GE Multilin G650, Manual

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5-84 G650 Generator Protection & Control System GEK-113285A
5.5 CONTROL ELEMENTS 5 SETTINGS
5
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 (please refer
to the voltage correspondence table (Table 5–80:), and the angle of the busbar voltage the one that corresponds to Vx
Angle, when the Auxiliary Voltage setting as been selected as V
X
.
5.5.4.5 ALGORITHM
G650 elements perform the synchronism check by basically establishing and comparing three parameters:
Module difference of voltage phasors
Δ
V (V)
Phase angle of voltage phasors
Δϕ
(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 will 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 will 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, G650 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
Δ
V
Comparing the voltage values for line voltage (V1) and busbar voltage (V2) at both sides of the breaker, the relay can
determine the synchronism situation of the element (see Table 5–83:).
Being:
V
1
line voltage
V
2
bus voltage
V
L
Minimum acceptable voltage by setting to establish synchronism conditions (dead line and bus levels).
V
H
Appropriate voltage to establish synchronism conditions, configured by setting (live line and bus levels).