Arc Flash Report for the Broadway Steam Plant Boiler #3

Client: City of Pasadena Department of Water & Power

The City of Pasadena Power and Water Division was planning to remove Boiler #1 and Boiler #2 from the Broadway Steam Plant while continuing operation of Boiler #3 as a stand-alone unit. IEC was tasked to perform an arc flash evaluation on Boiler #3 in a stand-alone configuration. IEC evaluated the Boiler #3 Steam Plant electrical system from the point of interconnection with the grid to the 480V motor control centers using the Boiler #3 stand-alone configuration design without Boiler #1 and Boiler #2 operational. The detailed arc flash calculations were generated using SKM Power Tools version modeling software. Equipment data and settings for the plant modeling were collected and supplied by plant personnel. Short circuit currents were calculated at the 34KV, 13.8KV, 2.4KV, and 480V buses and then used to calculate the arc flash energy and boundary at the various bus voltages. The duration of the arc flash current was based on existing and new fuses, breakers and relays settings.

The results of the arc flash study were provided in a complete report to the client. IEC also recommended the City of Pasadena to consider: installation of arc flash labels, incorporation of arc flash study results into existing plant electrical operating and safety procedures, ensuring proper personnel protective equipment is available to trained personnel, and ensuring arc flash study results are incorporated into the plant training program. IEC also recommended reviewing the plants protection scheme, performing a protection coordination study, and revising protection equipment settings to decrease the potential arc flash incident energy.