Ngr Sizing

Calculation Size Generator Details: Generator Voltage (VL) (L-L) Maximum Over Voltage Frequency

Generator Transformer Details: Transformer Primary Voltage Transformer Seconary Voltage Voltage

Capacitance Per Phase: Generator !ining "a#acitance $ P%ase Generator "onnection "a#acitance $ P%ase Generator Transformer "a#acitance $ P%ase Generator Transformer "onnection "a#acitance $ P%ase Transformer "a&le "a#acitance $ P%ase Surge 'rrestor "a#acitance $ P%ase Ot%er "a#acitance $ P%ase Total Zero Sequence Capacitance (C): Total Zero Sequence Capacitance Reactance to Ground (Xc):

Neutral Earthing Transformer Size: Primary Voltage Voltage of t%e Grouning Transformer (V#) Seconary Voltage of t%e Grouning Transformer (Vs) Turns atio of t%e Grouning Transformer () eutral *art%ing Transformer + eactance (,+) eutral *art%ing Transformer eactance in P (,#u) eutral *art%ing Transformer .ase /V (.v)

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g Transformer (NGR/NET) :Calculate Size of NGR/Neutral Earthing Transformer: P%ase to eutral Voltage (V#0) + of Force fiel conition for eutral *art%ing Transformer  P%ase to eutral Voltage uner Force Fiel "onition (Vf) "a#acitive c%arging current$#%ase (=c) Total Capaciti!e c"ar#in# current ($t) ating of eutral *art%ing Transformer (Pr) eutral *art%ing Transformer overloaing factor  Si%e o& 'eutral art"in# Tran&or*er (+) esiual "a#acitive reactance (,ct) Required Reitance !alue at econdar, ide (Rec) Required Groundin# Reitor !alue at pri*ar, ide (Rp) eutral *art%ing Transformer Seconary "urrent eutral *art%ing Transformer Seconary esistor "urrent (for 35 Secons) eutral *art%ing Transformer eactance .ase(.ase ,)> eutral *art%ing Transformer eactance (,) 'eutral art"in# Tran&or*er X-R Ratio ault current t"rou#" 'eutral (in#le line to #round &ault) ($&)

:Results: Ratin# o& 'eutral art"in# Tran&or*er (+) S%ort time ating of eutral *art%ing Transformer atio of eutral *art%ing Transformer eutral *art%ing Transformer Seconary "urrent equire Grouning esistor value at # rimary sie (#)

Required Reitance at econdar, ide (Rec) eutral *art%ing Transformer Seconary esistor "urrent (for 35 Secons)

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