Impact Analysis and Development of New Protection Schemes for Distributed Generation in Distribution Systems

Texas A&M Engineering Experiment Station, College Station TX

Investigators

Abstract

Distribution systems are most commonly radial type and composed of overhead and underground lines. During the past decade, there has been increasingly more interest in utilizing distributed generators (DGs) in distribution systems to offer the best long-term solution to reliability, price and pollution issues for power utilities. Distributed generators provide a source of active electric power, and are directly connected to the distribution network or to the network on the customer side of the meter. Protection for distribution systems aims to minimize the duration of a fault and the number of customers affected by the fault. This entails the selection and coordination of appropriate protective devices. Presently, protection schemes for radial type distribution feeders are developed assuming there are no generation sources on the distribution system. Hence the protection schemes must be adapted for the new and different characteristics that the integration of DGs will bring to distribution feeder circuits. The PIs propose to perform studies of load and fault currents by developing new load flow and short circuit analysis methods for radial distribution feeders with DGs. Also the PIs propose to adapt the coordination and overcurrent relays methodology (directional and non-directional) for radial distribution feeder circuits when DGs are energized or not energized. The distributed generators that will be studied include AC generators (induction and synchronous) and inverter-connected generators (photovoltaic modules, fuel cells, etc.) The PIs will include one graduate student and three undergraduate researchers on the research project. Also the results will be integrated into two graduate courses.