Lightning Protection of Rotating Machines Directly Connected to Overhead Lines

Recommendations for lightning protection of rotating machines are presented. To protect the machine turn insulation, which is of primary interest, capacitors are placed at the machine and arresters out on the line. Minimum separation distances between the machine and most remote arresters are given for each machine voltage class. Variables are effectively or noneffectively grounded systems, ground resistance, expulsion or valve arresters, and use of overhead ground wire.