ABB REL650 series, Applications Manual

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(ZMRPSB, 68) during the power swing, even after the transient impedance leaves
ZMRPSB (68) operating characteristic and is expected to return within a certain time due
to continuous swinging. Consider the minimum possible speed of power swinging in a
particular system.
The tR1 inhibit timer delays the influence of the detected residual current on the inhibit
criteria for ZMRPSB(68). It prevents operation of the function for short transients in the
residual current measured by the IED.
The tR2 inhibit timer disables the output PICKUP signal from ZMRPSB (68) function, if
the measured impedance remains within ZMRPSB (68) operating area for a time longer
than the set
tR2 value. This time delay was usually set to approximately two seconds in
older power-swing devices.
6.7 Automatic switch onto fault logic, voltage and current
based ZCVPSOF
6.7.1 Identification
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Automatic switch onto fault logic,
voltage and current based
ZCVPSOF - -
6.7.2 Application
Automatic switch onto fault logic, voltage and current based function (ZCVPSOF) is a
complementary function to impedance measuring functions, but may make use of
information from such functions.
With ZCVPSOF function, a fast trip is achieved for a fault on the whole line, when the line
is being energized. ZCVPSOF tripping is generally non-directional in order to secure a
trip at fault situations where directional information can not be established, for example,
due to lack of polarizing voltage when a line potential transformer is used.
Automatic activation based on dead line detection can only be used when the potential
transformer is situated on the line side of a circuit breaker.
When line side potential transformers are used, the use of non-directional distance zones
secures switch onto fault tripping for close-in three-phase short circuits. Use of non-
directional distance zones also gives fast fault clearance when energizing a bus from the
line with a short-circuit fault on the bus.
Section 6
1MRK 506 334-UUS A
Impedance protection
166
Application manual