ABSTRACT:

In electric power system, the harmfulness to system because of lack of reactive power can not be ignored. STATCOM(Static Synchronous Compensator)is an important member of Flexible AC Transmission System, comparing with traditional reactive power compensation device, it not only decrease the volume and cost of the device, but also has faster response speed and more smooth regulating property. On the basis of thorough analysis on reactive power compensation device in existence, this paper study on three-level STATCOM. The device uses neutral-point clamping method to divide the inverter circuit into positive, negative and zero threelevel, so that each component subject to the maximum voltage reduced to half of the traditional inverter circuit.