Zinc Oxide Sheath Voltage Limiter for HV and EHV Power Cable: Field Experience and Laboratory Tests

This paper deals with laboratory tests in order to qualify a new type of sheath voltage limiter (SVL) based on Zinc oxide nonlinear resistor (ZnO). The aim of the tests was to determine the maximum performance of the SVL and to investigate the possibility of ageing phenomena. The research was based on several years of field experience gained on silicon carbide (SiC) SVL. The high performance and the better reliability of the ZnO SVL, compared with the traditional SiC one, allow greater freedom in the project design of cable installations, making possible an increase in cable length and in the permissible short circuit current. The new SVL is now being installed to protect special bonding connections of high power cables.