HYDROELECTRIC PLANT TOPIC - POWER HOUSE

PRESENTED BY,

A.ARUL LAWRANCE

M.TECH(RE)

HYDRO POWER

• A hydroelectric power station converts the kinetic, or movement, energy in flowing or falling water into electrical energy.

• Turbines and generators are helpful for extract energy from moving water.

HYDRO POWER PLANT

HYDROELECTRIC PLANT

PARTS OF A HYDROELECTRIC PLANT

• DAM :

Raises the water level of the river to create falling water. Also

controls the flow of water.

• TURBINE :

The force of falling water pushing against the turbine's blades

causes the turbine to spin.

A water turbine is much like a windmill.

The turbine converts the kinetic energy of falling water into

mechanical energy.

• GENERATOR :

Connected to the turbine by shafts and possibly gears so

when the turbine spins it causes the generator to spin also.

Converts the mechanical energy from the turbine into electric

energy.

• TRANSMISSION LINES :

Conduct and transmitts electricity from the hydropower plant

to homes and business.

TURBINE

• Hydraulic turbines are the machines which convert the energy

of flowing water into mechanical energy.

• The mechanical energy developed by a turbine is used to run

an electric generator which is directly coupled to the shaft of

the turbine.

TURBINE TYPES

• Pelton Turbine

• Francis Reaction Turbine

• Propeller and Kaplan Turbines

HYDRAULIC TURBINE MAY BE CLASSIFIED ACCORDING TO SEVERAL CONSIDERATIONS AS FOLLOWS:

• Action of the water flowing.

• Direction of flow of water.

• The head and quantity of water required.

• The specific speed.

ACCORDING TO THE ACTION OF THE WATER FLOWING

• Impulse turbine

• Reaction turbine

IMPULSE TURBINE :

All the available energy by water is converted into kineticenergy by passing through a nozzle. The high velocity jetcoming out of the nozzle then impinges on a series of bucketsfixed around the rim of a wheel.

Example :

Pelton wheel

REACTION TURBINE :

The runner utilizes both potential and kinetic energies. Thepotential energy is transformed into kinetic energy before thefluid enters the turbine runner.

Example :

Francis turbine, Kaplan turbine

ACCORDING TO THE DIRECTION OF FLOW OF WATER

• Tangential flow turbine

• Radial flow turbine

• Axial flow turbine

• Mixed flow turbine

• TANGENTIAL FLOW TURBINE

Water flows along the tangent to the path of the runner.

Example :

Pelton wheel

• RADIAL FLOW TURBINE

Water flows along the radial direction and mainly in the planeto the axis of rotation, as it passes through the runner. It maybe either inward flow or outward radial flow type.

• AXIAL FLOW TURBINE

Water flows parallel to the axis of the turbine shaft.

Example :

Propeller and Kaplan Turbines

• MIXED FLOW TURBINE

Water enters the blades radially and comes out axially,parallel to the turbine shaft.

Example :

Modern francis turbine

ACCORDING TO THE HEAD AND QUANTITY OF WATER REQUIRED.

• High head turbine (above 200m)

Example : Pelton wheel

• Medium head turbine (60m to 200m)

Example : Modern Francis turbine

• Low head turbine (less than 60m)

Example : Kaplan turbine

ACCORDING TO THE SPECIFIC SPEED

• Low specific speed (10 to 35rpm)

Example : Pelton wheel

• Medium specific speed (60 to 400rpm)

Example : Francis turbine

• High specific speed (300 to 1000rpm)

Example : Kaplan turbine

PELTON WHEEL

MAJOR PARTS OF PELTON WHEEL

Spear and nozzle.

Runner with buckets.

Outer casing.

Brake nozzle.

SPEAR AND NOZZLE

To regulate the water flow through the nozzle.

An adjustable spear is for good jet of water and helps to change

nozzle flow passage.

Nozzle which converts hydraulic energy into kinetic energy.

Present at the downstream end of the penstock.

RUNNER WITH BUCKETS

Runner consists of the circular disc and it is mounted on a

horizontal/vertical shaft.

Evenly spaced buckets have a shape of double semi-elliptical

ridge known as splitter.

BREAK NOZZLE

To stop the runner in a short time.

Small nozzle directs a jet of water on the back of buckets.

OUTER CASING

Used to prevent splacing of water and discharging water to

tailrace.

COMPARISION OF PELTON WHEEL WITH OTHER TURBINE

The number of nozzles can be increased or decreased

according to the quantity of water available.

Presence of draft tube in Kaplan and Francis turbines, where

the vacuum is created to form the effective head.

Pelton wheel operates in atmospheric pressure so there is no

draft tube in Pelton wheel.

LIMITATIONS

Pelton wheels are not used at the lower head (below 200m).

Because rotational speed become very slow and the runner

required faster.

Head from the height of the jet is being wasted.

FRANCIS TURBINE

COMPONENTS OF FRANCIS TURBINE

• Penstock

• Spiral Casing

• Guide Vanes (or) stay vanes

• Runner Blades

• Draft tube

• PENSTOCK

It is a large sized conduit which conveys water from theupstream of the dam to the turbine runner. Penstock requiredfor Francis turbine is larger than that of Pelton wheel.

• SPIRALCASINGIt around the runner of the turbine is known as volute casing. The purpose of casing is to provide an even distribution of water around the circumference of the turbine runner maintaining the approximately constant velocity for the water distributed.

• GUIDE VANESThe function of the guide or stay vanes is to convert the pressure energy of the fluid into the momentum energy. The guide vanes are operated either by means of a wheel (or) automatically by a governor.

RUNNER BLADESWater enter radially and leaves axially. The runner is connected to generator so electricity is produced.

DRAFT TUBE

The water is discharged to the tailrace through a gradually

expanding tube is called the draft tube.

Francis turbine is always suitable for straight divergent tube.

COMPARISION OF PELTON WHEEL AND FRANCIS TURBINE

• The parts of a Pelton wheel are more easily accessible and is

easier to repair them.

• For the same head the running speed of Francis turbine is

more than Pelton wheel. This reduces cost of generators and

dimensions of unit.

DIFFERENCE BETWEEN KAPLAN AND FRANCIS TURBINE

Francis turbine is medium specific speed but Kaplan turbine is

high specific speed.

Francis turbine is mixed flow reaction turbine but Kaplan is

only axial flow reaction turbine.

Kaplan turbines have adjustable blades but Francis turbine is

not adjustable.

KAPLAN TURBINE

MAJOR PARTS OF A KAPLAN TURBINE

PARTS OF KAPLAN TURBINE

• Scroll casing

• Guide vanes mechanism

• Runner of turbine

• Draft tube

• SCROLL CASING:

The water from penstock enters scroll casing and surrounds therunner. It provides an even distribution of water around thecircumference of the turbine runner maintaining the constantvelocity for the water distributed.

• STAY RING:

The function of stay ring is to direct the water from scroll casing to guide vanes.

• GUIDE VANES:

The guide vanes direct the water at an appropriate angle andregulates the quantity of water supplied to the runner.

• RUNNER BLADES:

The blades are attached to the hub and so shaped that water flowsaxially through the runner

DRAFT TUBE:

• A Draft tube connects the runner exit to tail race.

• It is a pipe of gradually increasing area used for dischargingwater from exit of turbine to tail race.

• By using draft tube, the kinetic energy rejected at the outletof turbine is converted to useful pressure energy.

• The turbine may be placed above the tail race and hence itcan be inspected properly.

OPERATION OF KAPLAN TURBINE

• The water from the penstocks enters the scroll casing and thenmoves to the guide vanes.

• From the guide vanes, the water turns through 90° and flowsaxially through the runner.

• The shaft of the turbine is vertical. The lower end of the shaft ismade larger and is called Hub.

• The vanes are fixed on the hub and hence Hub acts as runner foraxial flow turbine.

COMPARISON WITH OTHER TURBINES

• Another difference is that in Pelton turbine no draft tube isused whereas in Francis and Kaplan turbine draft tube isused.

• In Pelton turbine the pressure energy is converted in to kineticenergy completely and is fully utilized hence there is no needof draft tube.

• In reaction turbine, unutilized kinetic energy is available at theoutlet of turbine hence to utilize that kinetic energy in thewater a draft tube is used.

PROPELLER TURBINE

PROPELLER TURBINE

• Designed to work fully submerged, it is similar in form to aship's propeller and is the most suitable design for low headwater sources with a high flow rate such as those in slowrunning rivers.

• Designs are optimized for a particular flow rate andefficiencies drop of rapidly if the flow rate falls below thedesign rating.

• The Kaplan version has variable pitch vanes to enable it towork efficiently over a range of flow rates.

POWERHOUSE

• Turbine room

• Generator

• Service areas

GENERATOR

GENERATOR

• The generator converts the rotational power from the turbineshaft into electrical power.

• DC generators can be used with very small systems, buttypically are augmented with batteries and inverters forconverting the power into the AC power required by mostappliances.

• AC generators are normally used in all but the smallest systems.

• AC voltage is also easily changed using transformers, whichmakes it relatively simple to drive other types of devices.

• One critical aspect of AC power is frequency, typically measuredas cycles per second (cps) or Hertz (Hz).

• The major grids that interconnect large power generatingstations.

SERVICE AREA

• Offices

• Control and testing rooms

• Storage rooms

• Maintenance shop

• Auxiliary equipment rooms

SYSTEM CONTROL

• Governors and Controls

• Electronic Load Governors

• Load Management Systems

• Emergency System Shutdown

• Utility Grid Interface Controls

GOVERNORS AND CONTROLS

• Its help ensure that the generator constantly spins at its

correct speed.

• To illustrate, consider a hydro system without a governor, it

causes the generator to work harder.

• As long as you maintain this “perfect” load is known as Design

Load, power output will be correct.

ELECTRONIC LOAD GOVERNORS

• It works by automatically adjusting the load.

• It is highly effective for small systems up to about 12kW.

LOAD MANAGEMENT SYSTEMS

• An enhanced version of the electronic load governor, offering

not only the ability to regulate power usage.

• Small load adjustments work just like the electronic governor;

the variable electronic switch regulates power to the ballast

loads.

EMERGENCY SYSTEM SHUTDOWN

• It is an option that protects the system from overspeed, which

may damage the generator.

• It usually means removing all water power from turbine.

• Emergency shutdown of impulse turbines, such as Pelton

wheel, can be very fast because the water jet can simply be

deflected away from the turbine. Since the water flow doesn’t

change, there are no damaging surges.

UTILITY GRID INTERFACE CONTROLS

UTILITY GRID INTERFACE CONTROLS

• The grid interconnects very large, public utility power

generation systems.

• They will monitor the grid and ensure system is generating

compatible voltage, frequency, and phase.

• Automatic disconnection is critical to the safety of all parties.

• Turbine manufacturer can give you guidance on the most

efficient design, as well as grid interconnection controls and

safeguards.

THANK YOU

PRESENTED BY,

A.ARUL LAWRANCE

M.TECH(RE)