Transient Stability Improvement Analysis of DFIG Based Variable Speed Wind Generator Using IGBT- Bridge-Type Fault Current Limiter

Due to its many advantages such as the improved power quality, high energy efficiency and controllability, etc. the variable speed wind turbine using a doubly fed induction generator (DFIG) is becoming a popular concept and thus the modeling of the DFIG based wind turbine and improvement in the transient fault conditions is an important consideration. In this paper, Transient stability improvement has been done by using Superfluous Fault Current Limiter [SFCL]. A new design of SFCL IGBT- Bridge-type SFCL shunted with a variable resistor Rsh has been proposed. Rsh is modeled to decrease the terminal voltage deviation to minimum level by reducing the amount of current at the bus terminal. Comparison of Voltage deviation and current deviation with the resistive type SFCL and IGBT- bridge-type SFCL show considerable decrease in both quantities by using IGBT- bridge-type SFCL. The values of voltage deviation at the bus terminal is 8.223 e-8 % for proposed SFCL which is less than the resistive type SFCL that is, 14.4 e-8 %. The huge voltage sag has been considerably reduced by reduction of high level of current to 0.0004401 % in IGBT-bridge-Type SFCL from 0.0004624% in resistive type SFCL. Thus proposed SFCL has caused significant improvement in transient stability keeping the deviation in active and reactive power during faults to minimum level.