Research On Configuration Setting Of Relay Protection For Wind Farm

In recent years,doubly-fed induction generator(DFIG)has been widely used in wind farms.Due to different control strategies,fault types,fault location,access capacity and access methods,DFIG Of the transient characteristics of "polymorphism",to the wind farm to bring a great impact on the protection device,the traditional relay protection can not be applied.Therefore,it is necessary to explore its complex transient characteristics and propose a feasible new scheme of relay protection.Based on the study of the mathematical model of DFIG grid-connected system,this paper establishes the DFIG model based on different control strategies and analyzes the transient characteristics of the fault under different control strategies.The characteristics of short-circuit current are studied and the scheme of wind farm protection configuration And the setting principle,a fast and effective protection scheme and a wide-area protection scheme of the wind farm are proposed and simulated.Doubly-fed wind turbine converter has a variety of control strategies,this paper selected the vector control and direct power control of two control strategies for mathematical modeling and simulation modeling,and use these two simulation model analysis of the steady-state operating characteristics and fault temporarily The characteristics of steady-state operation and fault transient characteristics under different control strategies are analyzed and compared according to the simulation results,and a reasonable explanation is given.In view of the fact that the short-circuit current characteristic of DFIG is affected by many factors,this paper focuses on the influence of the operation of DFIG before the fault on the short-circuit current components of the crowbar during the fault.The expressions of short-circuit current and rotor short-circuit current are deduced,and the effects of slip on the frequency components of short-circuit current,transient DC component and attenuation speed are analyzed.Secondly,this paper proposes an adaptive inverse-time low-voltage directional protection strategy which can cooperate with the LVRT capability of the wind turbine and the fuse protection of the box-change protection in view of the shortcomings of the current protection of the collector lines in the wind farm.Fast,accurate and effective removal of faults.Finally,the wide-area protection is applied to the protection of the wind farm,andthe wide-area protection scheme based on the current protection is proposed.The fault location can be realized accurately and effectively,which can prevent the malfunction from appearing in the non-So that the protection of the upper and lower levels to maintain,for the wind farm relay protection provides a reliable and effective protection.