Research On Transient Stability Mechanism Of Wind Turbines With Full-scale Voltage Source Converter

In today’s era of rapid development of new energy,as the proportion of new energy continues to increase,the impact of new energy on the power system is deepening.Among them,the wind turbine as the main grid-connected power source,especially the wind turbines with full-scale voltage source converter,which has attracted much attention in recent years,is called wind turbines with full-scale voltage source converter in this paper,and its control system characteristics and grid-connected stability are in the It has been the research focus of many scholars in recent years.The research on the stability of wind turbines with full-scale voltage source converter consists of two aspects: static stability and transient stability.This paper mainly studies the transient stability of wind turbines with full-scale voltage source converter dominated by the phase-locked synchronization link.In order to reveal its transient stability mechanism,this paper firstly constructs a wind turbine with full-scale voltage source converter grid-connected station system model with a multi-time scale control system,and builds a mathematical model of the system under reasonable assumptions for typical fault transient processes.The differential equations of the system considering the dynamic characteristics of the phase-locked loop are refined,and the theory of the transient stability mechanism analysis of synchronous generators is analogous to the traditional power system.According to the change characteristics of electromagnetic power angle during the occurrence and removal of system short-circuit fault,the electromagnetic power angle theory for analyzing the transient stability of wind turbines with full-scale voltage source converter is proposed by referring to the theory of equal area rule.Based on the electromagnetic power angle theory,the transient stability criterion is proposed,and the full-power wind power is analyzed from five aspects: the bandwidth of the phaselocked loop,the depth of the fault voltage drop,the short-circuit ratio,the voltage phase angle mutation at the fault point,and the electrical distance between the wind turbine and the fault point.The influence of the transient stability margin of the gridconnected system of the unit is discussed,and the optimization direction of system parameters and control parameters that can help to improve the transient stability of wind turbines with full-scale voltage source converter is explored.Finally,based on the Matlab/Simulink simulation platform,the grid-connected station system model of the full-power wind turbine is built to verify the correctness of the conclusions.