An Investigation of Protection Devices Coordination Effects on Distributed Generators Capacity in Radial Distribution Systems

In the recent years, with the concept of Smart Grid, there are a great interest in integration of renewable energy based distributed generation (DG) units at distribution level. Along with a number of benefits, penetration of DG units in the distribution system imposes some serious challenges; protection requirements turns up as one of the most critical challenge in DG integration. In this paper the possibility and the potentiality of occurring mis-coordination between protection devices in radial distribution network is studied. The impacts of protection devices coordination on DG capacity are investigated. The penetration level, number, and location of interconnected DGs are used as parameters in order to verify the effects of DG on fault current level. The threshold value of DG capacity is presented while the existing protection scheme for distribution network can be maintained. Detailed simulations using MATLAB and PowerWorld simulators are inserted in order to explain and verify the results.