Appendix F Detailed Cover Type Tables - USDA Rural Development

Bemidji – Grand Rapids
Biological Assessment and Evaluation
three‐breaker ring bus with line switches, a new 230/115 kV transformer (approximately 187 million
volt‐amperes [MVA]), and associated 115 kV facilities to integrate this transformer into the existing
equipment.
Routes 1, 1A, 1B, and 1C would require construction of a new substation near the intersection of the
route and the existing Nary Junction – Cass Lake 115 kV line. It would be designed and constructed with
a 230 kV three‐breaker ring bus with 230 kV line switches. The facility would include a 230/115 kV
transformer of approximately 187 MVA that steps down the voltage to a 115 kV three‐breaker ring bus.
In addition, the new substation would require a control house, relay panels, foundations, steel
structures, and switches. The substation yard would be approximately 500 feet by 500 feet of yard fence
and require an access road.
Nary Breaker Station – In addition to the substation improvement mentioned above, Route 1A includes
a section where the proposed 230 kV line would be double‐circuited with an existing 115 kV
transmission line between Bemidji and Cass Lake. Double‐circuit construction, operation, and
maintenance can have impacts on the security and reliability of the transmission system that must
always be taken into account. The Applicants believe the Project could be double‐circuited with the
existing 115 kV transmission lines between Bemidji and Cass Lake without significantly affecting area
reliability, provided a 115 kV breaker station is constructed at Nary Junction.
This 115 kV breaker station would be located adjacent to the existing switch at Nary Junction on an
approximately five‐acre site with a fenced and graded area of approximately 200 feet by 200 feet. The
breaker station would consist of three 115 kV circuit breakers and associated switches, communications,
relay and control equipment, three 115 kV line termination structures, and a control house. An
improved access road and small parking lot would also be required to move equipment to the site.
Building this 115 kV breaker station sectionalizes the 115 kV circuits serving Bemidji, Cass Lake, Akeley,
and Badoura. This provides back‐up (redundant) transmission in the event of an outage of the proposed
230/115 kV double‐circuit transmission lines.
2.3.4 Transmission Line Design
While final engineering and design have not been completed, transmission line construction would likely
use two‐pole H‐frame structures for a majority of the route (Figure 3 – Structure Figures). These are the
typical structures used for a 230 kV transmission line located on wooded, rugged topography. They are
also suited for areas requiring longer spans to avoid or minimize the placement of structures in wetlands
or waterways. Each H‐frame structure would range in height from 70 to 90 feet, and be placed 600 to
1,000 feet apart.
Where conditions warrant, single‐pole structures may be used. For this Project, single pole structures
would typically be used in areas where the available right‐of‐way is limited, such as along roads in
developed areas. The height of single‐pole structures ranges from 80 to 100 feet, with the span between
structures from 400 to 800 feet.
The typical right‐of‐way for a 230 kV transmission line is approximately 125 feet wide. Ultimately, the
right‐of‐way width depends upon the recommended clearances between the conductor and other
facilities adjacent to the route. The width of the right‐of‐way may be reduced in certain high‐density,
developed areas with the use of single‐pole construction. The width of the right‐of way may also be
reduced where the new transmission line follows an existing linear corridor, such as another utility line
or roadway. On the other hand, a wider right‐of‐way may be required for longer spans of the
transmission line or where special design requirements are dictated by topography. The Applicants
would seek permanent easements providing the right to construct, operate, and maintain the
transmission line along the full width and length of its right‐of‐way, as necessary.
July 2010 Description of the Proposed Action Page 2‐5