New techniques for life cycle management of polymeric insulators in high voltage electricity networks

Abstract

Insulators manufactured from polymeric materials are widely used by many electricity companies although there is concern about how degradation of the polymeric material of insulators might affect their lifetime. The question arises as to how utilities might best manage large populations of degrading composite insulators that are often dispersed over great geographical areas. In this paper the complete life cycle costs of polymeric insulators in large electricity networks are examined and it is concluded that failures of inexpensive components can generate significant real costs to the network owners and great indirect costs to the community. The policy of replace on failure is discussed and it is suggested that the application of condition based maintenance is needed to reduce costs. Failure modes of insulators are reviewed and a new technique for determining numerical indicators of insulator condition, developed by the author and co-researchers, is described that is based on analysis of samples of polymeric insulation taken ‘live’ from the high voltage network. The condition indicators developed for EPDM and silicone rubber insulation are described and results from sampling in 11 kV and 132 kV networks are presented.

Keywords:

• Life cycle costs
• non-ceramic insulators
• composite insulators
• condition assessment

Additional information

Notes on contributors

D Birtwhistle

David Birtwhistle was born in Bradford, UK in 1944. He holds BEng(Hons) and MSc(Research) degrees from the University of Bradford (UK), a PhD from The University of Sydney and is a Fellow of Engineers Australia. He was with QUT for over 30 years, latterly as an Associate Professor He is now a consultant engineer. His main research interests have been connected with postgraduate education of engineers and high voltage electrical equipment. David has been a member of many committees of CIGRE, SAA and Engineers Australia, he is a Visiting Professor with Strathclyde University, Glasgow, and a NATA Assessor. He has received awards for outstanding contributions from QUT, CIGRE and Engineers Australia.

G Cash

Dr Greg Cash is a member of the Royal Australian Chemical Institute and was born in Brisbane Queensland Australia in 1950. Greg completed a BAppSc in Applied Chemistry at Queensland Institute of Technology in 1973 and after teaching in high schools and working as a research assistant returned to academia at QIT in 1983 where he completed a Masters degree in 1986. A PhD from Griffith University was awarded in 1991 and he has worked in polymer research since 1992. He is currently a Research Fellow in the Cooperative Research Centre for Polymers at both QUT and the University of Queensland. Over the last 10 years he has been involved almost exclusively with research into the degradation of polymeric materials used in high voltage insulation.

G A George

Professor Graeme George AM is a Fellow and Past President of the Royal Australia Chemical Institute and was born in Brisbane Australia in 1944. He has a PhD in Chemistry from the University of Queensland. Professor George has 30 years experience in studying the properties and performance of polymers (plastics, rubbers, textiles and composite materials) particularly when used in hostile environments, initially with the DSTO, Materials Research Laboratories and then with Queensland Institute of Technology and the University of Queensland.

D Hinde

David Hinde was born in Brisbane, Queensland, Australia in 1956. In 1976 he completed a four year electrical apprenticeship with the Southern Electric Authority of and graduated with a degree in electrical engineering from the Queensland Institute of Technology in 1988. He has worked in high voltage generation, transmission, and distribution for over 30 years, including 8 years of applied research, co-authoring several publications on high voltage plant condition monitoring. David has received several safety awards for the design of continuous insulation monitoring systems and other awards in control automation. He is currently the recipient of an industry sponsored PhD scholarship at QUT and is studying factors affecting the localisation of discharges on high voltage silicon rubber insulators.