Effect of UV treatment on the dielectric strength of BOPP capacitor film
The effect of UV treatment on dielectric breakdown strength of metallized biaxially-oriented polypropylene (BOPP) capacitor film was studied. Results from Weibull statistical analysis indicate that an optimal UV exposure level of ~3.4 J/cm2 (200-400 nm) increases the breakdown strength at 1% probability by ~20%. UV spectroscopic analysis indicates that the antioxidant in BOPP was consumed almost entirely. The results suggest that antioxidant remaining in the BOPP after processing may have an unfavorable effect on the breakdown strength of the film
High energy density capacitor development at ABB Power T&D
This paper investigates the fundamentals involved in the manufacture of d.c. metallised film capacitors, namely the choice of base film, impregnant and metallisation pattern. Comparative testing of capacitors during production and on accelerated ageing under thermal and electrical stress enable capacitor life to be enhanced by two orders of magnitude from the optimum selection of film type, impregnant medium and electrode configuration. The relative life increases being: >10/spl times/life time due to film selection; >2/spl times/theoretical life for low loss dielectric liquids; >6/spl times/life for the successful design of metallised film electrodes.
In-House Industrial Production of the Superconducting Conductor for the 43 T Hybrid Magnet of LNCMI-Grenoble
The hybrid magnet being built at LNCMI-Grenoble is based on the combination of resistive inserts, made up of Bitter and polyhelix coils, with a large bore superconducting outsert. It will produce, in the first step, an overall continuous magnetic field of 43 T in a 34 mm warm bore aperture. The superconducting coil will provide a nominal magnetic field of 8.5 T in a 1.1 m cold bore diameter. It relies on the novel development of an Nb-Ti/Cu Rutherford Cable On Conduit Conductor (RCOCC) cooled down to 1.8 K by a bath of superfluid helium pressurized at 1200 mbar. After a brief reminder of the specificity of hybrid magnets, namely the strong electromechanical coupling between resistive and superconducting coils, the main requirements of the RCOCC for efficient and reliable magnet operation are given. The test and validation phases prior to the industrial production of the RCOCC are reported, including the trial production of the ½ hard-drawn (H02 cold-worked) Cu-Ag 0.05% hollow stabilizer in continuous lengths of 325 m. The novelty of the RCOCC development concerns the assembly and the induction soft-soldering of the Rutherford cable on the Cu-Ag hollow stabilizer allowing a strict control of the interstrand contact resistance. Studies, developments, and the integration of the industrial production line at LNCMI-Grenoble are presented together with the result of the production of all RCOCC unit lengths.