Cable Insulation Materials Research Articles

Testing Submergible Power Cables for Oil Well Applications

Abstract A downhole simulator can be used to test oil well power cable, providing results more quickly and economically than can be obtained from field testing. Electrical properties of the cable can be monitored durng the test. Thermal limits can be established. Field degradation mechanisms can be reproduced. TRW uses the facility to evaluate oil well cable designs and to test new cable insulation and protection materials. From this experience, submergible cables have been improved to meet the most severe downhole conditions being encountered throughout the world.

Radiation Resistance of Cable Insulating Materials for Nuclear Power Generating Stations

The radiation resistance of sixteen types of representative rubber and plastic materials for cable insulation was studied. The endurance of some crosslinked polymers under the combined environment of thermal aging-radiation-steam (high temperature) was also examined in relation to the chlorine contents of the base polymer and additives (antioxidant, vulcanizers, etc.). Crosslinked polyethylene insulation and polyvinylchloride jacket cables were tested by the IEEE Std. -383 method. The results showed that those cables were not satisfactory under loss of coolant accident (LOCA) simulating conditions. The cables utilizing EP rubber insulation and special chloroprene jacket have been found to pass the IEEE-383 test.

Classification and Standardization of Cables and Limiters for Secondary Network Systems

As useful information for the proper operation of secondary network systems, the Limiter Task Group has prepared the information given in the Appendix. The temperature classification test procedure (current-loading test) provides the means for classifying a combination of cable insulation and sheath material as to its "damage temperature" for operation with limiters. Numerous insulation and sheath combinations have been classified by this procedure and the standard classes L260 and L220 have been adopted for those combinations of insulation and sheath whose damage temperatures are at least 260 C and 220 C respectively. Included in the L260 class are the mineral-base and GR-S rubber insulations of the RH-RW type with neoprene sheath and in the L220 class are the oil-base and butylrubber ozone-resistant insulation with neoprene sheath. A simple oven test has been devised for preliminary testing and initial comparisons, before final classification by the current-loading test. Insulation-damage curves for the operation of cable in duct, have been adopted for 4/ 0 through 1,000-MCM cable of the L260 class, and tentatively adopted for 4/0 cable of the L220 class. For proper co-ordination with the L260 class of cable, the time-current characteristics of the present limiters have been adopted as standard for the L260 class of limiters. For the L220 class, the time-current curve for the 4/0 L220 limiter, has been tentatively adopted. The limiter has been found to be very effective in preventing smoke, fire, explosion, and the spread of damage that might result from roasting of cable insulation.