Low-, medium-, and high-pressure gas-filled cable

After preliminary development work systematic laboratory tests, closely simulating service conditions, were started in 1934 leading towards final development and improvement of gas-filled cable. The first full-size field installation of gas-filled cable was placed in service in 1938. The results of this work up to that time were summarized in an AIEE paper presented at the winter convention, January 1939. The present paper will deal with progress made since then, covering the whole range of voltage ratings from 10 kv to 138 kv, divided as follows: low-pressure gas-filled cable systems 10 kv to 40 kv, operating at gas pressures from 10 to 15 pounds per square inch; medium-pressure systems 40 kv to 69 kv, operating at gas pressures from 24 to 40 pounds per square inch; high-pressure systems 69 kv to 138 kv, operating at gas pressures from 150 to 200 pounds per square inch.