| 摘要 |
A capacitive voltage divider, for instance for medium or high voltage, comprising a series circuit of at least two capacitors C1, C2, one of which serves as a measuring capacitor C2, which series circuit may be connected between a primary voltage and a reference voltage whereby a measuring signal is derived from the measuring capacitor C2 as a secondary voltage, which measuring signal may consist of an A.C. voltage component and an unwanted D.C. voltage component and wherein a leakage inpedance R1 has been connected across the measuring capacitor for discharging the D.C. voltage component, including control means for the reception of the measuring signal and the derivation of the true unwanted D.C. voltage component from the measuring signal, characterized by compensating means for receiving the measuring signal and for compensating the D.C. voltage component in the measuring signal with the said derived true D.C. voltage component. As shown, filter F1 blocks the D.C. component so that comparator D provides only the D.C. component to a logic circuit B1 which closes S1 or S2 (depending on polarity) C3 is thus charged from a source Vref1 or Vref2. When C3 is charged to the mains voltage as C2, comparator D gives zero output, opening S1 or S2 and the measuring signal output is free from D.C. <IMAGE> |
