On the Enhancement of Fault Ride through Capability of Wind Farms

The capacity additions to wind power generation are taking at regular interval all over the world and have exceeded 300GW. Most of these plants are vulnerable to grid faults and other abnormal conditions and may certainly trip. Reconnection results in severe transients causing deep sags and sustained interruptions. Such a situation must be avoided by keeping wind generator synchronised to the grid. This is possible if generators are employed with fault ride through capabilities. Fault ride through capability is one of the mandatory requirements for wind generators and has been specified in many National grid codes including that of India. The inherent capability of wind generators to safely glide during grid fault condition is limited. The ride through capability of wind generators need to be enhanced by different mechanisms. The controllable devices used to limit fault current magnitude by introducing dynamic impedance or using by-pass switches. This paper deals with fault ride through capability enhancement by using different apparatus such as STATCOM, Pitch angle Controller and DC link voltage controller. These are demonstrated through simulation case studies.