Project: T203700 #3398B-5

The primary objective of this project is to review the current knowledge of “best practices” in designing EHV overhead lines. Primary focus here will be the mechanical aspects of line design. The information should be presented to TODEM members in a way that they can understand. It is also expected that the document will provide a quick reference guide so that a less experienced engineer can understand the issues and the technical content and follow the EHV line design process in a transparent manner. Another objective of this project is to educate the younger engineers who are joining our workforce at an increasing rate. The knowledge base for EHV AC line design is getting smaller due to the dramatic changes that have occurred throughout the industry over the past 25 years and many experienced engineers leaving the profession primarily due to retirement and/or restructuring of the industry.

The main objectives of this section include:

1) To conduct a comprehensive literature review on the mechanical property requirements on high voltage insulators from all over the world and produce a state-of-art report providing a basic understanding of mechanical load limits on different insulator types made by porcelain, glass and composite;

2) To review and report on the mechanical test and design requirements from the current main standards and recommendations;

3) To review and report on the mechanical design consideration and operational performance of multiple strings sets applied in EHV overhead lines.

4) To review and report on the main parameters that may influence the design mechanical properties and govern ageing performance of insulator system;

5) Include mechanical design requirements of common and specific hardware fittings related to the insulator strings.

The outcome of this study will enhance designers and utilities collective understanding about the issues related to the mechanical design of line insulators and hardware fittings as well as the guidelines to deal with the mechanical loading on different type of insulators.