COMPONENT MEASURING DEVICE FOR SYMMETRICAL COMPONENT OF THREE PHASE ALTERNATING CURRENT

摘要

PROBLEM TO BE SOLVED: To improve the operation speed of symmetrical component of a fundamental wave corresponding to a distorted wave by producing symmetrical component data corresponding to any one of three components of the distorted wave on measured input signal data. SOLUTION: A PLL circuit 7 produces a sampling signal on a shaped rectangular wave and outputs it to each of S/H circuits 3. A measured input signal data to undergo sampling are stored in a buffermemory 5 through an A/D conversion circuit 4. An operation section 8 produces symmetrical component data corresponding to any one of three components of a distorted wave on the measured input signal data, and then a symmetrical component to a fundamental wave is computed through FFT processing, etc., on the symmetrical component data. Therefore in the case of computing only a fundamental wave antiphase current being an important parameter, computation processing requiring a lot of time such as the FFT processing for extracting the fundamental wave component from the distorted wave can be finished by execution only once.