ABB RER620

Section 4 1MAC309294-MB F
Protection functions
256 RER620
Technical Manual
R1 is positive sequence line resistance in ohm/ (miles or kms) and is provided as a setting
X1 is positive sequence line reactance in ohm/ (miles or kms) and is provided as a setting
R0 is zero sequence line resistance in ohm/ (miles or kms) and is provided as a setting
X0 is zero sequence line reactance in ohm/ (miles or kms) and is provided as a setting
Line Length is the length of the line in the units of kilometers (Km) or miles and is provided
as a setting.
If R1, X1, R0, X0 are given in ohm/mile then the length of the line Line Length should be
given in the unit of miles
If R1, X1, R0, X0 are given in ohm/Km then the length of the line Line Length should be
given in the unit of Km’s.
Table 268 describes what will be the voltage phasor and current phasor under different
fault types.
Table 268: Relay voltage and current phasor identification
* indicates the respective current is ground compensated
Fault location
This module calculates the distance to fault and fault resistance from the voltage phasor
and current phasor selected based on type of the fault (see Table 268).
The algorithm uses the fundamental frequency phasor voltages and currents measured at
the relay terminal before and during the fault.
The algorithm basically is an iterative technique, performs a comparison of the pre fault
load impedance and apparent impedance during the fault, to estimate the distance to fault.
Estimated values of fault resistance, pre fault load impedance and line impedance are then
modified using the correction factors. And the corrected values are used to estimate the
final FLT_DIST and FLT_R.
During the auto-re-closure sequences the fault location is done with initial fault conditions.
FLTLOOP Current phasor Voltage phasor
AG Fault I_A* V_A
BG Fault I_B* V_B
CG Fault I_C* V_C
ABG Fault (I_A - I_B) (V_A - V_B)
BCG Fault (I_B - I_C) (V_B - V_C)
CAG Fault (I_C - I_A) (V_C - V_A)
ABCG Fault I_A V_A
AB Fault (I_A - I_B) (V_A - V_B)
BC Fault (I_B - I_C) (V_B - V_C)
CA Fault (I_C - I_A) (V_C - V_A)
ABC Fault I_A V_A