Discriminating ‘volume effects’ of cable thermal ageing using electrical diagnostics: Sensitivity study through calculations

摘要

Polymeric cable thermal ageing is a key end-of-life consideration for medium voltage (MV) cable, low voltage (LV) power cable, and LV instrumentation and control (I&C) cables. This is particularly true for generation plant cables. For example, in wind generation plants, low thermal design margins and component compatibility issues have been known to cause internal over-heating of conductors and accessory connectors, leading to premature cable system failures. In nuclear generation plants, cable proximity to external heat sources can often result in thermal stress being a dominant insulation ageing mechanism, a fact which is reflected in environmental qualification procedures for nuclear power plant cables. As such, numerous applied studies on electrical diagnostics for cable thermal ageing have been led by organizations such as the Electric Power Research Institute (EPRI) [1,2], the US Nuclear Regulatory Council (NRC) and Department of Energy (DOE) [3], the European Union [4].