Frequency Time Accumulation Protection Function Ftaqfvr (81A) - ABB Relion 670 Series RES670 Technical Manual

1MRK 511 365-UUS A
10.4
10.4.1
10.4.2
10.4.3
Phasor measurement unit RES670 2.1 ANSI
Technical manual
Frequency time accumulation protection function
FTAQFVR (81A)
Identification
Function description
Frequency time accumulation protection
Functionality
Frequency time accumulation protection FTAQFVR (81A) is based on measured system
frequency and time counters. FTAQFVR (81A) for generator protection provides the
BFI_3P output for a particular settable frequency limit, when the system frequency falls
in that settable frequency band limit and positive sequence voltage within settable voltage
band limit. The BFI_3P signal triggers the individual event timer, which is the continuous
time spent within the given frequency band, and the accumulation timer, which is the
cumulative time spent within the given frequency band. Once the timers reach their limit,
an alarm or trip signal is activated to protect the turbine against the abnormal frequency
operation. This function is blocked during generator start-up or shut down conditions by
monitoring the circuit breaker position and current threshold value. The function is also
blocked when the system positive sequence voltage magnitude deviates from the given
voltage band limit which can be enabled by EnaVoltCheck setting.
It is possible to create functionality with more than one frequency band limit by using
multiple instances of the function. This can be achieved by a proper configuration based
on the turbine manufacturer specification.
Function block
FTAQFVR (81A)
I3P* ERROR
V3P* TRIP
BLOCK TRIPACC
CBCLOSE TRIPCONT
CBOPEN BFI_3P
LOADINIT ACCALARM
HOLDACC STRORHLD
RESETACC FREQOK
VOLTOK
ANSI14000049-1-en.vsd
ANSI14000023 V1 EN
Figure 108: FTAQFVR (81A) function block
Frequency protection
IEC 61850 IEC 60617
identification identification
FTAQFVR f<>
Section 10
ANSI/
IEEEidentification
81A
313