Short-Circuit AnalysisIEC Standard
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC
CORTO CIRCUITO
Estndar de ANSI/IEEE & IEC. Anlisis de fallas transitorias (IEC 61363). Efecto de Arco (NFPA 70E 2000)
Caractersticas principales:
Efecto de Arco (NFPA 70E-2000) Integrado con coordinacin de dispositivos de proteccin. Evaluacin automtica de dispositivos.
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 2
HUBUNG SINGKAT STANDARD IEC
Purpose of Short-Circuit Studies
A Short-Circuit Study can be used to determine any or all of the following:
Verify protective device close and latch capability
Verify protective device interrupting capability
Protect equipment from large mechanical forces (maximum fault kA)
I2t protection for equipment (thermal stress)
Selecting ratings or settings for relay coordination
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 3
Types of Short-Circuit Faults
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 4
HUBUNG SINGKAT STANDARD IEC
Types of SC FaultsThree-Phase Ungrounded FaultThree-Phase Grounded FaultPhase to Phase Ungrounded FaultPhase to Phase Grounded FaultPhase to Ground Fault
Types of Short-Circuit Faults
Fault CurrentIL-G can range in utility systems from a few percent to possibly 115 % ( if Xo < X1 ) of I3-phase (85% of all faults).In industrial systems the situation IL-G > I3-phase is rare. Typically IL-G .87 * I3-phase In an industrial system, the three-phase fault condition is frequently the only one considered, since this type of fault generally results in Maximum current.
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 5
Short-Circuit Phenomenon
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 6
)tSin(Vmv(t) +=i(t)v(t)
HUBUNG SINGKAT STANDARD IEC
i(t)v(t)
(1) ) t Sin(Vmdtdi L Riv(t) +=+=
expression following theyields 1equation Solving
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 7
Offset) (DC
TransientState Steady
t) - sin(
ZVm ) - tsin(
ZVmi(t)
LR-e
++=
AC Current (Symmetrical) with No AC Decay
DC Current
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 8
HUBUNG SINGKAT STANDARD IEC
AC Fault Current Including the DC Offset (No AC Decay)
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 9
Machine Reactance ( = L I )
AC Decay Current
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 10
HUBUNG SINGKAT STANDARD IEC
Fault Current Including AC & DC Decay
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 11
IEC Short-Circuit Calculation (IEC 909)
Initial Symmetrical Short-Circuit Current (I"k)
Peak Short-Circuit Current (ip)
Symmetrical Short-Circuit Breaking Current (Ib)
Steady-State Short-Circuit Current (Ik)
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 12
HUBUNG SINGKAT STANDARD IEC
IEC Short-Circuit Calculation Method
Ik = Equivalent V @ fault location divided by equivalent Z
Equivalent V is based bus nominal kV and c factor
XFMR and machine Z adjusted based on cmax, component Z & operating conditions
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 13
Transformer Z Adjustment
KT -- Network XFMR
KS,KSO Unit XFMR for faults on system side
KT,S,KT,SO Unit XFMR for faults in auxiliary system, not between Gen & XFMR
K=1 Unit XFMR for faults between Gen & XFMR
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 14
HUBUNG SINGKAT STANDARD IEC
Syn Machine Z Adjustment
KG Synchronous machine w/o unit XFMR
KS,KSO With unit XFMR for faults on system side
KG,S,KG,SO With unit XFMR for faults in auxiliary system, including points between Gen & XFMR
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 15
Types of Short-Circuits
Near-To-Generator Short-Circuit
This is a short-circuit condition to which at least one synchronous machine contributes aThis is a short circuit condition to which at least one synchronous machine contributes a prospective initial short-circuit current which is more than twice the generators rated current, or a short-circuit condition to which synchronous and asynchronous motors contribute more than 5% of the initial symmetrical short-circuit current ( I"k) without motors.
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 16
HUBUNG SINGKAT STANDARD IEC
Near-To-Generator Short-Circuit
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 17
Types of Short-Circuits
Far-From-Generator Short-Circuit
This is a short circuit condition during which the magnitude of the symmetrical ac component of This is a short-circuit condition during which the magnitude of the symmetrical ac component of available short-circuit current remains essentially constant.
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 18
HUBUNG SINGKAT STANDARD IEC
Far-From-Generator Short-Circuit
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 19
Factors Used in If Calc
calc ip based on Ik
calc ib for near-to-gen & not meshed network
q calc induction machine i for near to gen & not meshed network q calc induction machine ib for near-to-gen & not meshed network
Equation (75) of Std 60909-0, adjusting Ik for near-to-gen & meshed network
min & max calc ik
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 20
HUBUNG SINGKAT STANDARD IEC
IEC Short-Circuit Study Case
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 21
Types of Short-Circuits
When these options are selected
Maximum voltage factor is used
Minimum impedance is used (all negative tolerances are applied and minimum resistance temperature is considered)
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 22
HUBUNG SINGKAT STANDARD IEC
Types of Short-Circuits
When this option is selected
Minimum voltage factor is used
Maximum impedance is used (all positive tolerances are applied and maximum resistance temperature is considered)
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 23
Voltage Factor (c)
Ratio between equivalent voltage & nominal voltage
Required to account for:
Variations due to time & place
Transformer taps
Static loads & capacitances
Generator & motor subtransient behavior
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 24
HUBUNG SINGKAT STANDARD IEC
Calculation Method
Breaking kA is more conservative if the option No Motor Decay is selected
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 25
IEC SC 909 Calculation
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 26
HUBUNG SINGKAT STANDARD IEC
Device Duty Comparison
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 27
Mesh & Non-Mesh If
ETAP automatically determines mesh & non-meshed contributions according to individual contributions
IEC Short Circuit Mesh Determination Method 0, 1, or 2 (default), , ( )
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 28
HUBUNG SINGKAT STANDARD IEC
LL--G FaultsG Faults
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 29
Symmetrical Components
L-G Faults
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 30
HUBUNG SINGKAT STANDARD IEC
Sequence Networks
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 31
L-G Fault Sequence Network Connections
ZZZV3I
I3I
021
efaultPrf
af 0
++
=
=
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 32
0=gZif
HUBUNG SINGKAT STANDARD IEC
L-L Fault Sequence Network Connections
21
efaultPrf
aa
ZZV3I
II12
+
=
=
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 33
21
L-L-G Fault Sequence Network Connections
ZZZZZ
VI
I0III
20
201
efaultPrf
aaaa 012
++
=
==++
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 34
0=g Zif
HUBUNG SINGKAT STANDARD IEC
Transformer Zero Sequence Connections
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 35
becan faultsG -Lcase.severemost theisfault phase-3aGenerally
Solid Grounded Devices and L-G Faults
orGeneratorsifcasethebemayThis
I: then trueare conditions thisIf
& : ifgreater
1f3
1021
1.4
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 37
Complete reports that include individual branch contributions for:
L-G Faults
L-L-G Faults
L-L Faults
Unbalanced Faults Display & Reports
One line diagram displa ed res lts that incl de
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 38
One-line diagram displayed results that include:
L-G/L-L-G/L-L fault current contributions
Sequence voltage and currents
Phase Voltages
HUBUNG SINGKAT STANDARD IEC
Total Fault Current Waveform
Transient Fault Current Calculation (IEC 61363)
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 39
Percent DC Current Waveform
Transient Fault Current Calculation (IEC 61363)
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 40
HUBUNG SINGKAT STANDARD IEC
AC Component of Fault Current Waveform
Transient Fault Current Calculation (IEC 61363)
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 41
Top Envelope of Fault Current Waveform
Transient Fault Current Calculation (IEC 61363)
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 42
HUBUNG SINGKAT STANDARD IEC
Top Envelope of Fault Current Waveform
Transient Fault Current Calculation (IEC 61363)
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 43
IEC Transient Fault Current Calculation
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 44
HUBUNG SINGKAT STANDARD IEC
Complete reports that include individual branch contributions for:
L-G Faults
L-L-G Faults
L-L Faults
Unbalanced Faults Display & Reports
One-line diagram displayed results that include:
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 45
g p y
L-G/L-L-G/L-L fault current contributions
Sequence voltage and currents
Phase Voltages
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 46
HUBUNG SINGKAT STANDARD IEC
1996-2009 Operation Technology, Inc. Workshop Notes: Short-Circuit IEC Slide 47
HUBUNG SINGKAT STANDARD IEC