Novel Technique to Improve the LVRT Performance of Wind Turbine Generators and its Impact on Multi Machine Power Grid

Abstract

As per the new grid codes, wind turbines (WTs) are required to remain connected to grid under grid faults and continue to supply reactive power into the grid. In electrical power system, Low Voltage Ride Through (LVRT) is the capability of wind turbine generators to stay connected in short periods of electrical transient. Voltage sags and sudden transient occurs in the system for short duration of time, there is instability and loss of the control of active and reactive power in the system. The system absorbs more reactive power from the grid, so to overcome this problem, This project proposes Fault Current Limiters (FCLs) methods available in literature to improve the LVRT capability of Fixed Speed Induction Generator (FSIG) and Doubly-fed Induction Generators (DFIGs) based WTs during transient states. From literature Capacitive Bridge type Fault Current Limiter (CBFCL), new bridge type fault current limiter (NBFCL), Non Superconducting Fault Current Limiter (NSFCL) and Inductive Bridge type Fault Cur- rent Limiter (IBFCL) is adopted and the modification in control strategy has been carried out and comparision of FCLs can be given for the SMIB system. One of the FCL is implemented in WSCC 9-bus system and the comparision of result for FCLs can be shown for symmetrical faults.