PERFORMANCE ANALYSIS OF ISLANDING SCHEME FOR RURAL ELECTRIFICATION USING SHP AS DISTRIBUTED GENERATION

Abstract

In today‘s power system, distributed generation (DG) has gained significant acceptance technically and commercially as promising alternative energy sources due to increasing energy demand, high cost of energy, effort to displace low efficient conventional generating sources, environmental concerns, energy market deregulation and development of DG technologies. Generally, the geographically remote communities get electric power supply from local distribution network based on Renewable Energy Sources (RES) based DG. Small Hydropower (SHP) is an attractive alternate energy resource for the rural electrification. The potential small-scale sites are located close to the locality of scattered rural villages permitting secure and economic power generation for domestic and industrial end users. However, a rural isolated plant is a not an appreciated system where the plant capacity may not match the local demand. DG necessitates integration to form or connect to the nearby distribution network to augment the power supply or export the surplus power. On contrary, the penetration of DG into existing utility system imposes unprecedented technical, economic, planning and commercial challenges. The most pressing technical issue is active distribution systems unplanned islanding. International standards, IEEE Standard 1547 prohibits the DG operation during loss of grid (LOG) due to utility operational need to avoid protection conflicts, personnel safety hazards and possible power supply deviation from desired quality standards. Such disconnection drastically reduces the expected benefits of DG penetration. The dissertation aims to present ‗planned islanding scheme‘ to support an autonomous operation of a remote SHP based DG on the rural distribution network envisaged as the corrective control measure against the cascading effect of LOG event or undesired contingencies. It aims to enhance the operational and power supply reliability, security and quality for rural consumers. In particular, to develop SHP based DG resources operate with islanding capability to realize as a viable technology at present and future. It highlights the islanding mechanism, detection techniques, island control and protection measures, and island operational performance characteristics of SHP DG on rural distribution network and challenges associated with DG integration. The literature review with regard to scope of islanding is presented in order to acknowledge the extent of islanding technology prevalence and contemporary challenges to be addressed with further researches. Based on research gap identified, the research objective of ―islanding of parallel synchronous and induction generator base SHP Plant on rural distribution network‖ is proposed. The basic theory and analysis using MATLAB/Similink tool on operation dynamics, governor and excitation control strategy and islanding strategy of parallel synchronous and induction generator on rural distribution network is presented. The proposed scheme performance is investigated using MATLAB/Simulink tool. The frequency and voltage are assumed as performance parameter. The result demonstrated the success of ‗master-salve‘ parallel operation strategy of ac generators while the islanding on scheme has been investigated.