345-kV Bosque Switch
Location: Bosque County, Texas
Client: Brazos Electric Power Cooperative
Completion Date: March 2000
The Bosque Switch project was constructed to provide an interconnection point for a new generating facility. The project consisted of new 345-kV and 138-kV switchyards constructed in the vicinity of an existing 345/138-kV substation. An adjacent 345-kV transmission line was modified to loop through the new 345-kV switchyard. A new 138-kV transmission line was constructed to connect the new switchyard to the existing substation. Both switchyards were designed for a future breaker-and-a-half configuration.
- Electrical, civil and structural design
Burns & McDonnell was responsible for the complete design of Bosque Switch. Services included electrical, civil, and structural design; including grading, grounding, physical layout, transmission line, foundations, lighting, and relaying. In addition, Burns & McDonnell specified all equipment, materials, and installation requirements and assisted Brazos with procurement and administration of these items. Construction and equipment contract assistance included reviewing contract drawings for compliance.
Transmission Line Design
Burns & McDonnell was responsible for the design of a 138-kV transmission line. In its short half-mile, the 138-kV line crosses another 138-kV line, a 69-kV line and a distribution line. Burns & McDonnell assisted the Owner with right-of-way procurement, developed the plan and profile drawings, and provided guying and other miscellaneous details.
- Provided for a “fast-track” construction schedule — from preliminary design to energization in eight months.
- Tapped a 345-kV transmission structure by converting it to a double deadend using isolating suspension insulators to electrically divide the existing line into two circuits.
- Provided EPC services for the portions of the switchyards owned by the generation interconnecting company, including deadend structures, circuit breakers, and switches.
- Coordinated phasing, grounding, raceway, backup station service, and relaying interfaces with the generating facility.