The KLPD is a small, consumer-owned, electric utility on the southern coast of Maine. The utility has had a single electric substation since the 1950s which has served the community faithfully to meet the demands of a quickly growing community and to provide redundancy to its system. KLPD elected to build a new substation on a site in West Kennebunk. This site is adjacent to existing Central Maine Power Company (CMP) 115kV transmission lines.
KLPD engaged SGC Engineering to assist it with the design and construction of this vital infrastructure. SGC provided electrical and civil engineering as well as land surveying services. In addition, SGC provided procurement assistance, bidding services and construction administration.
The substation was designed to take 115kV power from the CMP lines and transform it into four 12.5kV distribution circuits. This is accomplished by using two identical sets of breakers, switches and transformers with a top rating of 18kVA. The units are can be operated individually or in tandem depending on the power needs of the community. SGC designed the “low side” bus work so that the four distribution circuits can be fed by the two transformers in various combinations, thus providing KLPD with flexibility.
An important design consideration was locating the station in close proximity to existing homes. The district wanted to be a good neighbor and have the station blend into the scenery. The station was pushed back into the lot to take advantage of the existing trees and make the station less visible. The control building was also designed to blend with the surroundings by utilizing natural materials and colors.
Given the station’s proximity to gravel pits which are popular recreational hotspots, the District wanted to make the station “vandal proof”. Gates and large boulders were placed at strategic points to limit access. In addition, the control building was constructed with cement blocks and vandal resistant security doors.
From the outset, SGC worked with KLPD staff to provide a substation that meets the specific needs and requirements of the District. All aspects of the design were tailored to KLPD’s needs while providing an effective solution that is practical and serviceable.
The Northwest Reliability Project (NRP) consists of a series of infrastructure projects directed at improving the reliability of the Vermont high voltage electric transmission system. SGC is supporting VELCO in obtaining the required environmental permits to construct a 27-mile 115kV line between New Haven and South Burlington, VT and four new or expanded substations along the route.
For construction, VELCO needs a U.S. Army Corps of Engineers permit and a number of State permits, including a Conditional Use Determination. SGC is responsible for preparing the permit applications and the supporting documentation including:
SGC is responsible for assuring the viability of the access routes with respect to impacts on wetlands and other environmental resources, and archaeological sensitive areas. SGC directed archaeological and environmental consultants to perform the required assessments along the proposed off-corridor access routes. By conducting these assessments, VELCO gains assurance of achieving permit compliance.
SGC designed the rebuilt 115kV line section of approximately 12 miles in the Downeast region of Maine. Using a combination of LIDAR, survey, and original plan and profile drawings, a model of the existing line was created in PLS-CADD. In working with Bangor Hydro Electric Company (BHE), SGC developed a plan for structure replacement based on pole conditions. BHE’s plan was to leave as many existing structures in place as possible. SGC created a plan for the line that allowed new structures to be placed outside the wetlands when practicable.
Another facet of the design was the creation of dead-end sections to improve reliability. This project started at a point just beyond a section that had been leveled due to the cascade effect caused by the infamous ice storm of 1998. The damaged section was rebuilt but this final section remained at risk to those same conditions. The design included three new dead-end structures, creating four tension sections.
The line was redesigned using the existing conductor. The new, taller structures allowed for the conductor tension to be reduced slightly, minimizing strain on the old line. SGC’s PLS-CADD model of the existing line proved very accurate in developing the sagging tensions during construction.
SGC supported the construction effort during a difficult winter for line building work. Much of the line was routed through areas that had been designated for frozen conditions during construction due to minimize wetland impacts. SGC assisted BHE in providing timely construction support when conditions forced adjustments. When line construction was complete, nearly 80 structures out of the existing 108 in that section were replaced.
Through the creative use of technology, SGC was able to realize cost savings with respect to the permitting and design of a new 138kV transmission line planned by Maine Public Service Company. From the original construction drawings, SGS developed a PLS-CADD model for an existing 69kV transmission line, running adjacent to the proposed line route. This modeling effort required the drawings to be scanned and digitized. By referencing the PLS-CADD model to ground coordinates using GPS data, SGC was able to import current wetland delineation surveys, completed using GPS, enabling the client to proceed with the design process.
To meet the reliability and economic needs for electric power that have developed in New England, Bangor Hydro Electric Company (BHE) is pursuing the construction of an 84-mile long, 345kV tie-line from Maine to Canada. This line will connect with another 64-mile section in New Brunswick, Canada to reach its final destination. BHE authorized the project team, which included SGC, to secure permits for the new transmission line. To this end, a unique, proactive stakeholder approach, with respect to the public input process, was taken. The stakeholder approach was adopted to bring concerned parties into the process during the early stages, making them a party to the design that would be permitted. SGC played a vital and active role throughout the stakeholder process by supplying ongoing technical support for the project, interacting with stakeholders, and supporting data gathering efforts. The stakeholder strategy proved successful as the permits were issued and construction of the line is undeway. The Project Team was nominated by BHE’s parent company, Emera, for the CEO Awards for Excellence.
To meet the reliability and economic needs for electric power that have developed in New England, Bangor Hydro Electric Company (BHE) is pursuing the construction of an 84-mile long, 345kV tie-line from Maine to Canada. This line will connect with another 64-mile section in New Brunswick, Canada to reach its final destination. SGC staff have been at the forefront of this project since its inception. They supported and managed the entire study process to secure New England regional approval. The high complexity of the project study was a function of the multiple and inter-Area electric systems involved as well as the marginal electrical system in the service area. SGC staff was instrumental in coordinating the design effort among all parties and submitting successful applications for reliability and economic support from NEPOOL and ISO-NE.
SGC was contracted by Green Mountain Power (general contractor) to provide construction project management services. Responsibilities included supervising and coordinating subcontractor activities to meet a challenging schedule for completion of substation construction.
This project entails the expansion and re-configuration of an existing 115-48kV substation in Highgate, VT for VELCO. A 48kV breaker was installed in the final available position of an existing 48kV ring bus. This was implemented to support additional switching options for the multiple 48kV distribution lines that are fed by the substation. The existing 115kV yard was completely de-commissioned and replaced by a new 115kV ring bus with five breakers and supporting equipment including CVTs, LAs, motor-operated and manual switches, grounding switches, and station service equipment.
A dynamic project scheduling effort was required to provide bi-weekly schedule updates, incorporating changes to the schedule, as well as monthly progress reports. To support the substation construction, field engineering was provided. Other activities to support GMP included cable take-offs, subcontractor change order reviews, and review of material substitution submittals.
Due to its complexity and aggressive schedule, the project demanded SGC personnel to pay great attention to detail in project management, construction supervision, engineering, and purchasing support.