Enhanced reactive power allocation of full converter wind generation system

Abstract

More stringent grid codes have been set by transmission regulators requiring the wind farms to have proper fault ride through (FRT) capability and actively participate in maintaining network stability following severe disturbances. This may not be easily achieved as the intermittent behavior of wind turbines are highly affected by the environment factors as wind speed. This paper investigates reactive power allocation of full converter wind generators (FCWGs) with different wind speeds in order to comply with the E.ON Netz grid code. This is done by sensing the voltage drop at the point of common coupling (PCC) and using the level of wind speeds to define a power index for extended PQ support of FCWGs. A test system consisting of four FCWGs connected to power grid is simulated using MATLAB/Simulink by introducing types A and F faults for 500ms. Simulation results show that FCWGs with lower wind speeds are able to deliver more reactive power as compared to machine working under higher wind levels. Furthermore, the proposed technique can enhance the FRT capability of FCWGs without violating the DC-link voltage limits during the fault while also improving voltage profiles at PCC in compliance with the E.ON Netz Grid Code.