Research On Comparison Of Constant And Variable Speed Wind Power System

Nowadays, under the stress of energy and environment, it is a long-term energy resource strategy to develop wind electricity in the world. The two main ways to generate electricity in the large and middle scale wind field are Constant Speed Constant Frequency (CSCF) asynchronous generator and Variable Speed Constant Frequency (VSCF) doubly-fed asynchronous generator. The dynamic characteristics of these two kinds of wind generators are different, so the impact on the power system is different. The dissertation compared Constant Speed Constant Frequency Wind Power System (CSCFWPS) and Variable Speed Constant Frequency Wind Power System (VSCFWPS) with steady and transient simulation.This dissertation expounds four kinds of operation status and the relationship of power flow besides the principle of Maximum Power Point Tracking (MPPT) in VSCFWPS on the basic of summarizing the basic theory of CSCFWPS and VSCFWPS. The models of the wind and wind turbine besides asynchronous generator and doubly-fed asynchronous generator are decided to use.Three generator five points system including the wind field as one point is built basing on MATLAB/SIMULINK, which is made use of to compare the simulation of these two kinds of wind power system in some operation ways and when the disturbing wind has happened.The results of simulation are that in the steady state, the range of the operation voltage of VSCFWPS is smaller than that of CSCFWPS, the fluctuant of the voltage and power transmitted into the power system are smaller than that of CSCFWPS, The VSCFWPS could get back to the steady state while the CSCFWPS could not, which loses its stability when grounding short circuit from 1.8s-2.2s and strong disturbing wind have happened in the weak power system. So the conclusion has been given that the steady and transient characteristics of VSCFWPS are better than those of CSCFWPS, VSCFWPS has obvious predominance in the weak power system.