Study of Dynamic response of DFIG during grid interconnection and fault condition

Abstract

Modern technology in the wind turbines has increased the penetration of wind power generation up to considerable level in the power system grid. This leads to more complex, sophisticated and reliable interconnection requirements for reliable power system operation. According to the requirements, the wind farm operation shall not affect the grid dynamic behavior and operation e.g. starting up, cut off, wind speed variations etc, but in actual scenario when grid is attributed to fault and voltage dips, the disconnection of the wind farm creates shedding of loads results in unreliable power supply. This occurs mostly in the case of 3 phase faults in transmission network. For this reason depending on the voltage level of the connection point, network operators require wind farms to have Fault Ride Through (FRT) capabilities and so to withstand specified voltage dips. There are more areas of problems and constraint such as grid capacity constraints, power quality issues, protection issues and ancillary services issues. In order to mitigate above mentioned problems, the study and analysis of wind turbines in power system are required. For performing these studies there is need of steady state and dynamic models of various configurations of wind turbine. Due to various advantages variable speed wind turbines are preferred to fixed speed wind turbines. Among variable speed wind turbines doubly fed induction generator (DFIG) based wind turbines are more popular because of their inherent capabilities. In the present study a dynamic model of DFIG based WECS has been developed and various studies have been performed in PSCAD/EMTDC.