Modern Trends in Power Plant

Published on June 2016 | Categories: Documents | Downloads: 44 | Comments: 0 | Views: 286
of 85
Download PDF   Embed   Report

Comments

Content

RUPESH P SHEWARE

Thermal Power Plants

Total Installed Capacity as on 31st Dec 2011
 Total Installed Capacity

186654 MW

Installed capacity in MW ( as on 31st Dec2011
120000 104021 100000 80000 60000 40000 38748.4 17742.83 4780 0 Coal Hydro Gas Nuclear 1199.75 Diesel New Renewables 20162.24

20000

Installed capacity in %( as on 31st Dec2011)
3

1

11 Coal

10

Hydro Gas 56

Nuclear
Diesel New Renewables

21

Renewable Installed capacity( MW)
149 3121 Wind

2788

Bio_mass

Small_hydro
Solar 14105

In financial year ending 2011 energy breakup
Description Domestic Commercial Agriculture Industry Railway Inters-state Others Total Ex-Bus Generation plant) Not Sold T&D Loss Energy ( MU) 131383 44432 123724 181168 10064 12697 43733 547201

788355 241153 30.58939183

Chapter-III, Table-I, HLP ,Shungru Report

India Power Story
PLAN 1st1951-1956 2nd1956-1961 3rd1961-1966 Annual Plan 1966-1969 4th 1969-1974 5th 1974-1979 Annual Plan 1979-1980 6th 1980-1985 7th 1985-1990 Annual Plan 1990-1991 Annual Plan 1991-1992 8th Plan 1992-1997 9th Plan 1997-2002 10th Plan 2002-2007 11th Plan 2007-2012 Total TARGET( MW ) 1300 3500 7040 5430 9264 12499 2813 19666 22245 4212 3811 30538 40245 41110 78700 282373 ACHIEVEMENT ( MW ) 1100 2250 4520 4120 4579 10202 1799 14226 21401 2776 3027 16423 19119 21180 52063 178785 ACHIEVEMNT ( % ) 84.6 64.3 64.2 75.9 49.4 81.6 64.0 72.3 96.2 65.9 79.4 53.8 47.5 51.5 66.2

ANNUAL PER CAPITA CONSUMPTION OF ELECTRICITY ( IN KWH )
COUNTRY ICELAND USA population ( in million ) 0.32 311.59 2001 26143 12406 2011 36583.7 12606.93

JAPAN
TAIWAN UK MALAYSIA BRAZIL IRAN CHINA INDIA PAKISTAN SRILANKA

127.82
23.17 62.64 28.86 196.65

7579
6215 5759 2749 1845 1698

7924.22
10141.75 5685.35 3859.49 2034.32 2315.24 2568.33 490.97 413.57 372.62

1344.13 1241.49 176.74 20.87

1019 474 413 300

Electricity by definition is electric current that is used as a power source! This electric current is generated in a power plant, and then sent out over a power grid to your homes, and ultimately to your power outlets.

Electric current generation - whether from fossil fuels, nuclear, renewable fuels, or other sources is usually based on the:

A Simple AC Generator
V N dΦ dt

23.2

 We noted earlier that Faraday’s law dictates that if a coil

of N turns experiences a change in magnetic flux, then the induced voltage V is given by
 If a coil of area A rotates with respect to a field B, and if

at a particular time it is at an angle  to the field, then the flux linking the coil is BAcos, and the rate of change of flux is given by
dΦ dsin  d  BA  cos  cos dt dt dt

In September of 1831, Michael Faraday made the discovery of Electromagnetic Induction.

Faraday attached two wires to a disc and rotated the disc between the opposing poles of a horseshoe magnet creating an electric current.

Energy/Power
 Sources of energy : There are two main sources of energy. They are conventional

and non conventional sources of energy.



flowing water and fossil fuels (coal, petroleum, natural gas).

i) Conventional sources of energy :- are wood,

 ii) Non conventional sources of energy :- are

solar energy, wind energy, biomass energy, ocean energy (tidal energy, wave energy, ocean thermal energy), geothermal energy, nuclear energy etc.  Some sources of energy are renewable like sun, wind, flowing water, ocean, wood, biomass etc.  Some sources of energy are non renewable like coal, petroleum and natural gas.

LAYOUT OF THERMAL POWER PLANT
WTP

C/M

Boiler

Turbine

Generator

CHP

ESP

ASP

ASH BUND

Hydro Power Video

Thermal Power Plant Cycle

WIND MILL

WIND ENERGY FARM

FIXED DOME TYPE BIOGAS PLANT

SOLAR CELL

SOLAR PANELS

SOLAR LAMP

TIDAL ENERGY

Boiler Overview

What exactly is the turbine? Turbine is an engine that converts energy of fluid into mechanical energy

The steam turbine is steam driven rotary engine.

Construction of steam turbines

How does the steam turbine work?

 Impulse stage – whole pressure drop in nozzle (whole enthalpy drop is

changed into kinetic energy in the nozzle)  Reaction stage – pressure drop both in stationary blades and in rotary blades (enthalpy drop changed into kinetic energy both in stationary blades and in the moving blades in rotor)

Classification of steam turbines
a) way of energy conversion - impulse turbines - reaction turbines

Advantages of turbines
 Large power achieved by relatively small size
 High efficiency  Simple design

 High revolution

Ash handling Plants

DM Plant

New Techniques in Power plant

Boiler
Natural Circulation Vs. Once Through System

Rankine Cycle Subcritical Unit 1
1 - 2 > CEP work 2 - 3 > LP Heating 3 - 4 > BFP work 4 - 5 > HP Heating 5 – 6 > Eco, WW 6–7> Superheating 7 – 8 > HPT Work 8 – 9 > Reheating 9 – 10 > IPT Work 10–11 > LPT Work 11 – 1 > Condensing

Rankine Cycle Supercritical Unit
1 - 2 > CEP work 2 – 2s > Regeneration 2s - 3 > Boiler Superheating 3 – 4 > HPT expansion 4 – 5 > Reheating 5 – 6 > IPT & LPT Expansion 6 – 1 > Condenser Heat rejection

Boiler Supercritical Technolgy
             

What is Supercritical Technology? • The supercritical technology is the thermodynamic state where there is no clear distinction between the Water and Steam phase in the Rankine Cycle • Water reaches to steam state at a critical pressure above 22.1 MPa at 374 oC. 4 Rankine Cycle • The “efficiency “of the thermodynamic process is the heat energy fed into the Rankine cycle is converted into electrical energy. • Heat energy input to the Rankine cycle is kept constant, the output can be increased by selecting high pressures and high temperatures. • The key components are supercritical once through boiler and high pressure & high temperature steam turbine.

Generator Excitation

EXCITAION
The exciter is the "backbone" of the generator control system. It is the power source that supplies the dc magnetizing current to the field windings of a synchronous generator thereby ultimately inducing ac voltage and current in the generator armature  Two basic kinds of excitors  • Rotating (Brush and brushless)  • Static exciters (Shunt and series) The amount of excitation required to maintain the output voltage constant is a function of the generator load. As the generator load increases, the amount of excitation increases.  • Reactive lagging pf loads require more excitation than unity pf loads  • Leading pf loads require less excitation than unity pf loads

AVR PRINCIPALS OF AUTOMATIC VOLTAGE CONTROL

Voltage transformers provide signals proportional to line voltage to the avr where it is compared to a stable reference voltage. The difference (error) signal is used to control the output of the exciter field. For example, if load on the generator increases, the reduction in output voltage produces an error signal which increases the exciter field current resulting in a corresponding increase in rotor current and thus generator output voltage. Due to the high inductance of the generator field windings, it is difficult to make rapid changes in field current. This introduces a considerable "lag" in the control system which makes it necessary to include a stabilizing control to prevent instability and optimize the generator voltage response to load changes. Without stabilizing control, the regulator would keep increasing and reducing excitation and the line voltage would continually fluctuate above and below the required value. Modern voltage regulators are designed to maintain the generator line voltage within better than +/1% of nominal for wide variations of machine load.

Excitaion System

Brushless Exciter

 While brushless excitation system eliminate the

 BRUSHLESS EXCITATION

need for brushes, commutator & slip-ring.  It uses bridge rectifier circuit consists of SCR & diode.  The bridge rectifier circuit placed on the rotor.  The bridge rectifier circuit rotates with the speed of the rotor.  The A.C supply given to the bridge rectifier by the principle of “Electromagnetic Induction”.  Bridge rectifier being represented by a transformation from A.C voltage to D.C voltage.  The D.C output of the rotating rectifier is applied to the D.C rotating field of the motor

BREAKERS

Air Blast & Oil Circuit Breakers

SF6 & Vacuum Circuit Breakers

Comparison between SF6 & Vacuum breaker
Criteria Summated current cumulative SF6 Breaker 10-50 times rated short circuit current 5000-10000 times 5000-20000 C-O operations 5000-20000 C-O operations Vacuum Circuit Breaker 30-100 times rated short circuit current 10000-20000 times 10000-30000 C-O operations 10000-30000 C-O operations 5-10 years

Breaking current capacity of interrupter Mechanical operating life No operation before maintenance

Time interval between servicing Mechanism Outlay for maintenance
Reliability Dielectric withstand strength of

5-10 years

Labour cost High, Material cost Labour cost Low, Low Material cost High High High High Very high

What are Relays?
 Relays are electrical switches

that open or close another circuit under certain conditions.

Relay Purpose
   

Isolate controlling circuit from controlled circuit. Control high voltage system with low voltage. Control high current system with low current. Logic Functions

Relay Types
 Electromagnetic Relays (EMRs)
 EMRs consist of an input coil that's wound to accept a particular voltage

signal, plus a set of one or more contacts that rely on an armature (or lever) activated by the energized coil to open or close an electrical circuit.

 Solid-state Relays (SSRs)
 SSRs use semiconductor output instead of mechanical contacts to switch

the circuit. The output device is optically-coupled to an LED light source inside the relay. The relay is turned on by energizing this LED, usually with low-voltage DC power.

 Microprocessor Based Relays  Use microprocessor for switching mechanism. Commonly used in power system monitoring and protection.

How a Relay Works

Sold-State Relay

Solid State Relays
 These relays were developed with the advent of transistors,
 operational amplifiers etc. Their functionality is through  various operations like comparators etc. Their advantages   


 

are More flexible. Self checking facility. Less power consumption and low burden. Improved dynamic perfomance characteristics. High seismic withstand capacity. Reduced panel space.

Numeric Relays

Numerical Relays
 Operation of a numerical relay involves analog to
   

digital conversion of voltage and currents obtained from VT and CTs. These samples are fed to the microprocessor or DSP where the protection algorithms process these signals and necessary decisions are taken.

Advantage
 Its advantages are
 Maximum flexibility.  Provides multiple functionality.

 Self checking and communication facility.
 It can be made adaptive.

Why A System Needs Protection?
 There is no ‘fault free’ system.
 It is neither practical nor economical to build a ‘fault free’

system.  Electrical system shall tolerate certain degree of faults.  Usually faults are caused by breakdown of insulation due to various reasons: system aging, lighting, etc.

Electrical Faults
 majority are phase-to-ground faults
 phase-to-phase  phase-phase-phase

 double-phase-to-ground

Advantages for Using Protective Relays
 Detect system failures when they occur and isolate the faulted section from the remaining of the system.
 Mitigating the effects of failures after they occur.

Minimize risk of fire, danger to personal and other high voltage systems.

Protective Devices Comparison
Relays
 

Circuit Breakers
Activation

Fuses
Actuation

Acquisition Detection

Advantages/Disadvantages


Electromagnetic Relays (EMRs)  Simplicity  Not expensive  Mechanical Wear  Solid-state Relays (SSRs)  No Mechanical movements  Faster than EMR  No sparking between contacts  Microprocessor-based Relay  Much higher precision and more reliable and durable.  Improve the reliability and power quality of electrical power systems before, during and after faults occur.  Capable of both digital and analog I/O.  Higher cost

INTRODUCTION TO PLCS
Advantages of PLCs

• Less wiring. • Wiring between devices and relay contacts are done in the PLC program. • Easier and faster to make changes. • Trouble shooting aids make programming easier and reduce downtime. • Reliable components make these likely to operate for years before failure.

Programmable Logic Controllers
( Definition according to NEMA standard ICS3-1978)
A digitally operating electronic apparatus which uses a programming memory for the internal storage of instructions for implementing specific functions such as logic, sequencing, timing, counting and arithmetic to control through digital or analog modules, various types of machines or process.

65

PLC Size
1. SMALL - it covers units with up to 128 I/O’s and memories up to 2 Kbytes. - these PLC’s are capable of providing simple to advance levels or machine controls. - have up to 2048 I/O’s and memories up to 32 Kbytes. - the most sophisticated units of the PLC family. They have up to 8192 I/O’s and memories up to 750 Kbytes. - can control individual production processes or entire plant.

2. MEDIUM 3. LARGE

66

Major Components of a Common PLC
POWER SUPPLY

From SENSORS
Pushbuttons, contacts, limit switches, etc.

I M N O P D U U T L E

PROCESSOR

O U T P U T

M O D U L E

To OUTPUT
Solenoids, contactors, alarms etc.

PROGRAMMING DEVICE

67

SCADA ( Supervisory Control & Data Acquisition System )

Computer Control Networks
3. DCS
•Most comprehensive
To other Processes
Operator Control Panel Supervisory (host) Computer Main Control Computer Operator Control Panel Archival Data Storage

Data highway To other Processes

Local data acquisition and Local control computers Computer

Local Computer
Local Display

Local Computer
Local Display

PROCESS

DCS Elements-1



  

Local Control Unit: This unit can handle 8 to 16 individual PID loops. Data Acquisition Unit: Digital (discrete) and analog I/O can be handle. Batch Sequencing Unit: This unit controls a timing counters, arbitrary function generators, and internal logic. Local Display: This device provides analog display stations, and video display for readout. Bulk Memory Unit: This unit is used to store and recall process data.

DCS Elements-2
 General Purpose Computer : This unit is programmed by

a customer or third party to perform optimization, advance control, expert system, etc  Central Operator Display: This unit typically contain several consoles for operator communication with the system, and multiple video color graphics display units  Data Highway : A serial digital data transmission link connecting all other components in the system. It allow for redundant data highway to reduce the risk of data loss  Local area Network (LAN)

DDC

DCS

Advantages of DCS
 

Access a large amount of current information from the data highway. Monitoring trends of past process conditions.




Readily install new on-line measurements together with local computers.
Alternate quickly among standard control strategies and readjust controller parameters in software.



A sight full engineer can use the flexibility of the framework to implement his latest controller design ideas on the host computer.

DCS Vendors
 Honeywell
 Fisher-Rosemont  Baily

 Foxboro
 Yokogawa  Siemen

Cooling Towers
 Cooling towers are heat removal devices used to

transfer process waste heat to the atmosphere. Cooling towers may either use the evaporation of water to remove process heat and cool the working fluid to near the wet-bulb air temperature or, in the case of closed circuit dry cooling towers, rely solely on air to cool the working fluid to near the dry-bulb air temperature.

Types of Coolong Tower
  

With respect to drawing air through the tower, there are three types of cooling towers: Natural draft — Utilizes buoyancy via a tall chimney. Warm, moist air naturally rises due to the density differential compared to the dry, cooler outside air. Warm moist air is less dense than drier air at the same pressure. This moist air buoyancy produces an upwards current of air through the tower. Mechanical draft — Uses power-driven fan motors to force or draw air through the tower.




Induced draft — A mechanical draft tower with a fan at the discharge (at the top) which pulls air up through the tower. The fan induces hot moist air out the discharge. This produces low entering and high exiting air velocities, reducing the possibility of recirculation in which discharged air flows back into the air intake. This fan/fin arrangement is also known as draw-through. (see Image 3) Forced draft — A mechanical draft tower with a blower type fan at the intake. The fan forces air into the tower, creating high entering and low exiting air velocities. The low exiting velocity is much more susceptible to recirculation. With the fan on the air intake, the fan is more susceptible to complications due to freezing conditions. Another disadvantage is that a forced draft design typically requires more motor horsepower than an equivalent induced draft design. The benefit of the forced draft design is its ability to work with high static pressure. Such setups can be installed in more-confined spaces and even in some indoor situations. This fan/fill geometry is also known as blow-through. (see Image 4)



Fan assisted natural draft — A hybrid type that appears like a natural draft setup, though airflow is assisted by a fan.

Induced Draft Cooling Tower

Natural Draft Cooling Tower

Chimney

Bus Transfer Scheme
 There are two types of Bus transfers
 1) Transfer Bus scheme  2) Breaker and half Transfer scheme

Transfer bus

Breaker & Half
B
Line-I
Bus

Line-I

Message
 Why do we want cheap and abundant Electricity in India ?
 The answer is that without cheap and abundant electricity

no effort for the Industrialization of India can succeed.  Ask Another question ‘Why is industrialization necessary?  We want industrialization in India as the surest means to rescue the people from eternal cycle of poverty in which they are caught  Dr.B.R.Ambedkar. ( Dr.Ambedkar , Labour Memebers address to the first meeting of Reconstruction Policy
Committee on Public Work and electric Power , New Delhi , Oct 25 1943)

Sponsor Documents

Or use your account on DocShare.tips

Hide

Forgot your password?

Or register your new account on DocShare.tips

Hide

Lost your password? Please enter your email address. You will receive a link to create a new password.

Back to log-in

Close