Connections For 1Ph High Impedance Differential Protection Hzpdif - ABB REG670 Applications Manual

1MRK 502 071-UEN -
7.2.3.2
Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062
Application manual
Pos Description
1 Scheme earthing point
It is important to insure that only one earthing point exist in this scheme.
2 Three-phase plate with setting resistors and metrosils. Protective earth is a separate 4 mm screw
terminal on the plate.
3 Necessary connection for three-phase metrosil set.
4 Position of optional test switch for secondary injection into the high impedance differential IED.
5 Necessary connection for setting resistors.
6 Factory-made star point on a three-phase setting resistor set.
The star point connector must be removed for installations with 670 series
IEDs. This star point is required for RADHA schemes only.
7 Connections of three individual phase currents for high impedance scheme to three CT inputs in
the IED.

Connections for 1Ph High impedance differential protection HZPDIF

Restricted earth fault protection is a typical application for 1Ph High impedance
differential protection HZPDIF. Typical CT connections for the high impedance
based protection scheme are shown in figure 62.
Section 7
Differential protection
157