Electrical substation

Case Study

Maximising performance and overhauling a local substation electrical system


Due to commercial interests the client wishes to stay anonymous.




Our client is a leading sustainable energy company with $38 billion in assets and operations in 24 U.S. states and has two primary lines of business: networks and renewables. They needed to build a 115/34.5/12.47kV substation which aimed to address power limiting contingencies, increase system stability, overall performance, and protection of the owner’s electrical system.

The substation is comprised of:

• a 115kV ring bus with four 115kV circuit breakers
• two 115/34.5kV transformers
• six 34.5kV (69kV rated) bay box structures
with bus tie bay
• eight 34.5 breakers
• one 34.5/12.47kV transformer
• one 12.47kV breaker
• incoming 115kV transmission lines
• out-going 34kV sections
• one 34.5kV distribution feeder
• one 12.47kV distribution feeder

Our client had previously replaced an aging substation, offering better protection and expanded system capacity. The new substation is equipped with the latest protection and control schemes, SCADA system and HMI platform. These new protection and control systems feature IEC-61850 communication standards.

How we helped

SGC Engineering was involved in nearly every aspect of the project. Our team represented our client’s interests as the Owner’s Engineer for the project and was responsible for reviewing all aspects of the engineering and design for accuracy, suitability and conformance to our client’s standards.

Our team also prepared the relay settings for the project, which protects and controls all the equipment at the
substation, as well as the remote end substations. Our team engineered and designed the upgrades required at the remote end substations.

SGC worked diligently to produce a successful outage and construction sequence plan to ensure constructability while maintaining customer reliability through all phases of the project.

Powerful results

The project was completed safely, on time and within budget. Our client, set out an aggressive engineering and construction schedule and SGC helped them meet their energization target.

SGC Engineering was involved in nearly every aspect of the project.