R
X
Distance measuring zone
Directional line
Load encroachment
characteristic
"Phase selection"
"quadrilateral" zone
en05000673.vsd
IEC05000673 V1 EN
Figure 107:
Operating characteristic in forward direction when load encroachment
is activated
is valid for phase-to-ground. During a three-phase fault, or load, when the
quadrilateral phase-to-phase characteristic is subject to enlargement and rotation the
operate area is transformed according to figure
. Notice in particular what happens
with the resistive blinders of the "phase selection" "quadrilateral" zone. Due to the 30-
degree rotation, the angle of the blinder in quadrant one is now 90 degrees instead of
the original 60 degrees. The blinder that is nominally located to quadrant four will at
the same time tilt outwards and increase the resistive reach around the R-axis.
Consequently, it will be more or less necessary to use the load encroachment
characteristic in order to secure a margin to the load impedance.
Section 6
1MRK505222-UUS C
Impedance protection
228
Technical reference manual
Summary of Contents for Relion 670 series
Page 1: ...Relion 670 series Line differential protection RED670 ANSI Technical reference manual...
Page 2: ......
Page 40: ...34...
Page 50: ...44...
Page 60: ...54...
Page 126: ...120...
Page 384: ...378...
Page 496: ...490...
Page 556: ...550...
Page 602: ...596...
Page 620: ...614...
Page 794: ...788...
Page 864: ...858...
Page 988: ...982...
Page 998: ...992...
Page 1084: ...1078...
Page 1164: ...1158...
Page 1168: ...1162...
Page 1220: ...1214...
Page 1230: ...1224...
Page 1231: ...1225...