Siemens SIPROTEC 4 7UT6 Series Manual page 376

Mounting and Commissioning
3.3 Commissioning
Table 3-33
Protected Object Generator/Motor/
Busbar/Line
Phase Angle ↓
φ 180°
L1M2
φ 60°
L2M2
φ 300°
L3M2
1) Angles are valid if the high voltage side is defined as side 1, otherwise read 360° minus the stated angle
If considerable deviations occur, reversed polarity or swapped phases are expected on measuring location M2
or the actually tested measuring location.
•
Deviation in individual phases indicates reversed polarity in the related phase current connection or acycl-
ically swapped phases.
•
If all phase angles differ by the same value, phase current connections of side 2 are cyclically swapped or
the connection group of the transformer differs from the set group. In the latter case, re-check the
matching parameters (Section
Transformers" under addresses 314 for side 1, 324 and 325 for side 2, 334 and 335 for side 3, etc.
Consider also the assignment of the measuring location to the sides and the sides to the protected
object.
•
If all phase angles differ by 180°, the polarity of the complete CT set for measuring location M2 is incor-
rect. Check and correct the applicable power system data (see Section
margin heading "Current Transformer Data for 3-phase Measuring Locations"):
Address 511 STRPNT->OBJ M1 for measuring location 1,
Address 521 STRPNT->OBJ M2 for measuring location 2, etc.
For 1-phase busbar protection see Section
Transformer Data in Single-phase Busbar Protection".
If connection errors are assumed:
•
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. Check also the
corresponding setting for the CT data.
•
Repeat test and re-check the current angles
All pre-described test must be repeated until every measuring location of the main protected object has been
included in at least one test.
Measuring Differential and Restraint Currents
Before the tests with symmetrical currents are terminated, the differential and restraint currents are exam-
ined. Even if the above tests with symmetrical current should to a large extent have detected connection
errors, errors concerning current matching and vector group can nevertheless not be completely excluded.
The differential and restraint currents are referred to the rated currents of the protected object. This must be
considered when they are compared with the test currents. With more than 2 sides, the highest rated current
of any side of the protected object is the rated object current.
376
Displayed phase angle dependent on the protected object (three-phase)
Transformer with Vector Group Numeral
0 1
180° 150° 120° 90°
60° 30°
300° 270° 240° 210° 180° 150° 120° 90°
2.1.4 Power System Data 1
2 3 4 5 6
60° 30° 0°
0° 330° 300° 270° 240° 210° 180° 150° 120° 90°
under margin heading "Object Data with
2.1.4 Power System Data 1
1)
7 8 9 10
330° 300° 270° 240° 210°
60° 30° 0°
2.1.4 Power System Data 1
under margin heading"Current
SIPROTEC 4, 7UT6x, Manual
C53000-G1176-C230-5, Edition 09.2016
11
330°
under