ABB RELION RET670 Applications Manual page 763

1MRK 504 163-UUS A
Transformer protection RET670 2.2 ANSI
Application manual
analog quantities are fed to the IED via the transformer input module, the Analog to
Digital Converter and thereafter a Pre-Processing Block. In the Pre-Processing Block, a
great number of quantities for example, phase-to-phase analog values, sequence values,
max value in a three phase group etc., are derived. The different function blocks in the
IED are then "subscribing" on selected quantities from the pre-processing blocks. In
case of TR1ATCC (90) or TR8ATCC (90), there are the following possibilities:
• I3P1 represents a three-phase group of phase current with the highest current in
any of the three phases considered. As only the highest of the phase current is
considered, it is also possible to use one single-phase current as well as two-phase
currents. In these cases, the currents that are not used will be zero.
• For I3P2 and V3P2 the setting alternatives are: any individual phase current/
voltage, as well as any combination of phase-phase current/voltage or the positive
sequence current/voltage. Thus, single-phase as well as, phase-phase or three-
phase feeding on the LV-side is possible but it is commonly selected for current
and voltage.
Section 15
Control
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