For a Station in Columbus, Ohio, a leading utility wanted to create a new ring bus for feeding the three 138/13.8 kV transformers for the 13.8 kV station. The ring bus was to be fed from the two existing transmission lines that pass over the station, one of which fed the 138kV bus at either side of the station.
For this effort, the existing 138 kV bus including breakers has been replaced. The two overhead lines have been intercepted at two new steel A-frames located at the east and west sides of the station. The two transmission lines have been inter-tied to feed a new 138 kV ring bus, which includes breakers, disconnect switches and other miscellaneous equipment. This required new foundations and support structures. An extension to the existing pre-fabricated control building required the installation of a new concrete foundation. New prefabricated cable trenches have been installed for protection and control cables. After intertying the second transmission line to the bus at each end, the ring was completed by an overhead strain bus utilizing two poles to cross above Transformer #3.
This project encompassed engineering and design for civil, electrical physical layout, grounding and lightning protection systems. Civil design included complete design of equipment support steel framing, concrete foundations and a foundation design for the extension of an existing Drop-In Control Module to house all the new 138KV control panels. Electrical design included replacement of existing 138KV oil filled circuit breakers for new gas insulated circuit breakers and associated switches. RCMT provided engineering support during construction by responding to RFls and other construction questions.
An integrated design methodology was used which incorporated the use of a 3D model of the station to collaborate with client and the Construction Contractor to guide the design. 4D was created to support construction planning and progress reporting. Safety animations were done for each critical portion of construction.