A Presentation

ON NTPC ANTA POWER PLANT

submitted in partial fulfilmentfor the award of the degree

BACHELOR OF TECHNOLOGY

IN

Department of Electrical Engineering

Introduction on NTPC Ltd. NTPC ltd. is the largest power generating company of India.

A public sector company, it was incorporated in the year 1975 to accelerate power development in the country as a wholly owned company of the government.

Total installed capacity of NTPC Ltd. Is 43,128 MW.

15 coal based(24,395 MW).

3 gas based(3,955MW).

Power Evacaution from NTPC Anta

Power Lines Bhilwara

Two Lines for Jaipur

One Line for Kota and

One Line for Rawatbhata Power Plant

Gas TurbineGas turbine is a heat engine.The process includes:-

Compression:-Drawing air into the engine, pressurizing it and then feeding it to combustion chamber.

Combution:Typically made of a ring of fuel injector that inject a steady steam of fuel into combustion chamber where it mixes with the air. The combustion produces a hightemperature and high pressure gas steam that enters and expands through the turbine.

Expansion :-Of the product of combustion in a turbine.

Start-up of the GT:-

Start-up of the GT is driven with the help of starting equipment which runs the generator as a motor withspeed increasing from 0 to 600 rpm. At this speed piolet flame ignited in combustion chamber, fuel (gas/naphtha) enters and combustion take place.

Start-up of the Gas turbineThe speed increases further both with the help of generator motoring and the combustion of the fuel up to about 2000 rpm. At this speed starting equipment is switched off and only the generator is made ready for synchronisation with the grid. After synchronizations, the turbine load increases up to base load with more and more fuel entering the combustion chamber.

Application of Gas Turbine

Conventional applications are:-

Simple Cycle Operation Combined Cycle Operation

Electric utility companies use gas turbine predominantly in simple cycle and combined cycle applications.

Combined cycle operation is much efficient than open cycle operation.

Simple Cycle operationA simple cycle operation turbine is a type of gas turbine most frequently used in the power generation, aviation(jet engine) and oil and gas industry (electricity generation) and mechanical drives.

Combined Cycle Power plant

The Combustion Turbine:-Natural gas is mixed with air and burned in the combustion chamber to create the high pressure gasses needed to spin a turbine. This part of the plant is a single cycle combustion turbine. These are sometimes called CTs. CTs are normally designed to meet peak loads.

The Combined Cycle Power Plant:-A combined cycle power plant is a dual cycle power plant. The “2nd” part of the combined cycle is a heat recovery unit. It takes advantage of the energy in the exhaust gases to create steam. The steam spins a turbine to generate electricity. The combined cycle plants are normally designed to meet base and intermediate loads.

Heat Recovery Steam Generator

Waste Heat Recovery BoilerHeat Recovery Steam Generator (HRSG) have found application in a wide range of industries where the co-generation of steam and electricity is required, in order to obtain an independent power plant and negligible emission levels.

TransformerA transformer is a device that transfer electrical energy from one circuit to another through inductively coupled electrical conductor. A changing current in the first circuit(the primary) creates a changing magnetic field, in turn this magnetic field induces a changing voltage in the second circuit(the secondary). By adding a load to the secondary circuit one can make current flow in the transformer, thus transferring energy from one circuit to the another.

Basic Principle:-

The transformer is based on two principles: firstly that an electric current can produce a magnetic field (electromagnetism) and secondly that a changing magnetic field within a coil of wire induces a voltage across the ends of the coil (electromagnetic induction). By changing the current in the primary coil, it changes the strength of its magnetic field; since the changing magnetic field extends into the secondary coil, a voltage is induced across the secondary.

Types of transformer:- Autotransformer Polyphase Transformer Resonant Transformer Leakage Transformer Instrument Transformer

Construction of Transformer:- Laminated Iron Core MS Tank Radiator Fins Conservator Silicon Gel Breather H.T. bushing

Continue:-

L.T. Bushing Buchholtz Relay Transformer oil Tap Changer Level indicator H.T. and L.T. winding Explosion Vent

Method of Cooling Transformer AN (Air Natural) Cooling media

AF (Air Forced) A = Air

ONAN (Oil Natural Air Natural) G = Gas(C2F6)

ONAF (Oil Natural Air Forced) L = Synthetic Oil (Silicon Liquid)

OFAN (Oil Forced Air Natural) S = Solid Insulation

OFAF (Oil Forced Air Forced) O = Mineral Oil

ONWF (Oil Natural Water Forced) W = Water

OFWF (Oil Forced Water Forced)

Protection System of Transformer:-Buchhclotz RelayEarth Fault or Leakage ProtectionOverload Protection and Combined LeakageDifferential System and circulating current systemPressure Relief Device

Preventive Maintance of Transformer :-It can be categorized as hourly, daily, quarterly, half yearly, yearly, 5 yearly:-

Hourly Inspection: - Checking of winding temperature, oil temperature & load on HT & LT side.

Continue:-

Daily Inspection: - Checking of oil level in transformer & tap changer, relief vent (explosion vent) diaphgram color of silica gel. If white/pink, then replace & HT and LT voltage and suitable adjustment through tap changer if required.

Quarterly Inspection: - Checking of bushings for cracks and dirt deposits. Clean & replace if necessary, dielectric strength of oil and its water content, radiator fans, pump bearings, on load tap changer driving mechanism, gear box oil level, contacts, oil level in breather, top up oil if necessary and replace burnt or worn out contact.

Half Yearly Inspection: - Checking on load tap changer (OLTC) and driving gears mechanism, clean, adjust and replace contacts and brake shoe etc.

Yearly Inspection:- Testing of transformer oil for acidity, water content, dielectric strength &

Tan Delta & filter if necessary. Measurement of insulation resistance & compare with the value at the

time of commissioning. Tighten all gasketed joints e.g. tank cover, radiators. Check all relays, alarm contacts & their operation.

Five Yearly Inspection:- Over all inspection by lifting of core & coils, washing them with clean, hot

dry oil tight all nuts & bolts, on LT bus bar. Painting of transformer externally. Dehydration & filtration of oil (It has to be done 1 ½ to 2 year intervals).

Motor

Electromechanical device that converts electrical energy to mechanical energy.

Mechanical energy is used to: Rotate pump impeller, fan, blower Drive compressor Lift materials Motors in industries are used as 70% of electrical power.

Working of Motor:-

Types of MotorElectric Motors

Alternating Current (AC) Motors

Direct Current (DC) Motors

Synchronous Induction

Three-PhaseSingle-Phase

Self ExcitedSeparately Excited

Series ShuntCompound

AC Motor:-

Electrical current reverses direction

Two parts: stator and rotor•Stator: stationary electrical component•Rotor: rotates the motor shaft

Speed difficult to control

Two types:-•Synchronous motor•Induction motor

Components of Motor

Rotor:-Squirrel cage:-Conducting bars in parallel slots.

Wound rotor:-3-phase, double-layer, distributed winding.

Stator:-Stampings with slots to carry 3-phase windings.

Wound for definite number of poles.

AC Motor:- Synchronous motor• Constant speed fixed by system frequency• DC for excitation and low starting torque: suited for low

load applications• Can improve power factor: suited for high electricity use

systems• Synchronous speed (Ns)

F = supply frequency

P = number of polesNs = 120 f / P

Induction MotorThree-phase induction motor:-

•Three-phase supply produces magnetic field•Squirrel cage or wound rotor•Self-starting•High power capabilities•1/3 to hundreds HP applications: pumps, compressors, conveyor belts, grinders•70% of motors in industry!

Speed and slip:-•Motor never runs at synchronous speed but lower “base speed”•Difference is “slip”•Install slip ring to avoid this•Calculate % slip:

% Slip = Ns – Nb x 100 Ns

Ns = synchronous speed in RPMNb = base speed in RPM

Generator Generator is the electromagnetic device that converts mechanical energy into elecrical energy. Construction of Generator:- A typical Generator has following main components. Stator Frame comprising of casing and stator core Rotor Exciter Slip Rings and Brushes (not applicable for all designs) Bearings and Bearing Pedestals Cooling System Other systems e.g. Static Frequency Converter for starting of gas turbine.

Name Plate Rating in Generator in NTPC

Applicable Standard IEC 60034Generator Type WY18L-095LL

Apparent Power 135 MVATerminal Voltage 10.5 kVRated Current 7423 A

Frequency 50 HzSpeed 3000 RPMInsulation Class (Stator and Rotor)

F

Type of Cooling Air CooledNo. of Phases 3 PhasesExcitation System Slip Rings with Brushes

THANKS