Page 77 - SACE Tmax XT - Catalogue

PROTECTION TRIP UNITS 3/43

03
OQ Reactive overpower (ANSI 32OF)
t
With a constant trip time (t = k), this trips when the reactive power exceeds the set threshold in the
direction from the generator to the network.
Q27

t27
Q

OP Active overpower (ANSI 32OF)
t
With a constant trip time (t = k), this trips when the active power exceeds the threshold set in the delivering
direction from the generator.
Q27

t27
P

UP Active underpower (ANSI 32LF)
t
With a constant trip time (t = k), this trips when the active power delivered by the generator is lower
than the set threshold. It is possible to disable the protection temporarily to manage the start-up
P23
phase by setting a time window from the closing of the circuit-breaker, by using an electric signal or via
incoming communication to a relay.
t23
P

RQ Second protection against loss of field or reverse reactive power (ANSI 40 or 32R)
Q
This functions as the above mentioned RQ protection. These two functions can be active and used at
kq kq2
the same time, thus allowing the under-excitation curve of the generator to be accurately followed and
P
avoiding unwanted disconnections.
Q25
Q24
ROCOF Rate of change of frequency (ANSI 81R)
f(Hz) frequency
after fault This enables both positive and negative frequency variations to be detected rapidly. The threshold is
failure
constant and the function trips when the frequency variation in Hz/s is greater than the set threshold.
It is possible to set the operating mode to: active, alarm only, or deactivated. The protection enables
50/60Hz
frequency the identification and disconnection of the area where the fault has occurred while maintaining
after fault
operation in the rest of the installation.
Time