Functions
2.16 Phase Rotation
SIPROTEC, 7SK80, Manual
E50417-G1140-C344-A4, Release date 08.2010
237
2.16 Phase Rotation
A phase rotation reversal is implemented in the 7SK80 using binary inputs and parameters.
Applications
• Phase rotation reversal ensures that all protection and monitoring functions operate correctly even with
counter-clockwise rotation, without the need for two phases to be reversed.
2.16.1 Description
General
Various functions of the 7SK80 only operate correctly if the phase rotation of the voltages and currents is
known. Among these functions are negative sequence protection, undervoltage protection (based on positive
sequence voltages) and several measured quantity monitors.
If an counter-clockwise phase rotation is present, 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 is changed), a reversal signal
sent to the binary input routed for this purpose is sufficient to inform the protective device of the phase se-
quence 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 2-90 Message logic of the phase rotation reversal
Influence on Protection and Monitoring Functions
The swapping of the phases affects only the calculation of the positive and negative sequence quantities and
the calculation of phase-to-phase quantities by subtracting two phase-to-Ground voltage and vice versa so that
the phase-selective messages, fault values and operational measured values are not distorted. This function
thus influences the negative sequence protection, the voltage protection, the flexible protection functions and
some of the monitoring functions that generate messages if the defined and calculated phase rotations do not
match.
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