FAULT CURRENT CALCULATIONS AND RELAY SETTINGFull description
FAULT CURRENT CALCULATIONS AND RELAY SETTINGDescription complète
Training Electrical protection
board notes class xii
geologi struktur
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FAULT CODESDescripción completa
AB 330 SYSTEMs FAILUR PROCEDUREFull description
Guide For Fault Analysis
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GOOD
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A
FAULT CURRENT CALCULATION FOR HT (UP TO NEAREST MOTOR TERMINAL FROM SOURCE)
1
FAULT CURRENT CURRENT AT 33KV AT 33KV SWITCHGEAR SWITCHGEAR AT AT APTRANSCO APTRANSCO END
1.1
Calculati Calculation on for source source impedance impedance (Zo) System Voltage (KV)
=
33
Sorce Fault MVA
=
500
Source Impedance (Z0) in Ohm
=
ZO
1.2 1.2
Faul Faultt Curr Curren entt at 33KV 33KV Swit Switch chge gear ar at APTR APTRAN ANSC SCO O End End (IF0 (IF0))
IFO
KV MVA 2
System KV Short Circuit MVA
ohm
=
Square (33) 500
ohm
=
2.178
ohm
=
1.1 1.1 X KV √ 3 √ 3 X ZO
kA
=
1.1 x 33 √ 3 X 2.178
kA
=
9.62
kA
2
FAULT CURRENT CURRENT AT 33KV AT 33KV SWITCHGEAR SWITCHGEAR AT AT PROPOSED PROPOSED SUBSTATI SUBSTATION ON
2.1
Main Incoming power supply through 33kV, 1R X 3C X 300Sq.mm. Aluminium armoured Cable from APTRANSCO Substation to Plant Substation Resistanc e of cab le le ( R ) (Resistance / Km) = ohm/Km 0.130 Length of Cable (L)
=
No.of Run (N)
=
1
No.
=
RxL (N x 1000)
ohm
=
0.195
ohm
Actual Resistance of Cable (Ra) Ra
2.2
Reactance of cable (X) (Reactance/Km)
=
Actual Reactance of Cable (Xa) Xa
2.3
Impedance of Cable (Za) Za
2.4
Tota Totall Impe Impeda danc ncee at 33KV 33KV SWGR SWGR at Subs Substa tati tion on‐1 ‐1(Z (Z1) 1)
2.5 2.5
Faul Faultt Curr Curren entt at 33KV 33KV SWGR SWGR at Prop Propos osed ed Subs Substa tati tion on (IF1 (IF1))
Z1
1500
0.100
Meter
ohm/Km
=
XxL (N x 1000)
ohm
=
0.150
ohm
=
√(Ra2 + Xa2)
ohm
=
0.2460
ohm
=
Za + Zo
=
2.425
=
1.1 1.1 X KV 3 X Z1
ohm
kA
( 1.1 X 33) (√ 3 X 2.425)
kA
8.643
kA
Selected Fault KA at 33KV Bus IF1
3
=
25 kA
FAULT CURRENT CURRENT AT PRIMARY AT PRIMARY OF OF 8MVA, 8MVA, 33/6.9KV TRANSFORMER 33/6.9KV TRANSFORMER AT PROPOSED AT PROPOSED SUBSTATI SUBSTATION ON
33KV, 1R X 3C X 300Sqmm (E) Aluminium armoured armoured Cable is connected between 33KV HT Panel & 8 MVA Transformer 3.1
Resistance of cable (Resistance / Km)
=
Length of Cable (L)
=
No.of Run (N)
=
1
No.
=
RxL (N x 1000)
ohm
=
0.00325
ohm
Actual Resistance of Cable (Rb) Rb
3.2
Reactance of cable (X) (Reactance/Km)
=
Actual Reactance of Cable (Xb) Xb
3.3
Impedance of Cable (Zb)
25
0.130
0.100
ohm/km Meter
ohm/Km
=
XxL (N x 1000)
ohm
=
0.0025
ohm
=
√(Rb2 + Xb2)
ohm
Zb
3.4
Tota Totall Imp Impedan edance ce at 33KV 33KV SWGR SWGR at Subs Substa tati tioon‐1 n‐1(Z1 (Z1) Z2
3.5 3.5
Faul Faultt Curr Curren entt at 33KV 33KV SWGR SWGR at Prop Propos osed ed Subs Substa tati tion on (IF1 (IF1))
IF2
4
=
0.0041
ohm
=
Zb + Z1
ohm
=
2.430
ohm
=
1.1 1.1 X KV 3 X Z2
kA
=
( 1.1 X 0.15) (√ 3 X 2.43)
kA
=
8.625
kA
FAULT CURRENT CURRENT AT AT SECONDARY OF SECONDARY OF 8MVA 8MVA TRANSFORMER AT SUBSTATION SUBSTATION Power Transformer 8MVA, 33/6.6 KV , 8.35% Impedance (as per IS‐2026)
4.1
4.2
Primary Voltage of Transformer
Vp
=
33
KV
Secondary Voltage of Transformer
Vs
=
6.6
KV
Transformer Capacity
=
8000
KVA
% Impedance
=
8.35
%
Transform Transformer er Impedance Impedance (Zc)
= Zc
= (8.35/100) x 6.6) (8000/1000)
2
Zc
=
ohm
Total Impedanc e on secondary side (Z3 )
Z3
4.3 4.3
(% Imp/100) x KVs2 ohm (KVA / 1000)
Faul Faultt Curr Curren entt at Seco Second ndar aryy side side of 8MVA 8MVA Tran Transf sfor orme mer( r(IF IF3) 3)
