Case Study

Non-Transmission Alternative – Cap Bank Upgrades

Client challenge:

Our client is a leading sustainable energy company with $38 billion in assets and operations in 24 U.S. states. They operate two primary lines of business: Networks and Renewables. In an effort to improve reliability, the Non-Transmission Alternative (NTA); a project which is part of a hybrid solution to eliminate the need to rebuild a transmission line, a 34.5kV line that extends radially between two remote substation. This will address the N-1 and maintenance outage violations.

Additionally, the client needed to expand the existing Boothbay Substation to accommodate the addition of a second capacitor bank.

How we helped:

Our team was commissioned to complete this expansion, which included a complete relay upgrade, yard expansion and a new yard access. The project required the expansion of the yard to allow space for the capacitor bank, while also allowing access from the local roadway.

The team completed the following:

  • upgraded the existing station and equipment up to our client’s latest standards
  • added motor operators to existing disconnect switches
  • replaced hook stick disconnects with gang operated switches
  • installed circuit switchers and free standing CTs for two transformers
  • implemented the latest protection and control schemes and installed a new SCADA and HMI platform.

These new protection and control systems were in accordance with IEC-61850 standards. The integration platform included a touch screen HMI and fiber optic OT network configuration.

Our team was responsible for all civil, substation electrical, protection and control and relay settings design. These included conceptual design, Geotech, studies, equipment specifications, outage sequencing, coordination studies, construction and commissioning support. Additionally, we performed field construction management services.


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

34.5/12.47kV Substation

34.5kV bay structure, Capacitor Bank, and IPO Circuit Breaker

Transformer high side Circuit Switcher