Coordinating protection and control of dispersed generation

Modern protection relays proved to improve the reliability of power systems and their performance. It is now possible to meet all conditions of power utilities towards secure private and cogeneration plants. The authors demonstrate the adequacy of the protection when voltage controlled overcurrent relays are utilised. For 11 kV systems, such types of protection relays are very common as they are economical and easy to set. Also the modern digital ROCOF relays enhance load shedding methods and the degree of power system security is now much higher. However to insure a high quality of supply, a proper generation and power system operation strategy must be planned and followed