how to calculate the ngr capacity(nutral grounding resistor)

Answer Posted / raghavendran.r

As far I know the formula is Rngr = Vln/Ig.

where Ig is the current flowing through the Neutral Grounding resistor(let through fault current), which depends upon the type of system you haver chosen, i.e High impedance grounding or Low resistance earthing.

The let through ground fault current through the neutral is low for High resistance earthing and its High for low resistance earthing.

But the important condition is that the let through fault current should be greater than the system capacitive charging current to avoid transient over voltage.

Is This Answer Correct ?    2 Yes 1 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

what happend to DC shunt motor if its field winding insulation becomes slightly weak? will that motor can run on full load or not explain in detail. thanks

1167


what about SAP/MRP regarding manufacturing of electric motors and all drives?

1583


As per standard, transformer body earthing and other Equipment earthing (Equipment earthing) did not connect. but in LT side termination we are doing metal glanding in both side Transformer to PCC Panel through armoured cable, now X'mer body earthing and PCC Pane earthing (Equipment earthing) both are connect.is this safe for X'mer or other equipment?

1195


specific difference of ICT&Auto Transformer

1378


How to prepare electrical preventive maintenance plan & shedule of machine tools in manufacturing unit.

1714






How to Decide the Location of Earth pit for Compressor in Oil Depo? and How to measure the resistance of earth pit Pls explain me with the help of Circuit Diagram?

1915


How convergengr of nr method is not dependent on selection of slack bus and how gauss siedel method depends?

1340


can some one clearly explain why -48 volt DC use in telecom site????

1224


what is the difference between earth leakage and earth fault?

1740


does buccholz in a transformer use batteries

3922


Difference between low impedance and high impedance Restricted Earth Fault

2630


Importance of fault current in power transformers and how to monitor the same? How is it different from winding temperature?

1327


Earth bits close or open. Which is correct

1315


I HAVE A INCOMING 100A MCCB TPN 25KA, CABLE LENGHT OF 80M 70MM CABLE SIZE FROM MAIN SUBBOARD TO NEW DB.BASE ON THE FAULT LEVEL SETTING OF 45KA.I WOULD LIKE TO FIND OUT 25KA ENOUGH KA. APPRECIATE IF SOMEBODY CAN ASSIST ME WITH FORMULA FOR THIS. FRM: JEFF

3516


What are the advantages and disadvantages of short-pitched winding?

602