水利水电工程专业英语

Specialized En glish

for

Graduates of 2011

Con te nts

1 HYDROPOWER PLANT (1)

1.1 Hydropower (1)

1.2 Adva ntages of Hydropower (1)

1.3 Disadva ntage of a Hydropla nt (2)

1.4 Multi-Purpose Uses (2)

1.4.1 Irrigati on (3)

1.4.2 Flood con trol (3)

1.4.3 Navigati on (3)

1.4.4 Recreati on (3)

1.4.5 Fish Breedi ng (4)

1.5 Typical Comp onents of a Hydroelectric Plant (4)

1.5.1 Dam or Barrage (4)

1.5.2 Water-C on duit System (4)

1.5.3 Power House (5)

1.5.4 Tail Race (5)

1.5.5 Electrical Power Tran smissi on (5)

1.6 Classification of Hydroelectric Plants (5)

1.6.1 Base-Load and Peak-Load Plants (6)

1.6.2 Plants can also be classified as follows: (6)

1.6.3 Classification on the Basis of Available Heads ...................................................... 10..

3 HVAC

........................................................................................................................................... 42 .............. 3.1 Backgro und

.................................................................................................................... 42 ........... 2 HYDRAULIC TURBINES . (14)

2.1 Introduction ....................................................................................................................... 1.4.

2.1.1 Sub-systems of a Water Turb ine .......................................................................... 1.4

2.2 Classification of Water Turbines (15)

2.3 Pelton Turbi ne 2.

3.1 Injector ................................................................................................................... 1.7

2.3.2 Runner ................................................................................................................... 1.7

2.3.3 Number of Nozzles 2.3.5 Cas ing

2.4.1 Main Comp onents ................................................................................................ 24 .........

2.4.2 Scroll Case ............................................................................................................ 24 ........

2.4.5 Runner (27)

2.4.6 Draft Tube ............................................................................................................. 29.

2.4.8 Bottom Ri ng (31)

2.4.9 Shaft .................................................................................................................... 31.

2.4.11 Dewateri ng of Turb ine ......................................................................................... 32 ......

2.5 Propeller and Kapla n Turb ine .......................................................................................... 32 ......

2.5.1 In troduct ion .......................................................................................................... 32 ........

2.5.2 Improveme nt in Efficie ncy (33)

2.5.3 Main Comp onents of the Runner (34)

2.5.4 Locati on of Servomotor (36)

2.5.7 Shaft of the Hydro un it ......................................................................................... 37 ......

2.5.8 Over-speed Protective Devices ............................................................................. 37 ......

2.6 Deriaz Turb ine ................................................................................................................. 38 ..........

1.6 ........

1.9

2.3.4 Distributor .......................................................................................................... 20 ..........

20 ......... 2.3.6 Jet Brake ............................................................................................................... 22 ..........

2.3.7 Tail Water Depressor System

.......................................................................... 23 2.4 Fran cis Turbine ............................................................................................................. 23 ..........

2.4.3 Stay Vanes Ring ................................................................................................. 25 ........

2.4.4 Guide Vanes Mecha nism (26)

2.4.7 Head Cover ......................................................................................................... 30 .........

2.4.10 Turbi ne Pit Liner .............................................................................................. 32 ........

2.5.5 Scroll Case ........................................................................................................... 36 ..........

2.5.6 Automatic Air Valves (37)

2.6.1 In troduction ......................................................................................................... 38 ......... 2.6.2 Servomotor 40 .........

3.2 Heating ............................................................................................................................ 45 ............

3.3 Ven tilati on ...................................................................................................................... 47 ............

3.3.1 Mecha ni cal or forced ven tilati on

3.3.2 Natural ve ntilation 3.4 Air con diti oning ............................................................................................................... 49 .........

3.5 En ergy efficie ncy ........................................................................................................... 52 ..........

3.5.3 Ven tilati on En ergy recovery (53)

3.5.4 Air con diti oning en ergy (54)

3.6 Air Filtrati on and Clea ning (54)

3.6.1 Clean Air Delivery Rate and Filter Performance

1 HY DROPOWER PLANT

1.1 Hydropower

It is the power gen erated by using water as the en ergy-suppl ying age nt. In this case, water is allowed to flow from a higher level to a lower level through a turbine where the potential energy of water is converted into kinetic energy and the turb ine, in turn, rotates a gen erator to produce electricity.

Hydropower gen erati on depe nds upon the availability of rain water. Clouds are

formed because of the heating of seawater by the sun. They move towards the land, where low-pressure zones are formed and as they get cooled, moisture starts precipitat ing. The rain water starts movi ng towards lower levels because of gravity, through a system of natural drains consisting of nullahs , rivulets, rivers and so on. This water can be stored in reservoirs created on the rivers, by con structi on of dams and can be used to gen erate power. After generation, the

47. 4.8.

3.3.3 Airborne III nesses ............................................................................................... 49 ........

3.5.1 Heati ng en ergy .................................................................................................. 52 ........

3.5.2 Geothermal Heat Pump

(53)

..........................................54.. 3.7 HVAC in dustry and sta ndards .. (55)

3.7.1 In ternatio nal ........................................................................................................ 55 .........

3.7.2 North America (USA) ............................................................................................... 55..

3.7.3 Europe (United Kingdom) (57)

3.7.4 Australia ............................................................................................................... 58 .......... 3.7.5 Asia (I ndia) .......................................................................................................... 58 .........

water is let out into the river and gradually travels further and ultimately reaches the sea. Here it is heated up by the sun to start the next cycle. Therefore, hydropower is nothing but conv ersi on of solar en ergy in to electricity through a circuitous route.

1.2 Adva ntages of Hydropower

Hydropower gen erati on is non-wasti ng self-reple nishing and non-pollut ing.

It is a physical phe nomenon and no chemical cha nge is invo Ived. Water come out un cha nged from the turb ine after impart ing its en ergy and can be used again either for power generation or for irrigation. In fact, this is done in multi-purpose river-valley schemes like the Chambal Valley development in India and the Tennessee Valley development in U.S.A. In the case of the Chambal Valley developme nt, power is gen erated with the help of the same water in three powerhouses, situated one after another on the river, before being released in to irrigati on can als. As aga inst this, coal, oil or nu clear fuel can only be used on ce.

The supply of water is automatic and the water utilized in one seas on is reple ni shed by n ature in the n ext seas on. The water reaches the powerhouse site on its own-no mining operations and transportation are invoIved as in the case of coal or oil.

Waterpower is clean as it does not produce any pollutants, whereas in the case of thermal or nu clear power gen erati on polluti on is in evitable, as toxic by-products are emitted.

The hydropower plants have very high efficiencies. The turbine efficiency is above 90 perce nt and the overall efficie ncy can be above 80 perce nt which is much higher than that of thermal plants. The hydro-plants are long lasting and many plants are still in service even 40 years after commissioning. The perce ntage of outages is very low, as shutdow ns for repairs and maintenance are fewer. The plants are available for instant loading and a set can start taking full load within five minutes, starting from the standstill position, whereas thermal pla nts may take about five to six hours.

1.3 Disadva ntage of a Hydropla nt

The initial investments are very heavy and the specific cost is high compared to a thermal plant. The time needed for construction is quite long and it affects the economy adversely as returns start flowing in late. When a lake is formed, la nd submerge nee creates its own problem.

As the availability of water varies from year to year, i n low rain fall years the plant capacity is under-utilized.

Any way the adva ntages far outweigh the disadva ntages.

1.4 Multi-Purpose Uses

As already started earlier, a nu mber of additi onal ben efits can be obta ined from water stored besides gen erat ing power, such as irrigati on, flood con trol, navigation and so on. The multi-purpose use of water gives much better returns on inv estme nt and there is marked improveme nt in the cost-be nefit ratio.

1.4.1 Irrigation

The water being discharged from a powerhouse can be fed into a canal network to provide irrigation facilities to land situated down stream. As a matter of fact, in many multi-purpose projects in India, water is stored predo minan tly for irrigati on purposes with power gen erati on play ing a sec on dary role.

1.4.2 Flood con trol

Creati on of lake on a river has the in here nt possibilities of flood moderati on.

The flood waters may be fully or partly absorbed in the lake and only regulated qua ntities of water are allowed to pass dow nstream, protecti ng the lower areas from floods. This aspect assumes great importa nee in the case of rivers, which go on devastating large tracts of fertile land and valuable property year after year.

1.4.3 Navigatio n

The formati on of storage reservoir in creases the no rmal water level in a river.

Many pools and shallow stretches of the river get submerged un derwater and a

sufficient depth of water becomes available for ship to navigate these stretches. Thus facilitates econo mic tran sport of cargo and passe ngers.

The multi-purpose development of the river Danube in Europe is a typical example of combining navigation with power generation. It 'nking up with

the river Rhine has allowed the ships to pass from the North Sea to the Black Sea. Barrages have been constructed at a number of points in the river

in creas ing the upstream water levels and power is being gen erated at these places. The only additional construction needed is to provide navigational locks at the sites of the barrage for the unin terrupted moveme nt of a ship.

1.4.4 Recreation

Creati on a reservoir of water con siderably enhan ces the beauty and charm of surro unding areas and tourist resorts and pic nic spots are being developed in these areas. 145 Fish Breed ing

It can take place on a large scale and fish can be made available econo mically

to the populati on liv ing in the n eighbori ng areas.

1.5 Typical Components of a Hydroelectric Plant

The mai n comp onents are (Fig.1.1): (i) The dam, (ii) The water-c on duit system, (iii) The powerhouse, (iv) The tail-water system, (v) The switchyard, and (vi) The tran smissi on lin es.

1.5.1 Dam or Barrage

A dam or a barrage is con structed on the river course result ing in an in crease

in the upstream water level because of the formation of a reservoir whose storage capacity is decided by the water requireme nt for power gen erati on.

1.5.2 Water-Co nduit System

Water-c on duit system carries water from the reservoir to the power statio n. It may con sist of a pressure tunnel an d/or pipes called pen stocks which may be laid above ground or un dergro und. One pen stock may feed a nu mber of turbines, where a number of branches have to take off. Flow-control valves may be

provided before water is admitted to the turbines. A surge tank is occasi on ally provided to restrict the effects of water hammer.

Fig.1.1 Typical layout of a high head hydroelectric pla nt

1.5.3 Power House

The powerhouse accommodates the turbines and generators, the control equipme nt and in some cases the tran sformers. Its locati on can be either at the surface or un dergro und and it may be away from, at the foot of, or in the body of, the dam.

1.5.4 Tail Race

The water, after passing through the turbine, is discharged into the tailrace which, in turn, carries it to a river.

The tailrace can be an ope n cha nnel as in the case of a surface powerhouse,

or a tunnel as in the case of an underground powerhouse. The discharge from all the turb ines is collected in the tail race at its beg inning by mea ns of branch cha nn els. The tailrace may discharge in to the origi nal river itself or, in rare cases, some other river when there is an inter-basin transfer of water.

1.5.5 Electrical Power Tran smissi on

The electrical power gen erated by the gen erators is fed to the step-up tran sformers by mea ns of cables as the gen erati ng voltage may be much less than the transmission voltage. The power is then supplied to the transmission network via a switchyard where the switching and protective equipment is in stalled. The switchyard is located within a short dista nce of the powerhouse.

Transmission lines take off in different directions to supply power to the con sumers.