5 / 2024-03-19 10:13:21

Development of a 750 kV Extra High-voltage Ecomincal Fault Current Limiter

fault current limiter,extra-high-voltage,fast vacuum switch,current limiting ratio

The objective of this study is to present the development and test verification of a fast-vacuum-switch-based 750-kV extra high-voltage fault current limiter (FCL). The FCL is three-phase independent, with each phase comprising four current limiting reactors, 12 fast vacuum switches, one 550 kV insulating platform, and one centrally installed capacitive voltage transformer (CVT). The current limiting reactors are parallel connected with the fast vacuum switches. The current limiting reactors are 11.3 mH, with each of the two inductors first parallel-connected and then series-connected, to achieve a high current limiting ratio of 45% in 100 kA current limiting conditions. The fast vacuum switches consist of two parallel circuit branches with each branch composed of 6 series-connected switches. In this way, a nominated current of 5000 A and a nominated voltage of 252 kV could be achieved for the fast vacuum switches in current-conducting conditions. The CVT component, comprising three capacitors of 8895 pF, 161510 pF, and 7267 pF, is used to stabilize the voltage potential of the insulating platform in one aspect, power the switches and control gear, and carrier communicate with the substations in other aspects. A prototype of single-phase 750 kV extra high-voltage FCL is developed, with its fault current limiting performance, dielectric performance, temperature rising, electromagnetic compatibility performance et al., verified by a series of tests.