As is known about renewable energy sources, especially wind and solar, the generation sites are mostly available at remote geographical locations which are at a considerable distance from the demand centres. Moreover, such distant wind/solar resources do not have sufficient nearby grid capacity for integration of large-scale development with the transmission system. This raises the issue of evacuation from the generation centre to the substation which is connected to state-level transmission unit.
Another issue with wind energy is that generally high wind generation is encountered at the time of low demand. In Rajasthan, wind generation pattern is different from other wind-rich states as its peak generation time varies from other wind energy producing states. However, even this production does not always coincide with peak demand. This is why large-scale wind/solar integration may introduce new patterns in the flow of power which may cause congestions in transmission and distribution networks in case of a conservative planning.
At present, most of the wind plants are not capable of operating during severe voltage sags (ride through capabilities) caused by system faults. In case this happens and a large amount of wind generation trips in certain pockets, the system will be adversely affected, magnifying the effect of faults.
Also, some of the wind turbines consume reactive power from the systems, which can adversely impact the systems during disturbances/high loadings unless suitable mitigating measures are taken. Harmonic voltage distortion at the connection point of wind farms and solar parks are likely to increase due to the deployment of power electronic equipment for RE generation integration.
Many IPPs have raised a concern that the grid integration issue is already delayed, keeping the high pace of renewable energy development. They say that while both solar and wind energy farms can be developed quickly; the grid infrastructure development takes time. It should have been developed earlier than developing the renewable energy sources.
It was decided that infrastructure requirements would be assessed in seven states that are rich in renewable energy resources as well as have considerable installed capacity and are leading the way in renewable energy installation. These seven states are Tamil Nadu, Maharashtra, Karnataka, Andhra Pradesh, Gujarat, Rajasthan and Himachal Pradesh. All the states have tremendous renewable energy potential but in some states one resource is more abundant than the other. In Tamil Nadu, wind is leading the charge while in Himachal Pradesh hydro is powering the renewable energy expansion. In Gujarat and Rajasthan, both solar and wind are growing at a rapid rate and the potential for both is very high. In the remaining three, potential for all three – wind, solar and hydro – exists in sizeable amounts.
source: powergrid ,IREDA