In recent years, the service load tends to increase with more frequent train operation, increased speeds and multiplied power. As the load capacity of train becomes larger, the reactive power of load causes larger voltage drops. It is anticipated that the feeding voltage would drop below the lower limit of the allowable voltage range. With advancement of power electronics technology, voltage drops in the feeding line and voltage fluctuations on the 3-phase side can be reduced, and the power factor at substations can be improved by compensating for the reactive power using a single-phase static var compensator (SVC). This paper describes the principle of voltage compensation using SVC with TSC installed at a sectioning post in San-yo Shinkansen and introduces the results of site investigation.