Reclassification of askarel transformers-field application and results

In early 1986, Westinghouse Electric Corporation introduced a PCB (polychlorinated biphenyl) reconditioning process which guarantees reclassification of askarel-filled transformers to non-PCB status (below 50 p.p.m.) quickly and with only two short power interruptions. The authors describe the proprietary process, the extensive test program, and field results. Actual case history results are described of in-service askarel transformers, many of which were processed in six months or less and reclassified at levels less than 20 p.p.m. Transformer size, as well as other variables such as loading and internal configuration, may slightly affect processing time. Data also show that leaching was insignificant over two years after reclassification. It is concluded that askarel transformer reconditioning using at least one approved servicing procedure is field-proven and available for fast reclassification with minimum power interruptions, and that for selected PCB applications such reclassification is practical and economically feasible