Tertiary Reactor Protection - ABB RELION RET670 Applications Manual

Section 7
Differential protection
7.2.4.4
170
It can clearly be seen that the sensitivity is not so much influenced by the selected
voltage level so a sufficient margin should be used. The selection of the stabilizing
resistor and the level of the magnetizing current (mostly dependent of the number of
turns) are the most important factors.

Tertiary reactor protection

Reactive power equipment (for example shunt reactors and/or shunt capacitors) can be
connected to the tertiary winding of the power transformers. The 1Ph High impedance
differential protection function HZPDIF (87) can be used to protect the tertiary reactor
for phase faults as well as ground faults if the power system of the tertiary winding is
direct or low impedance grounded.
1MRK 504 163-UUS A
Transformer protection RET670 2.2 ANSI
Application manual
M16850-118 v5