Study On The Distributed Voltage Stabilization In Demand Side With Control Strategy And Numerical Simulation

With the rapid popularization of distributed generation and the nonlinear load, power system reactive power disturbance is increasingly severe which causes the network voltage fluctuation or flicker, and leads to the instability of the power grid in different degrees. The reactive power compensation of the distributed power grid in demand side can effectively balance the reactive power, and maintain a stable voltage, and improve the power factor of the power grid. So, the quality of power supply is ensured to be good. More advanced static var compensator and static synchronous compensator are centralized reactive power compensation, which usually control the power supply quality on the macro scope and is suitable for large capacity area substation. But the response speed and the response accuracy are not ideal with small capacity of distributed power grid. Electric spring is expected to be a breakthrough to solve the above problems because of its characteristic of facing demand side and suitabling for distributed voltage regulator.In order to improve the quality of electric power in demand side, a distributed voltage stabilizing scheme was investigated, which can balance reactive power of low voltage distribution network in demand side. The basic principle of ES was analyzed and the hardware filter circuit was improved. Optimized distributed voltage power grid topology was built, and the regional network distributed voltage regulator topology was proposed. In addition, this paper analyzed the limitation of the reactive power and the noncritical load to the whole system. This paper optimized the system control strategy with adopting SPWM inverter modulation mode. Double loop control was carried to set amplitude compensation and phase compensation based on PI control. And control parameters were set by combining theory and experience. Simulation was carried out on the MATLAB/SIMULINK platform, and two topological units were combined to simulate the distributed voltage regulator with different capacity of reactive power disturbance. By analyzing the simulation datas and waveforms, and comparing their THD values, it is proved that the filter characteristics of the network side and the inverter side are improved, and the faster response speed and higher accuracy are achieved with a better voltage stabilizing effect. At the same time, it is proved that combining two topological units can effectively overcome the inherent limitations of hardware. To sum up, the distributed voltage stabilizing scheme in demand side is suitable for the occasions where contain critical loads and large voltage fluctuation. It can stabilizate voltage from point to point in demand side, which overcomes the limitations of traditional reactive power compensation, and more suitable for distributed low voltage distribution network system with reactive power disturbance.