ABB RET670 Applications Manual page 38

Section 3
IED application
32
Tripping from pressure relief/Buchholz and temperature devices can be done through
the transformer IED where pulsing, lock-out contact output and so on, is performed.
The binary inputs are heavily stabilized against disturbance to prevent incorrect
operations at for example dc system capacitive discharges or DC ground faults.
The binary inputs are heavily stabilized against disturbances to prevent incorrect
operations during for example during DC system capacitive discharges or DC ground
faults.
Distance protection functionality for phase-to-phase and/or phase-to-ground faults is
available as back-up protection for faults within the transformer and in the connected
power system.
Versatile phase, ground, positive, negative and zero sequence overcurrent functions,
which can optionally be made directional and/or voltage controlled, provide further
alternative backup protection. Thermal overload with two time-constants, volts per
hertz, over/under voltage and over/under frequency protection functions are also
available.
A built-in disturbance and event recorder provides valuable data to the user about
status and operation for post-fault disturbance analysis.
Breaker failure protection for each transformer breaker allows high speed back-up
tripping of surrounding breakers.
The transformer IED can also be provided with a full control and interlocking
functionality including Synchrocheck function to allow integration of the main and/or a
local back-up control.
Out of Step function is available to separate power system sections close to electrical
centre at occurring out of step.
RET670 can be used in applications with the IEC 61850-9-2LE process bus with up to
two Merging Units (MU). Each MU has eight analogue channels, normally four current
and four voltages. Conventional and Merging Unit channels can be mixed freely in
your application.
The advanced logic capability, where user logic is prepared with a graphical tool,
allows special applications such as automatic opening of disconnectors in multi-
breaker arrangements, closing of breaker rings, load transfer logic and so on. The
graphical configuration tool ensures simple and fast testing and commissioning.
Serial data communication is via optical connections to ensure immunity against
disturbances.
1MRK504116-UUS C
Application manual