In this article we will discuss about the  difference between Ammeter and voltmeter . we will also know about the symbol of voltmeter and ammeter .

Difference between ammeter and voltmeter

Difference between Ammeter and voltmeterAmmeter and voltmeter are used to measure current and voltage respectively. A  ammeter is an instrument which is use to measure electric current in a circuit .  A voltmeter is also a measuring device which is use to measure potential difference between two point .

Working of voltmeter and Ammeter.

Ammeter is use for measuring current and voltmeter is use for measuring voltage.
By using both parameters we calculate the resistance of circuit by suing ohms law
V=IR
Where ..
V  is Voltage ,  which is measure by Voltmeter
I  is  Current  ,  which is measure by Ammeter
R  is Resistece which opposes flow of electric current
 
For measurement of current ammeter is to be connected in series to the circuit
Or if there is AC current it can be measured by clam CT. but for measurement
Of current only can be measured by two contact points.

 

Now let we know major differences between ammeter and voltmeter-
Difference Between Ammeter and Voltmeter.
 


                    Ammeter

                 Voltmeter

1.Ammeter is use for measure amount of current

1. Voltmeter is use for measure potential difference between two points.

2. Ammeter is connecting in series to measure current.

2. Voltmeter is connecting in parallel for measure voltage.

3. Ammeter has low resistance in its circuit.

3. Voltmeter has high resistance in its circuit.

4.it is less accurate as compared to voltmeter

4. It is more accurate as compared to ammeter.

5. For range extension of ammeters a low value resistance is connected in parallel to the circuit, which is called shunt.

5. For range extension of voltmeter a high value non inductive resistance is connected in series so that it measure high voltage as compared to erlier.

6. Symbol of ammeter is

Difference between Voltmeter and Ammeter

6. symbol of voltmeter is

Difference between Ammeter and voltmeter

Hence these are some difference between  Ammeter and Voltmeter if you will find any incorrect  in above article you must comment below in comment box.
 

For knowing  more about the Voltmeter and Ammeter you must watch this video.
 

Electricity Deregulation

In this article we will know about the electricity deregulation . we will know that what is need of electricity deregulation .

Electricity Deregulation 

Introduction  of electricity deregulation

Electric supply industry has undergone many significant changes during the last few years in almost all countries of the world. Many vertically integrated utilities have been replaced by separate generation, transmission and distribution companies. The electricity market is becoming more competitive. In many cases the large industrial and commercial consumers have the option of selecting their energy supplier. It is anticipated that this choice may extend to residential level also. All these change in electric supply industry are collectively referred to as ‘electricity deregulation’.
Electricity deregulation

Need For Electricity Deregulation

Previously one electric utility was responsible for generation, transmission and distribution of electrical energy. At the consumer premises the utility maintained an energy meter to record the energy used by the consumer. This meter was read monthly (or bimonthly) and the consumer want charged as per this reading. The utility was also responsible for repair and maintenance of all equipment and lines from generation up to the point where meter was installed.
The objective of any electric utility should be to generate electricity at minimum cost, transmit and distribute it efficiently and provide a reliable and high quality service to consumers. However this objective was not being fulfilled and electric utilities became monolithic and unresponsive consumer needs. This require un bundling of electric utilities into separate generation, transmission and distribution companies and many other changes to ensure that reforms are carried out successfully.

Generating Companies 

It is the company responsible for electric generation. Gen cos have relationship with large whole sale customers for marketing the electricity. Gen-cos have specialized personnel to optimize the generation schedule, hydro thermal mix and other allied activities so that electricity is generated at minimum cost and resource are utilized optimally.

Transmission Companies 

It is responsible for transmission of electrical energy. It must allow all corners access to its transmission network on an equal basis. A level playing field must exist for all market participants as they transmit electricity to different parts of region. A Transmission company  can be owned by a utility but its operations must be separate and independent of operations and functions of the utility.

Distribution Companies 

Distribution companies supply electrical energy to the consumers. They are responsible for setting up, renovate and maintain the distribution network in the area. They also look after the metering and billing functions. They must maintain voltage and frequency within proper limits as prescribed by the state laws and regulatory commission. They must also ensure reliability and security. 

Retail Companies 

Their job is to market the electrical energy to the retail customers. Other related service like lighting retrofits, energy audits etc. may also be performed by it. They are also called energy service provider (ESP). Energy trading is the most important function of a retail company.

Metering In Deregulation Market 

Previously the metering function was also performed by the single organization which controlled generation, transmission and distribution. With debuting of generation, transmission and distribution operations, metering is one area which will be affected immensely. Meter ownership, access to meter data, timing readings, interval metering, load profiling, load research metering, automated meter reading, data management, and sharing of returns are some of issue affected by deregulation process.

   Meter ownership

Meter is the physical interface between the utility consumers. Since metering is a part of distribution operation, the Distribution companies claim that they are the natural owners of the meters. However the retail companies also have interest in meter ownership and are interested to install and maintain meters. Ownership of meter increases a company‘s market power. As a result of above the task of installing and maintaining meters is likely to be assigned to meter service provides (MSP). Addition of MSP is like to balance the interest of Distribution companies and retail companies. Moreover it means better service to the consumer. Whenever a consumer is not satisfied with the service of one MSP, he can change the MSP. With more than one MSP operating in an area, the consumers will benefits in the form of better and prompt service and possibly reduced costs.

Access to Meter Data 

Many power need access to meter data. These include Discoms and retail companies. Discoms needed the meter data to compute the charges for distribution service. Retailers need this data to calculate the charges for generation services. To ensure proper exchange of meter data among the different power players, it is necessary to have a standard data format to avoid confusion. Electronic data exchange is very helpful in this respect.

Timing of Meter Reading 

Previously the electric utilities got the meter reading taken through meter readers once a month or once in two months. Many remote customers record the meter reading themselves and convey it to the utility (this process is likely to be unreliable). Timing of meter reading in the new regime is important power players, it is necessary to have to be shared between the different power players. In view of this recording of meter data at proper times and ensuring that this data is accurate is very important.the cost of electrical depends on the time of day. During peak load times the generation cost is more. During off-peak hours the generation cost is less. The difference in the generation cost during peak and off-peak hours to can also be substantial. In view of this real time market price of electricity changes from hour to hour in the whole sale market. Therefore it is necessary to know the amount of energy used in different hours of the day. this possible through the use of interval meters.
Electricity deregulation

Interval metering 

An interval meter is an electronic energy meter with storage with storage capability. It can keep a record of energy used on (say) hourly basis. This record is then aggregated over the billing cycle. Generally the reading of interval meters can be collected remotely. Introduction of interval metering increases the total volume of data. For hourly meter reading this means 30*24 i.e. 720 values per month instead of just one value. In view of this the use of interval meters is justified only for large industrial and commercial consumers.

Hence these are electricity deregulation if you find any incorrect in above article you must comment below in comment box.

Distribution Power Generation

 In this article we will study about Distribution power generation . we will discuss in detail about the distribution power generation and also studied about advantages of DG system. we will know their introduction and function.

Distributed Power Generation

Electricity demand is growing in all the countries of the world. The electric utility installed capacity in the world, at present, is about 3100000 MW and to meet the increasing demand about 80000 MW of new capacity has to be added every year. In USA the utility capacity is about 850 GW AND AN AVERAGE OF 15000 MW of new installed capacity is needed every year meet the increase in demand as well as to replace about 6000 MW of old plants which are require to be retired every year. In India the utility installed capacity is about 118 GW at present and is expected to increase by at least 5% every year in the coming years. The situation in many other countries is almost similar.
Another phenomenon taking place everywhere is power system deregulation and opening up of competition. This system is likely to compel the generating companies to setup small generating plants close to the customers. This system of generating is called decentralized or distributes power generation (DG).  The significant applications of DG system include back up (stand by) generation utility grid enhancement, peak shaving, load management etc. it has been estimate that DG, in the world, would be about 20% in near future.
The DG system are small in size, less than 10 MW and typically 1or 2 MW they feed into the distribution system directly and may be installed by the utility or by big consumers. They may be of any type but are most likely to be solar plants or wind energy plants,

Advantages of DG System

Distributed generation system offer promise to help in modernization and improvement of electric distribution system. The advantages will accrue to the utility, consumer as well as commercial power producers and can be summarized as under:

(a) Advantage for utilities

  •   Transmission capacity relief
  •  Distribution capacity relief 
  • Hedge against high market prices 
  •  Grid investment deferments
  •  Improved grid asset utilization 
  •  Improved grid reliability 
  •  Var support 
  •  Voltage support
  •  Contingency reserves 
  •  Energy and load management

(b) Advantage for consumers

  • Efficient use of energy from combined heat and electricity 
  • Improved reliability by having back up generation 
  • Incentives from utility to provide capacity reserve 
  • Low cost electricity 
  • Clean energy 
  • Improve power quality 

(c) Advantage for commercial power producer

  • Power market (to sell electricity) 
  • Ancillary services market (reactive power, stand by capacity etc.)
  •     To summarize the above advantage tend towards evolution of a new modernized electric power system greater flexibility and security.

Energy sources of Distribution power generation system

Indicates the various distributed generation energy sources. These can be classified into conventional sources. These can be classified into conventional and non-conventional.
The conventional sources include combustion turbines, reciprocating engines, micro turbines and fuel cells. Natural gas and petroleum are used for these forms of distributed generation. However there is growing trend towards using non-conventional sources. This is, evidently, due to the fact that natural gas and petroleum sources are fast depleting and also due to growing environmental concerns. Biomass, solar and wind energy distributed generation system are being increasingly added to the grids and these trends will continue in future.

Energy sources                                            Typical Rating                                                                  

  1. Conventional                                                ----------------

  • Combustion turbine                                    1 to 30 MW   (Mega Watt )                  
  • Raciprocating  Engines                                10 KW  to 10 MW
  • Microturbines                                              1  KW   to 300 KW 
  • Fuel Cells                                                     1 KW   to  20 MW

    2. Non Conventional                                           ---------------

  • Biomass                                                        1 to 5 MW
  • Wind Turbines                                               1 KW to 1 MW 
  • Solar                                                              1 KW to 20 MW 
  • Photo voltaic                                                   1 KW to 1 MW 

The non-conventional energy sources have the disadvantage of high investment cost. A significant part of this investment cost is the cost of power electronic interface.

Function of Power electronic Interface

 The output voltage of a distributed generation system may be dc (in case of photovoltaic system and fuel cells) or ac (in case of wind energy system). However, it is mostly a variable voltage and has to be made compatible with grid voltage. Therefore a power electronic interface is always needed between distributed generation system and grid.
(1) Power conversion from a variable dc (or ac) voltage compatible with grid voltage and frequency. Moreover the output voltage of distributed generation may be more or less than grid voltage.
(2) Output power quality assurance with total harmonic distortion (THD), low voltage and frequency deviation and low flickering.
(3) Protection of distributed generation system and electrical power systems, from abnormal voltage, current, frequency and temperature condition with additional function as anti-islanding protection and electrical isolation etc.
(4)   Control of distributed generation system coupled with objectives like maximum power point tracking of PV array, maximum power extraction from wind energy system, optimum efficiency of fuel cell system etc.

Solar Energy for Distributed Generation

Solar Energy

When light radiation falls on a p-n junction, a voltage is generation. The primary power comes from the striking photons. The use of solar insolation to generate electricity is increasing constantly over the past few years. As the world‘s electricity demand is increasing the use of photovoltaic system connected to the utility grid are attracting more and more attention of power planners. As the costs of PV modules and power electronic interface are showing declining trends, PV system are likely to play major roles in supplying the future electricity demands of the world.
PV system is an all electrical system and has no moving parts. Life time of PV modules can be 25 years or more. However the power generation capacity gets reduced drastically due to ageing.
 Many photo voltaic technologies exist. Constant research and development activities are going on to reduce the cost of photo voltaic.
When photo-voltaic cells are connected in series we get a reasonably high voltage (about 40 V or so). However the weakest among these cells determines the current rating. Many series strings are connected in parallel to increase the current rating.

 Hence these are Distribution Power Generation System . If you will find any incorrect in above article you must comment below in comment box.

If you want to know more about the Distribution power Generation you must sea this video.

Co-Generation Advantages, Co-generation Application

In this article we will know about  Co-generation advantages and their application .we will also know about the basic meaning of Co-Generation.we will also discuss about the topping and bottoming cycle.

Co-generation Advantages

Definition and Scope of Co-generation

Co-generation means sequential conversion of energy contained in fuel into two or more usable forms. In one manifestation the energy of coal is converted into heat in the boiler to produce steam. This steam is used to generate electrical energy and in addition provides heat for manufacturing process. In another manifestation gas is used in gas turbine to generate electrical energy. The remaining heat is used to produce steam in a heat recovery boiler. This steam is used for generating more electrical energy or is used as process steam for manufacturing process.
Co-generation advantages, application of cogeneration
Thus a conventional system uses energy of fuel to produce electrical energy for thermal energy (for manufacturing process) whereas a co-generation system produces both from the same primary fuel. A conventional system needs more fuel to give the same total energy output than a co-generation system. A co-generation system can be either an in plant power generation system or a reject heat utilization system.


Co-generation advantages, application of cogeneration

The implant power generation is used industries and is illustrated in. The industry needs both process steam and electricity. In conventional method steam is produced by a boiler and is electricity is either purchased from a utility or generated by a diesel generating set. If co-generation is used, the boiler is made to produce steam at a higher temperature and pressure than needed for manufacture purposes. This steam is a turbine generator set to produce electricity. The exhaust steam (from turbine) is used for manufacturing purpose.
The reject heat utilization system is used in power plants. Some steam is extracted from the turbine (at a suitable temperature and pressure) and supplied to a n adjacent industry for manufacturing purpose. This is illustrated.


 Co-generation Advantages

These are some Co-generation advantages  which are given below .

(a) Fuel economy. 

Co-generation result substantial economy in the consumption of primary fuels i.e. coal, oil, gas. The fuel economy results from higher thermodynamic efficiency of a co-generation system as compared to separate power producing systems and heat producing system. Moreover the extra fuel needed to generate electrically the same quality of steam produced for requirements is  only about 10%

(b) Lower capital costs.

 Many case studies have been conducted to estimate the costs per kW of installed capacity in power plants and the additional capital costs need to generate electricity by adopting co-generation systems. it is seen that an industry needing steam for processing has to invest in boilers. The extra investment needed to upgrade boiler so that electricity can also be generated is pretty small as compared to the cost of boiler. It has been estimated that incremental investment in co-generation system is only about 50% of the investment needed by an electric utility to supply the same power to industry. Thus co-generation result in enormous savings in capital costs.

(c) Low gestation period.

 A utility needs about 6 year to add a thermal generation system. However the installation of a co-generation system by an industry needs only about 3 years. The lower gestation period result in saving in interest, early utilization of facility, early return on investment and lesser chances of cost escalation of project.
Lower capital costs.
 Many case studies have been conductor to estimate the capital costs per kW of installed capacity in power plants and the additional capital costs needed to generate electricity by adopting co-generation systems it is seen that an industry needing steam for processing has to invest in boilers. The extra investment needed to upgrade boiler so that electricity can also be generation is pretty small as compared to the cost of boiler. It has been estimated that incremental investment in co-generation systems is only about 50% of the investment needed by an electric utility to supply the same power to industry. Thus co-generation result in enormous saving in capital costs. it most important co-generation advantage.

(d) Low gestation period. 

A utility needs about 6 year to add a thermal generation system. However the installation of a co-generation system by an industry needs only about 3 years. The lower gestation period results in saving in interest, early utilization of facility, early return on investment and lesser changes of cost escalation of project.
Saving to industry from power cuts and power supply interruption. In all developing countries including India the generation capacity is much less than the demand. The electricity supply authorities impose severe power cuts on industry especially when electricity demand for agriculture is high. Moreover the frequency and duration of supply interruptions are pretty large. The power cuts and supply interruption result in huge losses to industries. Many industries install diesel generating sets to keep their processes running. The generation cost per kW of these sets is very high. it is also co-generation advantages

If an industry opts for co-generation to meet its electricity demand, it will not face any power cuts. Moreover, a well designed co-generation scheme can be very reliable. Thus the industry will benefit in this respect also.

Co-Generation Technologies Advantage

The commercial co-generation technologies being presently used for topping cycles are steam turbine, gas turbine, combined cycle and diesel engine systems. In addition fluidized bed combustion (FBC), magneto-hydro-dynamic (MHD), fuel cells and some other conversion are being developed.these are also a type of Co-generation advantages.

(a) Steam turbine system. 

The steam turbine system uses the equipment similar to that in a thermal plant i.e. boiler, steam turbine, generator and other auxiliaries. The fuel used may be oil, natural gas, coal, wood or other similar materials. The high pressure steam produced by the boiler drives a steam turbine which is coupled to generator. The low pressure exhaust from the steam turbine is used for industrial process applications, space heating etc. Back pressure steam turbines are generally preferred because they exhaust low pressure steam and are more efficient. The boiler used by industries for producing process steam is generally low temperature low pressure boilers. If such an industry opts for co generation, replacement of these boilers by those producing, high temperature, high pressure steam is invariable necessary.
Co-generation advantages, application of cogeneration
If an industry installs steam turbine equipment for co-generation, the pollution level is likely to increase. Sulfur oxides. Nitrogen oxides. Particulates and fly would pose problems and special pollution control measures would be necessary.
Case studies revealed an energy saving of about 13% if steam turbine co-generation system is installed. The steam-turbine system has the added advantage of fuel flexibility.

(b) Gas turbine system.

 A gas turbine system consists of compressor, combustion chamber, gas turbine and generator. Air is compressed by the compressor and supplied to combustion chamber. Fuel (oil or natural gas) is burnt in the combustion chamber and heats the compressed air. This hot pressurized gas expands in a turbine which drives the generator. The exhaust from the combustion chamber is used as process heat. If necessary the hot exhaust gases can be used to raise steam in a waste heat recovery boiler where the heat of the gases is transferred to water.
Due to scarcity and high cost of petroleum products, the cost of electricity generated by this cycle is rather high. Gas turbines need more maintains than steam turbines. Case studies have revealed an energy saving of about 25% if this cycle is used for co-generation system. it is most used co-generation advantages.

(c) Combined cycle system. 

This system is a combination of gas turbine and steam turbine systems. The gas turbine exhaust is used in waste heat boiler to raise steam. If necessary additional fuel is added to waste heat boiler. The steam, from the boiler, is used in a back pressure turbine which drives another alternator to produce electricity. The low pressure exhaust from steam turbine is used as process steam. This system has greater flexibility for topping steam. Case studies have indicated an energy saving of about 35% by a combined cycle co-generation system.
 hence these are co-generation technologies advantages.
For knowing more about the Co-generation advantages you must watch this video.



Topping  and Bottoming Cycles

The implant power generation (co-generation) system can be topping cycles or bottoming cycle.
In a topping cycle, fuel is burnt in the boiler to produce high temperature steam. This steam is expanded in a turbine coupled to a generator to give electric power. The reject heat from the turbine is used for manufacturing process. The reject heat from process is used to generate electrical power.
Thus in a topping cycle electrical energy is produced first whereas in bottoming cycle heat energy is used first. Generally the steam require for industrial process is at low temperature whereas high temperature steam is needed for electric power generation. Therefore only the topping cycle is used. The bottoming cycle has very limited utility.
The overall efficiency of a topping cycle is around 75% as compared to a combined efficiency of about 55% for two separate systems (for producing electrical energy and steam).
Hence these are Co-generation advantages if you will find any incorrect in above article you must comment below in comment box.

MHD Power Generation

In this article we will studied about the MHD Power generation . we will also know about how to generate MHD power. We will studied about the open cycle MHD power generation and Closed cycle MHD Power generation. we have also studied about advantages of MHD power generation.

MHD power generation , Open cycle and closed cycle MHD system

 MHD Power  Generation

Advantage of MHD Power Generation

MHD generation offers several advantages as compared to other methods of electric generation. Some of these are:

(1) The conversion efficiency of an MHD system can be around 50 percent as compared to less than 40 percent for the most efficient steam plants.

(2) Although the costs cannot be predicted very accurately, yet it has been reported that capital costs of MHD plants will be competitive with those of conventional steam plants.

(3) Because of higher efficiency, the overall generation cost of an MHD plant will be less. It has been estimated that the overall generation cost in an MHD plant would be about 20% less than in convection steam plants.

(4) The higher efficiency means better fuel utilization. The reduced fuel consumption would offer additional economic and social benefits and would also lead to conversion of energy resources.


MHD power generation , Open cycle and closed cycle MHD system

(5) The efficient heat utilization would decrease the amount of heat discharged to environment and the cooling water requirement would also be lower.

(6) The research studies at Aveo Everett Research Laboratories (USA) and other institutions have show that the use of precipitator not only recover the seed material but also effectively traps most other pollution agents. Show the pullulating emissions of an MHD plant and a conventional steam plant. Thus an MHD plant offers great benefits in environment aspects of electric energy generation.

(7) It is possible to utilize MHD for peak power applications and emergency service (upto 100 hour per year). It has been estimate that MHD equipment for search duties is simpler, has the capability of operating in large unit sizes and the ability to make rapid start to full load.


MHD Power Generation ( Open cycle and working fluid)

MHD system may be an open cycle system or a closed cycle system. In an open cycle system the working fluid is used on the once through basis. The working fluid after generating electrical energy is discharge to the atmosphere through a stack. In a closed cycle system the working fluid is recycled to the heat source and thus used again and again. The operation of MHD generators directly on combustion products is an open cycle system. The working fluid is air. In closed cycle system helium or argon is used as the working fluid. The use of a nuclear reactor using solid fuel element for providing the heat energy for an MHD process requires that the working fluid should have the following three properties (i) it should be capable of providing heat transfer under reactor operating condition (ii) it should not require excessive compressor work (iii) it should not be rendered active within the reactor. Helium, most nearly, fulfill all these requirements.

MHD Power Generation Closed cycle 

 The MHD generator resembles a rocket engine surrounding by a huge magnet. The fuel, coal (or natural gas ) is burnt to produce hot gas. The hot  gas is then seeded with a small amount of an ionized alkali metal (cesium or potassium) to increase the electrical conductivity of the gas. The gas expands through the rocket like generator surrounded by powerful magnet. During the motion of the gas positive and negative ions move to the electrodes and constitute an electric current. The rejected gas passes through an air heater for preheating the inlet air. The seed material is recovered for successive use. The nitrogen and sulphur are removed (for pollution control) and the gases are discharged to the atmosphere. The developed view of an MHD channel          
For efficient practical realization an MHD system must have following features:



MHD power generation , Open cycle and closed cycle MHD system
MHD power generation feature are these...

(1) Air superheating arrangement to heat the gas to around 2500 C so that the electrical conductivity of the gas is increased.

(2) The combustion chamber must have low heat losses.

(3) Arrangement to add a low ionization potential seed material t other gas to increase its conductivity.

(4) Water cooled but electrically insulating expanding duct with long life electrodes.

(5) A magnet capable of producing high magnetic flux density (5to 7 teslas).

(6) Seed recovery apparatus-necessary for both environment and economic reasons

MHD Power Generation Open loop Cycle system

The closed cycle inert gas MHD system was conceived around 1965. Ti was thought that in this in this method all the advantage of the open cycle system would be retained and the main disadvantages of the open cycle system (viz. very high temperature requirements and a very chemically active flow) could be removed. As the name suggest, the working fluid, in a closed cycle, is circulated in a closed loop. The working fluid is helium or argon with cesium seeding.


MHD power generation , Open cycle and closed cycle MHD system
The working fluid is a mixture of atomic gases, without rotational and vibration modes. That interacts readily with thermal electrons. Therefore it is possible in closed cycle system to maintain the conduction electron in the flow at a higher temperature than the bulk gas. Since electron density tent to be governed temperature rather than gas temperature we can get substantially higher electron density and electrical conductivity than would exist at the same temperature in combustion gas flow.

The possibility of using a nuclear heat source with a closed cycle MHD system has also been investigated. However its feasibility has yet not been established.
Hence these are MHD power generation and their open cycle and closed loop cycle system . if you find any incorrect in above article you must comment below in comment box.

If you want to know more about the MHD power generation you must watch this video.

Earth Energy Application

In this article we will know about the earth energy and their application.

Introduction of Earth Energy

Earth is in state of thermal equilibrium. Energy received from the sun is lost at night. The small amount of energy generate by the decay of unstable isotopes of Uranium, Thorium etc. is dissipated form’s earth interior to oceans and atmosphere.

Heat generation within earth is around 2700 GW. The temperature difference within the earth depends on:

(1) The thermal properties of earth’s interior their radical and lateral variation.
(2)   Movements of fluid or solid rock materials occurring at rates of more than a few millimeters per year.

Earth energy and application

A potential geothermal source region should have high thermal gradient which is defined as:

                      Thermal gradient = Heat flux / Thermal Conductivity

Thermal gradient will be night if either heat flux is high or thermal conductivity is low. The heat energy in earth’s interior is due to radioactivity. Regions of higher radioactivity have higher heat flux and are potential geothermal sites.

Surface of the earth consist of about one dozen tectonic plates e.g. American plate, African plate, Arabian plate, Indian plate, Philippine plate, pacific plate etc. Each of these plates has thickness around 100 km and thousand of kilo meters of area. Earth’s interior is unable to lose heat, by conduction, as rapidly as it is generated by radioactivity. This lead to convective instabilities which mean that these plates are continuously in motion with respect to each other. 

A variety of processes along the margins of the plates lead to partial melting at depths between 15 to 200 km. the molten masses penetrate the surrounding rock and rise towards earth at rates varying from a few cms per day to a few cms per year thus result in volcanic activity. The molten masses which do not reach earth’s surface come to rest in the middle or upper part of the earth’s crust at depth less than 20 km. These liquid magmas may have temperature around 1000 C. The crystallization of these liquid magmas produces intrusive igneous bodies. The cooling and crystallization of igneous bodies gives rise to local heat flux.

 This heat flux constitutes the geothermal energy which may be used for variety of purpose including electricity generation. These local heat fluxes continue for thousands of years and form an inexhaustible source of energy. The majority of active geothermal areas tend to concentrate around the margins of major lithosphere plates.

Heat Extraction

The extraction of heat from the earth’s interior needs a natural or artificial heat exchange. In many geothermal areas natural sub-surface water circulating system bring out this heat giving rise to hot springs. A schematic representation of geothermal system 
Kilometer or so an impermeable crystalline magma above the magma is the impermeable crystalline rocks which are overlain by localized pockets of permeable rocks. One such localized pocket is show in this figure. The localised pockets are bounded by fracture zones or fault alone which some relative motion of rock has occurred. Water circulated long fault lines. As it goes down and moves in the earth’s interior (path ABCDE) it is heated by the permeable layer which is in turn heated by conduction of heat from the magma. The hot water comes out through another fault and forms a hot spring.

Earth energy and application

Depending on the temperature and depth of the permeable rocks, the natural hydro thermal system can be divided into three categories. 

(1) Dry Steam System. The temperature of the permeable rock is very high. The whole of the water is converted into steam which gets superheated by the time it comes out of the surface. The Larderello (Italy) and Geysers (California) fields are dry steam systems.

(2) We Steam system. The temperature of permeable rock is not very high. By the time water comes out, only a part of it gets converted to steam. Therefore eruption gives water steam mixture.

(3) Hot Water System. The temperature of the permeable rock is rather low. The surface eruption provides hot water.

For proper exploitation of geothermal energy for electricity generation, extensive survey by geological and geophysical methods is necessary. When the area have been located after hese surveys, it is necessary to drill a number of holes at carefully selected sites. The cost of drilling the wells increases with the depth. The wells at Geysers field (California) are 2km deep, 51 cm diameters at top 22cm diameter at bottom.

The dry Steam of the high temperature dry steam system can be directly taken to the steam turbine and used for generating electricity.
The wet steam fields in the world have been estimated to be about twenty times more abundant than the dry steam fields. The wet systems yield about 20 per cent (by weight) and the remaining quantity of hot water. It is necessary to separate the steam and water at the surface before the steam can be used to drive the turbine. Generally, in such system, the steam is used for electricity generation and the hot water for other miscellaneous purpose. In New Zealand the hot water of a wet steam field is being used for industrial processes by a paper mill. In Iceland such water is used for industrial purposes and house hold heating. Similar is the case in Japan, USSR and Hungary. In Chile a project is being developed for using the steam, from a wet steam geothermal field for electricity generation and distillation of the hot water to yield fresh water and valuable minerals.

Hence these are Earth energy application if you will find any incorrect in above article you must comment below in comment box. 

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General Description Of Pumped Storage Plants

In this article we will know about the pumped storage plants. We have also studied about the how pumped storage plants are use full for hydel power plant.

General Description Of Pumped Storage Plants

A pumped storage plant is a special type of plant meant to supply peak loads. During peak load period, water is drawn from the head water pond through the penstock and generates power for supplying the peak load. During the off-peak period, the same water is pumped back from the tail water pond to the head water pond so that this water may be used to generate energy during the next peak load period. Thus, the same water is used again and again and extra water is needed only to take care of evaporation and seepage. Generally the pumping of water from the tail water pond to the head water pond is done at night when loads are low. The plant generates energy for supplying peak loads during day time. The off peak pumping maintains the firm capacity of the pumped storage plant. The reservoir capacity should be such that the plant can supply peak load for 4 to 11 hours. A general arrangement of pumped storage plant .

Pumped Storage Plant Advantage, Application

The earlier pumped storage installations used a separate pumped of pumping the water back into the head water pond. A recent development is a reversible turbine pump. During peak loads, the turbine drives the alternator and the plant generates electrical energy. During low loads, the alternator runs as a motor and drives the turbine which now works as a pump for pumping the water into the head water pond. This arrangement reduces the capital cost of the plant. The power for driving the motor is taken from the system. 

PUMPED STORAGE PLANTS FOR SUPPLYING PEAK LOADS

Every pumped storage scheme reduces dual conversion of energy, the efficiency being around 60 to 70 percent. The fact that the energy gained from a pumped storage plant is always less than the energy input, should not obscure the fact that this apparent loss to the system is negligible when compared with the substantial savings in fuel which are made when these plants are used in a mixed system. The most obscures economies are in the replacement of standby thermal plants and in the fact that the existing thermal plants can be run with fewer and less rapid load changes.

Pumped Storage Plant Advantage, Application

Modern generation systems are a mixture of hydro, steam and nuclear power stations so that energy can be generated most economically. If hydro contribution is small, the steam and nuclear stations have to be of sufficiently large capacity. The steam and nuclear plants operate more economically when run continuously at or near full load. At the time of low loads the excess energy generated by stem and nuclear plants can be used for driving the motor of the pumped storage scheme. The pumped storage plant would in turn supply peak loads. Thus the capacity of the steam and nuclear plants need be only for supplying the base loads and hence much less than what it would be if they were to meet the whole demand. In addition the steam and nuclear plants can be worked at almost unity load factor which ensures their most economic operation. 

Advantages Of Pumped Storage Plant

Pumped storage plants have very important advantage. Some of these are:
  
(i)
Peak loads can be supplied at a lesser cost that that incurred when these loads are supplied by steam and nuclear plants.

(ii) Standby capacity is available on short notice. Power engineers in utilities having pumped storage installations have long realized the benefit of quick switching on and off capacity of these installations. Pumped storage plants need a starting time of only 2 to 3 seconds and can be loaded fully in about 15 seconds. In the event of an outage on a unit, a pumped storage plant can be called upon to meet the generation deficiency (occurring due to the outage) thus ensuring reliable supply and avoiding the necessary of load shedding.

(iii) The load factor of steam and nuclear plants is increased thus ensuring their efficient and economic operation.

(iv) Since the base loads plants needs not be used to supply peak loads. The forced and maintenance outages of these plants are likely to be reduced.

(v) In the event of an extra demand coming up suddenly on the system, these plants can be immediately switched on to meet this extra demand.

(vi) Because of their ability to take up loads in a very small time, the use of pumped storage plants reduces the spinning reserve requirement of the systems.

(vii) They can be used for load for frequency control.       

Types Of Pumped Storage Installation

Pumped storage plants offer many benefits. However their feasibility and economics should be critically evaluated at the planning stage. During the power system planning studies, three types of pumped storage installation can be considered: 

(i) High head, daily daily/weekly cycle, peaking plants close to the load center.

(ii) Low/medium head, seasonal cycle plants, far-away from load center (peaking or non-peaking types). 

(iii) Medium head, daily/weekly cycle peaking plants at an existing cascade of reservoirs.

Hence these are basic description of pumped storage plant if you will find any incorrect in above article you must comment below in comment box.