Transmission Line Engineering

Transmission Line Engineering

Amid rising energy demands and aging infrastructure, electric utilities throughout North must meet today’s reliability needs while building capacity for the electricity demands of tomorrow. Embarking on an electric transmission improvement project with a reduced staff, under constrained schedules and in the face of public opposition, can be a daunting task for any utility.

At DiGioia Gray, we have extensive experience in power delivery services from 69kV through 765kV. We provide innovative engineering and construction services to design, maintain or upgrade power delivery systems in a cost effective, safe and reliable manner.

Transmission Line Design, Uprating and Upgrading

Whether it is with new construction or increasing the life and function of an existing line, DiGioia Gray’s experts are experienced in transmission line and structure design from inception to completion. State-of-practice finite element software programs — such as PLS-CADD, TOWER, PLS- POLE and RISA 3D — are used for structure and line designs. We integrate utility standards into the design by applying utility preferred methods of construction. Our staff members are experts in design codes and understand the engineering principles and reasoning behind various criteria. In fact, they have contributed to the creation of transmission line design codes and guides.

Geotechnical Investigations

DiGioia Gray’s staff study and document the hydrogeology that impacts a project through literature research and field investigations. Our work identifies geologic hazards, such as mine subsidence, karst areas, and wetlands, and characterizes subsurface and groundwater conditions. This geological framework allows the project team to optimize structure site selection and foundation design process potentially providing cost-savings by averting or addressing geotechnical issues early in the project.

Foundation Analysis and Design

Staff members at DiGioia Gray are nationally and internationally known for their expertise in designing foundations for transmission line structures. In addition, licensing and technical support for EPRI Foundation Analysis & Design (FAD Tools) software is managed by DiGioia Gray. The software includes modules for Single Pole Foundations (MFAD), H-Frame Foundations (H-FAD) and Tower Foundations (TFAD).

Construction Monitoring

DiGioia Gray is dedicated to advancing our clients’ interests and the integrity of their constructed projects. We provide quality control and cost protection throughout the construction process. We also monitor construction at every stage and verify that work is being executed safely, within budget and in accordance with contract documents. Further, we make sure the completed work meets or exceeds quality standards with minimal or no construction delays.

Transmission Line Inspections and Evaluations

Electric transmission lines are a critical and valued asset. While they are designed and built to last for decades, they are subject to corrosion, decay and wear. These processes are subtle, but after initial signs of deterioration are observed, the marginal rate of deterioration increases over time.

At DiGioia Gray, our inspections record deterioration processes observations and include an assessment of the components condition and a projection of that condition 5 to 10 years into the future when subsequent inspections may occur.

Structures can also be compromised by unforeseen impacts, such as vehicular accidents or unusual natural events, or could have unique structural characteristics due to upgrades, reinforcement or repairs executed to offset previous damage. Structure loads, design codes, design methods and ground profiles can change over time as well. Usually visual observations in conjunction with measurements are sufficient for structure assessment. However, if a refined evaluation is needed, the structure and line can be modeled using PLS-CADD, PLS-POLE and TOWER aided by GIS, aerial photography, and Lidar. These tools allow the engineer to analyze existing transmission facilities, an order of magnitude faster and more accurately than originally designed.

Emergency Restoration

At DiGioia Gray, we have many years of experience in the design and maintenance of transmission line structures. We work with utility engineering staffs to create a strategic restoration plan prior to an emergency. Should an emergency occur, we work with contractors, utility engineers, public entities and material suppliers to implement the rebuilding of facilities in a timely manner. Our engineers can design emergency restoration structures that simplify and facilitate rebuilding of the line.

Failure Investigations

DiGioia Gray staff members have investigated transmission line structural and foundation failures throughout the United States. For a typical project, we conduct a field investigation, perform destructive and non-destructive tests of concrete and steel, establish climatic loading conditions, perform structural and foundation analyses, deduce the probable cause of failure and provide design recommendations for replacement structures. We also provide expert witness testimony when the need arises.

Transmission Line Siting & Permitting

DiGioia Gray has an alliance with the internationally recognized Louis Berger Group (LBG). LBG provides environmental services to utility clients for the generation and transmission of energy. DiGioia Gray, in conjunction with LBG, provides environmental science, planning and economic development services. Together we are able to partner with clients to tackle a wide range of projects, including large-scale, complex and controversial projects that require significant stakeholder coordination and facilitation. Our team understands the requirements associated with such complex technical endeavors and we maintain the professional resources to provide a solid foundation of analysis and execution to support our clients’ programs and decisions.

With a resource base of more than 5,000 professionals and affiliate employees in more than 90 countries, LBG and DiGioia Gray are able to respond to local conditions while providing clients with the world-class scientific and industry experts of a leading global organization. LBG has more than 450 professionals dedicated to providing our clients with a full range of transmission consulting services to help support route selection, permitting and regulatory environmental compliance.

PCS Antenna Addition

Personal Communication Service (PCS) providers, or wireless carriers, are continually expanding and upgrading their network areas. Often times, this leads to providers utilizing existing structures, such as transmission line structures, to perform these services. DiGioia Gray has extensive experience reviewing PCS upgrades or new site requests to determine if the proposed loading is feasible. We perform an initial review of these sites and perform a full structural analysis if it is warranted. Once the initial review and any subsequent engineering is performed, DiGioia Gray can monitor the construction process.