Siemens 6MD85, Manual

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Larger Voltage Deviations
[dwistgro-060913-01.vsd, 2, en_US]
Figure 6-126 Actual-Voltage Curve During Larger Control Deviations
(1) Actual voltage outside the bandwidth
(2) The change to a higher tap occurs after T1 and then T2
(3) Actual voltage inside the bandwidth
(4) Actual voltage outside the limit for a fast step down. A fast step down mode is carried out until
the bandwidth is reached.
Fast Step Up Mode and Fast Step Down Mode
The fast step down mode and the fast step up mode allow a quick reaction to abnormal voltage situations.
Figure 6-126 shows such a situation at point (4). A fast step down mode occurs until the bandwidth has been
reached. The tap-position time between 2 consecutive lower adjusting commands results from the following 2
conditions:
•
The completion of a tap change command after the new valid position was detected
•
The measurement time for capturing the new actual voltage
The activity of the fast step down mode and the fast step up mode is displayed with the indications
(_:
14011:308) Fast Step Down active
and
(_:14011:307) Fast Step Up active
.
[losnlruk-090913-01.vsd, 2, en_US]
Figure 6-127 Logic of the Fast Step Down Mode
The fast step up mode works in a similar fashion.
Control Functions
6.9 Voltage Controller
SIPROTEC 5, High-Voltage Bay Controller, Manual 461
C53000-G5040-C015-9, Edition 11.2017