Research On Comprehensive Reactive Compensation Strategy Of High Proportion Wind Power Grid-Connected DC Delivery System

At present,for the three regions of northwest,northeast and north China where wind power resources are relatively rich in China,the space for wind power consumption is basically saturated,so there is an urgent need for cross-regional delivery.Located in the Xinjiang region of northwestern China,the structure of the power supply is relatively simple,the structure of the grid is also very weak,and the further access of high proportion of wind power brings many problems to the stable operation of the power system.Therefore,in order to better maintain the stability of the voltage in the power grid,the research and analysis of the comprehensive reactive power compensation strategy for the high-scale wind power grid-connected DC delivery system is of great significance.In order to improve voltage stability when the power system is single-phase,three-phase short-circuit fault or other serious faults,the most effective and basic method is to install the corresponding reactive power compensation device.This paper proposes a combined reactive power compensation scheme and its reactive power coordination control strategy,and optimizes the reactive power capacity by the improved particle swarm optimization algorithm,and applies it to the weak nodes of the wind farm to achieve simultaneous improvement of static and transient voltage.The purpose of stability.To this end,this paper conducts research in the following aspects:Firstly,the mathematical model of the doubly-fed wind turbine and the HVDC transmission system is established,and the wind power grid-connected DC delivery system model is proposed.It is followed by comparative analysis of the different compensation principles of the two dynamic reactive compensation devices.The modal analysis method determines the weak nodes of the wind farm for detailed analysis.Secondly,an improved reactive power optimization algorithm is proposed: the adaptive mutation operator chaotic particle swarm algorithm to solve the minimum compensation capacity required by the dynamic reactive power compensation device.The combined reactive power compensation scheme proposed in this article lays the foundation for wind farms.Finally,the wind power field in Hami area of Xinjiang is analyzed,and the PV/QV curves of the three main wind areas in the area are plotted.The active margins of each wind area are compared and analyzed.The Santanghu wind area is the high-permeability area of wind power in Hami area.Further,the simulation characteristics of the static and transient voltage stability of the wind farm are analyzed.The research results show that compared with the other five compensation schemes,the combined reactive power compensation scheme of SVG and shunt capacitor proposed in this paper can not only balance the rapid continuity of dynamic reactive power compensation device,but also the low cost and large capacity of parallel capacitor.Power compensation features,and has obvious advantages in improving static and transient voltage stability.