Qualification of XLPE tube systems for cooling high-voltage high power electrical equipment

The introduction in the mid-1970s of high-voltage high-current silicon thyristors for electrical power conversion created a need for extremely reliable but economical liquid cooling systems in which purified water-based coolants could be circulated. Research and development over 2¹/₂ years on XLPE tube systems and compatible nonmetallic connectors has resulted in a single-circuit purified glycol/water fluid system cooling a 150 MW back-to-back HVDC link in Canada. The author discusses the system requirements, electrical stress, conductivity control, electrolysis and temperature cycles. The author then discusses the thermal cycle testing and post ageing testing of the XLPE connectors. The suitability of XLPE for the cooling system is discussed