June 2017 | Jim Finch
Case Study: APS Gets a Modern Visualization Solution
In September 2011, an 11-minute system disturbance occurred in the Pacific Southwest, leading to cascading outages and leaving approximately 2.7 million customers without power from Arizona to Southern California. The Federal Energy Regulatory Commission’s (FERC’s) post event analysis traced the disturbance’s initiating event to what should have been a routine switching to isolate a capacitor bank in North Gila, Arizona. Despite careful planning for the switching, a simple human error—a skipped step in the process—created an arc over the switch and resulted in the automatic disconnection of the 500 kV Hassaympa-North Gila line.
While the loss of a single 500 kV transmission line at Arizona Public Service (APS) initiated the event, it was not the sole cause of the widespread outages. FERC also discovered that the September 2011 event stemmed primarily from weaknesses in two broad areas—operations planning and real-time situational awareness. Without adequate planning and situational awareness, entities responsible for operating and overseeing the transmission system could not ensure reliable operations within system operating limits (SOLs) or prevent cascading outages in the event of a single contingency.
Recognizing these limitations, APS improved its operations by improving operators’ visualization into contingency analysis and transmission grid situational awareness. The utility tapped the team at BRIDGE Energy Group to help it create the multiple complex data integrations required to deliver the vision. The team began by developing what would be the foundation for the project, including the integration of OSIsoft PI Historian and the architecture for AF Framework.
Links to past articles, in-the-news postings and press releases can be found here.