Evaluation of service quality of distribution systems with critically located generators

Abstract

Summary One of the main goals of distributed generation (DG) is to ensure excellent quality of service, without affecting the existing protection system. This study addresses the quality of service in radial electricity networks with distributed generators and assesses the effect of additional distributed generators on the continuity of supply. It is based on a previous identification of the network locations of DG that lead to a loss of protection coordination in the occurrence of faults corresponding to critical cases. Such circumstances are scarcely analyzed in the literature. The proposed methodology is based on a 2‐fold approach and uses an analytical method and a Monte Carlo simulation to study the behavior of an IEEE test network. Two situations, one without and one with distributed generators, are compared and analyzed. The load power and generation capacity values of the distributed injections were assumed to be constant for the purpose of simplification. Studying the worst‐case scenario of the impact of DG on the quality of service of the network can help support the distribution network operator when making investment‐related decisions for the protection system. The obtained results demonstrate the impact of DG on the quality of service of the distribution network. Small capacity additions at locations that are not identified as critical may improve the quality of service. On the other hand, a worse performance is observed when generation additions corresponding to the critical cases cause a loss of coordination in the existing protection system.