[dwphicor-171012-01.tif, 2, en_US]
Figure 6-128
Turning the Direction-Characteristic Curves with Cos φ Measurement with Angle Correction
If you set the Dir. measuring method parameter to sin φ and the φ correction parameter to 0, the
symmetry axis of the direction-characteristic curve coincides with the 3I0active axis and the V0 axis. Since the
portion of the current vertical to the direction-characteristic curve (= axis of symmetry) is decisive (3l0dir.),
here, the current 3l0reactive is included in the direction determination. If the current 3l0dir. (here = 3I0reac-
tive) exceeds the negative setting value Min.polar.3I0> for dir.det., the direction is forward. If the
current 3l0dir. exceeds the positive setting value, the direction is backward. In the range in between, the
direction is undetermined.
This direction measurement thus is appropriate for the determination of ground-fault direction in isolated
systems.
Protection and Automation Functions
6.15 Sensitive Ground-Fault Detection
572 SIPROTEC 5, Overcurrent Protection, Manual
C53000-G5040-C017-8, Edition 07.2017
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