A New Methodology to Prevent Sympathetic Tripping in Distributed Generation Protection using Discrete Wavelet Transform

In conventional electrical distribution systems usually the current flow has a single direction. However, this assumption is not always true nowadays due the growing presence of Distributed Generation (DG) sources, which results in operational situations where the distribution substation is not the only source of energy supply. Sympathetic tripping is an undesirable event that occurs when DGs sources are mistakenly disconnected because a fault occurs at a feeder near another DG source, and this fault is not quickly eliminated by network overcurrent protection. In order to minimize this problem, this work proposes a methodology based on the discrete wavelet energy gradient behavior. Computational simulations in a test distribution system show the feasibility of using the proposed methodology in real systems.