ABB Relion 670 Series Applications Manual page 230

Section 9
Frequency protection
FTAQFVR (81A) used to protect a turbine:
Frequency during start-up and shutdown is normally not calculated, consequently the protection
function is blocked by CB position, parameter
when CB is in open position e.g. excitation equipment and auxiliary services this may be
considered as normal condition and
set value of
EnaVoltCheck set to Disable .
tCont : to be coordinated to the grid requirements.
tAccLimit , FreqHighLimit and FreqLowLimit setting is derived from the turbine manufacturer's
operating requirements, note that
FreqHighLimit .
of
FTAQFVR (81A) used to protect a generator:
Frequency during start-up and shutdown is normally not calculated, consequently the protection
function is blocked by CB position, parameter
PickupCurrentLevel set to Disable .
EnaVoltCheck set to Enable , voltage and frequency limits set according to the generators
manufacturer's operating requirements. Voltage and frequency settings should also be
coordinated with the pickup values for over and underexcitation protection.
tCont : to be coordinated to the grid requirements.
tAccLimit , FreqHighLimit and FreqLowLimit setting is derived from the generator manufacturer's
operating requirements.
224
PickupCurrentLevel . Set the current level just above minimum load.
FreqLowLimit setting must always be lower than the set value
CBCheck enabled. If the generator supply any load
CBCheck is ignored when the load current is higher then the
CBCheck enabled.
1MRK 511 358-UUS A
Application manual