Transformer Neutral Grounding Resistor(MRD-NGRs)
Transformer Neutral Grounding Resistor Standards Carried Out:
1.DL/780-2001 Neutral Grounding Resistance in Power Distribution
2.GB6450 Dry-Type Power Transformer
3.DL/T620-1997 Overvoltage Protection and Insulation Co-ordination of AC Electrical Equipments
4.GB/T16927-1997 Experimental Technique of High Voltage
5.GB1208-1997 Current Transformer
6.GB4208-93 Shell Protection Grade (IP code)
7.IEEE32-1972 Standard Technique, Terms and Experiment of Neutral Grounding Device
8.GB311.1-1997 Insulation Co-ordination of Transmissional and Distributed Device of High Voltage.
9.DL/T593-1996 Common Specifications for Purchasing High Voltage Switch Equipment.
10.GB50150-1991 Electrical Equipment’s Hand-over and Test Standard of Electrical Device Installation Project.
Operation Conditions
1. Mostly applied outdoor in system of 50Hz and 60Hz
2. Max Altitude is 3500m. Because of high altitude and bad thermal discharging in plateau, please indicate in order if in this situation.
3. Ambient Temp is between -20°C~+70°C and relative humidity does not excess 95%.
4. Wind pressure does not excess 700Mpa (equivalent to 34m/s)
5. Earthquake intensity is less than 8 degree.
6. Thickness of ice coverage is less than 10mm
7. Air dusty grade is not higher than IV grade
8. No corrosive or explosive gas and conductive dust around installation site.
9. As the resistor is a heat generating component, it should be installed in place with some space left around, and be away from heat source.
Notice for purchase
1. system 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