Power quality monitoring enhances preventive maintenance program: detecting a substation transformer tap changer problem

This article discusses a power quality monitoring program underway between a semiconductor manufacturing facility and its serving utility, A description of the sophisticated monitoring program installed and maintained by the utility and a portion of the power quality monitoring installed within the manufacturing site distribution system is included. An incident, where monitoring pinpointed a utility substation transformer load tap changer problem, is presented in depth. The subsequent investigation and actions that took place to repair the tap changer without impacting the manufacturing facility are discussed. A fault in the tap changer compartment could have resulted if the tap changer problem had gone undetected. Steps taken to correct the tap changer problem averted a possible fault and subsequent transformer differential relay action