Superconducting cable and superconducting fault current limiter at Puji Substation

Abstract

We have undertaken research and development of superconducting cables and superconducting fault current limiters and have made significant progress in the last six years. At Puji Substation of Southern China Power Grid, a 35 kV superconducting cable system was installed and energized in 2004. In 2007, a 35 kV superconducting fault current limiter (FCL) was installed in the substation. After field tests and trial operation, this device was commissioned to live-grid operation in 2008. As of now, Puji Substation is the only substation in the world that has both superconducting cable and superconducting FCL operating in its network. The cable system consists of three 33.5 m warm dielectric superconducting cables, six terminations, and a closed cycle liquid nitrogen cooling station. Up to date, it has delivered more than 400,000,000kW·h of electricity to the customers, including 4 factories and a residential population of about 100,000. The FCL is a saturated magnetic type superconducting fault current limiter. Its performance has been tested under live-grid operation conditions. The testing results show that the FCL has low impedance at normal power transmission and reliable fault current limiting capability in a short-circuit situation. These results are in good agreement with the design expectations. Technical details of the installation, operation and some testing data for the cable and fault current limiter are reported in this article.