Analysis of the increase in harmonic of the MG power system and improvement plan for this increase

The KSTAR requires a large pulse power in order to supply power to PF coils. Accordingly, for large-capacity plasma experiments, The MG with a capacity of 200 MVA was installed and operated. The MG power system consists of the PF MPS that powers superconducting magnetic coils and the RPC & HF system that remove reactive power and harmonic generated by the PF MPS. When the MG, the PF MPS, and the RPC & HF system were joined together for an interconnected operation under superconducting magnetic loads, the PF MPS operated at up to 152 MVA. In this operation under superconducting magnetic loads, the measurement and analysis of power characteristics were mainly focused on two aspects for the purpose of checking the stability of the MG power system: the MG power system's range of conditions for stable operation, and characteristics of harmonic based on its characteristics. This paper presents the MG power system's range of conditions for stable operation by comparing it with the 154 kV grid power system, the causes of gradual increase in harmonic based on characteristics of the MG power system, details of the experiments conducted for identifying such effects, and measures of improvement based on the results of those experiments.