| 摘要 |
<p>PURPOSE:To measure a positive-phase current with high sensitivity by additionally providing a separate transformer. CONSTITUTION:Ring iron cores 8a-10a are arranged on each 3-phase transmission/distribution line and the 1st transformers 8-10 are provided with the secondary windings 8b-10b and tertiary windings 8c-10c wound up to these cores. These windings 8b-10b are connected to a common resistor 11 for load in parallel and also the windings 8c-10c are connected in series then a photoelectric voltage sensor 12 is provided between both terminals of this series circuit to detect a voltage proportional to a zero-phase current. At this time, the ring iron cores 13a, 14a are arranged in at least two phases of the circuits for the windings 8b-10b and the 2nd transformers 13, 14 are provided with the secondary windings 13b, 14b and the tertiary windings 13c, 14c wound up to these cores. Resistors 15, 16 are connected respectively to the circuits of each winding 13b, 14b of these transformers 13, 14, and photoelectric voltage sensors 17, 18 are connected to the circuits of the windings 13c, 14c. Thus, optical signals are conducted to a signal processing circuit for positive-phase current through an optical transmission passway and detected.</p> |
