Anti-Islanding Protection by Power Line Signaling and Wavelet Transform

Abstract

Conventional distribution systems are radially constructed, main substation transmits power to downstream stations i.e. in one direction. But, in modern deregulated system with renewable energy sources (RES) that is the distribution generators (DG) make these power flow as bidirectional. So the most important requirement for the DGs is to detect island conditions. In distribution system when some parts get isolated from the remaining system, but remains energized through the DGs, it is called islanding. This paper represents a technique for anti-islanding protection based on innovative power line signaling. In this technique, substation sends a signal to the DG sites through feeder lines of the distribution system. If the signal is not detected by the DG site then it can be inferred that DG is islanded from the system. In this paper a remote islanding detection method that is power line signaling and an active islanding detection method i.e. waveform distortion technique is combined for the anti-islanding protection.