1.INSULATION RESISTANCE MEASUREMENT:
The live terminal of instrument shall be connected to the NGR winding and earth terminal to ground the readings shall be taken 15 seconds and 60 seconds and the ratio called absorption coefficient should be more than 1.3. Other details may be referred to IR measurements of transformer/ reactor.
2. CAPACITANCE AND TAN-δ MEASUREMENT OF BUSHINGS:
Only one bushing is there in NGR. Its capacitance and Tan-δ is measured by same process as used for Reactor i.e. in UST mode. And the value of Tan-δ of this bushing also should not be more than 0.7 %.
3. CAPACITANCE AND TAN-δ MEASUREMENT OF WINDING:
Only one winding is there in NGR. Its capacitance and Tan-δ is measured by same process as used for Reactor i.e. in UST mode. And the value of Tan-δ of this winding also should not be more than 0.7 %.
4.WINDING RESISTANCE MEASUREMENT:
Winding resistance measurement of NGR is done for checking its value is within specified limit or not as given by the manufacturer.
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