Impedance Characteristic; Basic Operation Characteristics - ABB REG650 Technical Manual

Section 6
Impedance protection
6.1.6.2
6.1.6.3
120

Impedance characteristic

The distance function consists of three zones. Each zone is self polarized offset
mho characteristics with reverse offset. The operating characteristic is in
accordance to figure 60.
jx
IEC09000172 V1 EN
Figure 60: Mho, offset mho characteristic
Zone 3 can be equipped with a load encroachment function which cuts off a section
of the characteristic when enabled. The function is activated by setting the
parameter LoadEnchModZ3 to On. Enabling of the load encroachment function
increases the possibility to detect high resistive faults without interfering with the
load impedance. The algorithm for the load encroachment is located in the Load
encroachment (LEPDIS) function, where the relevant settings can be found.
Information about load encroachment from LEPDIS function to zone measurement
is sent via the input signal LDCND in binary format.

Basic operation characteristics

Each impedance zone can be On and Off by setting OpModex (where x is 1-3
depending on selected zone).
The zone reach for phase-to-phase fault is set individually in polar coordinates. The
impedance is set by the parameter ZxFwd and ZxRev and the corresponding
1MRK 502 034-UEN -
Mho, zone3
Mho, zone2
Mho, zone1
R
IEC09000172_1_en.vsd
Technical Manual