Algorithms for Synchrophasor Enabled Digital Relay

The differential protection of buses, transformers and generators is a well-established protection principle that emphasizes the importance of synchronized phasor measurements. True differential protection was not possible before the introduction of synchronized phasor measurements. Differential protection is important for series compensated lines and tapped lines. Differential protection involves communication wires or communication band channels. The easy availability of synchronized measurements using Global positioning systems (GPS) technology and the improvement in communication technology makes it possible to consider true differential protection of transmission lines and cables by Synchrophasor Enabled Digital Relay or Phasor Measurement unit (PMU). There is no algorithm which can offer a panacea. Underlying every algorithm is a set of assumptions. The effectiveness of an algorithm depends on how far, in practice, the assumptions on which it is based are close to reality. The behaviour of the measured phasor between the 1PPS (pulse per second) points and the response. To non-steady-state (transient) conditions will vary with the algorithms used.