Distribution automation (DA), such as reclosers and sectionalizers, are important tools to maximize the reliability and resiliency of ComEd’s 34kV, 12kV, and 4kV lines. After a fault event occurs on the grid, ComEd’s distribution automation engineering department ensures there was proper operation of the DA devices, quantifies the number of customers protected by DA, and determines if any corrective actions are needed post-event.

For each fault that causes DA to reconfigure a ComEd circuit, an event record is automatically generated and stored in a central repository on an intranet site. The DA engineering team then analyzes each record and validates the proper operation of automated devices. Action can be taken immediately if the event analysis indicates a mis-operation of DA assets. The team also logs each device’s number of avoided customer interruptions (ACI). These ACI counts are crucial to tell the story of DA’s impact on system reliability and plan for the future installation of additional devices. For example, a recloser opening due to a downstream fault would protect and get ACI for upstream customers.

When there is a fault on one of ComEd’s sub-transmission 34kV distribution lines, the DA engineering team can perform a short circuit analysis to locate the fault regardless of whether a reconfiguration occurred. This location can be provided to maintenance crews to quickly find and repair the cause of the fault. The team uses several tools such as ADMS, CAPE, CYME, and CROSSBOW to retrieve the peak fault current, fault type, and circuit Thevenin resistance; these values are then used to calculate the approximate geographic location of the fault and generate a zone in which crews are instructed to patrol.

These processes have been continuously improved over the years and are essential to DA engineering. For the next evolution of Operational Analysis, the team is presently exploring enhancements through software coding that can automate monotonous steps of gathering data and running programs to unlock new opportunities.