What is Renewable energy ?

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ALTERNATIVE/RENEWABLE ENERGY

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any sustainable energy source that comes from natural environment.

It means energy is generated from absolutely natural powers and this energy sources can be replenished.

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CONCLUSION we need renewable energy

Renewable energy technologies are clean sources of energy that have a much lower environmental impact than conventional energy technologies.

Renewable energy will not run out. Ever. Other sources of energy are finite and will some day be depleted.

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Natural energy sourcesSOLAR ENERGY (the power comes from the sun and it can turned into electricity and heat)WIND POWER (conversion of wind energy into electricity) HYDRO POWER ( the power of water)BIOMASS (organic materials from plants)

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Renewable vs. Non-renewable

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What is an electricity?Electricity is the flow of electrical power or charge.

It is a secondary energy source which means that we get it from the conversion of other sources of energy, like coal, natural gas, oil, nuclear power and other natural sources, which are called primary sources.

The energy sources we use to make electricity can be renewable or non-renewable, but electricity itself is neither renewable or non-renewable.

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THE SCIENCE OF ELECTRICITY Atoms are the building blocks of the universe. Atoms are made of even smaller particles. The center of an atom is called the nucleus. It is made of particles called protons and neutrons. The protons and neutrons are very small, but electrons are much, much smaller. Electrons spin around the nucleus in shells a great distance from the nucleus. Atom would look like a tiny center of balls surrounded by giant invisible bubbles (or shells). The electrons would be on the surface of the bubbles, constantly spinning and moving to stay as far away from each other as possible. Electrons are held in their shells by an electrical force.

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The protons and electrons of an atom are attracted to each other. They both carry an electrical charge. An electrical charge is a force within the particle.

Protons have a positive charge (+) and electrons have a negative charge (-). The positive charge of the protons is equal to the negative charge of the electrons. Opposite charges attract each other.

When an atom is in balance, it has an equal number of protons and electrons. The neutrons carry no charge and their number can vary.

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The number of protons in an atom determines the kind of atom, or element, it is. An element is a substance in which all of the atoms are identical.

The electrons in the shells closest to the nucleus have a strong force of attraction to the protons. Sometimes, the electrons in the outermost shells do not. These electrons can be pushed out of their orbits. Applying a force can make them move from one atom to another. These moving electrons are electricity.

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How is electricity generated A generator is a device that converts mechanical energy into electrical energy. The process is based on the relationship between magnetism and electricity.when a magnet is moved inside a coil of wire, electrical current flows in the wire.

A typical generator at a power plant uses an electromagnet-a magnet produced by electricity-not a traditional magnet. The generator has a series of insulated coils of wire that form a stationary cylinder. This cylinder surrounds a rotary electromagnetic shaft.

When the electromagnetic shaft rotates, it induces a small electric current in each section of the wire coil. Each section of the wire becomes a small, separate electric conductor.The small currents of individual sections are added together to form one large current.

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Main Shaft

Hub

Rotor Shaft

Bearings

Gear

Brake

Clutch

Generator

Generator Rotor

Generator Stator

Hub

Main Bearing

Axle pin

Conventional

Gearless

The gear concept and gearless concept in a component comparison

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Selection of primary distribution voltage In wind farms power is generated at 400 KV. The utility grid will be generally at 230 KV or above. Transformation from 400 V to 230 KV directly would not be economical and also prudent practice.

Hence, normally the 400 V is stepped up to an intermediate voltage level say,11KV or 33KV. For longer distances and higher power evacuation 33KV would be economical. Hence primary distribution is at 33KV.

A Transformer located at the bottom of the wind energy generator converts the 3 phase AC power generated by WEC at 400V to 33,000V, i.e., 33KV. At WEC the energy is produced at a relatively low voltage of 400V, then stepped up by the tower mounted transformer to a higher voltage (33 KV AC) for transmission over long distances.

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Design of an Evacuation Sub-station

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Imp. Considerations in substation designSafety of personnel and equipmentReliability and SecurityAdherence to Statutory obligations

I.E. rules, Environmental aspectsElectrical design considerationsStructural design considerations Ease of maintenancePossibility to Expand

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FUNCTIONS OF EVACUATION SUB-STATIONEvacuation substations are designed to accomplish the following functions: Connect wind energy convertors to the systems. Change voltage from one level to other with out changing the frequency. To measure electric power and quantify for payment(bulk metering). Regulate voltage to compensate for system voltage changes. Switch transmission (switching stations) and distribution circuits into and out of grid system Measure electric power qualities flowing in the circuits. Eliminate lightning and other electrical surges from the system.

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Functions of substation equipments

EquipmentFunction1. Bus-BarIncoming & outgoing ckts. Connected to bus-bar2. Circuit BreakerAutomatic switching during normal or abnormal conditions3. IsolatorsDisconnection under no-load condition for safety, isolation and maintenance.4. Earthing switchTo discharge the voltage on dead lines to earth5. Current TransformerTo step-down currents for measurement, control & protection6. Voltage TransformerTo step-down voltages for measurement, control & protection7. Lightning ArresterTo discharge lightning over voltages and switching over voltages to earth

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Functions of substation equipments Contd

8. Shunt reactorTo control over voltages by providing reactive power compensation9. Neutral-Grounding resistorTo limit earth fault current10. Coupling capacitorTo provide connection between high voltage line & PLCC equipment11. Line TrapTo prevent high frequency signals from entering other zones.12. Shunt capacitorsTo provide compensations to reactive loads of lagging power factors13. Power TransformerTo step-up or step-down the voltage and transfer power from one a.c. voltage another a.c. voltage at the same frequency.14. Series CapacitorCompensation of long lines.

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Functions of Associated system in substation

SystemFunction1. Substation Earthing system-- Earthmat-- Earthing spikes-- Earthing risersTo provide an earthmat for connecting neural points, equipment body, support structures to earth. For safety of personnel and for enabling earth fault protection. To provide the path for discharging the earth currents from neutrals, faults, Surge Arresters, overheads shielding wires etc. with safe step-potential and touch potential.2. Overhead earth wire shielding or Lightning masts.To protect the outdoor substation equipment from lightning strokes.3. Illumination system (lighting)-- for switchyard-- buildings-- roads etc.

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Contd..

4. Protection system -- protection relay panels -- control cables -- circuit breakers -- CTs, VTs etc.To provide alarm or automatic tripping of faulty part from healthy part and also to minimize damage to faulty equipment and associated system.5. Control cableFor Protective circuits, control circuits, metering circuits, communication circuits6. Power cableTo provide supply path to various auxiliary equipment and machines.7. PLCC system power line carries communication system -- line trap -- coupling capacitor -- PLCC panelsFor communication, telemetry, tele-control, power line carrier protection etc.

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8. Fire Fighting system -- Sensors, detection system -- water spray system -- fire prot. panels, alarm system -- watertank and spray systemTo sense the occurrence of fire by sensors and to initiate water spray, to disconnect power supply to affected region to pin-point location of fire by indication in control room.9. Auxiliary standby power system -- diesel generator sets -- switchgear -- distribution systemFor supplying starting power, standby power for auxiliaries10. Telephone, telex, microwave, OPFFor internal and external communication

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400kV Circuit Breaker

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400kV Isolator

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400kV Current Transformer

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400kV CVT

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400kV Surge Arrester

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TransformerA transformer is a static piece of apparatus by means of which electric power in one circuit is transformed into electric power of the same frequency in another circuit. It can raise or lower the voltage in a circuit but with a corresponding decrease or increase in current.

Principle: A transformer is a device that Transfers electric power from one circuit to another. It does so without a change of frequency. It accomplishes this by electromagnetic induction and where the two circuit are in mutual inductive influence of each other.

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Internal & External lines Internal lines are over head lines that connect the tower mounted transformer and the VCB yard. The conductor is usually(Aluminum conductor steel reinforced). The conductors are supported at every 50 meter by electric pole. External lines connect two are more VCB yards to a power evacuation substation. The choice of the conductor is similar to internal lines. Normally, ACSR coyote or Panther conductor is used for external lines.

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VCB & METERING YARD A circuit breaker is an automatically-operated electrical switch designed to protect an electrical circuit 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. Vacuum circuit breakerWith rated current up to 3000 A, these breakers interrupt the current by creating and extinguishing the arc in a vacuum container. These are also operated by current sensing protective relays operated through Current transformers. These are generally applied for voltages up to about 35,000 V, which corresponds roughly to the medium-voltage range of power systems.

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ELECTRICAL CLEARANCES1. MIN.GROUND CLEARANCE 2. MIN.CLEARANCE ABOVE HIGHEST FLOOD LEVEL3. CLEARACE AND SWING ANGLES4. AIR CLEARANCE5. POWER LINE CROSSINGS6. TELECOM.LINE CROSSINGS7. RAIL TRACK CROSSINGS

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Clearances to Ground and Roads(distance in Meters)Sl.NoDescription11 KV33 KV1Minimum vertical clearance to over head line conductora) Across the street6.16.1b) Along the street5.85.8c)At other places5.25.2

Clearances to Buildings (distance in Meters)Sl.NoDescription11 KV33 KV1Minimum vertical clearance to buildings3.73.72Minimum horizontal clearance to buildings1.321.82

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Clearances to Communication lines (Distance in meters)Sl.NoDescription11 KV33 KV1Minimum vertical clearance between power and communication lines2.142.44

Clearances between power lines when crossing each other (Distance in meters)Sl.NoDescription11 KV33 KV111 KV and 33 KV2.442.442132 KV3.053.053220 KV4.584.584400 KV5.495.495800 KV7.947.94

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