Load Encroachment, Quadrilateral Characteristic Function Activated - ABB REL670 2.2 IEC Applications Manual

Section 8
Impedance protection
8.3.3.8
8.3.3.9
8.3.3.10
232
RFFwPP ≤ ⋅ Z ⋅
1 6 .
load
min
IEC13000276 V1 EN-US
Set the fault resistance coverage RFRwPP and RFRwPE to the same value as in
forward direction, if that suits the application. All this is applicable for all
measuring zones when no Power swing detection function ZMRPSB is activated in
the IED. Use an additional safety margin of approximately 20% in cases when a
ZMRPSB function is activated in the IED, refer to the description of Power swing
detection function ZMRPSB.
Load impedance limitation, with Phase selection with load
encroachment, quadrilateral characteristic function activated
The parameters for shaping of the load encroachment characteristic are found in the
description of Phase selection with load encroachment, quadrilateral characteristic
function (FDPSPDIS).
Setting of minimum operating currents
The operation of Distance protection zone, quadrilateral characteristic (ZMQPDIS)
can be blocked if the magnitude of the currents is below the set value of the
parameter IMinOpPP and IMinOpPE.
The default setting of IMinOpPP and IMinOpPE is 20% of IBase where IBase is
the chosen current for the analogue input channels. The value has been proven in
practice to be suitable in most of the applications. However, there might be
applications where it is necessary to increase the sensitivity by reducing the
minimum operating current down to 10% of IBase. This happens especially in
cases, when the IED serves as a remote back-up protection on series of very long
transmission lines.
Setting IMinOpIN blocks the phase-to-earth loop if 3I
setting of IMinOpIN is 5% of IBase.
The minimum operating fault current is automatically reduced to 75% of its set
value, if the distance protection zone has been set for the operation in reverse
direction.
Directional impedance element for quadrilateral characteristics
The evaluation of the directionality takes place in Directional impedance
quadrilateral function ZDRDIR. Equation
that the fault is in forward direction for phase-to-earth fault and phase-to-phase
fault.
R
 
1
∂ − ⋅ ∂
cos sin
 
X
 
1
146 and equation
1MRK 506 369-UEN B
(Equation 145)
<IMinOpIN. The default
0
147 are used to classify
Line distance protection REL670 2.2 IEC
Application manual
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