hi akhilesh ..integration of renewable energy resources is a good topic the main areas of power quality improvement is when the sources generate the energy that can be converted in to AC power using some power converters.these converters can create power quality problems..u can look in this.one more point is if wind plant is offshore and far distance from the load,we should transmit the power with help of HVDC..so can look in this interms of power quality.to improve the power quality
1) go with D-STATCOM technology
2) go with PV-STATCOM technology to improve voltage profile in bettere way