Orbital’s expert engineering staff supports each stage of transmission line design. This starts with the identification of a viable permittable route between the terminal substations. In parallel with acquiring ownership of needed parcels or easements across the parcels, the permit process is initiated to assess the viability of the chosen route. Conceptual designs are prepared to assist in the permitting and public hearing process as necessary. Detailed design of the line and spotting of the towers is aided by analytical software such as PLSCAD. Design and fabrication specifications are prepared by the engineer who also provides procurement support. Our multi-discipline substation design team prepares the specifications, calculations and drawings to support permitting and issue of the construction bid packages. During construction of the transmission lines and the terminal substations, our project management team provides construction management, QA/QC and field engineering services.
A successful route design considers more than the topography between two endpoints. The route also considers existing ROW ownership, easements and the permitted use, as well as the current use. Acquiring new ROW segments requires consideration of the ownership: is it publicly or privately owned, is there environmental or archeological restriction, the difficulty of the permitting process including potential political opposition. More expensive underground routing may be the prudent option in highly congested or contested areas.
After completion of the survey of the desired ROW, acquiring additional parcels can be a lengthy and expensive process. It all starts with researching records of deeds to identify current ownership of each parcel. This is followed by negotiating equitable compensation with the private owners and acquiring easements from government agencies that manage public lands. Orbital assists clients with researching records of deeds and communicating with government agencies that manage public lands.
Lack of timely permits will delay the completion of a project and significantly impact cost. Orbital permitting managers identify the needed permits, the respective issuing agencies, and their filing requirements and turnaround time. From this information a permitting schedule is developed that is logically tied to the key project milestones. Orbital, consistent with their awarded scope, will act as agents for the client and submit the permit applications, actively communicate with the permit agency review staff, attend public hearings and make design adjustments to address comments from the authorities that have jurisdiction. By providing complete permitting services integrated with the design process, Orbital provides additional assurance of a successful project.
The details of transmission tower fabrication, while similar, vary among tower manufacturers depending on their specific fabrication processes. That is why most towers are designed by the fabricator’s design staff in response to a detailed design and fabrication specification developed by the engineer. The engineer typically will prepare the specification, perform technical and commercial evaluations of the bids and make an award recommendation to the client. After award to the fabricator, the engineer will review the vendor calculations and drawings and return appropriate comments to the fabricator to assure the resulting design is compliant with the specification. Orbital’s engineering staff develops NESC compliant load trees and load cases as input to the specification.
Transmission Substation Design (69 kV - 500 kV)
Our experienced staff have designed substations with voltages up to 500 kV. These project range in complexity from the replacement of switches, breakers, bus equipment, transformers, reactors and phase angle regulators, the addition of line terminals, transformers, control equipment and structures to the design of new substations.
Our services encompass the full range of disciplines required for these complex projects from electrical power engineering, relay protection and controls design, equipment specification, physical layout of the yard and control house, communications whether by carrier, fiber, copper or microwave, civil engineering in support of grading, drainage and permitting support and structural engineering for the design of structures, foundations and buildings.