Generator Neutral Ground Resistor
CONTENTS
1. preface.............................................................................................3
1.1 Selection of Generator Neutral Grounding Mode.........................3
1.2 Generator Grounds via High Resistance.......................................4
2. Brief Introduction to Product..........................................................5
2.1 Scope of Application.....................................................................5
2.2 Operation Environment.................................................................5
3. Product Model Descript ion.............................................................6
3.1 Parameters of Grounding Transformer.........................................6
4. Structure of Complete Device.........................................................7
4.1 Composed Elements.....................................................................7
4.2 Cubicle Outline..............................................................................7
4.3 Recommended Technical Parameters of MRD-FD Type Generator Neutral Resistor................................................................7
5. Installation and Maintenance of Complete Equipment...................9
5.1 Diagram of Installation and Wiring...............................................9
5.2 Precautions on Equipment...........................................................10
6. Ordering Instructions.....................................................................10
7. Cautions of Site Installation..........................................................10
8. Checking and Testing....................................................................12
9. Maintenance..................................................................................13
10. Packaging, Transportation and Storage.......................................14
1. Preface
1.1 Selection of Generator Neutral Grounding Mode
Generator is the driving force in power system, which must have the right ability to respond to sudden failure in operation, to which the mode of generator neutral grounding is closely related.
-solid grounding
-Neutral-point grounding via low-resistance
-Neutral-point ungrounded
-Neutral-point grounding via arc-suppression coil
-Neutral-point grounding via high resistance
Allowable Current Associated with Single-Phase Ground
Of Generator Stator
Generator Nominal Voltage(kV) Generator Nominal Capacity(MW) Allowable Fault Current Value(A)
6.3 ≤50 4
10.5 Steam turbine generators 50~100 3
Water turbine generator 10~100
13.8~15.75 Steam turbine generators 125~200 2
Water turbine generator 40~225
18~20 300~600 1
1.2 Generator Grounds via High Resistance
The generator neutral grounding via high resistance is able to effectively restrain fault current, thereby effectively preventing the stator winding from breaking down, and lowering transient over-voltage associated with arc flash grounding.
There are a number of solutions for neutral point grounding via high resistance, among which, the combination of single-phase grounding transformer with resistor is the best. The MRD-FD grounding type of resistor cabinets produced by our company is of small size and light weight. Grounding transformer is shock-resistant, fire-retardant, and with small size. The resistor is made from special materials, possessing stable performance and strong flowing-through capability.
2. Brief Introduction to Product
2.1 Scope of Application
MRD-FD type neutral ground resistor cabinet is complete equipment specially used by generators in power plant which adopts high-resistance grounding for neutral. The voltage grade for generator mainly ranges from 6kv to 20kv. When one point of the stator grounds, the device is able to limit the grounding current at a reasonable value, and effectively restraint arc flash transient overvoltage associated with single-phase grounding.
2.2 Operation Environment
1,Applies to indoors.
2,Ambient temperature: between -40 and +40 centigrade.
3,The altitude shall not exceed 3000m.
4,Relative humidity be or lower th