PROJECT TITLE: Electrical Design of a New, Innovative OHL Transmission Tower made in Composite Materials
PhD period: 2014.11.01 – 2017.10.31. (has been prolonged till 2018.05.28.)
Section: Electric Power Systems
Research programme: Modern Power Transmission Systems
Supervisor: Claus L. Bak
Co-Supervisor: Filipe Faria da Silva
Collaborators: Bystrup Architecture Design & Engineering, Tuco Marine ApS and DTU Mechanical Engineering.
Funding: The Danish National Advanced Technology Foundation (HTF).
The transmission system is going under major changes now and in the years to come. This is driven by the need for including large share of renewable energy sources; sources like wind and solar power that are becoming more popular and of course large plants are being installed in modern power systems around the world. On the other hand, power transmission systems, which traditionally are made as large steel lattice structures that were developed over 70 years ago, are very negatively dominant with regards to visual impact. For this reason, public opinion is increasingly and strongly opposing both existing and planned overhead transmission lines (OHLs). This has been reflected by the Danish Cable Act, which will underground almost the entire Danish transmission system (420 and 170 kV) within the next 20 years, a plan that already commenced in many locations. Since underground cables are 6 to 12 times more costly and only technically feasible for short distances so the next generation of OHL is a need for a new design with benefits to both end-users (TSOs) and the public by developing new design pylons that are smaller, more compact and are more friendly visual impact.
Within this scope, Power Pylons of the Future (PoPyFu) targets a unique market opportunity for design-driven redevelopment of OHLs by developing innovative, composite-based pylons that enables new, value-added designs and technical solutions. New material approaches will enable innovative visual expressions and at the same time - through the integration of insulators in the pylon design - reduce the size of the pylons significantly. As a result, new OHL construction projects, previously subjected to strong community opposition, can now be realized as costly comparable with traditional pylons.
In order to help accomplishing this goal, electrical insulation design and insulation coordination will be studied for a 400 kV tower cross-arms made fully in composite material. Omission of shield wires or installation of surge arresters inside the hollow cross-arms will be investigated as a possible alternative to reduce tower height, allowing more compact designs of towers thus minimizing the visual environment impact of the lines.
The main objective of this project is to determine the proper shed profile for cross-arms and accordingly phase to phase clearance, ground potential access for ground wires and/or surge protection, transmission network consideration regarding traveling waves and short circuits, reduction of corona losses, radiofrequency (RF) magnetic fields and audible noise level and minimizing of electric and magnetic fields in order to decrease the Right of Way width.
ANSYS Finite Element Analysis (FEA) software and PSCAD simulation tools are going to be used for modeling of different parts of pylons and analyzing the power system for different lightning and switching surge overvoltages, respectively.
Publications in journals and conference papers may be found at VBN.