Evaluation of travelling wave based protection schemes for implementation in medium voltage distribution systems

This paper investigates travelling wave based protection schemes developed for high voltage transmission systems and their adaptation to medium voltage distribution networks in order to enable ultra high speed relaying (within a quarter of a cycle of the power frequency) on a medium voltage level. After different travelling wave algorithms are evaluated using simple test systems, they are applied to an industrial power system where fault detection within one millisecond is required. Difficulties that arise from typical characteristics of medium voltage distribution systems are outlined and requirements to measurement and signal processing systems are discussed.