Section 7 Impedance Protection - ABB RELION 670 Series Applications Manual

1MRK 511 364-UUS A
Section 7
7.1 Power swing detection ZMRPSB (68)
7.1.1 Identification
Function description
Power swing detection
7.1.2 Application
7.1.2.1 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 44. This locus can enter the operating characteristic of a distance
protection and cause, if no preventive measures have been considered, its unwanted operation.
Application manual
Impedance protection
IEC 61850
identification
ZMRPSB
IEC 60617 ANSI/IEEE C37.2
identification device number
68
Zpsb
SYMBOL-EE V1 EN-US
Section 7
Impedance protection
IP14499-1 v3
M14853-1 v3
IP14969-1 v1
M13874-3 v3
95