Automated Event Retrieval Reduces Operating Costs

In August 2007, Oncor Electric Delivery began installing a centralized automatic relay event retrieval and indexing system. With over 400 transmission substations and 3,600 relays capable of recording critical event data, Oncor wanted to improve their existing process of dispatching a technician to a substation each time a critical event occurred that needed further review. Beyond the obvious operating cost savings associated with retrieving critical event data, Oncor had additional ideas for using the data. Analyzing every event file where the relay sensed a fault condition and the breaker cleared it is an opportunity to gauge the health of the protection and control system. Relays that generate power system event reports ranging from a few cycles to a few seconds provide the opportunity to see fault inception, relay response, and breaker operation. To analyze every event file, Oncor developed a process to retrieve event records from their protective relays. It is often assumed that automatic event collection systems require installation of new and potentially costly communications equipment for high-speed data transfer. Additionally, proposed North American Electric Reliability Cooperation (NERC) Critical Infrastructure Protection (CIP) reliability standards are often interpreted as mandates to apply potentially expensive and complex firewalls or software security to associated communications channels. Considering the high costs of applying this equipment or software across 400 transmission substations, Oncor engineers immediately recognized significant cost savings if the recommended security guidelines and event collection requirements could be satisfied using existing installed communications equipment. Oncor met this goal with minimal hardware installations. This paper highlights the installed system and provides a summary of installation and operational benefits.