High ampacity, thin-wall, novel polymer cable. Final report
- Foster-Miller, Inc., Waltham, MA (United States)
Utilities are constantly faced with the challenge of providing higher ampacity cables that will fit into existing ducts in the cities. Therefore, a need exists to develop extruded cables that have a thinner insulation than conventional cables to provide the capability of installing higher ampacity cables into existing ducts. The goal of this project was to identify commercially available advanced polymers that are suitable for use in extruded distribution cables. The project consists of three tasks; this report describes the results of these tasks. In Task 1, a literature and vendor survey was conducted to identify candidate insulation materials. The mechanical and electrical properties of the candidates were measured in Task 2, yielding the following experimental results: all of the materials exhibited acceptable tensile strength values. LCP candidates, Vectra and HX6000, and Ultem exhibited very small elongation of less than 10%. Because of their high strength, cables with LCP insulation are too stiff to be bent or reeled at the required insulation thicknesses. This finding eliminated the LCP materials, Vectra and HX6000, from consideration. The dielectric constant of all of the materials was close to or below the benchmark of 3.5 at room temperature. However, the loss factors at 60 Hz of Ultem and PEEK exceeded the criterion of 0.001. Room temperature dielectric strengths of 20 mil thick specimens of Ultem and PEEK and 16 mil films of Aurum were 1600, 1100 and 1400 V/mil respectively. Based on these experimental results, Ultem, PEEK and Aurum, were selected for further evaluations. To reduce the costs and improve the ductility, Aurum and PEEK were blended with 50% and 30% Ultem respectively. The three neat materials and two blends were extruded onto single strand copper conductor at BICC. Three sets of extrusion trials were conducted to improve the quality of the extruded insulation. Although tremendous progress was achieved during the course of the project, voids and thickness non uniformity in the insulation were not completely eliminated. This result clearly indicates that it is possible to manufacture higher ampacity thin wall cables with the candidate insulation materials.
- Research Organization:
- Electric Power Research Inst. (EPRI), Palo Alto, CA (United States); Foster-Miller, Inc., Waltham, MA (United States)
- Sponsoring Organization:
- Electric Power Research Inst., Palo Alto, CA (United States)
- OSTI ID:
- 362504
- Report Number(s):
- EPRI-TR-111888; TRN: AHC29926%%159
- Resource Relation:
- Other Information: PBD: Dec 1998
- Country of Publication:
- United States
- Language:
- English
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