High voltage testing of an ROV electro-optical tether cable

Insulation life testing of an ROV tether cable was recently performed by MBARI and WHOI in cooperation with PCC and CTL. The testing was undertaken to determine whether higher cable operating voltages were possible for future ROV system designs and upgrades. The tests were performed on field-aged samples of 17.3 mm (0.68") steel armored electrooptical tow cable used in small, deep ROV systems such as MBARI's Tiburon and VMOI's JASON. The test results indicate that the cable is capable of long-term operation at higher voltages than presently used with these systems. Design work is now proceeding to incorporate this data into improvements in the power capacity of these vehicles. The paper reviews the basic architecture of ROV power transmission systems, discusses the factors affecting the insulation voltage stress, describes the cable test methods, and reports the results of the tests.