DSP-based Adaptive Protection for Feeders with Distributed Generations

Distributed generations (DGs) have been increasingly connected on the distribution feeders that impose challenges on traditional feeder protections. This paper proposes a new adaptive strategy for protection of distribution-system feeders connected with DGs using state-of-the-art digital signal processing (DSP) technology. The proposed strategy overcomes DGs-imposed technical challenges on feeder protection such as increase of fault current, change of prescribed fault flow paths, sympathetic tripping, unintentional islanding operation, continuous non-interruptible fault current, etc., as well as non-DG-caused problems such as undetected high-impedance ground faults. This paper shows the strategy for effective use of state-of-the-art DSP technology for real-time determination of correct protection operations for feeders with dispersed DG-connections against faults and surges resulting from lightning, equipment short-circuit, and switching of capacitors, DGs, large loads, etc.