Application - ABB REC670 Applications Manual

Section 9
Voltage protection
9.5.2
9.5.3
9.5.3.1
244

Application

The trip of the circuit breaker at a prolonged loss of voltage at all the three phases
is normally used in automatic restoration systems to facilitate the system
restoration after a major blackout. Loss of voltage check (LOVPTUV) generates a
TRIP signal only if the voltage in all the three phases is low for more than the set
time. If the trip to the circuit breaker is not required, LOVPTUV is used for
signallization only through an output contact or through the event recording
function.
Setting guidelines
Loss of voltage check (LOVPTUV) is in principle independent of the protection
functions. It requires to be set to open the circuit breaker in order to allow a simple
system restoration following a main voltage loss of a big part of the network and
only when the voltage is lost with breakers still closed.
All settings are in primary values or per unit. Set operate level per phase to
typically 70% of the global parameter UBase level. Set the time delay tTrip=5-20
seconds.
Advanced users settings
For advanced users the following parameters need also to be set. Set the length of
the trip pulse to typical tPulse=0.15 sec. Set the blocking time tBlock to block Loss
of voltage check (LOVPTUV), if some but not all voltage are low, to typical 5.0
seconds and set the time delay for enabling the function after restoration tRestore to
3 - 40 seconds.
1MRK 511 401-UEN A
SEMOD171876-4 v3
SEMOD171929-4 v5
SEMOD171929-8 v4
Bay control REC670 2.2 IEC
Application manual