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Staff Substation

Staff Substation, Cambria, WI

New Greenfield 138kV Switching Station

Realtime’s involvement with this project began with finalizing the Client’s facilities’ studies and exhibits within the pending generation interconnection agreement. The substation was a greenfield site, ultimately consisting of a ring bus arrangement.   The substation was designed to operate with (3) 138kV lines, and future expansion capabilities to (6) 138kV lines.  The station serves as a system tie between a wind farm and the local utility’s transmission grid.  After nearly (2) years of planning and design, the new 138kV switchyard was placed in service in May 2011.

The original scope was to design a (3) termination straight bus, looping an existing transmission line through the bus, and provide a tap to an adjacent wind farm collector station.  Around the time of this design’s completion, the scope had changed to now designing a ring bus arrangement.  Realtime expanded the design and completed the design package within schedule to meet the original in service date.  Changing gears and incorporating the ring bus design into the construction issue saved the Client approximately $460,000 in overall project cost. Realtime provided all engineering for the switchyard, including; grading, grounding grid, raceways, foundations, steel structures, bus, equipment specification including a 24’ X 36’ control building, and protection and control.

Realtime also provided the line loop through scoping, design engineering, procurement support, and construction support for (2) new, 90’ steel corner poles within existing right-of-way.  We completed our project work by providing new records for creation of a newly designated line.

Some interesting challenges included the following:  Coordinating efforts with the generation owner for a single, common, and jointly beneficial ground grid system of the switch station and the collector substation; as well, designing an integrated SCADA communications system that satisfied the requirements of multiple utility stakeholders.