| 摘要 |
PURPOSE:To make it possible to detect also delay or leading current >=90 deg. by detecting the reactive power of only a load to compensate the variation of reactive power in each half cycle. CONSTITUTION:A current transformer 6 and a resistor 7 generate a voltage signal proportional to a load current iF and input the voltage signal to an adding point 87, a current generating circuit 85 for effective power generates a sine wave having the same phase as that of a voltage waveform and inputs its output to the adding point 87 and a current generating circuit 86 for reactive power generates a sine wave having a phase delayed by 90 deg. from that of the voltage waveform and inputs its output to the adding point 87. The adding point 87 adds these three inputs momentarily and inputs its output to a reactive power detecting circuit 81, which detects reactive power on the basis of the input from the adding point 87 and a voltage signal outputted from a transformer 5 and inputs its output to a subtracting point 89. A reactive power signal generating circuit 88 outputs the same value as the reactive power of the current signal outputted from the circuit 86 and inputs its output to the subtracting point 89. Consequently, the reactive power compensating device reacts so that the reactive power of the load 4 varied in each half cycle is rapidly compensated.
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