Novel soft computing based relaying and protection schemes for electrical power systems

Electric power systems are evolving and expanding so there is a need to keep the power system relaying and protection systems on the same footing as the power system complexities. Recent generation of power transmission lines are designed to carry many fold power than their predecessors thanks to series compensation and use of other flexible AC transmission systems (FACTS) devices. This demands that the new fault detection and protection methods are reliable and fast. The electromechanical relays which worked well for the old generations of power systems cannot cope with the increasing demands imposed on them by new dynamic loads.;In this thesis, a UHS directional protection scheme for series compensated transmission line using Wavelet Transform is presented. The new synthetic relaying signals are transformed using Wavelet Transform instead of conventional filtering methods. The proposed relaying scheme is able to detect close-up faults as close as 10 km from the relay location as well as able to detect faults with a small fault incipient angle approaching 0°.;Also, in this thesis, a high speed distance protection scheme for series compensated transmission line using Wavelet Transform and artificial neural networks (ANN) is presented. In particular, the existing deficiencies and associated limitations with the already proposed high speed non unit distance protection schemes have been investigated and a modified solution using ANN is presented. The fault distance is estimated from the travelling waves directly.;High Impedance Faults (HIF) are a persistent problem in electric systems, distribution and utilization systems, process industries and mining. High impedance arc type faults are a serious safety hazard, threatening human and livestock safety. This thesis also presents a new application of fuzzy ARTMAP to investigate the long outstanding problem of HIF detection.;Ultra high speed (UHS) relaying is ideally suited for series compensated transmission line protection. UHS relaying can prevent grid utility system rotating blackouts like the one that spanned the north-eastern United States and eastern Canada in August 2003 and caused billions of dollars in losses.