Case Study

Standard 115/69kV Substation Design Library

Client challenge:

Our client, is a leading sustainable energy company with $38 billion in assets and operations in 24 U.S. states They operate in two primary lines of business: Networks and Renewables. SGC Engineering were commissioned to develop a complete Protection & Control Design Library drawing package for a standard 115/69kV substation using existing client standards and IED list. The project provided a standard guideline and consistency for consultants and contractors.

How we helped:

Our team were responsible for protection and control design. This included design in AutoCAD format with our client’s new symbols and nomenclature for the system one-line, power one-line, relay one-line, elementary, wiring, interconnection, and three-line wiring drawings.

The Substation Design Library Project is comprised of:

  • Six (6) 115kV circuit breakers
  • Eight (8) 69kV circuit breakers
  • Two (2) 115/69kV transformers
  • Six (6) line sections
  • Eight (8) 69kV voltage transformers
  • Eight (8) 115kV capacitor coupled voltage transformers

The vendor drawings, 115kV cap bank , 115kV meter package, 115kV and 34kV cap bank 115kV are used in the development of the drawings. The 69kV buses have the 69kV switches with the buses operated at 34.5kV, with 34.5kV VTs, LAs and fuse disconnects that feed to the station service padmount transformers. Thecontrol house equipment, cable trays, relay cabinets, fiber communications cables, and control cables meet the Bulk Power System (BPS) requirements. The project is included the latest protection and control schemes, SCADA system, IEC-61850 standards, and HMI platform.


The project was complete with no notable issues. All work was completed on time and on budget without putting additional burden on the client or client resources. The project was a direct award and not competitively bid; therefore, the work was appropriately estimated while demonstrating SGC’s valuable sales ability