Applications of magnetic coaxial pipe to current detection

Basic characteristics and applications of magnetic coaxial pipe to current detection are described in this paper. Skin and proximity effect in the pipe with tape-wound structure are discussed. Amorphous tape wound pipe exhibits very good performance for current detection at over several tens of kHz. A new ground fault detector is also developed by using a coaxial pipe in power line. A relay system using the detector breaked the line within 42ms, which is practically enough to protect the power line.