Research On Voltage Stability Control Of Power Grid Based On Electric Spring

In recent years,with the intensification of the energy and environmental crisis and the continuous development of new energy power generation technologies,the scale of grid connection for renewable energy generation has become increasingly larger.However,the intermittent and instability problems of renewable energy generation have brought challenges to the stable operation of the power grid.Starting from the input side,the electric spring adopts the form of input feedback,so that the power consumption of the load changes with the change of the generation,which provides a new idea for solving the problem of voltage instability caused by renewable energy.Therefore,this thesis takes the electric spring as the research object,and optimizes its control strategy to improve the stability of the load voltage in the power grid.Firstly,this thesis introduces the working principle and topological structure of the electric spring,and analyzes three working modes and power models for stable operation of the electric spring.Based on the analysis of the circuit phasor and the complex frequency domain model,the PI control is combined with the fuzzy control,and the variable theory domain is introduced to optimize the parameters of the PI controller,which improves the control precision and the adaptive ability of the system,simultaneously,making the effect of voltage stabilization control of the electric spring is effectively improved.Secondly,the typical topology structure including three-phase electric springs is analyzed and applied to the low-voltage distribution network to solve the voltage imbalance problem existing in three-phase circuits.The improved bacterial foraging optimization algorithm is used to control the three-phase electric springs.When the three-phase circuit is asymmetric,the three-phase electric springs can quickly stabilize the voltage on the critical load by optimizing the fitness function and step size of the bacterial foraging optimization algorithm.And reduce the imbalance of the circuit voltage.Finally,a simulation model based on variable universe fuzzy PI control method and improved bacterial foraging optimization algorithm is built in MATLAB/Simulink.The simulation results show that under the control strategy proposed in this thesis,the electric spring has a good voltage stabilizing performance,which improves the power supply quality of the power grid..