MRD-FD High Resistance Neutral Grounding Resistor (NGR)
There are several high resistance grounding (HRG) solutions, but a preferred choice is the combination of high resistance earthing resistor and single phase grounding transformer. Given this, our MRD-FD high resistance neutral grounding resistor (NGR) is especially designed and meticulously crafted to meet customer needs.
Advantage
1. This power resistor is utilized to reduce fault ground current, thus protecting stator winding and associated equipment of a generator from damage, and cutting down transient overvoltage of arcing ground fault at the same time.
2. Our neutral earthing resistor is equipped with single-phase, dry-type grounding transformer, resistor, disconnect switch, lightning arrester and other electrical components. So, it can be conveniently installed close to the neutral point of a generator as a whole.
3. The high resistance neutral grounding resistor is small and lightweight, while the grounding transformer, with little partial discharge, shows good resistance to flame and electrical surge. In addition, the resistor element is fabricated from special materials so as to ensure its stable performance.
- Resistor Element
- Schematic
| Rated capacity of generator (MW) | 100 | 125 | 200 (300) | 600 | 1000 | ||||
| Nominal voltage of generator (kV) | 10.5 | 13.8 | 15.75 | 18 | 20 | 20 | 24 | 24 | 27 |
| Max. capacitive current of single phase ground fault (A) | 4 | 5 | 6 | 8 | 10 | ||||
| Primary voltage of grounding transformer (kV) | (10.5) 10.5/√3 | (13.8) 13.8/√3 | (15.75) 15.75/ √3 | (18) 18/√3 | (20) 20/ √3 | (20) 20/ √3 | (24) 24/ √3 | (24) 24/ √3 | (27) 27/ √3 |
| Secondary voltage of grounding transformer (kV) | 0.22 | 0.22 | 0.22 | 0.22 | 0.22 | ||||
| Rated capacity of grounding transformer (KVA) | 30 | 30 | 50 | 50 | 63 | ||||
| Resistance at secondary side (Ω) | (0.35) 1.0 | (0.3) 0.8 | (0.2) 0.5 | (0.18) 0.4 | (0.15) 0.3 | ||||
| Ground protection voltage (kV) | (0.173) 0.1 | (0.173) 0.1 | (0.173) 0.1 | (0.173) 0.1 | (0.173) 0.1 | ||||
If the above technical parameters don't fit your demand, or you need more accurate data, please contact us directly. We will calculate the parameter according to your specific application demands.
Operating Condition
1. Mostly indoor applications
2. System frequency: 50Hz or 60Hz
3. Altitude: Not over 3500m (Please specify when ordering because high elevation leads to poor heat dissipation)
4. Ambient condition: -20℃~ 70℃, 95%RH at the most
5. Wind pressure: Not over 700MPa (equals to wind speed of 34m/s)
6. Seismic intensity: Lower than Class VIII as demonstrated by the China Seismic Intensity Scale
7. Environmental pollution level: Class IV or lower
8. Surroundings: No flammable or explosive objects, no corrosive gas or conductive dust
9. Our high resistance neutral grounding resistor will generate heat during work, thus leading to a big temperature rise. So, there should be certain space around our product during installation and operation.
Ordering Instruction
The following information is required when ordering our high resistance neutral grounding resistors.
1. Generator voltage
2. Grounding transformer ratio and resistance value
3. CT ratio
4. Wiring incoming and outgoing mode
5. Max. time on
6. Enclosure: Material, IP rating, color code and installation site
