Deterioration diagnosis of the passing years items

Deterioration diagnosis of the passing years items

This corporation has many aged deterioration circumstances by obtaining the cooperation of the electric power companies, concerning the Neutral Grounding Resistors, by local samples extraction. Following things were noted from the results.


Resistance value
    ・・・・・・Many items were over regulation value in the past fifteen years.
Insulation resistance value
     ・・・・・The insulation resistance value begins to fallby the passing years for 20 years.
Over case
    ・・・・・・Board thickness becomes the 1/3~1/4 by the passing years for 20 years.
Internal insulator(mica etc...)
    ・・・・・・Exfoliation, etc.inside insulation material occurs by the passing years for 20 years.
Screw tightening torque
    ・・・・・・An extreme decline starts with the passing years for 20 years.

Many the specification items of the resistors exceed the approved values from the results above with secular 20 year as a boundary and is judged as temporary life limit.


We recommend you to have a degradation check we put into effect by all means, when the usage characteristic which is abnormal measure of equipment of electric transmission and transformation installation is considered because progressing deterioration can be seen not only through twenty years of operating condition.

Other resistors for the electric power are as below.

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