Woodward highprotec MRI4, User Manual

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Supervision
Phase Sequence Supervision
The device calculates the phase sequence at each CT and VT (based on positive-sequence and negative-
sequence components). The calculated phase sequence (i. e. „ACB“ or „ABC“) is permanently compared with the
setting that has been made at [Field Para/General Settings]
»Phase Sequence«.
The menu [Operation/Status Display/Supervision/Phase Sequence] contains a specific (warning) signal for each CT
and VT. If the check of a CT / VT finds that the actual phase sequence is different from the setting under [Field
Para] then the respective signal becomes true (active).
The phase sequence supervision is especially useful during commissioning of the device because it helps making
sure that the
»Phase Sequence« setting under [Field Para] is correct
The supervision requires minimum values for the current (in case of a CT), or
for the voltage (in case of a VT, respectively), otherwise the phase sequence
cannot be reliably determined.
•
For a VT: The minimum voltage is 0.1⋅V
n
.
•
For a CT: The minimum current is 0.1⋅I
n
.
596 MRI4 DOK-HB-MRI4-2E