5-108 F650 DIGITAL BAY CONTROLLER GEK-106310-AF
5.5 CONTROL ELEMENTS CHAPTER 5: SETPOINTS
LL-DB OPERATION: Closing permission in live line – dead bus condition.
SLIP CONDITION: Internal signal indicating frequency slip between the line voltage and bus voltage
phasors.
BUS FREQ > LINE FREQ: Busbar Frequency higher than line frequency
BUS FREQ < LINE FREQ: Busbar Frequency lower than line frequency
VOLTAGE DIFFERENCE: Voltage difference in Volts between line and busbar
FREQ. DIFFERENCE: Frequency difference in Hz between line and busbar
Voltage and frequency values for the line and busbar can be obtained, both in primary and secondary values at:
Actual> Metering > Primary Values > Voltage
VBB Primary (KV) Busbar voltage in primary values
VL Primary (KV) Line voltage in primary values
Actual> Metering > Secondary Values > Voltage
Line Voltage (V) Line voltage in secondary values
Bus Voltage (V) Busbar voltage in secondary values
Actual> Metering > Frequency
Line Frequency (Hz) Line frequency in Hz
Bus Frequency (Hz) Bus frequency in Hz
The voltage angles can be obtained in primary metering values (Actual> Metering > Primary Values > Voltage), being the
line voltage angle, the one that corresponds to the voltage set in the frequency reference in General settings (refer to the
voltage correspondence table (Table 5-73: Voltage correspondence element 25), and the angle of the busbar voltage the
one that corresponds to Vx Angle, when the Auxiliary Voltage setting as been selected as VX.
5.5.2.5 Algorithm
F650 elements perform the synchronism check by basically establishing and comparing three parameters:
Module difference of voltage phasors DV (V)
Phase angle of voltage phasors Dj (º)
Frequency slip between two phasors S (Hz)
These parameters are continuously determined and managed once that element 25 has been enabled by setting, and
in open breaker conditions. It is necessary to consider that all calculations are made once the open breaker condition is
detected; if the breaker is closed or undefined, the synchronism element does not issue a closing permission signal, even
when closing conditions are met.
If voltage on one side of the breaker to be closed is null, the synchronism element cannot establish the synchronism check,
and therefore it does not issue synchronism permission. For these cases, usual in breaker maintenance situations, or in
new installations where voltage might not be present, but the breaker operation needs to be verified, F650 elements
incorporate closing permission logics for situations of:
Dead Line – Dead Bus (DL-DB)
Live Line – Dead Bus (LL-DB)
Dead Line – Live Bus (DL-LB)
In order to establish the closing permission signal, the first parameter used by the algorithm is the difference in magnitude
between line and bus voltages, and afterwards, the angle difference and frequency slip are verified.
Voltage Difference DV
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