Relevance and Applicability of Standards in Wind Farm Collector Circuit Design Process and Balance of Plant Selection

Abstract

Insulation breakdown in wind farm collector circuits indicates components are operating well above design ratings. Excessive temperatures exceeding 90 °C for long periods result in immediate damage to cross-linked polyethylene (XLPE) insulation. Long-term continuous damage will lead to insulation and componentry failure. The objective of this paper is to critically interrogate type testing parameters for extruded power cables and power cable accessories. All findings were sourced from IEC and AS/NZS standards, with assessment focusing on comparisons of relevance and applicability to wind farm applications. Design standards on which product testing is based for XLPE power cables and power cable accessories are not directly relevant to wind farm applications. The repetition of heating cycles utilized in the heating cycle type tests represents what’s known as cyclic load profiling. This is aligned closely to typical load profiles of traditional distribution networks. The high number of cable joint failures across Australian wind farms provides significant evidence to suggest that operating conditions across wind farms differ substantially to traditional distribution networks. Furthermore, it supports the disparity between component type test parameters and wind farm application parameters.