Electronic reactive power meter

Abstract

Abstract PURPOSE:To eliminate the influence of the change in temperature and the fluctuation of frequency by delaying a phase angle by a prescribed angle by the use of an electronic circuit without using the L or C of the voltage of a circuit to be measured. CONSTITUTION:RAM6 delivers memory data in a memory address designated by an address register 7 to a latch circuit 8, while storing the output of a transformer 1 for instruments through the intermediary of an A/D converter 4 and a switching circuit 5. Meanwhile, since the address register 7 is reset every 1/4 cycles of the waveform of voltage by a counter 11, a dividing circuit 12, a latch circuit 13 and a comparison circuit 14, the waveform of voltage inputted in the A/D converter 4 is supplied from the output side of a D/A converter 9 to a multiplying circuit 15 as the waveform of voltage delayed at a phase angle of 90 deg. and multiplied by the output of a current transformer 2 for instruments. The multiplied output is supplied to a counter 18 through the intermediary of an I/F converter 16 and a frequency dividing circuit 17. By this constitution, accurate and highly reliable reactive power can be obtained.

Inventors

• 👤 Tsutomu Ono

Bibliographic Details