When a Toledo refinery intended to improve long term reliability of a substation that provided power to critical process units, a feasibility study was required to appropriate funding.  This project consisted of the engineering for level 2 of 3, reviewing multiple options, their associated costs, constructability and operations impact.

Design options for modifications, maintenance, and/or complete replacements were considered for the 12 KV, 2.4 KV, and 600 VAC sections.  Included in the preliminary engineering review was considerations for safety concerns, environmental concerns, substation alarms, DC power, breaker conditions, transformers conditions, cabling and cable routing, metering, relaying, available capacity, spares, and enclosure conditions.

Engineering judgment was used on equipment conditions, remanufacturing or replacement of equipment, and space for future plant expansion.  Major plant outages are scheduled every four years.  Due to this, work must be completed in a minimal timeframe.  All the required work could not be completed in a single outage, thus it was determined to perform a refurbishment of some equipment to extend its service life to the next scheduled outage.  Lack of space for future substation switchgear additions was another issue.  This, coupled with the poor condition of the switchgear’s outdoor, walk-in metal enclosure led to the investigation of replacement of the 600VAC switchgear and motor control centers in a new location, allowing for the installation of the new equipment prior to the outage, further minimizing down time.  In all, four options were studied.


  • Design options for modifications, maintenance, and/or complete replacements for the 12 KV, 2.4 KV, and 600 VAC substation sections.
  • Preliminary engineering and probable costs for several feasible design options and associated recommendations.