ABB RELION 670 Series Technical Manual page 722

Section 11
Multipurpose protection
ANSI07000185 V1 EN-US
Figure 383: Connection of rotor ground fault protection
By using a two stage directional current measurement in the General current and voltage
protection (CVGAPC), as shown in figure 384, the ground fault current on the DC side of the
excitation is detected. The protection operates when the resistive component of the measured
injected current exceeds the pre-set operate level. Stage one provides an alarm signal and stage
two trips the generator after a short time delay for fully developed rotor ground faults.
716
Generator rotor winding
G
Connection to be done by
the panel builder / field
contractor
REG 670
I
V
Optional external
resistor
RXTTE 4
221 222
421
428
313
230 V AC
314
120 V AC
315
324
325
321
en07000185_ansi.vsd
1MRK 502 066-UUS B
0
Technical manual