Functions
2.10 Phase Rotation
SIPROTEC, 7RW80, Manual
C53000-G1140-C233-1, Release date 10.2010
111
2.10
Phase Rotation
A phase rotation function via binary input and parameter is implemented in 7RW80 devices.
Applications
• Phase rotation ensures that all protective and monitoring functions operate correctly even with anti-clock-
wise rotation, without the need for two phases to be reversed.
2.10.1
Description
General
Various functions of the 7RW80 devices only function correctly if the phase rotation of the voltages is known,
e.g. undervoltage protection (based on positive sequence voltages) and some measurement quantity monitors.
If an "acb" phase rotation is normal, the appropriate setting is made during configuration of the Power System
Data.
If the phase rotation can change during operation (e.g. the direction of a motor must be routinely changed),
then a changeover signal at the routed binary input for this purpose is sufficient to inform the protective relay
of the phase rotation reversal.
Logic
Phase rotation is permanently established at address
209
PHASE SEQ.
(Power System Data). Via the exclu-
sive-OR gate the binary input
„>Reverse Rot.“
inverts the sense of the phase rotation applied with setting.
Figure 2-34
Message logic of the phase rotation reversal
Influence on Protective and Monitoring Functions
The swapping of phases directly impacts the calculation of positive and negative sequence quantities, as well
as phase-to-phase voltages via the subtraction of one phase-to-ground voltage from another and vice versa.
Therefore, this function is vital so that phase detection messages, fault values, and operating measurement
values are not correct. As stated before, this function influences the voltage protection function, flexible protec-
tion functions, and some of the monitoring functions that issue messages if the defined and calculated phase
rotations do not match.
