ABB REG670 Applications Manual

The ImpedanceZC is the forward impedance giving the borderline between zone 1 and
zone 2. ZC should be equal to the transformer reactance ZT. The impedance is given
in % of the base impedance, see equation 150.
The angle of the impedance line ZB – ZA is given as AnglePhi in degrees. This angle
is normally close to 90°.
StartAngle: An alarm is given when movement of the rotor is detected and the rotor
angle exceeds the angle set for StartAngle. The default value 110° is recommended. It
should be checked so that the points in the impedance plane, corresponding to the
chosen StartAngle does not interfere with apparent impedance at maximum generator
load.
TripAngle: If a pole slip has been detected: change of rotor angle corresponding to slip
frequency 0.2 – 8 Hz, the slip line ZA – ZB is crossed and the direction of rotation is
the same as at start, a trip is given when the rotor angle gets below the set TripAngle.
The default value 90° is recommended.
N1Limit: The setting N1Limit gives the number of pole slips that should occur before
trip, if the crossing of the slip line ZA – ZB is within zone 1, that is, the node of the pole
slip is within the generator transformer block. The default value 1 is recommended to
minimize the stress on the generator and turbine at out of step conditions.
N2Limit: The setting N2Limit gives the number of pole slips that should occur before
trip, if the crossing of the slip line ZA – ZB is within zone 2, that is, the node of the pole
slip is in the external network. The default value 3 is recommended give external
protections possibility to split the network and thus limit the system consequencies.
ResetTime: The setting ResetTime gives the time for (PSPPPAM) function to reset
after start when no pole slip been detected. The default value 5s is recommended.
8.4.3.1 Setting example for line application
In case of out of step conditions this shall be detected and the line between substation
1 and 2 shall be tripped.
IED
ZB
Line impedance = ZC
ZA = forward source impedance
IEC07000014_2_en.vsd
IEC07000014 V2 EN
Figure 137: Line application of pole slip protection
If the apparent impedance crosses the impedance line ZB – ZA this is the detection
criterion of out of step conditions, see figure 138.
1MRK 502 071-UEN - Section 8
Impedance protection
Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062 267
Application manual

ABB REG670 Specifications

General

Brand	ABB
Model	REG670
Category	Protection Device
Language	English