Three-phase delta submarine cable characteristics

THE RECENT INSTALLATION by the British Columbia Electric Company of a 3-phase delta-connected submarine power cable circuit, in which two of the conductors are single-core cables and the third conductor is the ground path, appears to be an innovation in submarine cable practice. The circuit is laid in the Pacific Ocean from the British Columbia mainland to an island about three miles off shore. The depth of the sea water in the channel is about 800 feet. When the project first was conceived, it was taken more or less for granted that armored 3-conductor cable would be installed, since this type of cable previously had been the conventional choice for submarine power cable work. However, upon detailed analysis it was found that single-conductor cable would have outstanding advantages. These advantages were evident in all three main aspects of the project; namely, the dollar economy of the complete installation, the physical handling of the cable, and the electrical operation of the circuit. The studies made lead to the conclusion that in many submarine installations, the traditional use of 3-conductor cable might well be abandoned in favor of single-conductor cable.