2 V
Comp a 100%
n p
´ D
= ´ ´
´
EQUATION1984-ANSI V1 EN (Equation 431)
where:
•
DV is the deadband setting in percent.
• n denotes the desired number of difference in tap position between the
transformers, that shall give a voltage deviation V
di
which corresponds to the dead-
band setting.
• p is the tap step (in % of transformer nominal voltage).
• a is a safety margin that shall cover component tolerances and other non-linear
measurements at different tap positions (for example, transformer reactances
changes from rated value at the ends of the regulation range). In most cases a
value of a = 1.25 serves well.
This calculation gives a setting of Comp that will always initiate an action (start timer)
when the transformers have n tap positions difference.
OperSimTap: Enabling/disabling the functionality to allow only one transformer at a
time to execute a Lower/Raise command. This setting is applicable only to the
circulating current method, and when enabled, consecutive tap changes of the next
transformer (if required) will be separated with the time delay t2.
OperUsetPar: Enables/disables the use of a common setting for the target voltage VSet.
This setting is applicable only to the circulating current method, and when enabled, a
mean value of the VSet values for the transformers in the same parallel group will be
calculated and used.
OperHoming: Enables/disables the homing function. Applicable for parallel control
with the circulating current method, as well for parallel control with the master-
follower method.
VTmismatch: Setting of the level for activation of the output VTALARM in case the
voltage measurement in one transformer bay deviates to the mean value of all voltage
measurements in the parallel group.
tVTmismatch: Time delay for activation of the output VTALARM.
Section 3 1MRK504116-UUS C
IED application
696
Application manual
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