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7/29/2019 220 kV AIS Switchyard
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Project By
Mohammed Mahmooduddin
Syed Abbas Noori
Syed Obaidur Rahman
Under guidance of
Mrs. Ajaz Fatima(internal)
Mr. M.A. Ahmed(external)
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PROJECT
To design the switchyard is to evacuate the power from 375 MWCombined Cycle Power Plant.
Purpose:
The substations are very much essential to Evacuate power from generating stations.
Transmit to the load centers.
Distribute to the utilities & ultimate consumers
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WHY SUBSTATIONS ? The Electrical power generation from Hydel, Thermal,
Nuclear and other generating stations has to beevacuated to load centers.
The generation voltage is limited to 15/18 KV due to thelimitation of the rotating machinery.
This bulk power has to be stepped up to higher voltages
depending on quantum of power generated anddistance to the load centers.
Again the power has to be stepped down to differentlower voltages for transmission and distribution
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TYPES OF SUBSTATIONS
The substations are classified as
a)Generating substations (Switchyard)
b) Grid substations
c) Switching stations
d) Secondary substations.
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Generating substations (Switchyard)
The generating substations are step up stations as thegeneration voltage needs to be stepped up to theprimary transmission voltage so that huge blocks ofpower can be transmitted over long distances to loadcenters
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grid substations The grid substations are created at suitable load
centers along the primary transmission lines
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Switching stationsSwitching stations are provided in between lengthy primarytransmission lines
To avoid switching surges.
For easy segregation of faulty zones. For providing effective protection to the system in the A.C.network.
The switching stations also required wherever the EHT lineare to be tapped and line to be extended to different load
centers without any step down facility at the switchingstations. The number of outgoing lines will be more than the
incoming lines, depending on the load points
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Secondary substations Secondary substations are located at actual load points
along the secondary transmission lines where thevoltage is further stepped down to sub transmission &primary distribution voltage.
Distribution substations are created where the sub-transmission voltage and primary distribution voltage
are stepped down to supplyvoltage and feed the actual consumers through a
network of distribution and service lines.
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TRANSMISSION SUBSTATION
DISTRIBUTION SUBSTATION
COLLECTOR SUBSTATION
CONVERSION SUBSATION
SWITCHING SUBSTATION
ADJUST THE ABOVE HERE
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SELECTIONOFSITE
Selection of site for construction of a Grid
Sub Station is the first and important activity.
This needs meticulous planning, fore-sight,skillful observation and handling so that the
selected site is technically, environmentally,
economically and socially optimal and is thebest suited to the requirements.
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SOCIALANDCOMMUNITY ENVIRONMENTAL
What are the predicted futureenergy requirements of the
community?
What is the land zoning of the
site and its proximity to
residents? What is the likely visual impact,
considering the direct line of
sight, substation height and
visual screening options?
Can the substation be locatedas to not disturb surrounding
residents and if not, can a
design solution be determined?
Are there any potential impactson declared rare flora or fauna,
priority flora or threatened
ecological communities?
Is the site likely to impact anunderground water protection
area or wetland system?
Is a design option likely to
impact on any knownIndigenous or European
heritage sites?
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TECHNICALREQUIREMENTS
Is the location close to the load area that it will service?
Is the substation located as close as possible to existingtransmission lines, from which it will draw its power?
Does the site allow for connection of in-coming transmission lines
and out-going underground distribution lines?
Is the site far enough away from underground copper cables (eg.telecommunications cables) and the steel pipelines used by gas and
water companies, so that earthing and voltage induction issues can
be avoided. Where this cannot be avoided, costs to mitigate are
extreme.
Could a standard design be accommodated on the site, or are therespecial design considerations?
Physical constraints such as slope, geology, water table and
flooding.
Engineering features such as vehicle access, earthworks and
services.
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ECONOMICREQUIREMENTS
As a regulated body, can we satisfy the
Economic Regulation Authority that the most
cost effective solution has been identified? What alternative solutions are available?
Can cost effective improvements to the design
reduce the visual impacts on the community?
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REQUIREMENT OF LAND/AREA
The site should have sufficient area to properly accommodate the Sub
Station buildings ,structures ,equipments, etc. and should have the
sufficient area for future extension of the buildings and / or switchyard.
The requirement of land for construction of Sub SUBSTATION1. 400 kV 20.0 Hectare
2. 220 kV 6.0 Hectare
3. 132 kV 3.5 Hectare
While preparing proposals for acquisition of private land and allotment
of Government.
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SYSTEMBUSES
The main criterias to be considered during selection of
one particular Bus Bar Arrangement Scheme among
others
i. Simplicity of system
(ii) Easy maintenance of different equipments.
(iii) Minimizing the outage during maintenance.(iv) Future provision of extension with growth of demand
(v) Optimizing the selection of bus bar arrangement
scheme so that it gives maximum return from the system.
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Types of system
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DOUBLE BUS SYSTEMWITH BYPASS
ISOLATORS This is combination of the double bus
system and main and transfer bussystem.
In Double Bus System with Bypass
Isolators either bus can act as main bus
and second bus as transfer bus.
It permits breaker maintenance withoutinterruption of power which is not
possible in double bus system but it
provides all the advantages of double
bus system.
It however requires one additionalisolator (bypass isolator) for each feeder
circuit and introduces slight complication
in system layout. Still this scheme is best
for optimum economy of system and it is
best optimum choice for 220KV system.
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EQUIPMENTSCOMMONLYFOUNDIN
SWITCHYARD Lightening arrestor
Current transformer
Voltage transformer Power transformers / I.C.T.
Bus bar and clamp fittings
Support structure Isolators
Circuit Breaker
Wave traps
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EQUIPMENTSINASUB-STATION
Transformers :
- Transforms the voltage levels from higher to lower level
or vice versa, keeping the power constant.
Instrument transformers :
- For stepping-down the electrical parameter (Voltage or Current) to
a lower and safe value for Metering and Protection logics.
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Earth switch :
- Used to connect the charged body to ground to discharge thetrapped charge to have a safe maintenance zone
Lightning arrestors :- Safe guards the equipment by discharging the high currents
due to Lightning.
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EQUIPEMENTSOverhead earth wire :
- Protects the O/H transmission line from Lightning strokes.
Wave Traps/Line traps :
- Used in PLCC circuits for Communication and Protection of
Transmission lines
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Reactive Power control devices :
- Controls the reactive power imbalance in the grid byswitching ON/OFF the Shunt Reactors, Shunt Capacitors etc.,
Current Limiting Reactors :
- Limits the Short circuit currents in case of faulty conditions
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EQUIPMENTINBUSCOUPLERBAY
Circuit breakers Makes or automatically breaks
the electrical circuits underLoaded condition
Interrupting short-circuit current
Reliable protection of motors
Protection of leads and itsoptimum utilisation
Protection of installations
Integration in the control circuit Switching under normal service
conditions
Disconnecting function
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Operates under off-load
conditions
Physically isolates the electric
circuit
Does not have any current
making & breaking capacity
Used in addition to C.B.
isolators