Application - ABB RELION 620 Series Technical Manual

Section 10
Recording functions
10.2.5
788
Table 569: protection relay voltage and current phasor identification
FLTLOOP
AG Fault
BG Faul
CG Fault
ABG Fault
BCG Fault
CAG Fault
ABCG Fault
AB Fault
BC Fault
CA Fault
ABC Fault
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
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.

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.
Current phasor
I_A 1)
1)
I_B
I_C 1)
(I_A - I_B)
(I_B - I_C)
(I_C - I_A)
I_A
(I_A - I_B)
(I_B - I_C)
(I_C - I_A)
I_A
1MAC504801-IB E
Voltage phasor
V_A
V_B
V_C
(V_A - V_B)
(V_B - V_C)
(V_C - V_A)
V_A
(V_A - V_B)
(V_B - V_C)
(V_C - V_A)
V_A
Table 569.
620 series ANSI
Technical Manual