Three-phase transient state estimation algorithm for distribution systems

The detection of the source and severity of disturbances is important as this allows network companies to respond faster and remediate the problem more quickly. After an event, knowledge of the severity of a disturbance at various busbars gives understanding of what equipment was subjected to and an indication of possible improvements needed to mitigate further events. Owing to the cost, it is impractical to fully monitor the network, however, with judicious selection of measurement points, and using state estimation techniques, allows information at unmonitored locations to be determined. Hence, a cost effective detection system can be developed. This study documents a new three-phase transient state estimation algorithm and demonstrates its performance with realistic background harmonic voltage distortion and with measurement error. The transient state estimation is based on the numerical integrator substitution method (Dommel´s method for discretising the differential equations).