1. Application
M16637-3 v13
The IED provides fast and selective protection,
monitoring and control for two- and three-winding
transformers, autotransformers, step-up transformers
and generator-transformer block units, phase shifting
transformers, special railway transformers and shunt
reactors. The IED is designed to operate correctly over a
wide frequency range in order to accommodate power
system frequency variations during disturbances and
generator start-up and shut-down.
The IED has a fast, low-impedance differential
protection function with very low requirements on the
CTs. It is suitable for differential applications with
multi-breaker arrangements with up to six restraint CT
inputs. The differential protection function is provided
with a 2nd harmonic and waveform-block restraint
feature to avoid tripping for CT saturation and
transformer inrush current, and 5th harmonic restraint
to avoid tripping for transformer overexcitation.
The differential function offers a high sensitivity for
low-level internal faults by using a sensitive differential
protection feature based on an amplitude measurement
and directional comparison of the negative sequence
components.
Multiple low impedance restricted earth-fault protection
functions are available as a sensitive and fast main
protection against winding earth faults. This function
includes a internal/external fault discriminator for
additional security.
Additionally, a high impedance differential protection
function is available. It can be used for different
applications including restricted earth fault protection
as winding protection, autotransformer differential
protection, shunt reactor protection, T-feeder
protection, busbar protection and generator differential
protection.
Tripping and alarm signals from pressure relief,
Buchholz and temperature devices can be sent directly
to the IED via binary input channels for alarm and back-
up purposes. The binary inputs are highly stabilized
against disturbances to prevent incorrect operation due
to, for example, DC system capacitive discharges or DC
earth faults.
Distance protection functionality is available as back-up
protection for faults within the transformer and in the
connected power system.
Positive, negative and zero sequence overcurrent
functions, which can optionally be made directional
and/or voltage controlled, provide further alternative
backup protection. Thermal overload, overexcitation,
over/under voltage and over/under frequency
protection functions are also available.
Breaker failure protection for each transformer breaker
allows high speed back-up tripping of surrounding
breakers.
A built-in disturbance and event recorder provides
valuable data to the user about status and operation for
post-fault disturbance analysis.
The IEDcan optionally be provided with full control and
interlocking functionality including a synchrocheck
function to allow integration of the main or local back-
up control functionality.
A pole slip protection function is also available in the IED
to detect, evaluate, and take the required action for pole
slipping occurrences in the power system. The electrical
system parts swinging to each other can be separated
with the line(s) closest to the centre of the power swing,
allowing the two systems to be stable when separated.
The IED can be used in applications with the IEC
61850-9-2LE process bus with up to six merging units
(MU) depending on the other functionality included in
the IED.
Logic is prepared with a graphical tool. The advanced
logic capability allows allows for special applications
such as automatic opening of disconnectors in multi-
breaker arrangements, closing of breaker rings and load
transfer logic. Logic can be monitored and debugged
online in real time for testing and commissioning.
Forcing of binary inputs and outputs is a convenient way
to test wiring in substations as well as testing
configuration logic in the IEDs. Basically it means that all
binary inputs and outputs on the IED I/O modules (BOM,
BIM, IOM & SOM) can be forced to arbitrary values.
Central Account Management is an authentication
infrastructure that offers a secure solution for enforcing
access control to IEDs and other systems within a
substation. This incorporates management of user
accounts, roles and certificates and the distribution of
such, a procedure completely transparent to the user.
Flexible Product Naming allows the customer to use an
IED-vendor independent 61850 model of the IED. This
customer model will be used as the IEC 61850 data
model, but all other aspects of the IED will remain
unchanged (e.g., names on the local HMI and names in
the tools). This offers significant flexibility to adapt the
IED to the customers system and standard solution
M11788-3 v10
Communication via optical connections ensures
immunity against disturbances.
Transformer protection RET670 2.1 IEC
1MRK 504 155-BEN F
Issued: March 2019
Revision: F
ABB
3
