Underimpedance Protection For Generators And Transformers Zgcpdis (21G) - ABB REG650 Technical Manual

1MRK 502 043-UUS B
Section 7
7.1
7.1.1
7.1.2
Technical Manual
Impedance protection
Underimpedance protection for generators and
transformers ZGCPDIS (21G)
Identification
Function description
Underimpedance protection for
generators and transformers
Functionality
The underimpedance protection for generators and transformers ZGCPDIS(21G), has
the offset mho characteristic as a three zone back-up protection for detection of phase-
to-phase short circuits in transformers and generators. The three zones have
independent measuring and settings that gives high flexibility for all types of applications.
A load encroachment characteristic is available for the third zone as shown in figure
57.
Impedance protection
IEC 61850 IEC 60617
identification identification
ZGCPDIS
Section 7
ANSI/IEEE C37.2
device number
21G
133