Design and Analysis of a kA-Class Superconducting Reactor

Abstract

Abstract —This paper presents the designs of kiloampere-classreactors with high temperature superconducting (HTS) BSCCOtapes. The HTS solenoidal windings of the 100 A-class andkiloampere-class reactors consist of 34 coil layers and 136 coilturns in total. The structural design and performance evaluations,including critical current and ac loss calculations are discussedfor a single-phase grounding fault case and compared with a con-ventional copper reactor. The method to apply the HTS tapes andthe principal features of the HTS reactors have been theoreticallyidentified. Index Terms — AC loss, BSCCO, current limiting reactor, neu-tral grounding reactor, superconducting reactor. I. I NTRODUCTION R EACTORS ARE widely used in modern power systems,which provide functions such as limiting currents, com-pensation of power, and inductive connection to ground. Powerquality and reliability problems are normally caused by theabnormal operations of large-scale equipments and the short-circuit faults caused by the power system itself. High tempera-ture superconductors (HTSs) have been successfully applied inthe advanced reactor developments. As an example, a numberofreactor-basedsuperconductingfaultcurrentlimiters(SFCLs)including the saturated iron-core type [1], [2], transformer type[3], [4] reactor type [5], [6], and non-inductive type [7] aremadeavailabletoreducethefaultcurrentlevelsontransmissionand distribution networks.The power system faults mainly include three-phase shortcircuit, two-phase short circuit, two-phase grounding short cir-cuit and single-phase grounding short circuit. The single-phasegrounding faults, for example, account for about 91.23% of thetotal number of power system faults in the 6434 power trans-mission lines of 220 kV Chinese power grid in 2008. It meansthat single-phase grounding faults need to be solved urgently toimprove the whole power system quality and reliability [8].In the neutral indirectly grounded power systems, the single-phase grounding fault occurs most frequently. The three-phaseline voltages still keep symmetrical states and have negligibleimpact to the local power equipments. Therefore, the powersystem is allowed to continue running up to few hours before