This following article is based on an edited version of the presentation given at INSULATOR 2000 in Barcelona by Brian Pokarier, Manager Engineering & Projects, Powerlink Queensland

INTRODUCTION

Powerlink Queensland owns and operates a transmission network stretching over 1700 km from the tropical north of Australia to the temperate south. The system, valued at around A$ 2,000 million, is one of the world’s longest and consists of a backbone 4500 circuit km of 275 kV supported by 4800 circuit km of 132 kV/110 kV.

The transmission line network is still predominately insulated with ceramic discs, however over the last ten years polymeric insulators have found a wider use, quite often for specific reasons. Substation insulation has traditionally been porcelain posts with some trials using polymeric materials.

Powerlink has a history as a government-owned monopoly which carried out its own planning and infrastructure development, relatively protected from market-driven forces. Until recently, the prime focus of such utilities was to extend the life of existing assets and to find ways of driving the older assets harder.

The establishment of an Electricity Market in Australia has caused many transmission utilities to re-focus their attention. Instead of driving their older assets harder they are now more concerned with improving asset value and reducing O&M costs.

The introduction of the Electricity Market in Australia in 1998 essentially introduced a whole new set of criteria for decision-making in all areas within Powerlink’s operations -even so far as the way insulation is selected and maintained. The new market forces, which include a National Electricity Code, penalize a transmission network owner if it has inadequate network availability such that generators are constrained. At the same time, other penalties exist if the network owner is shown to have over-developed its infrastructure unnecessarily. Given these new rules, the current thrust for utilities in the Australian Electricity Market is to concentrate on optimizing asset value as well as reducing operating and maintenance (O&M) costs.