Allowable capacity of ACDG considering inverse time overcurrent protection

Abstract

SUMMARYThe integration of distributed generation (DG) into distribution system has a lot of impacts on the original current protection. The influences of alternating current (AC)-connected DG on inverse time overcurrent protection are analyzed in this paper. Based on the setting and coordination principles of protection, four constraints for the allowable capacity of AC-connected DG are advised to ensure the reliability of protection. A specific example is given to show the calculation process. In order to increase the allowable capacity, some improvement methods are proposed. Two different integration points are compared, and finally the one requiring less of protection modification is chosen. The effectiveness of the measures is also verified through the example.

Defining the practical constraints of inserting DG units in distribution systems regarding protection schemes

“…Recently, the connection and the exploitation of distributed generators and their controlling technologies to distribution systems have become a necessity around the world. The advantages of utilizing DG units include economical, environmental, and technical benefits . The economical aspects include their high efficiency and the lower power losses.…”