MR TRAFOGUARD ISM, Operating Instructions Manual

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6 Functions and settings
Maschinenfabrik Reinhausen GmbH 2016 91 5163667/00 EN TRAFOGUARD® ISM®
Determining bandwidth
In order to set the correct value, the transformer's step voltage and nominal
voltage must be known. Note that a large bandwidth will result in a large
control deviation.
The bandwidth must always be greater than the following value:
Figure 77: Calculation of minimum bandwidth
U
n-1
Step voltage of tap position n-1
U
n
Step voltage of tap position n
U
nom
Nominal voltage
The following transformer values are used to determine the minimum band-
width:
Nominal voltage U
nom
= 11,000 V
Step voltage in tap position 4 U
Step4
= 11,275 V
Step voltage in tap position 5 U
Step5
= 11,000 V
Setting the bandwidth
To set the bandwidth, proceed as follows:
1.
Go to Settings > Parameters > Control > Bandwidth .
2. Enter bandwidth.
3. Press the Accept button to save the modified parameter.
Delay time T1
Delay time T1 delays the issuing of a tap-change command for a defined pe-
riod. This prevents unnecessary tap-change operations if the tolerance
bandwidth is exited briefly.
6.2.3