Retrofit XLPE cable systems for the EHV range

Abstract

The dielectric fluid in the high pressure fluid filled (HPFF) cable system pipe is not environmentally friendly and is leaking into the surrounding soil, due to pipe corrosion. Therefore power utilities are forced to exchange the oil to an environmentally friendly one or to develop a retrofit cable system, eliminating the oil completely. On this basis, ConEd/New York initiated a development project to be governed by EPRI, which has the aim to present a new fully tested 345 kV XLPE cable retrofit system which is environmentally friendly. ABB High Voltage Cables/Sweden was selected to be the principal investigator for this project. Prefabricated joints tested for 345 kV are going to be used in the system. The joints will be installed inside the steel pipe sleeves in order to get a smooth temperature profile along the cable route as well as a protection from the outside. A one-year pre-qualification test program has been performed at STRI. The circuit comprised 110 m of XLPE cable, 5 m of HPFF cable, one prefabricated EPDM joint, one composite joint, two transition joints and two outdoor terminations. The XLPE cable and EPDM joint have been surrounded by circulating water at a temperature of 60 /spl deg/C, in order to simulate worst conditions for the cable system. The pressure has been held slightly above 1 bar over pressure.