Avista received a new load request from a growing industrial customer with an tight schedule. Commonwealth provided design services for the distribution addition at one of Avista’s substations. This design included the civil/structural, physical, electrical design incorporating the design criteria in the protection and integration plans provided by Avista as well as, material procurement, and transmittal of final design.
The finished addition at this site consists of a single 13 kV distribution lineup with two underground feeders. The 30 MVA 115-13 kV transformer is protected by a breaker and the four-position distribution structure has three positions initially installed, two feeders, and the auxiliary position. The yard was laid out for a future 30 MVA transformer serving three feeders. The entire distribution portion of the yard was positioned to allow a future conversion from a single-main bus configuration to a double-breaker, double-bus layout.
An additional relay panel for transformer protection was designed in the existing panel house replacing the empty panel position reserved for the future second transformer. The existing Master Termination Cabinets and SCADA panels were evaluated to determine if they have enough space for this addition. Commonwealth provided the complete design in two months, allowing construction to proceed on time to meet the customer’s schedule.