Impedance Characteristic - ABB Relion 670 Series Technical Reference Manual

Section 6
Impedance protection
6.9.2.2
306
A-G B-G
A-G B-G
A-G B-G
A-G B-G
A-G B-G
A-G B-G
ANSI05000458 V2 EN
Figure 157: The different measuring loops at phase-to-ground fault and phase-to-
phase fault.
The use of full scheme technique gives faster operation time compared to switched
schemes which mostly uses a pickup of an overreaching element to select correct
voltages and current depending on fault type. Each distance protection zone performs
like one independent distance protection IED with six measuring elements.

Impedance characteristic

The distance measuring zone includes six impedance measuring loops; three intended
for phase-to-ground faults, and three intended for phase-to-phase as well as, three-
phase faults.
The distance measuring zone will essentially operate according to the non-directional
impedance characteristics presented in figure
characteristic is illustrated with the full loop reach while the phase-to-phase
characteristic presents the per phase reach.
C-G A- B
C-G
A- B
A- B
C-G
C-G A- B
C-G A- B
C-G A- B
75 and figure 76. The phase-to-ground
1MRK505222-UUS C
Zone 1
B - C C-A
Zone 2
B -C C- A
Zone 3
B-C C -A
Zone 4
B-C C -A
Zone 5
B -C C -A
Zone 6
B - C C-A
ANSI05000458-2-en.vsd
Technical reference manual