抄録
Since ceramics resistor type NGR (Neutral Grounding Resistor) have been developed as new materials for power equipment, about 15 years have been passed. This paper describes cumulative application records of ceramics resistor type SFe gas insulated NGR and typical construction of 22 kV, 66 kV, 110 kV NOR, and monitoring methods measuring residual leakage current of 110 kV NGR depending on neutral unbalance voltage of power transformers and using thermal detection devices of ceramics resistors of 66 kV NOR.
