ABB Relion Technical Manual page 118

Section 6
Differential protection
52
152
ANSI09000162 V1 EN
Figure 37: Treatment of measured currents within IED for transformer differential function
112
ADM
Figure 37 shows how internal treatment of measured currents is done in case of a two-
winding transformer.
The following currents are inputs to the power transformer differential protection
function. They must all be expressed in power system (primary) A.
Trafo
Data
Instantaneous (sample based)
Differential current, phase A
Instantaneous (sample based)
Differential current, phase B
Instantaneous (sample based)
Differential current, phase C
Negative sequence diff current
& NS current contribution from
individual windings
Fundamental frequency (phasor
based) Diff current, phase A &
phase current contributions from
individual windings
Fundamental frequency (phasor
based) Diff current, phase B &
phase current contributions from
individual windings
Fundamental frequency (phasor
based) Diff current, phase C &
phase current contributions from
individual windings
Settings for Zer. Seq.
Current Reduction
1MRK 502 048-UUS A
Differential function
ID_A
ID_B
ID_C
IDMAG_NS
IDMAG_A
IDMAG_B
IDMAG_C
IBIAS
MAX
ANSI09000162_1_en.vsd
Technical manual