ABB REG670 Applications Manual page 298

Section 8
Impedance protection
292
1
w
=
j C
Z
rot
ref
EQUATION2511 V1 EN
Where:
w p
= ×
2 f
inj
EQUATION2512 V1 EN
The injected frequency f
fundamental frequency (50 or 60 Hz). The injected frequency can be set within the
range 75 – 250 Hz with the recommended value 113 Hz in 50 Hz systems and 137 Hz
in 60 Hz systems.
R is a resistance in the REX061 unit used to protect against overvoltage to the
series
injection unit. Such overvoltages can occur if the unit is fed from static excitation
system.
The injection unit REX060 is connected to the generator and to IED as shown in figure
155.
Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062
of the square wave, is a set value, different from the
inj
1MRK 502 071-UEN -
Application manual