🏭GAS TURBINE POWER PLANT 🏭

🏭GAS TURBINE POWER PLANT🏭

✏️The generating station in which the gas turbine is used as a prime mover in order to convert the mechanical energy into electrical energy is known as a gas turbine power plant.  In a gas turbine power plant air is used as a working fluid.  The gas turbine power plant consists of many components such as filter compressor combustion chamber gas turbine alternator and the motor.  Firstly the air from the atmosphere is fed into the filter in order to general remove the dust particles and then it is fed into the compressor.  The air is generally comprised in the compressor and then it is fed into the combustion chamber.  The combustion chamber consists of two valves, one valve where the fuel is fed (fuel inlet) and the other valve, where the compressed air from the compressor is fed into the combustion chamber.  The gas turbines can make use of variety of fuels like solid, liquid and gas but most likely the natural gas is used as fuel because it has 80 percentage of the Methane and small amount of some other gases and is widely used in the gas power plants.  Once the fuel is fed into the combustion chamber where heat is added to the air and thus raising the temperature of the air.  Here there are two ways of adding the Heat and they are first one used by means of burning the fuel and the second method used by means of using the air heater in order to heat the air.  In the gas turbine power plant we can also observe that there is a coupling made in between the compressor and gas turbine.  Is not compulsory to place that compressor, gas turbine, alternator and motor all in the similar shaft, based on a requirement we can make use of them in our own way.

✏️Next, the high temperature high pressure air from the combustion chamber is fed into the gas turbine and in the gas turbine, the compressed air expands and this expanded air hits the blades of the turbine which rotates and produces mechanical energy which helps to rotate the alternator or generator and hence the mechanical energy is converted into electrical energy.  After the expanded air hits the blade of the turbine, the air is generally released into the atmosphere by means of using the duct.There are generally two types of gas turbine power plants, they are:

1️⃣Open cycle gas turbine power plant 

2️⃣Closed cycle gas turbine power plant 

✏️Here, another reason why the compressor, gas turbine and alternators are mounted on the same shaft because of that the part of the mechanical power of the turbine can be utilised for the operation of the compressor.  We are not going to make use of the gas turbine power plant like hydroelectric power plant, steam power plant or thermal power plant but it can be used as a stand back/back-up power plant for the hydroelectric power station, nuclear power station as a starting point for driving auxiliaries in power plant equipment etc.

📝Site selection for gas portable power plant:

1. Distance from the load centre
the plant should always be located near the load centre in order to reduce the transmission cost and as well as to reduce the losses.

2. Availability of land
the land that we are planning to construct the gas turbine power plant should be available in cheap cost or price, so that the capital loss can be reduced.

3. Availability of fuel
the fuel which is used in the gas turbine power plant that is the natural gas should be available at a reasonable rate or at less cost.

4. Availability of transportation facilities
While buying the land we need to make sure that there is any kind of transportation facility like Wagon/train route, road transport, water transport, air route etc., so that it will be helpful for us to transport the material.

5. distance from the populated area
the land where we have selected to establish the gas turbine power plant should be constructed away from the populated area because the operation of the gas turbine power plant will be very much noisy so that it can affect the people living near the plant may get disturbed.

6. Type of land
we have to select a land such that it has high bearing capacity/stability, so that it can handle all the equipment’s without any trouble because a lot of vibrations will be transmitted to the foundation from the compressor and turbines.

📝Advantages and disadvantages of gas turbine power plants:

✏️ADVANTAGES:

👉It is simple in construction when compared to that of the steam power plant since no boilers or any other equipment’s are used.

👉Gas turbine power plants are also smaller in size when compared to other power plants.

👉The initial and operational cost are low, when compared to other for plants like steam power plant, hydro power plant etc.

👉Gas turbine power plants require very much less amount of water, since no condenser is used in gas turbine power plant.

👉Maintenance cost is less.

👉Gas turbine power plants can be started quickly.

👉Less losses occur in the gas turbine power plants that is because in the steam turbine power plant we make use of the boiler which will be in continuous operation even when the steam turbine is running no load.

✏️DISADVANTAGES:

👉Initially, we will face a small problem in starting the gas turbine power plant it is because before starting the turbine the compressor is to be operated and in order to turn on the compressor we require some external power source but however, once the operation of the gas turbine power plant starts then we do not require any external power source.

👉The output of the gas turbine power plant is very low, since the greater power developed by the turbine is used in driving the compressor.

👉The overall efficiency of the gas turbine power plant is very low that is approximately about 20 % that is because the expanded air after hitting the turbine is generally allowed to be left into the atmosphere and is not reused again.

👉Here, in the gas turbine power plant the combustion chamber will have a temperature of about 3000 degree Fahrenheit, so that results in the reduction in the life of the combustion chamber.       

         

✏️In the gas turbine power plant we can also make use of the liquids like kerosene, gas oil or Diesel oil but the cost will be more and we can also make use of the coal but we not use a coal because the coal handling and ash handling methods needs to be followed, as coal handling and ash handling methods are very much difficult and also efficiency will be very much low.

✏️Nowadays, natural gas is used for combustion in gas turbine and it is transported by a pipe network in many parts of the country, since the natural gas does not eliminate the smoke or it does not pollute the environment and the main reason for making use of natural gas is because it is eco-friendly/it does not harm the environment.


✏️In the near future, we may also make use of the hydrogen gas and Biogas as fuel for the gas turbine power plants and several methods may also be introduced in order to increase the efficiency of the gas turbine power plants.  Nowadays there is also some methods which is used to improve the thermal efficiency of a gas turbine power plant that is by making use of a regenerator.

📝APPLICATIONS OF GAS TURBINE POWER PLANT :

👉It can be used as a peak load plants that is because they can be started quickly and loaded easily.

👉Base load plants: in most of the cases the gas turbine power plants are not used as a base load plant because the operational cost of the gas turbine power plant is very much high but if the natural gas is abundantly available at some side it may be economical to make use as the base load plants

👉Auxiliary power plant: for thermal stations or steam power plant or the coal power plant we can make use of the gas turbine power plant of size about 25 megawatt or 30 megawatt so that for the starting of the auxiliary equipment of the power plant.  Since the gas turbine power plant is very small we can place that either inside the building or we can make a separate site for placing the gas turbine power plant, outside the building.

👉NUCLEAR REACTION AND CLASSIFICATION OF NUCLEAR REACTOR 📝

🎪CLASSIFICATION OF NUCLEAR REACTORS🎪

✏️A nuclear reactor can be classified in different ways such as on the basis of types of cores used, moderator used, coolant used, fuel used and neutral energy.

👉On the basis of type of core used:

1️⃣Homogenous reactors

2️⃣Heterogenous reactors

👉On the basis of moderator used:

1️⃣Graphite reactors

2️⃣Beryllium reactors

3️⃣Light water reactors

4️⃣Heavy water reactors

👉On the basis of coolant used:

1️⃣Ordinary water cooled reactors

2️⃣Heavy water cooled reactors

3️⃣Gas cooled reactors

4️⃣Liquid metal cooled reactors

5️⃣Organic liquid cooled reactors

👉On the basis of neutron energy used:

1️⃣Thermal reactors

2️⃣Fast reactors

👉On the basis of fuel material used:

1️⃣Enrich uranium

2️⃣Natural uranium

3️⃣Plutonium

4️⃣Thorium

✏️A hetero-genous reactor has a large number of fuel rods with a coolant circulating around them and carrying away the heat produced during the fission process. In a homogenous reactor, the moderator and fuel are mixed together the solution is critical in the core.


✏️Due to difficulties in maintenance, induced radioactivity, erosion and corrosion, homogeneous reactors are not commonly used natural uranium also cannot be used. Light-water cooled moderated reactors using slightly and enriched uranium fuel are the most commonly used for power production.

📝Power reactors in use:
✏️power reactor is commonly employed in nuclear power plants are described as follows: 

📝Boiling water reactor (BWR)
✏️This is the simplest type of water reactor as the name suggests this other reactors where coolant balls in the reactor Pressure Vessel itself the boiling water reactor utilizes enriched uranium as the fuel and light water as both moderator and coolant.  A boiling water reactor operates at a relatively lower pressure of about 76 bar in such a way that the water balls in the core at about 285 degree Celsius.  Steam water mixture leaves the core with water separator from steam in a steam separator.  Steam dryer is used to produce dry steam required to run the turbine for power generation.  A boiling water reactor assembly consists of 90-100 fuel rods and their up to 750 assemblies in a core holding up to 140 tons of Uranium.  A number of safety devices are installed to achieve immediate isolation of the reactor from the engine house in case of a malfunction.  The diagram of the boiling water reactor is shown in the figure below:

📝ADVANTAGES:
✏️The reactor vessel and associated components operate at a substantially lower pressure of about 70-75 bars (1020-1090 psi).

✏️Can operate at lower core power density levels using natural circulation without forced flow.

✏️Boiling water reactor may be designed to operate using only natural circulation so that recirculation pumps are eliminated entirely.

✏️Simple in construction.

✏️Elimination of heat exchanger circuit resulting in reduction in cost and gain in thermal efficiency.

📝DISADVANTAGES:
✏️Since steam is produced from water which is passing through the reactor the radioactive contamination of turbine mechanism is possible and better steam pipes are required to avoid the radioactive fear.

✏️Waste of steam will also lower the efficiency of the plant.


✏️It is not suitable for meeting a sudden increase in the load.



📝PWR (PRESSUROZED WATER REACTOR) 

✏️Water can be used as a moderator and coolant for power reactors. The fuel used is slightly and enriched uranium in the form of thin rods or pallets and cladding is either of stainless steel or zircaloy.  Water under pressure is used as both moderator and coolant. This type of reactor is extensively developed in USA. the most important limitation in power pressurized water reactor is the critical temperature of water.  The current pressure must be greater than the saturation pressure to suppress boiling which is maintained at about 155 bars.  A circulating pump is used to maintain the water around the core which absorbs heat. the pressurized water reactor power plant is composed of two loops in series the coolant loop, also called as primary look and water steam or working fluid loop. the cool and pics of the heat from the reactor and transfer it to the working fluid to generate steam to run the turbine generator system similar to that of the steam power plant.  a pressure Riser and search tank which is tapped into the pipe loop is used to maintain the constant pressure in the water system throughout the load range.  There is also some modification to increase the efficiency of the cycle by the inclusion of an oil fired super-heater between the main heat exchangers and the turbine.  There is also an economy is there along with some feed water heaters since the water passing through the reactor becomes a radioactive and therefore the entire primary circuit including the heat exchanger has to be shielded.

📝ADVANTAGES:
✏️It is cheap as ordinary water is used as moderator and coolant.

✏️It is very compact in size compared to other reactors.

✏️Power density of a reactor is relatively high.

✏️Reactor takes care of the load variation by using the pressurizer and surge tank.

📝DISADVANTAGES:
✏️Low thermal efficiency about 20 percentage.

✏️Greater heat loss due to use of heat exchanger.

✏️Due to high pressure a strong Pressure vessel is required.

✏️There is lack of flexibility in recharging.

✏️More safety devices is required.


📝HEAVY WATER COOLED AND MODERATED REACTOR (CANDU TYPE REACTOR) 

✏️Heavy water has almost the same characteristics as that of the ordinary water. Is boiling point at atmospheric pressure is 101.4 degree Celsius and its density at room temperature is only 10 % above the density of water.  Heavy water moderated and cooled reactors are extensively developed and used in Canada and are called Canadian deuterium uranium (CANDU) reactors.  this reactors use pressurized heavy water and suitable for those countries which do not produce the enriched uranium and the figure of the CANDU reactor is shown in the figure below: 

✏️This reactor uses the natural uranium as fuel which is comparatively cheaper than the enriched uranium. Other advantages are low Pressure Vessel no control rods and low fuel consumption the moderators being at low temperature is more effective in slowing down the neutrons.  The construction of equipment requires less time than the others. The main drawback of this type of reactor is its cost, as a heavy cost of heavy water is extremely high and also there is also the problem of leakage and a proper safety design is required.

📝GAS COOLED REACTOR
✏️The gas cooled reactor in which the gas is used as a coolant and graphite is used as the moderator and is shown in the figure below:

✏️The advantages of gas cooling is that the maximum temperature of the working fluid can be selected independently, rising temperature does not necessarily imply raising of cool and pressure as with the liquid cooled reactors.  Normally carbon dioxide or helium is used as the coolant all the gases are inferior to water in heat transfer but offer several advantages such as safer than water cooled reactor less severe erosion problem and natural uranium can be used as fuel.  Helium a suitable coal and compared to carbon dioxide as it is chemically inert has good heat transfer capability and a low neutron absorption. Being a monoatomic gas it can produce more power for the given temperatures in the Brayton cycle and higher efficiency.

📝FAST BREEDER REACTOR

✏️A fast breeder reactor is different from the thermal reactors on the basis of their thermal reactor uses Fissile nuclear fuel and produces heat, whereas a fast breeder reactor produces heat and at the same time convert fertile material into fissile material.  It is possible to make a fast reactor producing more physical material than it consumes.

✏️The advantage of using high energy neutrons in a reactor has been known since early days of the nuclear science.  In a fast breeder reactor the average neutron yield of a pigeon caused by a fast neutron is greater than in the thermal reactors.  The absorption cross sections are low and conversion factor is high also no moderator is needed in this reactor.

✏️Coolant with excellent heat transfer properties is required to minimise the temperature drop from the fuel surface to the coolant and also it must be non-moderating.  This rules out water and the best coolants for fast breeder reactors are liquid metal such as sodium.  Such reactors are also called as liquid metal cooled reactor or LMCR.  Due to induced the radioactive of liquid Sodium an intermediate loop also use a sodium or sodium potassium as coolant and between the primary radioactive coolant and the steam cycle.  Therefore there is a need of two heat exchangers. The primary loop design can be either pool type / loop type. In pool type system, the reactor core, primary pumps and intermediate heat exchangers are placed in a large pool of liquid sodium contained reactor vessel, whereas in loop type system all are placed outside the vessel. The diagram of liquid metal fast breeder reactor is shown in figure below:

👉EARTH TESTER AND MEGGER👈

✏️EARTH TESTER 

📝Earth tester is an instrument which is used to directly measure the earth resistance.  The diagram of the earth register is shown in the figure below:

📝Earth tester consists of various components like DC generator current reverser rectifier current coin potential coin link and then Earth electrode.  In the figure the total and represent the flow of alternating current and the state line represent the flow of direct current or DC.

📝It consists of a hand driven DC generator and direct reading ohmmeter. There is a potential coil and a current coil which is fixed to the spindle and which are free to rotate about a vertical Axis between the poles North and South Pole of a permanent magnet.  The test voltage generated by the generator is usually 500 Volts 1000 volts, the additional constructional features of the earth  tester are:

1) rotating current reverser: Current reverser is a switch or other contrivance for reversing the direction of current in a conductor.
2) Rectifier: A rectifier converts AC to DC.

📝Both these additional features consist of simple commutator which are made up of L shaped segment which are mounted on the shaft of the hand driven DC generator. Each commutator has four fixer brushes one pair of each set of brushes is so positioned that they make contact alternatively with one segment and then with the other at the commentator rotates, the second pair of each set of brushes are so position on the commutator so that continuous contact is made with one segment whatever may be the position of the commutator. In the figure we can see that the Earth tester has got 4 component that is P1 C1 and P2 C2.  In the figure we can observe that the terminals P1 C1 are shorted whereas the terminal P2 and C2 are connected to the electrodes P and C.  The shorted P1 and C1 terminals is then given to the earth electrode or it is connected to the earth electrode E as shown in the figure above.


✏️WORKING OF EARTH TESTER:

📝when the handle of the DC generator is driven at a constant speed, the alternating current flows through the earth through the dotted line connection and the DC current flows to the coils of the instrument.  The deflection of the pointer depends on the ratio of the voltage across the potential coil and the current through the current coil. The deflection of the pointer directly reads the earth resistance on a calibrated scale.  Earth tester is basically a permanent magnet moving coil instrument which operates on direct current only but by including a reverser and rectifier, it is possible to make measurements with alternating current or AC flowing through the earth. The rectifier is used to convert AC to DC. The sending of an AC through the earth eliminates unwanted effects due to the production of back EMF in the coil on account of electrolytic action when their current flows through the earth.





✏️MEGGER

📝Megger is an instrument used to measure very high resistance of the order of mega-ohms such as the insulation resistance of cables, transformers etc.

CONSTRUCTION: 

📝It consists of a hand driven DC generator and direct reading ohmmeter there is a potential coil/PC and a current coil/CC which are fixed to the spindle and which are free to rotate about a vertical Axis between the poles North and South of a permanent magnet.  The coils are connected through flexible leads also called as ligaments, which exert restoring torque on the moving system. The current coil is connected in series with the resistance R1 connected between the generator terminal and the supply line marked through resistance R1 limits the current through the current coil and controls the range of the instrument. The potential coil is connected in series with the compensating coil and the protection resistance or two and across the generator terminals.  The compensating coil is used to get better scale proportions. A guard ring is provided to shunt leakage current over the test terminals. The terminal G is known as a guard terminal which is used to connect the guard ring to the insulation under test. The test voltage generated by the generator is usually 500 volts or 1000 volts.If the megger shows the value in between 2MEGAOHM to 1000MEGAOHM,tgen we can consider it as a good value and if the megger shows the value below 2Mohm then, it is considered as an bad value. 

For example : for 1000 volts =1 mega ohm,in megger, so

📝If I consider a 2400v motor then the megger needs to give the value as 2.4 mega ohm, then we can say it as it is in good condition. 

WORKING:
📝The high resistance which is required to be measured is connected between the test terminals line (L) and ground (G). The generator handle is then steadily rotated at uniform speed till the pointer gives a steady reading.  This reading gives the value of the resistance. The satisfactory working of the megger may be tested as follows.

📝The test terminal line and ground are kept open. Now the resistance across L and G is infinite. The generator handle is rotated, due to which current flows through the potential coil and there is no current to the current coil. Therefore the pointer rotates in such direction that the pointer deflects and comes to rest at the point market infinite on the scale.

📝The test terminals are short circuited and the generator handle is rotated. At this condition, a very large current flows to the current coil and a small amount of current flow through the potential coil the resultant torque produced deflects the pointer in the opposite direction and makes a pointer to read zero marking on the scale.

📝After checking for the above two extreme readings on the scale, the high resistance to be measured is connected between the test terminals. The generator handle is rotated, now reasonable amount of current flow in both potential coil, as well as in the current coil and torque produced deflect the pointer on the calibrated scale which gives the value of the resistance that is being measured.

😉my 2nd day of internship in the Transformer service and manufacture company 🎉

🥳MY 2ND DAY IN THE INTERNSHIP 🥳

🤩 today I want to share about my second day of my internship where we learnt about a lot of things that is a beautiful Transformers they are one is the dry type transformer and another one is the oil type transformer.  today we generally got over new problem Transformer that is nothing but the  a trap transformer is in a burnt condition.  

👆DRY TYPE TRANSFORMER 👆

as we know the dry type transformer generally consists of three phases   the three windings in which two windings are damaged and the repair of providing of the dry type transformer will generally cost about ₹2.5 lakh rupees.  that place we can generally get a new dry type transformer.  so the decision has to be made by the customer on whether to buy a new dry type transformer or to generally repair the windings of the damaged dry type transformer. 

👆OIL TYPE TRANSFORMER 👆

 eventually they cannot take the decision at the sudden moment they might take the decision after sometime.  and inspection is also done by the government Electricity Board company as how did the dry type transformer catch fire And   how the windings have been burnt.  generally the dry type transformer student catch fire and it is very important to know what the  fault is in the dry type transformer.  the winding pattern of the dry type transformer this comparatively different when compared to that of the oil type transformer.  in the dry type transformer we can generally find the spacing between the windings that is generally in order for the proper air flow.  interactive Transformer generally make use of copper windings covered with animal come for insulation purpose.  the most important thing that we need to remember in a dry type transformer is the   bushings are different when compared to that of the bushings of the oil type transformer.  the size of the dry type transformer whole Transformer body is very much smaller than compared to that of oil type transformer.  the main advantages of the dry type transformer is here we are not making use of any Transformer oil.  but the maintenance cost is very much high in dry type transformer.  one of the problem is that if the water is mixed with oil of the transformer then it creates a very huge problem that is either during the testing process we may not get the correct or exact values all the performance of the transformer  may decrease instantly.  the next question that arises is how to really find out as how the water is mixed with the Transformer oil this weekend generally find out either by means of the manure method that is generally by checking the oil with the hand is the oil quality is bad then we need to replace the all with the new Transformer on the vegetable oil.  as we know that the current will generally flow to the water so it will affect the insulation how the Transformer windings.  and the process generally involved in oil changing process is firstly we need to remove all the oil  from the Transformer and we need to lift the Transformer windings by means of the hydraulic lift and let the Transformer windings be there in the hydraulic lift for many Har so that all the Oils will be generally wiped out generally fall in the Transformer tank.  after sometime you can disappear in the Transformer tank as well the Transformer windings and then after removal of the oil from the Transformer winding we are going to place it in a Transformer oven.  the transformer is generally kept in oven we need to generally keep it for either 12 hours or 24 hours.  the Transformer oven we need to set up the temperature as well as in the control panel we can also see how many minutes it generally takes to generally complete the   oil drying process.  after the 24 hours we are going to do the different test on the Transformer windings to check the practical value with the theoretical value.  and then only we can decide what to do next with that Transformer or to find out the fault in a transformer.  generally we feel about 340 litres of Transformer oil of the vegetable oil in a transformer this both in a conservative oil tank as well as in the Transformer tank.  hear the oil be used in a transformer tank it should not be a new all we can use the reused oil generally by transferring that oil into the oil filtration tank 

👆OIL FILTRATION MACHINE👆

and then again recycling it into a clean oil and then finding that oil into the Transformer tank. The cost of oil filtration machine varies from ₹60,000 to some ₹1lakh rupees depending on our requirements. for the recycling process of the oil we are generally having a separate machine or we generally quality oil filtration vehicle.  if I generally wanted to know about oil filtration vehicle in simple words that is it generally consists of two valves,  Oneness the inlet valve we will generally the dirty  oil and the other is a outlet valve  where we will get a clean oil,  and all coming out of the outlet valve   will be very hot.   during starting the colour of the transformer all will be generally white aur pure white,  and the oil is generally useless then it will be  Radisson colour.  the oil which cannot be used again is generally given to the scrap which can be used for mechanical purpose and for industrial purpose so on.  the most important thing in the Transformer oil is the ingredients used in the Transformer oil is very dangerous to human health so the government is generally thinking thinking of making use of a pure vegetable oil for the Transformer oil in the upcoming future.  we have come to the end of the section where in my internship today I learnt about the oil running process in a transformer and the step by step sequence what we need to follow during the  oil changing process of the transformer and I'm very eager to learn many more things about the Transformer in in the upcoming days of my internship.