ABB Relion 670 Series Technical Reference Manual page 232

Section 6
Impedance protection
226
The outline of the characteristic is presented in figure 105. As illustrated, the resistive
blinders are set individually in forward and reverse direction while the angle of the
sector is the same in all four quadrants.
LdAngle
LdAngle
RLdRev
ANSI05000196 V1 EN
Figure 105: Characteristic of load encroachment function
The influence of load encroachment function on the operation characteristic is
dependent on the chosen operation mode of FDPSPDIS (21) function. When output
signal PHSELZ is selected, the characteristic for FDPSPDIS (21) (and also zone
measurement depending on settings) will be reduced by the load encroachment
characteristic (see figure 106, left illustration).
When output signal DLECND is selected, the operation characteristic will be as the
right illustration in figure 106. The reach will in this case be limit by the minimum
operation current and the distance measuring zones.
X
RLdFwd
LdAngle
LdAngle
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Technical reference manual