Figure 3 The system node voltage amplitude is calculated using the power flow calculation method under the droop control of the distributed wind-storage system mentioned in this invention. Figure 4 The system node voltage phase angle is calculated using the power flow calculation method under the droop control of the distributed wind-storage system mentioned in this invention.

[0019] Figure 5 Different droop control rated voltages are used in the power flow calculation method under droop control of the distributed wind-storage system mentioned in this invention. V 0 |System node voltage distribution.

[0020] Figure 6 It is the system convergence region with different load levels and initial power flow values ​​using the power flow calculation method under the droop control of the distributed wind-storage system mentioned in this invention. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments. It should be understood that the embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0022] Example: Figure 1 As shown in the figure, this invention provides a method for calculating the fault power flow of a distributed wind-storage system based on droop control. The specific implementation steps are as follows: S1. Construct a droop control model that considers the characteristics of a distributed wind storage system: With the large-scale grid connection of wind farms, problems such as frequency drop and voltage drop have gradually emerged at the grid connection points. Due to the limitations of wind resources, distributed wind and energy storage systems have differences in the real-time output power of each wind turbine, which makes the support capabilities of each wind turbine significantly different. The essence of droop control is to simulate the power-voltage / frequency regulation characteristics of traditional synchronous generators, so that the static inverter (the core interface device of the wind and energy storage system) has the ability to stabilize the system autonomously, and ultimately achieve voltage and frequency stability, reasonable power distribution and multi-unit collaborative operation.

[0023] Droop control is achieved by simulating the primary frequency regulation characteristics of a generator. The active-frequency and reactive-voltage droop characteristics of a synchronous generator are as follows: (1); in, ω 0 , V 0 These are the rated values ​​for angular frequency and voltage amplitude, respectively. ω , V These are the actual output values ​​of angular frequency and voltage amplitude, respectively. P n , Q n These represent the actual active and reactive power outputs of the wind power storage system, respectively. K p , K q These are the droop control coefficients for active power-frequency and reactive power-voltage, respectively. Based on the active power-frequency droop control characteristics, the active power output of the wind-storage node is obtained as follows: (2); Based on the reactive power-voltage droop control characteristics, the reactive power output of the wind-storage node is obtained as follows: (3); To eliminate the impact of grid harmonics when the wind-storage system is connected to the grid, a low-pass filter is added at the front end of the droop control to filter out higher-order harmonics during actual grid connection. The transfer function of the low-pass filter is: (4); in, K This is the scaling factor for the low-pass filter. ω a This is the cutoff angular frequency of the low-pass filter; s For the Laplace operator.

[0024] Based on the low-pass filter transfer function and the active-frequency droop control characteristics, the output equation of the actual active power at the wind-storage node is obtained, specifically: (5); in, ω p The cutoff angular frequency of the low-pass filter in the active-frequency control branch; Based on the low-pass filter transfer function and reactive-voltage droop control characteristics, the output equation for the actual reactive power at the wind-storage node is obtained as follows: (6); in, ω q This is the cutoff angular frequency of the low-pass filter in the reactive power-voltage control branch.

[0025] S2, Fault Power Flow Calculation: The integration of large-scale wind power generation weakens the system's ability to operate safely and stably. Therefore, droop control is needed to improve system stability, and accurate power flow distribution calculations are required to effectively assess its support capacity. Existing power flow calculation methods only treat wind and energy storage as equivalent power sources, considering only their external output characteristics and neglecting the internal droop control characteristics and active voltage and frequency regulation capabilities of the wind-energy storage system. This makes them unsuitable for ill-conditioned conditions such as sudden load changes and rapid increases in wind power output, leading to deviations between the calculated power flow results and the actual distribution. Existing power flow calculation methods primarily rely on the Newton-Raphson method, which mainly includes power balance equations for slack nodes, PQ nodes, and PV nodes. This step is an improvement based on existing power flow calculation methods combined with step S1.

[0026] (1) Establish balance nodes, PQ Nodes and PV Power balance equations for nodes; (7); in, S i for PQ Complex power of a node, P i for PV The active power of the node, Represents the given PV Node voltage amplitude, This represents the setpoint voltage at the slack node. Y ik The ()th node admittance matrix i , k ) elements.

[0027] (2) For distributed wind storage systems, wind storage ( WS The nodes are used to describe the droop control characteristics inside, and their specific power balance equations are as follows: WSThe power balance equations of a node consist of the output equations for actual active power and actual reactive power. WS The power balance equations for the nodes are as follows: (8); Combining the basic principles of the Newton-Raphson method, WS Node power correction obtained WS Node model, WS The power correction equation for the node is: (9); (10); in, P is , Q is These represent the given active power and given reactive power of the corresponding node, respectively. S base This is a power reference value. V base This is the voltage reference value.

[0028] (3) Combining formula (9) WS Node models and traditional power flow calculation methods PV Nodes and PQ The power flow calculation model for the entire distributed wind-storage system can be summarized as follows: (11); (12); (13); in, P n , Q n These are the active power reference value and reactive power reference value for the corresponding node, respectively. The specific calculation formula is as follows: (14); (15); in, a For admittance angle, b , c They are nodes n ,node m voltage phase angle, Y nm For nodes n and nodes m Mutual admittance between them N for PQ Nodes and PVTotal number of nodes.

[0029] Figure 2 This demonstration showcases the distributed wind-storage system topology used for verification of this invention. The verification system comprises an IEEE 33-node standard system, five distributed wind-storage systems, and a synchronous generator connected together. Specifically, each of the five distributed wind-storage systems is equipped with either two or three wind turbines (WTs), forming a complete wind turbine generator unit. Each distributed wind-storage system is connected to an energy storage station (ESS), and all these distributed wind-storage systems are under droop control. Due to the frequency and voltage regulation effect of the droop control, the operating conditions (such as output power and rotor speed) of each distributed wind-storage system differ significantly.

[0030] To verify the effectiveness of the proposed power flow calculation method for a distributed wind-storage system under droop control, different power flow calculation methods were used for this nodal system, including: the traditional power flow algorithm without considering droop control; and the Newton-Raphson method considering droop control. A test system was built using the MATLAB / Simulink simulation platform. Figures 3 to 4 In the diagram, the red line represents the system power flow distribution of the traditional power flow algorithm without considering droop control, while the black line represents the system power flow distribution of the Newton-Raphson method considering droop control. For example... Figure 3 and Figure 4 As shown, the Newton-Raphson method considering droop control can calculate the corresponding values ​​well, whether it is the node voltage magnitude or the node voltage phase angle, demonstrating the effectiveness of the proposed power flow calculation method under droop control for distributed wind-storage systems. Figure 5 In the middle, the red line represents the droop control rated voltage. V 0 The system voltage distribution is 1.00, with the black line representing the droop control rated voltage. V 0 |=1.01 System voltage distribution; Blue line represents droop control rated voltage| V 0 The system voltage distribution with a value of 1.02. For example... Figure 5 As shown, as the rated voltage in the droop control increases, the voltage distribution of the entire system gradually improves overall. This trend can be explained by equation (6). V 0 As the voltage increases, the reactive power output of the distributed wind power storage system will gradually increase, thereby improving the overall voltage distribution of the system. Figure 6 In the diagram, red dots indicate convergence to an inoperable solution, green dots indicate convergence to a operable solution, and white dots indicate non-convergence. For example... Figure 6As shown, when the load level is less than 18, the proposed power flow algorithm can converge to a workable point, but when the load level is greater than 18, the system cannot converge to a workable solution under any initial power flow value.

[0031] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A fault power flow calculation method for a distributed wind-storage system based on droop control, characterized in that, The specific implementation steps are as follows: S1. Construct a droop control model that considers the characteristics of a distributed wind storage system: (1) The droop control is achieved by simulating the primary frequency regulation characteristics of the generator and the active-frequency and reactive-voltage droop characteristics of the synchronous generator. (2) Based on the active power-frequency droop control characteristics, the active power of the wind-storage node is obtained; based on the reactive power-voltage droop control characteristics, the reactive power of the wind-storage node is obtained. (3) In actual grid connection, a low-pass filter will be added to the front end of the droop control to filter out high-order harmonics; based on the transfer function of the low-pass filter and the active-frequency droop control characteristics, the output equation of the actual active power of the wind-storage node is obtained; based on the transfer function of the low-pass filter and the reactive-voltage droop control characteristics, the output equation of the actual reactive power of the wind-storage node is obtained. S2, Fault Power Flow Calculation: Establish balance nodes, PQ Nodes and PV Power balance equations for nodes; For distributed wind and storage systems, the introduction of wind and storage nodes is... WS The nodes are used to describe their internal droop control characteristics. WS The power balance equations of a node consist of the output equations for actual active power and actual reactive power; based on the fundamental principles of the Newton-Raphson method, the following steps are performed: WS Node power correction obtained WS Node model; Combination WS Node models and traditional power flow calculation methods PV Nodes and PQ The node is used to summarize the power flow calculation model of the entire distributed wind and storage system to obtain the final power flow calculation model; by inputting the system grid structure, wind and storage system control parameters, and load size into the power flow calculation model, the power flow parameters of each node can be obtained.

2. The fault power flow calculation method for a distributed wind-storage system based on droop control as described in claim 1, characterized in that: In step S1, the active-frequency and reactive-voltage droop characteristics of the synchronous generator are specifically as follows: (1)； in, ω 0 , V 0 These are the rated values ​​for angular frequency and voltage amplitude, respectively. ω , V These are the actual output values ​​of angular frequency and voltage amplitude, respectively. P n , Q n These represent the actual active power and reactive power output of the wind power storage system, respectively. K p , K q These are the droop control coefficients for active power frequency and reactive power voltage, respectively.

3. The fault power flow calculation method for a distributed wind-storage system based on droop control as described in claim 1, characterized in that: In step S1, the active power output of the wind-storage node is obtained based on the active power-frequency droop control characteristics as follows: (2)； Based on the reactive power-voltage droop control characteristics, the reactive power output of the wind-storage node is obtained as follows: (3)； in, ω 0 , V 0 These are the rated values ​​for angular frequency and voltage amplitude, respectively. ω , V These are the actual output values ​​of angular frequency and voltage amplitude, respectively. P n , Q n These represent the actual active power and reactive power output of the wind power storage system, respectively. K p , K q These are the droop control coefficients for active power frequency and reactive power voltage, respectively.

4. The fault power flow calculation method for a distributed wind-storage system based on droop control as described in claim 1, characterized in that: The transfer function of the low-pass filter is: (4)； in, K This is the scaling factor for the low-pass filter. ω a This is the cutoff angular frequency of the low-pass filter; s For the Laplace operator.

5. The fault power flow calculation method for a distributed wind-storage system based on droop control as described in claim 1, characterized in that: The output equation for the actual active power of the wind-storage node is obtained as follows: (5)； in, ω p The cutoff angular frequency of the low-pass filter in the active-frequency control branch; Based on the low-pass filter transfer function and reactive-voltage droop control characteristics, the output equation for the actual reactive power at the wind-storage node is obtained, specifically as follows: (6)； in, ω q This is the cutoff angular frequency of the low-pass filter in the reactive power-voltage control branch.

6. The fault power flow calculation method for a distributed wind-storage system based on droop control as described in claim 1, characterized in that: Establish balance nodes, PQ Nodes and PV The power balance equations for the nodes are as follows: (7)； in, S i for PQ Complex power of a node, P i for PV The active power of the node, Represents the given PV Node voltage amplitude, This represents the setpoint voltage at the slack node. Y ik The ()th node admittance matrix i , k ) elements.

7. The fault power flow calculation method for a distributed wind-storage system based on droop control as described in claim 1, characterized in that: The power balance equation for the WS node is as follows: (8)。 8. The fault power flow calculation method for a distributed wind-storage system based on droop control as described in claim 1, characterized in that: Combining the basic principles of the Newton-Raphson method, WS The power correction equation for the node is: (9)； (10)； in, P is , Q is These represent the given active power and given reactive power of the corresponding node, respectively. S base This is a power reference value. V base This is the voltage reference value.

9. The fault power flow calculation method for a distributed wind-storage system based on droop control as described in claim 1, characterized in that: In step 2, combined with WS Node models and traditional power flow calculation methods PV Nodes and PQ The nodes summarize the power flow calculation model of the entire distributed wind-storage system to obtain the final power flow calculation model, which is as follows: (11)； (12)； (13)； in, P n , Q n These are the active power reference value and reactive power reference value for the corresponding node, respectively. The specific calculation formula is as follows: (14)； (15)； in, a For admittance angle, b , c They are nodes n ,node m voltage phase angle, Y nm For nodes n and nodes m Mutual admittance between them N for PQ Nodes and PV Total number of nodes.

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