**4. Conclusion**

The chapter provides the challenges regarding the integration of wind energy in to the power systems. Today the worldwide trend of wind power penetration is increased. The integration of high penetration level of wind power into existing power system has significant impact on the power system operation.

The wind turbines connected to weak grids have an important influence on power system. The weak grid is characterized by large voltage and frequency variations, which affects wind turbines regarding their power performance, safety and allied electrical components. The strength of the distribution system is important from the point of power quality. The needs for consistent qualification of power quality characteristics of wind turbines, the International Electro-Technical Commission to facilitate for power quality parameters for various issues are presented. The latest grid code requirements are to ensure that wind farms do not adversely affect the power system operation with respect to security of supply, reliability and for power quality.
