Reactive Power Coordination Optimization Method Of Region Grid With High Penetration Of Power Electronics

In recent years,with the development and utilization of new energy,the power grid has begun to show the "double high" development characteristics of high penetration of new energy and high proportion of power electronic devices,resulting in a series of problems of power grid stability.Virtual synchronous generator（VSG）control technology is an important solution to these problems,and it will be more and more widely used in the future.In order to comply with this development trend,reactive power coordination and optimization of power grid system based on virtual synchronous generator and new energy has become one of the research focuses.Thesis analyzes the reactive power and voltage control strategy of a new photovoltaic and energy storage system model with VSG control technology.The objective function of reactive power optimization is constructed based on VSG control parameters.And the particle swarm optimization algorithm is used to solve and adjust the system parameters,so as to control and adjust the output power.In the distribution network environment,it is combined with the traditional reactive power compensation device to achieve the purpose of reactive power optimization and voltage regulation.The main contents of thesis are as follows:（1）According to the working principle of synchronous generator,the system structure and model of virtual synchronous machine are established.Combined with the working principle of photovoltaic power generation and energy storage,a new energy system and control strategy of VSG co-controlled photovoltaic storage are designed and proposed.（2）In the microgrid system,based on the principle of minimizing active power loss and voltage deviation,the objective function and constraint conditions of reactive power optimization involving VSG control parameters are constructed,and the particle swarm optimization algorithm with penalty function is used for tuning.Under two typical load fluctuation scenarios including high proportion motor and arc furnace impact load,the reactive power optimization effect of VSG coordinated control PV storage control strategy is simulated and analyzed,and compared with the compensation effect of distribution static var generator（D-STATCOM）,which verifies the effectiveness of this strategy in suppressing voltage fluctuation in microgrid system.（3）The VSG co-controlled PV storage system is applied to the distribution network,and it is considered to be combined with the D-STATCOM compensation device to realize the reactive power optimization in the distribution network area.By analyzing the influence of different grid connection positions and different grid connection capacities of VSG co-controlled PV storage system in the power grid,the optimal grid connection point and optimal capacity ratio of the system are determined,and the distribution system model including VSG co-controlled PV storage system and D-STATCOM device is completed.Taking the minimum network loss and voltage as the optimization objective,the objective function of distribution network reactive power optimization is established,and then the PSO optimization algorithm is used to solve it.The obvious optimization effect of the cooperative control strategy is verified by comparative simulation.