抄録
This paper describes a method of automatic washing for salt contaminated insulators. An average value of leakage current along the surface of the pilot insulator in a period is detected, for this is a function of the quantity of salt contamination and moisture on the pilot insulator. In each cycle (about 1min. per cycle), the program signals give one by one the instructions on a start and an end of the integration of leakage current, a detection of the integrated value, a stop of the washing action and a reset of the integrator. Here the integrator consists of RC circuit and the detector consists of the silicon controlled rectifier (SCR) whose firing voltage is used as a reference value. If the integrator output proportional to the average value of leakage current rises above the firing voltage of the SCR, a signal of washing is sent to the pump motor or the valve. Then the insulators on line are washed all together during the appointed period.
Finally, by the various experiments this method was proved to have enough accuracy and reliability for practical use. The conclusions are summarized as follows.
(1) An average value of leakage current is justified to be the detecting variable.
(2) The RC circuit used as the integrator is proved to be easy in maintenance.
(3) Because of the fairly short period of the detecting action, the insulator is kept in a sufficiently safe condition under expected environment.
