10.4 Frequency time accumulation protection function
FTAQFVR (81A)
GUID-124A1F91-44C0-4DB6-8603-CC8CA19AE2A6 v3
10.4.1 Identification
GUID-87605DA0-EAA6-4A6C-BF03-7FDB187E1B29 v2
Function description IEC 61850
identification
IEC 60617
identification
ANSI/
IEEEidentificatio
n
Frequency time accumulation
protection
FTAQFVR f<> 81A
10.4.2 Functionality
GUID-020CE8CF-9BEA-455D-ACBD-13023B93B4D1 v4
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.
10.4.3 Function block
GUID-E3D2093B-8A97-4037-AAFE-5483489BF350 v2
FTAQFVR (81A)
I3P*
V3P*
BLOCK
CBCLOSE
CBOPEN
LOADINIT
HOLDACC
RESETACC
ERROR
TRIP
TRIPACC
TRIPCONT
BFI_3P
ACCALARM
STRORHLD
FREQOK
VOLTOK
ANSI14000049-1-en.vsd
ANSI14000023 V1 EN-US
Figure 368: FTAQFVR (81A) function block
Section 10 1MRK 502 066-UUS B
Frequency protection
680
Technical manual
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