ABB RELION REF615R, Technical Manual

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Table 395: protection relay voltage and current phasor identification
FLTLOOP Current phasor Voltage phasor
AG Fault
I_A
1)
V_A
BG Faul
I_B 1)
V_B
CG Fault
I_C
1)
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
1) indicates the respective current is ground-compensated
Fault location
Fault location calculates the distance to fault and fault resistance from the voltage phasor
and current phasor selected based on the type of the fault
Table 395 .
The algorithm uses the fundamental frequency phasor voltages and currents measured at
the protection relay terminal before and during the fault.
The algorithm basically is an iterative technique that 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
modified using the correction factors. The corrected values are used to estimate the final
FLT_DIST
and
FLT_R
.
During the autoreclosure sequences, the fault location is done with initial fault conditions.
10.2.5 Application
Electrical power system has grown rapidly over the last few decades. This resulted in a
large increase of the number of lines in operation and their total length. These lines
experience faults caused by storms, lightning, snow, freezing rain, insulation breakdown
and short circuits caused by birds and other external objects. In most cases, electrical faults
manifest in mechanical damage, which must be repaired before returning the line to
service. The restoration can be expedited if the location of the fault is either known or can
be expedited with reasonable accuracy.
Section 10
1MRS240050-IB C
Recording functions
530 REF615R
Technical Manual