Abstract
Tracking has been defined as the formation of a carbonized conducting path across the surface of an insulating material between electrodes maintained at a potential difference.
In Japan, polyvinyl chloride resin is widely used as an insulation for distribution cable (F-cable) in the home runs. The F-cable would sometimes be ignited by an arc which occurs between deposited carbon caused by heat of a scintillation discharge and electric wire under conditions of moisture, salt fog or dust.
There has been many recent studies of protection method of electric ignition caused by tracking failure on F-cable, however, no satisfactory solutions seem available as yet.
In this paper, in order to develop the electric protection system which makes a correct dia gnosis of tracking trouble at plural precaution lines, the detection equipment which corresponds to tracking trouble at the precaution lines of 8 branch-circuits was designed, and the trial manufacture equipment was proposed as the convenient method. As the same time, in order to evaluate the tracking failure of F-cable, a new evaluation method which integrates the load current and the tracking current with respect to time by using a microcomputer was proposed.
As the results obtained by the responce confirmation test method resembling the IEC (International Electrotechnical Commission) tracking test, the authors confirmed that the present system responded to current signals in the tracking failure under a load or no load. On the other hand, the evaluation method of tracking failure by using the current integration by parts was confirmed as an effectual method for practical use.
