Function of Line supports

 Function of Line supports:- The function of line supports is obviously to supports the conductors. Line supports must be capable of carrying the load due to insulators and conductors including the ice and wind loads on the conductors along with the wind load on the supports itself.The line supports are various type including;- 1. wood 2. steel 3. Reinforced concrete poles 4. steel tower.

The main requirements of the line supports are:- 

1. High mechanical strength to withstand the weight of conductors and wind load.

2. Light in weight without the loss of mechanical strength.

3. Cheaper in cost.

4. Low maintenance cost.

5. Longer life.

6. Good looking.

1.Wooden poles:- These supports are cheapest , easily,available, provide insulating properties and  are extensively used for the distribution purpose specially in rural electrification keeping the cost low.Their use is usually limited to pressures (22kv) and for short spans (upto 60 mtr) To prevent decay owing to snow and rain, the wooden poles are protected by an aluminium, Zinc,or cement cap at the top.

Normally the wooden pole lenths is 10 to 12 mtr .The main drawback of wooden supports are less mechanical strength, smaller life.

2. Steel Poles:- The steel pole are three type (a) tabular poles (b) rail poles (c) rolled steel joists. The tabular pole are  of cross-section,the rail poles are of the shape of track used for railways and rolled steel joists are of I cross-section. such poles possess greater mechanical strength  and permit to use longer spans (50-80 m)  but cost is higher.

The advantages of tabular poles are that these poles are lighter in weight and easy ti install.

3. RCC Poles:- Poles made of reinforced cement concrete (RCC) usually called the concrete poles are used for low voltage distribution lines upto 33kv.These poles are two types in shape. one type is of square cross-section from bottom to top .The other type has rectangular bottom and square top with rectangular holes in it

4. Lattice steel Tower:- The Lattice steel tower are used for transmission at 1kv and 33kv and broad-base, lattice-steel taower are mechanically stronger and have got longer life due to their robust construction long spans (300m and above) can be used and are much usefull for crossing fields,valleys, railways lines,river.

Natural sources of Energy.

 Natural sources of Energy:-  There are some following natural sources of energy of which may be converted into electrical energy.   

1. Water        2.Fuels       3. Nuclear Energy      4. sun

5. Wind         6. Biomass.

1. Water:-  The potential energy of water collected at higher level or the kinetic energy of water flowing at high velocity can be used to run the turbines.These turbines or prime-mover are known as hydraulic turbines. Generators are coupled to these prime -movers which convert mechanical energy into electrical energy.In this case capital cost is very high but running cost is very low as no fuel is used.The largest hydro-electric power station is built in south America on the river Parana. It has 18 turbines generating 12600 million watts (12600 MW). In India one of the major hydro -electric power project is Bhakra Nangal project. The dam is erected across the river Sutlej and a lake called Gobind sager is crected behind it. Bhakra power plant has two power houses.overall capacity is 1200MW.

2.Fuel:- The most common source of energy is fuel.In nature ,fuel is available in solid,liquid or gaseous.

(a) solid fuel :-The main solid fuel is coal,which is available in nature in a very huge quantity.By the combustion of coal in the boiler heat energy is produced which is utilized to produce steam.The steam is utilized to run the the steam turbines to which generator are coupled.The electrical energy is generted.

(b) Liquied fuel:- From petroleum bulk of oil fuels ranging from petrol to heavy oil are obtained from the refineries. The main liquid fuel is diesel.In this case,diesel oil is injected into the piston cylinder of a diesel engine,where combustion of oil takes place which developes mechanical energy.

(c) Gaseous fuels:- Natural gas, when available in abundance at site,is used to run the gas turbines or it is burnt to produced steam which is used to run the turbines.A generator is coupled to the turbines to generate electrical energy.

3. Nuclear Energy:- The heavy substance whose nucleus whose can be broken into fragment is called nuclear fuel. The only substance found in nature which fissions and is capable of propagating nuclear chain  reaction is uranium .By fission of nuclear ,binding energy is released in the form of heat energy.which is utilized for conversion of water into steam.steam is utilized to drive steam turbines.A generator is coupled to the turbines to generate electrical energy.

4. Sun:-  This is primary sources of energy . Sun radiates energy in the form of electro-magnetic waves, which includes heat ,light, and lot of ultra violet radiation. The solar plant converted sun light into  the electrical energy. 

5.Wind:-  wind pressure is developed due to heating and cooling of the atmosphere which generates convection currents. This wind pressure is utilised in wind mills to drive small generators. The energy generated by the generated is used to charge the bank of batteries for continuous use.power generation in this case is limited and depend upon the velocity of wind.

6. Biomass:-  Biomass contain chemical energy .It can be burnt to give energy. you might have seen people in village burning cowdung cakes as fuel. This is a crude method of using biomass. A better method is to convert biomass into a gas called biomass. Biogas is prepered in the biogas plant.In this case biomass is mixed with water and a slury is made.By the action of bacteria on the biomass ,biogas is produced which is stored in the tank.

comparison between various type of power station

 comparison between various type of power station :- 

Hydro-power plant:- 1.Capital cost is very high on account of heavy cost of erection of  dam and machinery.

2.No fuel is used its running cost is very low.

3.They can be started instantly

4.They require a large space for reservoir and construction of dam.

5.Very less maintenance is required.

6.They depend upon the rain fall and a long dry season may affect the power generation.

7. These plants are located at places where dams can be errected and huges quantity of water is collected at a sufficient head.

8. These power plant are located far away from load center therefore long transmission lines are required and hence cost of transmission and distribution is very high.

9. As no fuel is used,therefore cost of trans-potation of fuel is nil.

10.These plant are most simple and clean.

Steam power-plant:- 1.  Capital cost is low in comparison to that of hydro and nuclear power stations.

2. Running cost is low as compared to disesel power power station due to low cost of fuel.but more than hydro and nuclear power stations.

3. They require long time for starting.

4. They require smaller space in comparison  to that of hydro and nuclear power station but more than diesel power stations.

5. They need more maintenance as compared to diesel and hydro power plant.

6. coal- fuel is limited and coal mines may get exhaust.

7.These plants are located near  the load center having the facilities  such as supply of fuel ,water transportation facilities.

8. These plants are located near the load center.

9. Cost of transportation of fuel is very high.

10. These plants are not so simple and atmosphere is polluted by fumes and residues of pulverized fuel.

Diesel power plant:- 1. Capital cost is minimum.

2. Running cost is very high.

3. They can be started quickely.

4. They require very less space.

5.They need more maintenance as compared to other.

6.Diesel oil- fuel is not available in plenty.

7.These plants can be installed at any place,

8.Transmission and distribution cost almost nil.

9. These plants are simple and clean compared to steam power plants.

10. These plants are also less reliable due to non-availbility of fuel.

Nucleare power stations:- 1.Capital cost is very high.

2. Running cost is very low as compared to diesel power stations.

3. They require long time for starting.

4. They require smaller space than hydro electric power station.

5.They need much more maintenance than other power plants.

6.These plants are located near to load center.

7. Cost of  transportation of fuel is very low.

8. These plant is very complicated to operate and special care is taken to remove the radioactive.