JPS5657968A - Insulation degradation detector - Google Patents

Abstract

PURPOSE: To enable electric discharge detection to be easily performed and enable direct degradation decision to be performed by measuring the sustaining characteristic of the partial electric discharge at the AC application time contributing directly to degradation.

CONSTITUTION: The pulses generated by a starting pulse generator 9 are charged as the starting pulses of a phase regulator 10. The pulses generated by this are led to a surge generator 11. The surge generated causes the secondary side potential of a high voltage transformer 3 to be raised by a pulse transformer 4. In a pulse counter 8, the partial electric discharge pulses which are being still produced from the electric apparatus 5 to be tested with the superposed high voltage pulse annhilation time after superposing of the high-frequency surge on the AC high voltage upon receiving the starting signal from a delay circuit 12 as a starting point are counted. The count number is led to a comparing-discriminating circuit 13, where it is compared with the preset output voltage of a counter 14. The output of the comparing- discriminating circuit 13 is led to a contact signal generator 15 which in turn triggers an alarm 16.

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