NGR Neutral Grounding Resistor For Protecting Transformer

.Standards Carried Out:

DL/ 780-2001 Neutral Grounding Resistance in Power Distribution

GB6450 Dry-Type Power Transformer

DL/ T620-1997 Overvoltage Protection and Insulation Co-ordination of AC Electrical Equipments

GB/ T16927-1997 Experimental Technique of High Voltage

GB1208-1997 Current Transformer

GB4208-93 Shell Protection Grade ( IP code)

IEEE32-1972 Standard Technique, Terms and Experiment of Neutral Grounding Device

GB311.1-1997 Insulation Co-ordination of Transmissional and Distributed Device of High Voltage.

DL/ T593-1996 Common Specifications for Purchasing High Voltage Switch Equipment.

GB50150-1991 Electrical Equipment� s Hand-over and Test Standard of Electrical Device Installation Project.

2.Notice for purchas:

1. systm rated voltage

2.short-time withstand current;

3. normal resistance;

4. with current transformer or not; transformation ratio, capacity and compound deviation of the current transformer;

5. method of wiring ( optional) : a. wire in from the top, and out at the bottom, b. wire in and out from the bottom, c. wire in and out from the side, d. wire in from the side and out at the bottom;

6. durable time for short-time withstand current;

7. material of resistance cabinet, protection grade of ( IP) , color code and installation site of the resistor cabinet;

8. with earthing record and temperature and humidity control equipment or not