ABB REC670 Applications Manual page 145

1MRK 511 401-UUS A
Bay control REC670 2.2 ANSI
Application manual
transformers in the feeder circuit (for example, in the transformer bushings). It is often
required to separate the protection zones that the feeder is protected with one scheme
while the T-zone is protected with a separate differential protection scheme. The 1Ph
high impedance differential HZPDIF (87) function in the IED allows this to be done
efficiently, see Figure 52.
Section 7
Differential protection
139