Permormance Analysis of Distribution System with Distributed Generation, A Case Study of Nepal

Abstract

This paper presents analysis of impact of synchronous machine based distributed generation (DG) in distribution networks at various penetration levels. Higher DG penetration level raises important issues about distribution system operation. Therefore, new techniques are needed to determine the maximum amount of DG that may be installed without requiring major changes in the existing electric power system. In this paper, DG is placed at the terminal points of the lateral one at a time and both real and reactive power is injected at power factor ranging from unity to zero. Limiting factor for maximum penetration primarily taken is load bus voltage at upper voltage limit of 1.05 pu. Variation in substation voltage is taken as another important constraint. System under consideration for studies is the radial distribution network originating from Chaumala Substation that is situated in Kailali district of Nepal. This paper reveals that maximum allowable voltage rise perspective is recommendable if substation voltage is regulated at 1.05 pu but if substation voltage is kept at 1.00 pu, highly utopist scenario of penetration occurs. So, conductor ampacity or line loading perspective shall be suitable. Further, if DG is injected taking substation voltage at 1.05pu, there is a chance of under voltage at bus that is situated at the end of the critical branch. On contrary, if substation voltage is taken to be 1.00pu, voltage dip is severe at the bus situated very close to substation.Lastly, if the DG is placed closer to the substation, its penetration level should be increased and vice versa.