抄録
This paper proposes a contactless method to measure a surge voltage waveform on an overhead transmission line and on a cable sheath enclosed in a corrosion-proof layer. To measure surge voltage and current waveforms on the overhead line, the method is based on electro-magnetic coupling between the overhead line and a surge sensor, composed of a closed loop which is a distributed parameter line. The surge waveform is estimated from the induced voltage to the closed loop and from a Z-parameter theory. To measure a cable sheath voltage waveform, the method is based on electro-static coupling between the sheath and a detecting electrode, which is portable and detachable, and is composed of quite simple components and its potential dividing ratio is adjustable by a lumped capacitor. The proposed method is inexpensive and easy to measure surge waveforms with reasonable accuracy, and also is applicable to a surge measurement on a live line because of its contactless nature.
