IEEE 1793-2012 pdf download IEEE Guide for Planning and Designing Transition Facilities between Overhead and Underground Transmission Lines
Once the necessary components have been identified, the lavout of the transition site or structure can bedetermined to provide an cfficicnt design that incorporates site selection, community/environmental impact.safety, construction, operation, maintenance, and physical constraint considerations. This guide will discussfactors to consider for either type of transition.
31 Site selection
When planning for an underground to overhead transmission line transition, be it a single transition polc(typically referred to as a “monopole transition) or a more complex transition station, one should considerseveral issues relating to the siting of the structure or station. Some of the issues to be considered are asfollows:
Environmentaland permitting considerations
Community considerationsPhysical site considerationsEconomic considerations
3.1.1 Environmental and permitting considerations
A primary consideration when siting an underground to overhead transmission facility is to be aware ofand to the extent possible, avoid activity in or near the following types of environmentally sensitive areas.Wetland areas: Wetlands provide habitat for many plant and wildlife species in addition toproviding a method for replenishing the earth’s reserve of fresh water, There are threecharacteristics that define a wetland: 1) standing water, 2) aquatic vegetation, and 3) hydric (orhydraulic) soils. lf any of these three characteristics exist, then there is a high potential for awetland. These types of areas may be protected on national, regional, and local levels, Variouspermits may be required if a wetland is to be disturbed, or if work will occur within designatedwetland “buffcrarcas.
Wildlife impacts: Construction activity may take place in and around the habitat of protectedanimals and/or plants. During site selection, each site should be examined to determine if anyprotected animals or plants are in the arca.It would then be necessary to cvaluate the impact thatinitial construction and the final installation would have on these animals and/or plants. A fulldetermination should be made in order to properly design the facility. For example, nesting standsor wildlife guards may need to be incorporated into the transition facility. There may be seasonalrestrictions on when construction can occur in order to reduce effects on wildlife. In most areas.there are dedicated national, regional, and/or local agencies in place that can be a resource for helpin determining the potential wildlife impact.
Archaeological sites:Construction activity in and around known archaeological sites may beregulated on a national, regional, or local level. If a regulatory agent knows of or suspects that anarchacological site exists at or near the site of the planned facility, further investigation may beAn archacologist may need to be engaged to assist in working with the governingrequired.historical agencies as well as to address the process of working in or around these sites. lfarchaeological artifacts are discovered in the course of construction, there may be requirements tosuspend work until a thorough investigation is completed.
Land contamination sitesgenerally come from industrialprocesses，storage facilitiesdisposal activities (landfills). During site selection, each siteshould be screened for the potential of having contaminated soils. Likely areas include existing orabandoncd industrial developments orland adjacent to these developments. Also, land adjacent tocommercial marine activities and railroads has a high potential to contain contaminated soils. Insome cases, contammination plumes have been known to igrate a significant distance from the