ABB Relion 670 series, Technical Reference Manual

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R
X
Distance measuring zone
Phase selection
”Quadrilateral” zone
IEC09000049-1-en.vsd
) / ( phase
W
) / ( phase
W
IEC09000049 V1 EN
Figure 108: Operating characteristic for FDPSPDIS (21) in forward direction for
three-phase fault, ohm/phase domain
The result from rotation of the load characteristic at a fault between two phases is
presented in fig
109 . Since the load characteristic is based on the same measurement as
the quadrilateral characteristic, it will rotate with the quadrilateral characteristic
clockwise by 30 degrees when subject to a pure phase-to-phase fault. At the same time
the characteristic will "shrink" by 2/√3, from the full
RLdFw and RLdRv reach, which
is valid at load or three-phase fault.
1MRK505222-UUS C
Section 6
Impedance protection
229
Technical reference manual