Characterization of cable insulation materials: Volume 2, Dynamic mechanical spectroscopy studies
- Battelle Columbus Div., OH (United States)
The dynamic mechanical properties of service-aged high molecular weight polyethylene (HMWPE) and cross-linked polyethylene (XLPE) cable insulations were measured. HMWPE and XLPE miniature cable insulations that had been subjected to thermal aging and combined electrical/thermal aging in the laboratory were also studied. Measurements were made as functions of three independent variables -- temperature, frequency, and strain amplitude. Project data show that service aging of HMWPE results in a significant increase in the intensity and value of the alpha transition temperature. The other major transitions, the beta and gamma, did not appear to be significantly affected by service aging. In contrast with HMWPE, the one service-aged XLPE insulation included in the study showed no major trends. Laboratory-aged HMWPE and XLPE materials tended to display a different behavior than their field-aged counterparts. When effects were observed, the beta rather than the alpha transition temperature was primarily affected, suggesting that field-aging and accelerated aging in the laboratory under dry conditions involve different mechanisms. Overall, the data do not clearly satisfy any of the four models relating dynamic mechanical behavior and the morphology of polyethylene. The most satisfactory fit, however, is to a model proposed by Boyd, in which the value and intensity of the alpha transition temperature are ascribed to the degree of tie molecule strain and number of tie molecules present in the system. The report attempts to interpret these results within a familiar context of physical phenomena believed to be of importance in electrical aging. The report also proposes possible explanations for the lack of precise fit to any existing model, and why more satisfactory results were obtained for HMWPE than for XLPE insulations. 23 refs., 39 figs., 3 tabs.
- Research Organization:
- Electric Power Research Inst., Palo Alto, CA (United States); Battelle Columbus Div., OH (United States)
- Sponsoring Organization:
- EPRI; Electric Power Research Inst., Palo Alto, CA (United States)
- OSTI ID:
- 5339942
- Report Number(s):
- EPRI-EL-7076-Vol.2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
ELECTRIC CABLES
ELECTRICAL INSULATION
ELECTRICAL INSULATORS
MECHANICAL PROPERTIES
POLYETHYLENES
AGING
DEFORMATION
DIELECTRIC MATERIALS
ELASTICITY
SPECTROSCOPY
THERMAL TESTING
UNDERGROUND POWER TRANSMISSION
VISCOSITY
CABLES
CONDUCTOR DEVICES
ELECTRICAL EQUIPMENT
EQUIPMENT
MATERIALS
MATERIALS TESTING
NONDESTRUCTIVE TESTING
ORGANIC COMPOUNDS
ORGANIC POLYMERS
POLYMERS
POLYOLEFINS
POWER TRANSMISSION
TENSILE PROPERTIES
TESTING
240301* - Power Transmission Lines & Cables- Power Cables- (1990-)
360603 - Materials- Properties