Case Study

Greenfield 185MW Wind Farm Project

Client challenge:

Our client performs a wide range of construction services for both public and private clients. They required engineering and permitting services for a windfarm system and grid interconnection. For this project, a collector system, collector interconnection substation, and transmission line needed to be designed.

SGC was commissioned to complete the collector system, collector interconnection substation, transmission line designs and provide permitting support. The collector interconnection substation was a greenfield design and SGC was not involved in the remote end upgrades.

The 115kV side of the collector substation includes arresters, voltage transformers, a circuit breaker, and a gang operated disconnect switch along with a 115/34.5 kV, 150/200/250 MVA transformer. The 34.5kV side includes arresters, voltage transformers, disconnect switches, and five feeder circuit breakers. A 60MVAR synchronous condenser was also installed on the delta tertiary of the transformer by GE. The design included a control shelter which houses the AC/DC systems as well as the protection and control equipment. A 20-mile, 115 kV transmission line connects the collector substation to the interconnecting utility substation.

The collection system consisted of five 34.5 kV feeder circuits connecting fifty-six 3.3 MW Vestas V112 turbines to the collector substation. The collection system consisted of both underground and overhead cabling.

How we helped:

Our team was responsible for the collection system and transmission line designs as well as substation civil, electrical, protection and control designs. This included a 30%, 75%, and an IFC design, along with a final record drawing submittal. We also completed all required studies, protection settings, arc flash study, equipment specifications, and provided construction support.

Powerful results:

The project was competitively bid and awarded to SGC. We completed the project on time, under budget and there were no notable issues with the final design. The client was pleased with the final product and has continued to utilize SGC on subsequent renewable projects.