ABB Relion, Техническое руководство

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With the circuit breaker open, the total capacitance will be smaller compared to normal
operating conditions. This means that the neutral point 3
rd
harmonic voltage will be
reduced compared to the normal operating condition. Therefore, there is a 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 52a
is activated the set sensitivity is valid. If the generator circuit breaker is opened the binary
input 52a 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
VN3: the magnitude of the 3
rd
harmonic voltage measured in the neutral point of the
generator
VT3: the magnitude of the 3
rd
harmonic voltage measured in the terminal point of the
generator
ANGLE: the angle between the phasors VN3 and VT3 given in radians
DV3: the magnitude of the 3
rd
harmonic differential voltage
BV3: the magnitude of the 3
rd
harmonic bias voltage
V_N: the fundamental frequency voltage measured in the neutral point of the generator
9.5.8 Technical data
Table 183: STEFPHIZ (59THD) technical data
Function Range or value Accuracy
Fundamental frequency level UN
(95% Stator EF)
(1.0–50.0)% of
VBase
± 0.5% of V
n
Third harmonic differential level (0.5–10.0)% of
VBase
± 5.0% of V
n
Third harmonic differential block
level
(0.1–10.0)% of VBase ± 5.0% of V
n
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
-
Section 9
1MRK 502 048-UUS A
Voltage protection
318
Technical manual