Impact of Power System Protection and Fault Current Limiters on Component Failure Rates

Abstract

Over-currents due to faults are known to be the dominant cause of performance deterioration or failure of power systems and/or their components. Many ways are available to mitigate the undesirable consequences of over-currents. However, due to the importance of the subject, there is a need to study and compare the impact of fault current limiters on component failure rates and, therefore, system reliability. Reported studies appear to have investigated the effects of current limiters qualitatively rather than quantitatively. This is mainly due to the lack of appropriate models to effectively capture and quantify the direct impact of over-currents on component failure rates. The main stream of present power system reliability evaluation methods is generally based on statistical measures of system outages rather than on actual electrical parameters such as fault current values. This paper utilizes a failure rate model already published by the authors to show its effectiveness in capturing the impact of fault current levels on component failure rates. The new model would be very useful in system reliability evaluation and studies of utility asset management programs. The impact of the new failure rate model on system reliability indices and utility asset management programs will be studies and published in a separate future document.