Fault Ride through Improvement in DFIG based Wind Turbine in Conventional Grid System

Abstract

According to latest grid codes, wind turbines (WTs) are required to remain connected to grid under grid faults and continue supply reactive power into the grid. In Electrical Power System, fault ride through is the capability of wind turbine generators to stay connected in short periods of electrical transient. Voltage dips and sudden transient occurs in the system for short duration of time, there is instability and loss the control of active reactive power in the system. The system absorbs more reactive power from the grid, so to overcome this problem, This Project proposes available in literature control strategy to improve the FRT capability of Doubly-fed Induction Generators (DFIGs) based WTs during transient states. There are different methods used for improvement of Fault ride through (FRT) capability, like crowbar system, super conducting fault current limiter (SFCL), gate controlled series capacitor (GCSC), Static synchronous compensator (STATCOM), and Parallel R-L crowbar with series R-L circuit protection and Capacitive Bridge type Fault Current Limiter (CBFCL) etc. Capacitive Bridge type Fault Current Limiter (CBFCL) is adopted from literature and the modification in control strategy has been carried out and results are compared for SMIB system with conventional crowbar system. The control strategy given in literature for CBFCL is also implemented in WSCC 9-bus system and results are compared with conventional crowbar system for symmetrical faults at generator bus and load bus.