Electronic Thesis and Dissertation Repository

Degree

Doctor of Philosophy

Program

Electrical and Computer Engineering

Supervisor

Dr. Tarlochan Sidhu

Abstract

High Voltage Shunt Capacitor Banks (HV-SCBs) are critical substation assets that are primarily used to improve power factor and thus power transmission capability. Over temperature, over voltages, manufacturing defects can cause internal failures of capacitor elements. With today’s sensitive protection available in numerical relays these failures will be detected and SCBs will be taken out of service. But determining the phase and section in which capacitor elements have failed is important for utilities to decrease downtime of SCBs. This thesis proposes methods to address the challenges in fault location of SCBs. The proposed methods apply calibrating factors that compensate for pre-existing inherent unbalances, and system voltage unbalances. They can mitigate the gradual capacitance change due to temperature effects or natural aging. The presented fault location methods are further enhanced to detect the number of failed elements. The proposed methods can be integrated into common unbalance protection of the multi-functional numerical SCB relays and put forth solutions to condition monitoring of SCBs. Advance maintenance alarms for fuse saving in externally-fused SCBs, and reducing the search space for the faulty cans with fuseless or internally-fused designs are the significant outcomes of the proposed methods. The proposed methods are simulated in a relay modeled in MATLAB and the voltages/currents are played back from COMTRADE records of PSCAD electromagnetics transient simulations. Detecting consecutive failures, ambiguous failures, and delivering the number of failed elements for each alarm in fault reports are valuable to the utility community and have been verified for the proposed methods.


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