SYNCHROPHASOR TECHNOLOGY ASSISTED PROTECTION SCHEMES FOR ACTIVE DISTRIBUTION NETWORK

Abstract

Ever-increasing electricity demand, depleting coal and oil reserves, and global warming all have led to the increased interest in the integration of renewable energy resources into the distribution network (DN). The concept of integrating energy sources on the customer side of the meter or at the DN voltage level is called distributed generation. Though distributed generation is a promising way of fulfilling the global energy demand, the transformation of passive DN into active DN (ADN) has led to the rise of new protection and operational challenges. The protection challenges include the possibility of accidental islanding formation and failure of protection relay coordination. Islanding refers to a condition in which some part of the DN is isolated from the rest of the utility network while the isolated part remains energized consisting of generation and load. This condition can lead to unwanted circumstances like unsynchronized reclosing and power quality deterioration of the system and can cause security concerns to the maintenance personnel. Hence, islanding detection and distributed generator (DG) de-energization are a crucial part of ADN protection. Faults are frequently occurring disturbance events in DN. Most permanent faults occur due to mechanical failures like broken conductors or insulation failures. For system restoration, the mechanical failures are to be rectified which requires knowledge about the location of the fault. Fast and accurate fault location determination can help in faster crew dispatch and system restoration which results in an improvement in power quality and reliability. Further, these important factors determine the per-unit pricing of electrical energy in deregulated energy markets. Though research in fault location in DN is a topic of research for several decades, there is a need to address new challenges posed by the introduction of distributed generation. With the advent of distributed generation, deregulated energy markets, and demand-side management, the DN has become more dynamic in nature requiring continuous monitoring of network parameters for stable, reliable, and economic operation. As a result, new monitoring devices like frequency disturbance recorders (FDRs), micro-PMUs, smart meters (SM), etc., with communication capabilities have been developed. The data from these devices can be utilized to overcome the drawbacks associated with the existing applications for islanding detection and fault location.