8.14 Power swing detection ZMRPSB (68)
8.14.1 Identification
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Power swing detection ZMRPSB
SYMBOL-EE V1 EN
68
8.14.2 Application
8.14.2.1 General
Various changes in power system may cause oscillations of rotating units. The most
typical reasons for these oscillations are big changes in load or changes in power system
configuration caused by different faults and their clearance. As the rotating masses strive
to find a stable operate condition, they oscillate with damped oscillations until they reach
the final stability.
The extent of the oscillations depends on the extent of the disturbances and on the natural
stability of the system.
The oscillation rate depends also on the inertia of the system and on the total system
impedance between different generating units. These oscillations cause changes in phase
and amplitude of the voltage difference between the oscillating generating units in the
power system, which reflects further on in oscillating power flow between two parts of the
system - the power swings from one part to another - and vice versa.
Distance IEDs located in interconnected networks see these power swings as the swinging
of the measured impedance in relay points. The measured impedance varies with time
along a locus in an impedance plane, see figure
225. This locus can enter the operating
characteristic of a distance protection and cause, if no preventive measures have been
considered, its unwanted operation.
1MRK 506 369-UUS - Section 8
Impedance protection
Line distance protection REL670 2.2 ANSI 435
Application manual
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