ABB Relion 670 series, Technical Reference Manual, Page: 353 / 1232

6.11 Power swing detection ZMRPSB (68)
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Power swing detection ZMRPSB
Zpsb
SYMBOL-EE V1 EN
68
6.11.1 Introduction
Power swings may occur after disconnection of heavy loads or trip of big generation
plants.
Power swing detection function (ZMRPSB, 68) is used to detect power swings and
initiate block of selected distance protection zones. Occurrence of ground-fault
currents during a power swing inhibits the ZMRPSB (68) function to allow fault
clearance.
6.11.2 Principle of operation
Power swing detection (ZMRPSB ,68) function comprises an inner and an outer
quadrilateral measurement characteristic with load encroachment, as shown in
figure
184 .
Its principle of operation is based on the measurement of the time it takes for a power
swing transient impedance to pass through the impedance area between the outer and
the inner characteristics. Power swings are identified by transition times longer than a
transition time set on corresponding timers. The impedance measuring principle is the
same as that used for the distance protection zones. The impedance and the
characteristic passing times are measured in all three phases separately.
One-out-of-three or two-out-of-three operating modes can be selected according to the
specific system operating conditions.
1MRK505222-UUS C
Section 6
Impedance protection
347
Technical reference manual