ABB RELION REX640 Technical Manual page 1410

Condition monitoring functions
If the input GEN_MOD_LOC is 1, indicating that the generator is in local mode, then
the Fueling fault detection module is disabled. If the quality status of the local
active power input is faulty, then the module is disabled and INT_BLKD output is
activated.
If one of the generators present in the same subnetwork is faulty, then that
generator is removed from comparison in the Fueling fault detection module.
The input ENG_LOD_UNLD suggests whether the engine is in loading or unloading
condition. When the engine is in loading condition (confirmed by GCB position
change from open to close) the fueling fault detection is disabled until the
generated power reaches 80% of the average loading of generators in the same
subnetwork or until the elapsing of
function is in unloading condition (i.e. GCB continues to remain in closed position),
then the module is blocked until the elapsing of
change and ENG_LOD_UNLD input may not come together, by using settings (
time signal status - Wait time for Load/Unload signal and Wait time status signal
- Wait time for GCB status and Load/Unload signal) the confirmation of loading/
unloading of engine is done.
Correlation algorithm:
The Correlation algorithm compares the active power of the local generator, to its
expected behavior in the current governor mode.
The algorithm can be disabled through the setting
Correlation algorithm uses different criteria based on the governor mode.
The governor mode information is obtained through the four binary inputs
GOV_MOD_ISOC, GOV_MOD_DRP, GOV_MOD_CDRP and GOV_MOD_BASE. The governor
and AVR modes of other generators are obtained through inputs GEN1_DATA ...
GEN8_DATA. In case any generator in the same subnetwork is communicated to be
faulty, through the inputs GEN1_DATA ... GEN8_DATA, then that generator is not
considered in the Correlation algorithm.
If the input GOV_MOD_ISOC is active, the function monitors the system frequency
and active power of all generators in the same subnetwork and with the same
governor mode. If the frequency of the network exceeds the set
over and above the margin
than the rest of the generators by a margin
deemed faulty and OV_FUEL_FLT output is activated.
If the frequency of the network is below the set
above the margin
rest of the generators by a margin
faulty and UN_FUEL_FLT output is activated. The fueling fault detection algorithm
in isochronous mode needs at least 2 generators in parallel and operating in same
mode.
When the input GOV_MOD_DRP is active, the function compares the local active
power and system frequency with the set droop curve. Deviation above or below
this curve (for over and under fueling conditions respectively) by a margin greater
than
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The function has 8 active power inputs, P1 ... P8. The input
corresponding to the setting
as the local active power.
Local generator Num is set to "1", then P1 is considered as
For example, if
the local generator active power output.
Max Freq Dev Isoc , and if the local active power is less than the
Max Freq deviation , indicates a failure of the governor or the fuel system. The
Disable time , whichever is faster. When the
Disable time . As the GCB status
Local generator Num , would be considered
Max Freq Dev Isoc , and if the local active power is more
Max P Dev Crl , then the generator is
Expected frequency over and
Max P Dev Crl , then the generator is deemed
1MRS759142 F
Disable Fuel Crl .
Expected frequency
Technical Manual
Wait
REX640