Siemens SIPROTEC 4 7UT6 Series Manual page 375

[webmon-diff-messwertsek-zeig, 1, en_GB]
Figure 3-33
•
Phase angle measurement for measuring location M1 with test current:
Check the phase angle under Measurement values → Secondary → Phase angles of side 1 of the
protected object. All angles are referred to Ι
φ ≈ 0°
L1 M1
φ ≈ 240°
L2 M1
φ ≈ 120°
L3 M1
If the angles are wrong, reverse polarity or swapped phase connections on measuring location M1 may
be the cause.
– Switch off the test source and the protected object (shut down the generator) and earth it.
– Re-check the plant connections to the device and the test arrangement and correct them.
– Repeat test and re-check the current angles.
•
Phase angle measurement for measuring location M2 with test current:
Check the phase angle under measurement values → secondary → phase angles of measuring location
M2 of the protected object. All angles are referred to Ι
Consider that always the currents flowing into the protected object are defined as positive: That means
that, with through-flowing in-phase currents, the currents leaving the protected object at measuring
location M2, have reversed polarity (180° phase displacement) against the corresponding in-flowing
currents at measuring location M1.
Exception: With transverse differential protection, the currents of the corresponding phase have equal
phase!
For clockwise phase rotation and without phase displacement, the angles should be approximately:
φ ≈ 180°
L1 M2
φ ≈ 60°
L2 M2
φ ≈ 300°
L3 M2
When measuring across a power transformer, approximately the values according to
SIPROTEC 4, 7UT6x, Manual
C53000-G1176-C230-5, Edition 09.2016
Phasor Diagram of the Secondary Measured Values — Example
.
L1M1
.
L1M1
Mounting and Commissioning
3.3 Commissioning
Table 3-33.
375