ABB REG670 - Percentage Restrained Differential Operation

GlobalBaseSel: Selects the global base value group used by the function to define
(IBase), (UBase) and (SBase).
InvertCT2Curr: It is normally assumed that the secondary winding of the CTs of the
generator are earthed towards the generator, as shown in figure
68. In this case the
parameter InvertCT2Curr is set to No.
IEC06000430-2-en.vsd
IEC06000430 V2 EN
Figure 68: Position of current transformers
If Generator differential protection GENPDIF is used in conjunction with a
transformer differential protection within the same IED, the direction of the terminal
CT may be referred towards the step-up transformer. This will give wrong reference
direction for the generator differential protection. This can be adjusted by setting the
parameter InvertCT2curr to Yes.
Operation: GENPDIF is set On or Off with this setting.
7.3.3.2 Percentage restrained differential operation
The characteristic of the restrain differential protection is shown in figure
69. The
characteristic is defined by the settings:
• IdMin
• EndSection1
• EndSection2
• SlopeSection2
• SlopeSection3
Section 7 1MRK 502 071-UEN -
Differential protection
170 Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062
Application manual