Tertiary Reactor Protection - ABB Relion 670 Series Applications Manual

Section 6
Differential protection
The magnetizing current is taken from the magnetizing curve for the current transformer cores
which should be available. The current value at
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.
6.1.4.4

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.
3·87
ANSI05000176 V2 EN-US
Figure 49: Application of the1Ph High impedance differential protection HZPDIF (87) function on a reactor
116
TripPickup is taken.
1MRK 511 358-UUS A
M16850-118 v5
ANSI05000176-2-en.vsd
Application manual