Field investigation and analysis of incipient faults leading to a catastrophic failure in an underground distribution feeder

This paper deals with the subject of incipient faults in underground distribution systems and their progression over time leading to an eventual permanent failure. Field data recorded from an underground distribution feeder were analyzed in both time and frequency domain to identify the symptom parameters and characterize the observed incipient behavior. This exploratory data analysis sheds additional light on the progressive characteristics and nature of these self-clearing faults and advances the fundamental knowledge in an effort to detect such pre-mature failures before developing into a full-blown fault.