ABB REC650 Applications Manual page 119

1MRK 511 286-UUS A
Application manual
The protection measures the residual current out on the protected line. The protection
function has a directional function where the residual voltage (zero-sequence voltage) is
the polarizing quantity.
The residual voltage and current can be internally generated when a three-phase set of
voltage transformers and current transformers are used.
ANSI05000149 V1 EN
Figure 45: Connection of polarizing voltage from an open (ANSI-broken) delta
The different steps can be described as follows.
Step 1
This step has directional instantaneous function. The requirement is that overreaching of
the protected line is not allowed.
Current protection
67N
xx05000149_ansi.vsd
Section 6
113