A survey of industry practices regarding shielding of substationsagainst direct lightning strokes

Results of a survey of industry practices regarding shielding of substations against direct lightning strokes are presented and analyzed. The survey is based on responses from 114 companies, including consultants and utilities both from within and from outside North America. The survey identifies the shielding design methods in use, the factors affecting the selection of a shielding method, the shielding design criteria and the governing factors, the performance of the different shielding methods and miscellaneous related aspects. The survey revealed a large number (35) of shielding failure incidents; 34 occurred in systems designed using either the fixed-shielding angle method or Wagner's 1942 method