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IDMTL Operating Time Calculation

Calculation:

Fault Current I 1.00 A NI 0.14 0.02

Current Setting Is 0.10 A VI 13.5 1

Time Multiplier Tm 0.50 EI 80 2

Curve NI LTI 120 1

K 0.14

α 0.02

1.49 Sec.

Created By, N.Thiruvenkadam, Easun Reyrolle Ltd., Hosur

Operating Time

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Over Current Relay Operating Angle for R, Y & B phase (Leadin

Va^+Vb^+Vc^ = 0

Make :characteristic Angle :

RΦ operating angle : 225 To 45

YΦ operating angle : 105 To 285

BΦ operating angle : 345 To 165

Earth Fault Current Relay Operating Angle for R, Y & B phase (

Va^+Vb^+Vc^ = 3Vo

Make :Characteristic Angle :

RΦ operating angle : 45 To 225

YΦ operating angle : 285 To 105

BΦ operating angle : 165 To 345

45

-45

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)

agging)

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At 45 Deg

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100 MVA

Primary Voltage 230 KV

Secondary Voltage 110 V

Primary Current 300 ASecondary Current 1 A

Primary Voltage 110 KV

Secondary Voltage 110 V

Primary Current 300 A

Secondary Current 1 A

5.02%

251.022 A

Full load current in LV side 524.864 A

HV CT Secondary Current 0.837 A

LV CT Secondary Current 1.750 A

ICT for HV Side 1.195

ICT for LV Side 0.572

15.9 A0.2 A0.8 A8.0 A0.20.20.3

Transformer MVA

HV SIDE

LV SIDE

% Imedance for Normal Tap

IR2

Diff Slope

Diff. 2nd Har. Ratio

Diff. 5th Har. Ratio

Full load current in HV side

ID>>

ID>

IR1

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20 MVA

Primary Voltage 33 KV

Secondary Voltage 110 V

Primary Current 1000 ASecondary Current 1 A

NCT Sec. Resistance 6.7 Ohms

Lead Resistance 1 Ohms

Total Resistance 0 Ohms

REF Relay Ct. setting 0.1 A

Primary Voltage 33 KV

Secondary Voltage 110 V

Primary Current 1000 A

Secondary Current 1 A

NCT Sec. Resistance 6.7 OhmsLead Resistance 1 Ohms

Total Resistance 0 Ohms

REF Relay Ct. setting 0.1 A

10.80%

349.909 A

Full load current in LV side 349.909 A

HV CT Secondary Current 0.350 A

LV CT Secondary Current 0.350 A

Base MVA 20 20

Base Voltage 33 33

Base Current 349.909 349.909

Base Impedance 54.450 54.45

Fault Impedance 5.878 5.878

P.U Fault Current 9.263 9.263

Fault Current 3241.101 3241.1009

Fault MVA 185253.80Maximum through current 3.241 3.241

on CT secondary

Voltage Setting in REF 24.956 24.956

5% More 26.204 26.204

REF Resistance 262.043 262.043

Full load current in HV side

Transformer MVA

HV SIDE

LV SIDE

% Imedance for Normal Tap

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FAULT LOCATION:

Full Line length 15 KM

Line reactance 2.623 ΩMeasure Reactance 1.68 Ω

Fault Location 9.607 KM

Error calculation

Texp 40

Tact 30.9error% -22.75

FAULT LOCATION = Meas

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