Siemens 7UT51 Instruction Manual page 12

1
Introduction
7UT51 v3
SWITCH-OFF – The switch-off of a function means
that the protective function has been established as
Enabled; however, the function is turned Off.
VA – Rated Apparent Power
Vn or V – Rated phase to phase voltage or if the
N
transformer is a LTC, Vn = (2 X Vmax X Vmin) /
(Vmax + Vmin).
Vector Group – Integer n that represents the phase
shift from the first winding to the second winding of a
power transformer, n x 30°. See Table 4.1 and
Table 4.2 for list of vector groups.
WinDIGSI – Windows based, Siemens software that
will enable the user to perform all settings and data
requisition with a PC through the relay's
communication port. At the computer, the data can be
easily read on the screen, changed, saved to disk, or
printed.
WinDIGRA – A full-function digital oscillographic
analysis (Windows based) software that will allow the
user to view captured waveforms.
Winding – In this document it will refer to the side of
the transformer or tertiary. Winding 1 is defined as
the reference winding. The reference winding is
normally that of the higher voltage; however, if a CT is
installed in the ground lead of a grounded wye
connected transformer, that winding must be used as
the reference winding in order to ensure increased
ground-fault sensitivity by correction of the zero
sequence current.
12 PRIM-2330C