Stabilization of the KSTAR power system for the first plasma operation

The KSTAR (Korea Superconducting Tokamak Advanced Research) facility is composed of thirty superconducting magnets for plasma experiment. The electric power system for the first plasma operation is made up of various electric devices including 170 kV GIS, 154 kV 50 MVA transformer, 22.9 kV circuit breaker systems and RPC & HF systems. When PF MPS was operated, reactive power and harmonic currents of 1±12 ns occurred instantaneously in the KSTAR electric power system due to the characteristics of the KSTAR superconducting coil for the first plasma generation. However, the measured voltage drop and harmonics seriously affect other experiment equipments as well. Therefore, the RPC & HF system for the superconducting tokamak device is important to compensate the reactive power and remove harmonics. In this paper, we discuss the stability of the electric power system and the operation results of the RPC & HF systems during the KSTAR first plasma operation. Also, the upgrade plan of the electric power system based on the KSTAR operation plan will be discussed.