PURPOSE: To suppress the harmonic of a distribution system by a method wherein the harmonic voltage of the distribution system is detected through a pole transformer and a voltage which cancels the harmonic voltage is applied from an active filter.
CONSTITUTION: Harmonic suppressors are distributed in a distribution system. Each harmonic suppressor is composed of the pole transformer 8 of the distribution system, a matching transformer 5 and an active filter(AF) 6 which are connected to the low voltage side of the pole transformer 8 and an LC filter 7 which is connected to them in series. That is, the voltage VT of the low voltage side of the pole transformer 8 is detected by the AF6 and its commercial frequency voltage component and other higher degree frequency components are converted into a DC component and an AC component respectively by a converter 6a. Further, the AC component is extracted through a high-pass filter 6b and the harmonic component is detected by an arithmetic unit 6c. The harmonic voltage component is multiplied by a gain K1 in a multiplier 6d and the resultant voltage V1 is supplied to the matching transformer 5 form the AF6. Therefore, a harmonic voltage is absorbed by the resultant harmonic voltage.
NORO YASUHIRO
KUROKAWA NORIHITO
ISHIGURO TAKASHI
