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1456887959-SEMINARREPORTONSWITCHYARDEQUIPMENTSPROTECTIONSYSTEMS.pdf (Size: 918.45 KB / Downloads: 10)
SALIENT FEATURES OF 132KV SWITCHTYARD:-
20 OPERATING BAYS
• 02 GENERATORS
• 04 GRIDCO FEEDERS
• 06 SMELTER FEEDERS
• BUS COUPLER
• BUS TIE CUM BUS COUPLER
• STATION TRANSFORMERS
• 01 BT BAY
• ISOLATION TRANSFORMERS
IMPORTANT COMPONENTS OF THE SWITCH YARD
1. BUSBARS:
TYPES OF BUSBAR ARRANGEMENTS:
1. Single Bus-bar Arrangement.
2. Single Bus-bar System with Sectionalization
3. Ring Bus-bar system
4. Double Main and Transfer Bus-bar Arrangement
5. Duplicate Bus-bars System
SINGLE BUS-BAR ARRANGEMENT
DEPARTMENT OF ELECTRICAL ENGINEERING,
V.S.S.U.T,BURLA 03-Nov-2013 11
In this arrangement a set of bus-bars is used for complete power station and
to this bus-bar are connected all generators, transformers and feeders
through circuit breakers and isolating switches.
SINGLE BUS-BAR SYSTEM WITH SECTIONALIZATION
DEPARTMENT OF ELECTRICAL ENGINEERING,
V.S.S.U.T,BURLA 03-Nov-2013 12
With increased number of generators and outgoing feeders connected to
the bus-bars, it becomes essential to provide arrangement for
sectionalizing the bus-bars so that a fault on any one section of the busbars
may not cause a complete shutdown. This is achieved by providing
a circuit breaker and isolating switches between the section.
RING BUS-BAR SYSTEM
DEPARTMENT OF ELECTRICAL ENGINEERING,
V.S.S.U.T,BURLA 03-Nov-2013 13
In this arrangement each feeder is supplied from two paths, so that in
case of failure of a section, supply is not interrupted.
DOUBLE MAIN AND TRANSFER BUS-BAR
ARRANGEMENT
DEPARTMENT OF ELECTRICAL ENGINEERING,
V.S.S.U.T,BURLA 03-Nov-2013 14
This arrangement incorporates all advantages of the double bus as well as
transfer bus scheme. This scheme needs a bus-coupler for the on load transfer of
circuits from one main bus to the other and a transfer coupler for taking out
circuit breaker of various circuits for maintenance.
BUS COUPLER:
• Two different bus sections of two different power transformers are
connected by means of a bus coupler.
• The bus coupler becomes useful when one of the power transformers
fails or a fault occurs in either of the bus sections.
3. INSULATORS:
• The overhead line conductors should be supported on the poles or
towers in such a way that currents from conductors do not flow to
earth through supports i.e., line conductors must be properly insulated
from supports. This is achieved by securing line conductors to supports
with the help of INSULATORS.
• The insulators provide necessary insulation between line conductors
and supports and thus prevent any leakage current from conductors to
earth.
CIRCUIT BREAKER & RELAYS:
• A circuit breaker is an automatically operated electrical switch designed
to protect an electrical current from damage caused by overload or
short circuit.
• Its basic function is to detect a fault condition and, by interrupting
continuity, to immediately discontinue electrical flow.
• The circuit breaker works along with the relays which give a tripping
signal in case of any irregularity or the faults.
• The circuit breaker then opens to open the circuit such that other
instruments of the system can be protected.
ISOLATORS: (GOD)- GROUP OPERATED DISCONNECTOR:
• It is used to make sure that an electrical circuit can be completely deenergised
for service or maintenance.
• It allows isolation of apparatus such as circuit breakers and
transformers, and transmission lines, for maintenance.
• GOD’s are provided to facilitate isolation of breakers supplying power to
various feeders. In 220kv Switchyard, they are designed as 29A, 29B,
29C & 29E as follows
29 A – main bus side GOD.
29 B - Equipment side GOD.
29 C - Transfer bus side GOD.
29 E - Earth GOD.
Current and voltage transformers
• Current or voltage instrument transformers are necessary for isolating
the protection, control and measurement equipment from the high
voltages of a power system, and for supplying the equipment with the
appropriate values of current and voltage - generally these are 1A or 5Α
for the current coils, and 120 V for the voltage coils.
LIGHTNING ARRESTER:
• A lightning arrester is a device used on electrical power systems
and telecommunication systems to protect the insulation and
conductors of the system from the damaging effects of lightning.
• The typical lightning arrester has a high-voltage terminal and a ground
terminal.
• When a lightning surge (or switching surge, which is very similar) travels
along the power line to the arrester, the current from the surge is
diverted through the arrestor, in most cases to earth.
CONCLUSION :-
• Switchyard is most essential part of the power system.
• It is the protective part of the whole power system.
• Switch yard is also most essential part for transmission, distribution, and
collection