ABB RET670 - Setting Guidelines

The operation of a generator having pole slip will give risk of damages to the generator
block.
• At each pole slip there will be significant torque impact on the generator-turbine
shaft.
• In asynchronous operation there will be induction of currents in parts of the
generator normally not carrying current, thus resulting in increased heating. The
consequence can be damages on insulation and stator/rotor iron.
• At asynchronous operation the generator will absorb a significant amount of
reactive power, thus risking overload of the windings.
PSPPPAM (78) function shall detect out of step conditions and trip the generator as
fast as possible if the locus of the pole slip is inside the generator. If the centre of pole
slip is outside the generator, situated out in the power grid, the first action should be to
split the network into two parts, after line protection action. If this fails there should be
operation of the generator pole slip protection, to prevent further damages to the
generator block.
3.6.13.2 Setting guidelines
Operation: With the parameter Operation the function can be set Enabled or DIsabled.
IBase: The parameter IBase is set to the generator rated current in A, according to
equation
315.
3
N
N
S
IBase
U
=
×
EQUATION1884 V1 EN
(Equation 315)
VBase: The parameter VBase is set to the generator rated Voltage (phase-to-phase) in kV
MeasureMode: The voltage and current used for the impedance measurement is set by
the parameter MeasureMode. The setting possibilities are: PosSeq, AB, BC, or CA. If
all phase voltages and phase currents are fed to the IED the PosSeq alternative is
recommended (default).
Further settings can be illustrated in figure
168.
1MRK504116-UUS C Section 3
IED application
377
Application manual