Project Scope

The Substation 2 Mechanical Relay Replacement Project was initiated to replace two antiquated oil-immersed 2300V circuit breaker switchboard control panels at the HollyFrontier Refinery West Plant. The location of the switchboard panels inside the substation had become a concern due to the potential arc flash hazard to refinery personnel from the overhead open and exposed knife switches and open bussed oil-immersed circuit breakers. 

The electro-mechanical overcurrent protective relays, voltmeters, ammeters, power factor meters, watthour meters, control circuits and switches and pilot devices were replaced and relocated to the existing segregated 125Vdc station battery room within the existing substation. In order to minimize substation construction, the existing switchboards and asbestos coated wire were disconnected and abandoned in place.

Excellence designed two new free-standing protective relay and control panels for eighteen new GEMultilin model 850 solid state feeder protection relays, new breaker control switches and new breaker position indicator lights.  Each Model 850 relay replaced the three single phase IAC overcurrent relays associated with each circuit breaker and metering functions of the existing switchboards. New circuit breaker wiring diagrams for the existing General Electric Oil Blast circuit breakers were created to document the metering, protective relay and control revisions. 

• E&I Engineering
• Relay & Control Panel Design
• Existing Equipment Documentation
• Relay Programming
• Procurement Services
• Construction Support

Notable Accomplishments & Challenges

• Replicating undocumented control circuitry of 1930’s vintage switchboard.