Y V Aruna Int. Journal of Engineering Research and Applications www.ijera.com ISSN : 2248-9622, Vol. 5, Issue 1( Part 4), January 2015, pp.45-50 www.ijera.com 45 | Page Implementation of Transformer Protection by Intelligent Electronic Device for Different Faults Y V Aruna, Beena S (Assistant Professors, Department of EEE, Cambridge Institute of Technology, Bangalore-36) ABSTRACT Protection of power system equipments was traditionally done by using electromagnetic relay, static relays, and numerical relays. At present the microprocessor based relays are replacing the old Electromagnetic relays because of their high level accuracy and fast operation. RET670(Transformer protection relay ), an IED (INTELLIGENT ELECTRONIC DEVICE) provides fast and selective protection, monitoring, and control of all types of transformer. The configured IED is tested under different fault conditions simulated by using mobile test kit to ensure IED’s reliable operation on site. With preconfigured algorithms, the IED will automatically reconfigure the network in case of a fault, and a service restoration is carried out within milliseconds by giving trip signal to the corresponding Circuit breakers. On receiving the trip signal the circuit breaker operates providing quicker isolation of transformers under the fault condition. This enables to have a complete and an adequate protection to the specified power transformer. Keywords – Transformer protection, IED, RET670 I. INTRODUCTION An Intelligent Electronic Device (IED) is a term used in the electric power industry to describe microprocessor-based controllers of power system equipment, such as circuit breakers and transformers. 1. RET670 Introduction RET670 provides fast and selective protection, monitoring and control for two- and three-winding transformers, autotransformers, generator- transformer units, phase shifting transformers, special railway transformers and shunt reactors. The transformer 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 as in Fig.1 A very fast differential protection function with settable CT ratio matching and vector group compensation makes this IED the ideal solution even for the most demanding applications. Since RET670 has very low requirements on the main CTs, no interposing CTs are required. It is suitable for differential applications with multi-breaker arrangements with up to six restraint CT inputs. The differential protection function is provided with 2nd harmonic and wave-block restraint features to avoid tripping for magnetizing inrush current, and 5 th harmonic restraint to avoid tripping for over excitation. The differential function offers a high sensitivity for low-level internal faults. The unique and innovative sensitive differential protection feature of the RET670 provides the best possible coverage for winding internal turn-to-turn faults, based on the theory of symmetrical components. Fig.1: Internal Conventions of the directionality in the IED. 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 earth faults. 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) as in fig1.1. Each MU has eight analogue channels, normally four current and four voltages. Conventional and Merging Unit channels can be mixed freely in your application. RESEARCH ARTICLE OPEN ACCESS
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Implementation of Transformer Protection by Intelligent Electronic Device for Different Faults
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Y V Aruna Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 5, Issue 1( Part 4), January 2015, pp.45-50
www.ijera.com 45 | P a g e
Implementation of Transformer Protection by Intelligent
Electronic Device for Different Faults
Y V Aruna, Beena S (Assistant Professors, Department of EEE, Cambridge Institute of Technology, Bangalore-36)
ABSTRACT Protection of power system equipments was traditionally done by using electromagnetic relay, static relays, and
numerical relays. At present the microprocessor based relays are replacing the old Electromagnetic relays
because of their high level accuracy and fast operation. RET670(Transformer protection relay ), an IED
(INTELLIGENT ELECTRONIC DEVICE) provides fast and selective protection, monitoring, and control of all
types of transformer. The configured IED is tested under different fault conditions simulated by using mobile test
kit to ensure IED’s reliable operation on site. With preconfigured algorithms, the IED will automatically
reconfigure the network in case of a fault, and a service restoration is carried out within milliseconds by giving
trip signal to the corresponding Circuit breakers. On receiving the trip signal the circuit breaker operates
providing quicker isolation of transformers under the fault condition. This enables to have a complete and an
adequate protection to the specified power transformer.
Keywords – Transformer protection, IED, RET670
I. INTRODUCTION An Intelligent Electronic Device (IED) is a
term used in the electric power industry to describe
microprocessor-based controllers of power system
equipment, such as circuit breakers and transformers.
1. RET670 Introduction
RET670 provides fast and selective protection,
monitoring and control for two- and three-winding
transformers, autotransformers, generator-
transformer units, phase shifting transformers, special
railway transformers and shunt reactors. The
transformer 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 as
in Fig.1
A very fast differential protection function with
settable CT ratio matching and vector group
compensation makes this IED the ideal solution even
for the most demanding applications. Since RET670
has very low requirements on the main CTs, no
interposing CTs are required. It is suitable for
differential applications with multi-breaker
arrangements with up to six restraint CT inputs. The
differential protection function is provided with 2nd
harmonic and wave-block restraint features to avoid
tripping for magnetizing inrush current, and 5th
harmonic restraint to avoid tripping for over
excitation. The differential function offers a high
sensitivity for low-level internal faults. The unique
and innovative sensitive differential protection
feature of the RET670 provides the best possible
coverage for winding internal turn-to-turn faults,
based on the theory of symmetrical components.
Fig.1: Internal Conventions of the directionality in
the IED.
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 earth faults. 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) as in fig1.1. Each MU has eight analogue
channels, normally four current and four voltages.
Conventional and Merging Unit channels can be
mixed freely in your application.
RESEARCH ARTICLE OPEN ACCESS
Y V Aruna Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 5, Issue 1( Part 4), January 2015, pp.45-50