Electrical Power Generation Notes2

 

UNIT 2

Syllabus: Diesel electric plants. Gas turbine plants. Mini, micro and bio generation. Concept of distributed generation.

DIESEL POWER PLANT 

A generating station in which diesel engine is used as the prime mover for the generation of electrical energy is known as Diesel power station. Diesel power plants produce power from a diesel engine. Diesel electric plants in the range of 2 to 50 MW capacities are used as central stations for small electric supply networks and used as a standby to hydro electric or thermal plants where continuous power supply is needed. Diesel power plant is not economical compared to other power plants. The diesel power plants are cheaply used in the fields mentioned below. 1.  Peak load plants 2.  Mobile electric plants 3.  Standby units 4.  Emergency power plants 5.  Starting stations of existing plants 6.  Central power station etc

  V i na nayyaka.B ka.B .G .G.. Ass A sstt.Pro .Pr ofe fess sso or , D ept E & E , BI B I E T, Da D avanage nagerr e

 

4.3.2 Advantages of diesel power plants 

1.  More efficient than thermal plant 2.  Design, Layout etc are simple and cheap 3.  Part load efficiency is very high 4.  It can be started quickly 5.  Simple & easy maintenance 6.  No problem with fuel & dust handling 7.  It can be located in the heart of town 8.  Less cooling water required. 4.3.3

Disadvantages 

1.  There is a limitation for size of a diesel engine 2.  Life of plant is comparatively less 3.  Noise pollution is very high 4.  Repair cost is very high 5.  High lubrication cost

  V i na nayyaka.B ka.B .G .G.. Ass A sstt.Pro .Pr ofe fess sso or , D ept E & E , BI B I E T, Da D avanage nagerr e

 

Apllications Of Diesel Power Plant:

  Emergency plant: To maintain the essential services when the supply from

•

the grid is not available. •

  Starting auxiliaries: They are used to start the auxiliaries in steam power stations.

  Mobile Plants: Mobile diesel plants mounted on trailers are used for

•

temporary and emergency purposes.

  Peak load plants: A diesel plant can be started and loaded quickly, so these

•

plants can be used as peak load plants.

  Standby plants: They can be used as standby plants when supply from grid

•

is not available.

  Remote Places: They can be used in remote locations where supply the grid

•

is not available. 4.3.1 General Layout of Diesel power plants

  V i na nayyaka.B ka.B .G .G.. Ass A sstt.Pro .Pr ofe fess sso or , D ept E & E , BI B I E T, Da D avanage nagerr e

 

General Layout of Diesel power plants Figure shows the arrangements of the engine and its auxiliaries in a diesel power plant. The major components of the plant are: Engine 

a)

Engine is the heart of a diesel power plant. Engine is directly connected through a gear box to the generator. Generally two-stroke engines are used for power generation. Now a days, advanced super & turbo charged high speed engines are available for power production. b)

Air supply system

Air inlet is arranged outside the engine room. Air from the atmosphere is filtered by air filter and conveyed to the inlet manifold of engine. In large plants supercharger/turbocharger is used for increasing the pressure of input air which increases the power output. Exhaust System 

c)

This includes the silencers and connecting ducts. The heat content of the exhaust gas is utilized in a turbine in a turbocharger to compress the air input to the engine. d) Fuel System 

Fuel is stored in a tank from where it flows to the fuel pump through a filter. Fuel is injected to the engine as per the load requirement.

  V i na nayyaka.B ka.B .G .G.. Ass A sstt.Pro .Pr ofe fess sso or , D ept E & E , BI B I E T, Da D avanage nagerr e

 

e) Cooling system 

This system includes water circulating pumps, cooling towers, water filter etc. Cooling water is circulated through the engine block to keep the temperature of the engine in the safe range.  f)

Lubricating sy system stem 

Lubrication system includes the air pumps, oil tanks, filters, coolers and pipe lines. Lubricant is given to reduce friction of moving parts and reduce the wear and tear of the engine parts. g)

Starting System 

There are three commonly used starting systems, they are; 1) A petrol driven auxiliary engine, 2) Use of electric motors, 3) Use of compressed air from an air compressor at a pressure of 20 Kg/cm”  Kg/cm”  h)

Governing system 

The function of a governing system is to maintain the speed of the engine constant irrespective of load on the plant. This is done by varying fuel supply to the engine according to load.

  V i na nayyaka.B ka.B .G .G.. Ass A sstt.Pro .Pr ofe fess sso or , D ept E & E , BI B I E T, Da D avanage nagerr e

 

  V i na nayyaka.B ka.B .G .G.. Ass A sstt.Pro .Pr ofe fess sso or , D ept E & E , BI B I E T, Da D avanage nagerr e

 

  V i na nayyaka.B ka.B .G .G.. Ass A sstt.Pro .Pr ofe fess sso or , D ept E & E , BI B I E T, Da D avanage nagerr e

 

GAS TURBINE POWER PLANT: With a neat schematic diagram, explain working of a gas turbine power plant. DEC 09.10, 6 M

With a neat sketch, explain working of a gas turbine power plant. JUNE 11, 8 M

Explain working of a gas turbine power plant, with a neat sketch, JUNE 11, 8 M

With a neat block diagram, discuss principle operation of open cycle gas turbine plant. Why is its efficiency low? DEC 08. 8 M

Explain principle of working of a gas turbine plant also explain open cycle and closed cycle gas turbine plant

JUNE 10. 10 M

Discuss the methods of increase the thermal efficiency of gas turbine plant JUNE 11. 10 M

Explain how the use of regenerator, intercooler & reheater in gas turbine plants help in improvement of thermal efficiency.

JUNE 09. 9 M

  V i na nayyaka.B ka.B .G .G.. Ass A sstt.Pro .Pr ofe fess sso or , D ept E & E , BI B I E T, Da D avanage nagerr e

 

  V i na nayyaka.B ka.B .G .G.. Ass A sstt.Pro .Pr ofe fess sso or , D ept E & E , BI B I E T, Da D avanage nagerr e

 

With a neat sketch, explain the principle of operation and working of biogeneration plant.

DEC 08. 8M

  V i na nayyaka.B ka.B .G .G.. Ass A sstt.Pro .Pr ofe fess sso or , D ept E & E , BI B I E T, Da D avanage nagerr e

 

MICRO GENERATION Micro generation is the small-scale generation of heat and power by individuals,

small businesses and communities to meet their own needs, as alternatives or supplements to traditional centralized grid-connected power. Although this may be motivated by practical considerations, such as unreliable grid power or long distance from the grid, the term is mainly used currently for environmentallyconscious approaches that aspire to zero or low-carbon f o ootprints. otprints. It differs from micro power in in being principally concerned with heavy, fixed power plants rather than high mobility  DISTRIBUTED GENERATION:

Explain the concept of distributed generation   When

JUNE 09. 5M

small generators of capacities around 2 - 50 MW output are installed

at typical points in the area such that each of these generators supply power to a small number of consumers nearby then it is called distributed generation.   The

generators may be operated through renewable energy sources such

as solar, wind or gas turbines, small hydro or micro turbines as these are most economical choices.

  V i na nayyaka.B ka.B .G .G.. Ass A sstt.Pro .Pr ofe fess sso or , D ept E & E , BI B I E T, Da D avanage nagerr e

 

  Dispersed

generation is use of still smaller generating units of less than 500

kW and use for individual houses or small business. The distributed or dispersed generators may be standalone or grid connected depending on the requirement.   Distributed

generation proves to be economical as it requires to

transmission network and reduced need of distribution equipments. Another advantage is this generation is portable or compact as compared to big power stations located far away from consumers. Also they are modular and reloadable.   The

fuel cells and micro gas turbines are two new types of techniques

evolved in distributed generation.   The

main challenge is to upgrade existing technology and to promote

development, demonstration of   new and upcoming technologies for widespread adaptation of distributed generation. 

  V i na nayyaka.B ka.B .G .G.. Ass A sstt.Pro .Pr ofe fess sso or , D ept E & E , BI B I E T, Da D avanage nagerr e

 

  V i na nayyaka.B ka.B .G .G.. Ass A sstt.Pro .Pr ofe fess sso or , D ept E & E , BI B I E T, Da D avanage nagerr e