T-Feeder Protection - ABB Relion 670 Series Applications Manual

1MRK 511 358-UUS A
6.1.4.3

T-feeder protection

In many busbar arrangements such as breaker-and-a-half, ring breaker, mesh corner, there will be
a T-feeder from the current transformer at the breakers up to the current 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 48.
Application manual
Section 6
Differential protection
M16850-4 v7
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