ABB REG670 - Setting Guidelines

The factors k
1
and k
2
[Ω] are derived during the calibration measurements under
commissioning. As support for the calibration, the Injection Commissioning tool must
be used. This tool is an integrated part of the PCM600 tool.
In connection to this calibration, the reference impedance is also derived. In case of a
rotor earth fault with fault impedance Z
f
, the measured admittance is:
1 11
measured ref f
Z ZZ
=+
=
111
f meas ured ref
ZZZ
=−
EQUATION2405 V2 EN
The real part gives the fault conductance.
1 11
Re
f measured ref
RZZ

=−



EQUATION2421 V2 EN
RAlarm and RTrip are the two resistance levels given in the settings. The values of
RAlarm and RTrip are given in Ω.
An alarm signal ALARM is given after a set delay tAlarm if R
f
< RAlarm.
A start signal START is given if R
f
< RTrip.
For the tripping times, see figure 158.
Accuracy for ROTIPHIZ is installation dependent because harmonics in static
excitation system, large variation of the ambient temperature and variation of rotor
capacitance and conductance to ground between standstill and fully loaded machine
will limit the possible setting level for the alarm stage. As a consequence 50 kΩ
sensitivity can be typically reached without problem. Depending on particular
installation alarm sensitivity of up to 500 kΩ may be reached.
8.7.3 Setting guidelines
8.7.3.1 Setting injection unit REX060
The rotor injection module (RIM) in the REX060 generates a square wave signal for
injection into the field winding circuit (rotor circuit). The injected voltage and current
are connected to the measuring part of REX060. The signals are amplified giving
voltage signals for both the injected voltage and current, adapted to analogue inputs of
IED.
Section 8 1MRK 502 071-UEN -
Impedance protection
294 Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062
Application manual