IMPACT OF DISTRIBUION GENERATION ON PROTECTION COORDINATION

Abstract

The future of electric power distribution systems is one that incorporates extensive amounts of advanced metering,
distribution automation, and distributed generation technologies. Most distribution systems were designed to be radial
systems and the major philosophies of their protection, namely, selectivity and sensitivity, were easily achieved. Settings for
overcurrent protective devices were static and based on the maximum load downstream of its location, with little concern of
major configuration changes. However, the integration of Distribution Generators (DGs) in radial distributions systems
causes bidirectional power flows and varying short circuit currents to be sensed by protective devices, thereby affecting the se
established protection principles. Since the protective coordination will be lost if the fault current flowing through any
protective device is changed, this may lead to the large damage in system and the decrease in system reliability. Due to the
fast-paced changing technologies in the field of electricity market liberalization, the incorporation of DG along with its
various distributed resource technologies have led to a profound change in electrical power system. Besides many positive
impacts of incorporation of DG into the electrical power system, it has introduced many inherent technical problems such as
miscoordination, reliability degradation and stable islanding