| 摘要 |
PURPOSE:To make it possible to determine in the live state that the phases coincide at both ends of a distribution line section by having a measuring signal overlapping the distribution line synchronizing a phase voltage of a specified phase at one end thereof while the measuring signal and the waveform of the phase voltage are detected at the other end thereof. CONSTITUTION:Output (a) of a voltage transformer 1 taking out a specified phase voltage (for example, black phase voltage) is applied to a waveform shaping circuit 2 to be shaped into rectangular waveform. Output (b) of the waveform shaping circuit 2 and output (c) of a measuring signal generator 3 are applied to a synchronizing circuit 4 while a measuring signal (d) is made to overlap the black phase voltage with a signal coupler 5. An electric field sensor 6 has a detector section comprising an electrooptic crystal 10 having a Pockels effect, which is arranged sequentially in the electric fields of respective phases to measure the electric field sequentially for each phase. The electric field sensor 6 converts light modulated by the electric field depending on the phase voltage of the preset phase to an electronic signal and outputs it while a signal voltage separation circuit 7 outputs a signal X2 by a measuring signal X1 and the phase voltage to be applied to a waveform shaping circuit 8. A phase discrimination circuit 9 detects the synchronism of each phase voltage with the measuring signal at the point B and hence, the phase synchronizing the measuring signal coincides with the specified phase at the point A. |
