Research On The Problem Of Grid Connection Technique And Running Quality Of Wind Power In The Context Of Electric Railway

With the rapid development of electric railway and growing installed capacity of wind power, the problem of that electric railway having an influence on wind power was more and more obvious. It was very important to study the problem of grid connection technique and running quality of wind power in the context of electric railway for practical application to avoid that wind turbines shutting down as the power quality of the PCC of wind power deteriorated by electric railway, and it was meaningful to projecting wind farms' location, controlling wind turbine and the protection settings theoretically and practically, also to the safe and stable operation of partial electric network.First of all, special project measurement on power quality was conducted contraposing the problem existing in the influence of electric railway on wind power, to study the principle of the influence combining the structure and characteristic of electric railway power supply system. Then wind farms' accident cases in recent years was listed to analyze and summarize the characteristics of influence of electric railway on the harmonic and three-phase imbalance level of the wind power 's PCC.This paper established the mathematical model of the grid-connected converter with LCL filter considering the effect of electric railway's harmonic to study the grid connection technique in the context of electric railway, through which can analyze and compare the principles of method to weaken the internal resonance peak based on damping resistance and capacitor current feedback active strategy. Then designing the parameter of PIR controller by the root locus method and frequency domain analysis method, on this basis, the active damping strategy based on PIR controller was built and proved by emulation. Thus the overburning problem of damping resistance was resolved effectively, meanwhile the influence of the distorted grid voltage on the grid-connected current of the grid-connected converter was suppressed.In allusion to the running quality problem of wind power in the context of three-phase imbalancing system by electric railway, establishing the mathematical model of DFIG. Then through large number of simulation and experiments, the steady state and transient operation data of wind power, disturbed by the electric railway, were obtained considering three-phase imbalance of electric railway, operational state of wind farm and robustness of electric network compositely. Screening the significant indexes of influencing the wind power operation and sensitive characteristic indexes in the context of three-phase imbalancing system by electric railway, by adopted the analysis of variance methods in mathematical statistics. In the last, operational sensitive domain of wind turbine described by threshold value of protection was proposed, in consideration of PCC's three-phase imbalance characteristic connected to the wind farm and the settings of its own protection. The method also was applied to field case to verify that it was meaningful to the protection settings and voltage controlling of wind turbines when the three-phase imbalance caused by electric railway was serious relatively.