Setting Of Characteristic - ABB REL650 Applications Manual

Section 6
Impedance protection
6.1.3.2
130
The following basics should be considered, depending on application, when doing the
setting calculations:
• Errors introduced by current and voltage instrument transformers, particularly under
transient conditions.
• Inaccuracies in the line zero-sequence impedance data, and their effect on the
calculated value of the ground-return compensation factor.
• The effect of infeed between the IED and the fault location, including the influence
of different Z /Z ratios of the various sources.
0 1
• The phase impedance of non transposed lines is not identical for all fault loops. The
difference between the impedances for different phase-to-ground loops can be as
large as 5-10% of the total line impedance.
• The effect of a load transfer between the terminals of the protected line, the fault
resistance is considerable and the effect must be recognized.
• Zero-sequence mutual coupling from parallel lines.
The setting values of all parameters that belong to ZQMPDIS (21) must correspond to the
parameters of the protected line and be coordinated to the selectivity plan for the network.
Use different setting groups for the cases when the parallel line is in operation, out of
service and not grounded and out of service and grounded in both ends. In this way it is
possible to optimize the settings for each system condition.
It is recommended to set CvtFltr to Enabled on lines with CVT to prevent CVT transients
KNMag and KNAng are the ground compensation settings for zone 2 to zone 5. For zone
1 this can be set separately in zone 1 settings.
GlobalBaseSel: Selects the global base value group used by the function to define (IBase),
(VBase) and (SBase).

Setting of characteristic

In five zone distance protection, quadrilateral and mho characteristic (ZQMPDIS, 21), the
following characteristics for phase to phase and phase to ground faults are possible:
• Quadrilateral characteristic
• Mho characteristic
• Combined quadrilateral and mho characteristic
Based on the application and type of faults separate characteristic for phase to phase and
phase to ground loops of each of the 5 zones can be set.
1MRK 506 334-UUS A
Application manual