South Gorham 345 kV Substation Expansion

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Client: Central Maine Power Company
Location: Maine, USA

POWER was the prime contractor to provide engineering, procurement, construction, construction management and testing and commissioning services for the addition and expansion of a 345 kV yard to the South Gorham Substation. 

Looking out for the bottom line

This project was completed on an open book E+PC basis designed to save the client money and speed the overall process for completion of the station. CMP received over $2M in savings from this project.

Critical transmission infrastructure 

The station is a bulk power supply for some of the largest load pockets from Portland, Maine, to the border of New Hampshire. The main project objective was to construct a replacement 345 kV substation, including a second 345 kV/115 kV 448 MVA autotransformer, seven 345 kV SF6 circuit breakers, two 345 kV buses, two 115 kV SF6 circuit breakers and reworking of two 345kV transmission lines. The project addressed power-limiting contingencies, increased system stability and enhanced overall performance and protection of the 345 kV transmission system in the region.

Good work begets good work 

Performance on the initial project led to an evaluation of the 115 kV bus rating and physical loading of the existing 115 kV South Gorham Substation bus considering the addition of the 345 kV substation equipment and increased fault duty. This evaluation resulted in a second project to replace the 115 kV breakers with those meeting the new system requirements.

Multidisciplinary services

POWER had a total turnkey scope that required studies, engineering, developing bid packages and bid and evaluating all equipment and subcontractors on the project. CMP issued purchase orders for the major engineered equipment while POWER purchased all other equipment and hired and managed all subcontractors. POWER’s responsibilities included full construction management, material management and overall project management with minimal support from CMP.