Siemens 6MD85, Manual

Page: 865 / 1256

The phase sequence of the system is set in the device via the
Phase sequence
parameter for generator
operation. The
Inverted phases
parameter is used to set which phase is swapped for the relevant meas-
uring point. The swap is communicated to the measuring point via the binary input signal
>Invert Phases
.
The changed phase sequence is then included for calculation of the measurands at the measuring point.
In accordance with
Figure 7-179 the phase sequence is set to
ABC
. A is swapped with C in motor operation.
The
Inverted phases
parameter must be set to
AC
for the measuring points of current measured values 2
and current measured values 3. As a result, the phase assignment for the differential protection IED2 and the
impedance protection IED3 is correct. The positive-sequence and negative-sequence current is calculated
correctly.
The following logic diagram shows the principle for determining the present phase assignment and measured
variables with the example of currents.
The switchover of the phase sequence is only authorized for a time at which no measured values are pending
at the selected measuring points. The switchover command must be present for at least 200 ms. The change
of phase sequence is only implemented if the measurands at the measuring points that are to be switched are
under 5 % of the rated variables. If the currents of the measuring points of current measured values 2 and
current measured values 3 of the example fall below 5 % of their rated variables, the switchover is released
and the set phases are switched with active binary input.
[lophrgph-190517-01.vsd, 1, en_US]
Figure 7-180 Measured Values for Changed-Over Phases
Application and Setting Notes
Parameter: Phase sequence
•
Default setting
(_:101) Phase sequence
=
ABC
ABC
Phase sequence A, B, C
ACB
Phase sequence A, B, C
Parameter: Inverted phases
•
Default setting
(_:106) Inverted phases
=
none
none
No phase exchange
AC
Phase A changed over with phase C
BC
Phase B changed over with phase C
7.23.4
Protection and Automation Functions
7.23 Phase-Sequence Switchover
SIPROTEC 5, High-Voltage Bay Controller, Manual 865
C53000-G5040-C015-9, Edition 11.2017