Research On The Performance Of The Grid-off Wind Turbine Generator System

Due to the particularity of users and environment, the off-grid wind turbine generator have high requirement to its reliability and security. The subject focuses on the research of horizontal axis wind turbine blade design, aerodynamic characteristics computation, the match of wind turbine and generator, and analyses the feasibility of controlling overspeed and overload by controlling load.Based on the programs of blade design and rotor aerodynamic characteristics calculation, wrote by Niejing, the subject proposes that the match of wind turbine and generator should be taken into account when design the blade. The subject optimizes the program. In this subject, different from the traditional method, the rated wind speed and design wind speed are taken as two parameters and be defined. Two wind turbine generators, which have same diameters, are designed based on different design wind speed and rated wind speed.The match of wind turbine and generator has great effect to the whole performance. In the subject, the curve of power-rev of wind turbine is divided three parts, which is before-peak, peak value and behind-peak. When the wind turbine generator works at different area, it has different performance. The subject analyzes the wind turbine generator's output when the load is changed. For the wind turbine generator which works at the before-peak area, the power output and rev fall deeply when the load reduced. Based on these characteristics, the subject validates the feasibility of control the wind turbine overspeed and overload by reducing load.At the end, the subject validates the theory analysis by test. We test the performance of two wind turbine generators. The test results prove that for the off-grid wind turbine generator the low design wind speed not only can improve the wind turbine power coefficient at low wind speed, but also can insure the control reliability at high wind speed. At the same time, we test the power output when the load changed and the time the wind turbine need from normal work to standstill when the load is lost suddenly. The results indicate that the wind turbine generator which works at the before-peak has higher reliability at the high wind speed.