Protection Coordination Planning Considering Distributed Generation

Abstract

Decentralization of the electricity market is one of the factors that has led to the increase in penetration of distributed generation (DG). This helps in reducing the emission of pollution, decreasing energy price and increasing efficiency of power transmission from generation to the customer. There are several challenges that need to be considered while planning distribution systems integrated with DG. One of the major concerns is the influence of DG on the protection system. The objective of the design of a protection system is to minimize the operating time of all relays considering the protection coordination constraints. However, the presence of DG influences the magnitude of short circuit current and may impact its direction. Introduction of DG to the power system may lead to non-selective protection actions in all types of networks. Recent drive towards the integration of renewable energy sources requires the utility operators to revise existing protection systems and the recent design approaches, if not, for every future DG installation the relay settings need to be modified to guarantee protection coordination which can lead to numerous changes in relay settings. This thesis presents a novel approach to the protection system planning problem considering future DG installations. The proposed method is capable of optimally identifying one set of relay settings valid for all possible future DG planning scenarios. The proposed method is formulated as a linear programming (LP) problem and the simplex algorithm is utilized to solve it. Comparative studies have been conducted to highlight the advantages of the proposed approach under various planning scenarios. Additionally, this work presents an approach to maximize the penetration level once the protection system is designed. The problem is formulated as a mixed integer non-linear (MINLP) approach and maximizes the capacity of installed units by optimally sizing and locating fault current limiters (FCL) considering fixed relay settings.

Date of Award	May 2015
Original language	American English
Supervisor	Hatem Zein El din (Supervisor)