Introduction

Abstract

At this time, the management of fault current in the modern transmission and distribution (T&D) systems is considered as a challenging issue within researchers and government and private electric utilities. Since some of the existing systems and most of the future systems would face with high fault current level. The potential world economic growth in recent decades and consequently the demand for electric energy are the main reasons for this problem. It is evident that the electricity utilities should be continuously upgraded their systems to handle the demand. The construction of new power plants, the interconnection of the networks, the application of distributed generations (DGs), and the utilization of parallel transmission lines and flexible AC transmission system (FACTS) are some of the upgrading programs. In addition to demand response, these activities pursue the important power system facets such as higher efficiency and reliability, longer service availability, and dwindling power loss, maintenance and development costs, environmental effects, and dependency on fossil fuels.