Detecting damaged cables using a preionized gas technique
- Science and Engineering Associates, Inc., Albuquerque, NM (United States)
- Sandia National Labs., Albuquerque, NM (United States)
Because of the difficulty in conducting electrical tests on unshielded cables installed in conduits, experiments were conducted to develop a preionized gas condition monitoring technique to detect localized degradation of installed unshielded cables in conduits. Breakdown testing of various types of damaged and undamaged cables was performed. Other test parameters examined were gas type, position of tie cable with respect to the conduit wall, length of cables, conduit configuration, conduit size, gas propagation in conduits, and other parameters necessary for practical implementation of the technique. The principal conclusion of the test program is that high potential testing of cables in the presence of preionized helium gas provides essentially the same information as high potential testing in water. Using helium requires no greater effort and eliminates the practical disadvantage of using water. A test criterion of 30 kVdc or 10 kVac would detect when 5 mils of insulation remain on one particular tested cable. No undamaged cable was noted to break down at these voltages. A high concentration of helium is required to achieve these results, but this is easily attained with straightforward. AC testing appears preferable to dc testing because of the variability testing. However, dc testing may warrant further investigation because of its inherent advantages. The level of damage that a cable can incur without compromising its functionality in an accident environment has not yet been determined and is a subject of ongoing research.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (United States)
- Sponsoring Organization:
- Electric Power Research Inst., Palo Alto, CA (United States)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 10131125
- Report Number(s):
- SAND--92-2917C; CONF-930254--2; ON: DE93007588
- Country of Publication:
- United States
- Language:
- English
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