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1MRK 502 071-UUS A
Generator protection REG670 2.2 ANSI and Injection equipment REX060, REX061, REX062
Application manual
Common base IED values for primary current (setting IBase), primary voltage (setting
VBase) and primary power (setting SBase) are set in a Global base values for settings
function GBASVAL. Setting GlobalBaseSel is used to select a GBASVAL function for
reference of base values. The setting VBase is set to the rated phase to phase voltage in
kV of the generator.
TVoltType: STEFPHIZ(59THD) function is fed from a voltage transformer in the
generator neutral. TVoltType defines how the protection function is fed from voltage
transformers at the high voltage side of the generator. The setting alternatives are:
•
NoVoltage is used when no voltage transformers are connected to the generator
terminals. In this case the protection will operate as a 3
protection.
•
ResidualVoltage 3V0 is used if the protection is fed from a broken delta connected
three-phase group of voltage transformers connected to the generator terminals.
This is the recommended alternative.
•
AllThreePhases is used when the protection is fed from the three phase voltage
transformers. The third harmonic residual voltage is derived internally from the
phase voltages.
•
PhaseA, PhaseB or PhaseC, are used when there is only one phase voltage
transformer available at the generator terminals.
The setting Beta gives the proportion of the 3
the generator to be used as restrain quantity. Beta must be set so that there is no risk of
trip during normal, non-faulted, operation of the generator. On the other hand, if Beta is
set high, this will limit the portion of the stator winding covered by the protection. The
default setting 3.0 will in most cases give acceptable sensitivity for ground fault near to
the neutral point of the stator winding. One possibility to assure best performance is to
make measurements during normal operation of the generator. The protective function
itself makes the required information available:
•
rd
VT3, the 3
harmonic voltage at the generator terminal side
•
rd
VN3, the 3
harmonic voltage at the generator neutral side
•
E3, the induced harmonic voltage
•
ANGLE, the phase angle between voltage phasors VT3 and VN3
•
DV3, the differential voltage between VT3 and VN3; (|VT3 + VN3|)
•
BV3, the bias voltage (Beta x VN3)
For different operation points (P and Q) of the generator the differential voltage DV3
can be compared to the bias BV3, and a suitable factor Beta can be chosen to assure
security.
CBexists: CBexists is set to Yes if there is a generator breaker (between the generator
and the block transformer).
Voltage protection
rd
harmonic undervoltage
rd
harmonic voltage in the neutral point of
Section 10
469
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