Grid stability with large wind power integration - a case study

Renewable energy resources are intermittent energy sources whose power output can vary widely within small time frames resulting in grid instability. The Integration of large scale wind power into power systems raises several questions which include integration with the network system, system stability, system operation and extensions of the network etc. At the earlier stage of wind power integration, there was little concern about its influence on the overall stability of a power system. However, with the increasing wind power integration, it may begin to have a significant influence on the power system transient stability margin. Most of the wind generators employed in wind power applications are Induction generators that operate asynchronously and are characterized by poor reactive power control capability. Additionally, an acceptable integration level of wind power has not been defined and depends on the amount of wind power that can be integrated without causing in-stability of the grid. In this paper the results of the studies carried out for Tamil Nadu state, having the highest wind power integration in India with the grid has been presented. The various issues addressed are - quantification of the maximum wind penetration levels without sacrificing the grid stability, the ride through capability at the point of connection of the wind farms, the reactive power requirement etc.