possibility to reduce the sensitivity of the protection when the generator circuit
breaker is open.
With the setting CBexists change of the sensitivity is enabled. If the binary input signal
CBCLOSED is activated the set sensitivity is valid. If the generator circuit breaker is
opened the binary input CBCLOSED is deactivated and the sensitivity is changed.
This is done by changing the factor Beta which is multiplied with a set constant
FactorCBopen.
In addition to the binary outputs also some analog outputs are available from the
protection function in order to enable easier commissioning:
E3: the magnitude of the 3
rd
harmonic voltage induced in the stator given in primary
volts
UN3: the magnitude of the 3
rd
harmonic voltage measured in the neutral point of the
generator
UT3: the magnitude of the 3
rd
harmonic voltage measured in the terminal point of the
generator
ANGLE: the angle between the phasors UN3 and UT3 given in radians
DU3: the magnitude of the 3
rd
harmonic differential voltage
BU3: the magnitude of the 3
rd
harmonic bias voltage
UN: the fundamental frequency voltage measured in the neutral point of the generator
9.5.8 Technical data
Table 183: STEFPHIZ technical data
Function
Range or value Accuracy
Fundamental frequency level UN
(95% Stator EF)
(1.0–50.0)% of
UBase
± 0.5% of U
r
Third harmonic differential level (0.5–10.0)% of
UBase
± 5.0% of U
r
Third harmonic differential block
level
(0.1–10.0)% of
UBase
± 5.0% of U
r
Timers (0.020–60.000) s ± 0.5% ± 25 ms
Filter characteristic:
Fundamental
Third harmonic
Reject third harmonic by 1–40
Reject fundamental harmonic by
1–40
-
1MRK 502 048-UEN A Section 9
Voltage protection
293
Technical manual
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