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In combined cycle power plant (CCPP), the Brayton cycle & Rankine cycles are combined. 2

Cont… The exhaust of gas turbine which is at a high temperature is supplied to steam generator as a input. The heat energy of exhaust gas is absorbed by water. This water converts in to high pressure steam which is supplied to the steam turbine and additional electricity is generated. Steam is taken from the turbine condense in steam condenser. This combine cycle power plant gives approximately 45% efficiency. Recent CCPP are designed to give efficiency as high as 58 %. 3

1) High overall plant efficiency 2)Low investment cost 3)Reliability of supply 4)Small amount of cooling water required 5)Saving of Fuel 6)Flexibility of operation 7)Simplicity of operation

 While the designing of combined cycle power plant, choise of voltage, economic load transfer, system stability should be studied.

CCPP in India: 2.ANTA,2 x 150 MW GT Rajasthan1 x 113 MW ST413 3.Auraya, U.P.4 x 111 MW GT 2 x 103 MW ST650 4.Kawas4 x 105 MW GT Gujarat2 x 105 MW ST630 5.Uchahar, U.P Gandhar4 x 111 MW GT 2 x 103 MW ST650 5.Faridabad, UP4 x 131 MW GT 2 x 138 MW ST800 8.Godavari Kankinada, AP Vatwa, Gujarat Sr. No. Name of power plant Unit wise performance Total installed capacity (MW) 1. Dadri, Near Delhi National capital Power project x 131 MW GT 2 x 146 MW ST 817

Sr. No.StateName of power stationCapacity (MW) 1.Andhra pradeshKothagydam AssamGauhati41 3.Bihar(i)Barauni145 (ii)Bokaro 975 (iii) Patratu Delhi(i)Rajghat 350 (ii)Badarpur Gujarat Dhuvaran (4X 63.5, 2X 140) Ukai (2X 120, 2X 200,1X 210) Wanakbori (7X 210) Gandhinagar (2X 120, 3X 210) Haryana (i)Faridabad 200 (ii)Panipat Madhy pradesh(i)Korba 420 (ii)Satpura 300 (iii) Amarkantak Maharastra(i)Nagpur 480 (ii)Nasik 280 (iii)Pants 90 9.OrrissaTalcher Tamil Nadu (i)Neyveli 600 (ii)Ennore Uttar Pradesh(i)Harduagarj 540 (ii)Obra West Bengal (i)Santaldih 480 (ii)Chandrapur 420 (iii) Bander 330

Sr. No.StateName of power Plant Location River Capacity (MW) 1Gujarat Ukai (4X 75, 2X2.5)Tapi305 Kadana (4X 60, 2X1) Mahi242 2 MaharashtraKoyna RajasthanDeharBeas.Satluj990 Bhakra Right bank Sat I tij770 Bliakra Left Bank Satluj540 Rana Pratap Saczar Chamba I172 4Andhra Pradesh Nagarjuna SagarKrishna810 SrisailamKrishna770 Lower silemGodavari460 Upper silem Godavari240 Machkund 115 5Jammu & KashmirSalalChenab 690 6PunjabRanjit SagarRanj it600 MukerianBeas 207 8OrissaUpper Indravatilndravati600 BalimelaMachukund360 Upper KolabKolab320 HirakundMahanadi305 9Madhya PradeshBansagarSone315 PenchNarmada160 Ghandhi Sagar Chambal KarnatakaKalinacii NagjhariKalinadi840 Varahi 230 GerusuppaSharvathi180 Kodasalli Kalinadi120 11Tamil NaduKunclahKundah 555 Kadampari Cauvery400 Kodiyar 100

Cont… Sr. No.State Name of power Plant Location River Capacity (MW) 12KeralaIdduki 780 SabarigiriPamba300 Kuttiadi UttaranchalChibroYam una240 Ramganga 196 ChillaGanga144 TanakpurSarda120 14ManipurLoktakLeimatak MeghalayaUmiam 114

Cont… Enriched Uranium as Fuel Water is used as coolant & moderator The water in the primary circuit gets heated by absorbing the fission energy in the reactor core & same energy is given in the heat exchanger to generate the steam. The water coming out of the heat exchanger is circulated by the pump to maintain the pressure in the circuit in the range of 100 to 130 atm. The water becomes radioactive when passing through the reactor ; therefore entire primary circuit including heat exchanger must be shielded to protect the operating persons. The electrical generator coupled with steam turbine generates electrical power.

1)The water which is used as coolant, moderator and reflector is cheap & easily available. 2)Requirement of control rods are less. 3)Secondary circuit is not affected by radiation, so normal turbine maintenance technique can be used. 4)Operation is safe & stable. 1)High primary circuit pressure requires strong pressure vessel. 2)High capital cost. 3)Corrosion problem.

Enriched Uranium is used as fuel and water is used as coolant. In this type of reactor steam is generated in reactor core itself & this steam is expanded in turbine. After expansion steam is condensed in condenser. Feed pump is used to circulate water back into reactor core.

1)The pressure inside the reactor vessel is considerably smaller than P.W.R. 2)The metal surface temperature is lower than P.W.R. 3)The boiling water reactor (B.W.R.) is more stable than any other type of reactor. 4)The thermal efficiency of this reactor is 30 %. 1)The steam leaving the reactor is slightly radioactive therefore, light shielding of turbine and piping is necessary. 2)More safety precautions needed which are costly.

The long form of CANDU is Canadian Deuterium Uranium. Natural Uranium is used as fuel and heavy water as moderator.

1)No control rods are required, so control is much easier. 2)Enriched fuel is not required. 3)A short time is needed to construct the reactor compared with P.W.R. and B.W.R. 4)Heavy water being good moderator. 1)The cost of heavy water is extremely high. 2)The leakage is major problem. 3)Very high standard of design, manufacture, inspection and maintenance are required