Production, Planning & Control in Power Sector

Dev Ashish E002Rajul Garg E013Shweta Gupta E018Sahil Sahni E049Manish Singla E054Varun Malhotra E033

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India ranked 5th in terms of Power Generation and 6th in Power Consumption

Governed by ministry of power

Expected to grow by 13.2 % in 2012-13

FDI of 100% is allowed in electricity generation

Sector MW % age

State Sector 86,275.40 42.01

Central Sector 62,073.63 30.22

Private Sector 56,991.23 27.75

Total 2,05,340.26

Indian Power Industry

Fuel MW %age

Total Thermal

1,36,436.18 66.44

Hydro 39,291.40 19.13

Nuclear 4,780.00 2.32

RES 24,832.68 12.09

Total 2,05,340.26 100.00

Year Per Capita Consumption

1950 15 KWH/per year

2007 612 KWH/ per year

2012 1000 KWH/ per year

As on 30-06-2012Source:CEA

Power Generation

66%19%

2%12% Total

ThermalHydroNuclearRES

Constitutes about 66% of the power generation in India

Thermal Power producers have less profit margin as compared to hydro power producers because of there large expenditure on fuel(coal, oil and gas)

Indian Thermal Power generation is expected to grow by 14.4 % in 2012-2013

Coal-based power generation would increase by around 19200 mw

Coal Gas Diesel Total

56.8% 9.2% 0.6% 100%

As on 31-07-2012 – Source CMIE, CEA

Thermal Power Generation

Power Generation Process

1. Coal Supply*Coal from the mine is delivered to the coal hopper, where it is crushed to five centimetres (2 inches) in size. *The coal is processed and delivered by a conveyor belt to the generating plant.

2. Pulverizer *The coal is then pulverized, or crushed, to a fine powder, mixed with air and blown into the boiler, or furnace for combustion.

3. Boiler *The coal / air mixture ignites instantly in the boiler.*Intense heat from the burning coal turns the purified water in the boiler tubes into steam, which spins the turbine to create electricity.

4. Precipitator,stack *Burning coal produces carbon dioxide (CO2), sulphur dioxide (SO2) and nitrogen oxides (NOx).*Bottom ash and Fly ash are also produced

Coal Fired Power Plant

Boiler

Diagrammatic Sketch

5. Turbine, generator * Water in the boiler tubes picks up heat from the boiler and turns into steam. Once the steam hits the turbine blades, it causes the turbine to spin rapidly.

6. Condensers and the cooling water system*The cold water is warmed by the steam, which condenses back into pure water and circulates back to the boiler to begin the process of generating electricity again.

7. Water treatment plant: water purification*To reduce corrosion, water must be purified for use in the boiler tubes.

8. Precipitator, Ash systems*Fly ash and bottom ash are removed from the plants and hauled to disposal sites or ash lagoons.

9. Substation, transformer, transmission lines*Once the electricity is generated, transformers increase the voltage so it can be carried across the transmission lines.*Once electricity is delivered to substations in cities and towns, the voltage flowing into the distribution lines is reduced, and then reduced again to distribute electricity to customers.

Players Involved

•Produces Power

•Has state as its beneficiaries based on a predetermined share

Central Generating Unit

(CGU)

•Manages grid operation of its region

•Daily schedule planning for power supply and dispatch

Regional Load Dispatch

Center(RLDC)

•Manages generation & distribution of power in state

• Interacts with RLDC for its share of power from CGU

State Load Dispatch

Center(SLDC)

Central Power Generating Station• Gauges Daily Declared Capacity (DC)

Regional Load Dispatch Center (RLDC)• Receives DC from power plant• Breaks up DC as per SLDC plant wise

share

State Load Dispatch Center (SLDC)• Calculate their respective load

requirement• Conveys their power requirement to

RLDC

Regional Load Dispatch Center (RLDC) • Determines the dispatch schedule for

CPGS• Conveys Dispatch & withdrawal

schedule to respective party

Dispatch Schedule

Demand Forecasting Process

Withdrawal Schedule

• RLDC conveys the Dispatch schedule to power plant & withdrawal schedule to SLDC

• It is a 15 min time slot specifying demand and supply power unit

• For eg : slot 1 can be 200MW. This means the scheduled demand by SLDC is 200 MW for the 15 mins of slot 1 and scheduled supply from CPGS is 200 MW

• Total of 96 slots in a day

Dispatch & Withdrawal Schedule

Tariff mechanism

Capacity charge towards reimbursement of the fixed cost of the plant, linked to the plant's declared capacity to supply MWs

Energy charge to reimburse the fuel cost for scheduled generation

UI charge for deviations from schedule, at a rate dependent on

system conditions.

For any deviation in planned schedule an Unscheduled Interchange (UI) Charge is levied on either parties

If SLDC draws more power than scheduled it has to pay for the excess drawl at a UI rate

The rate is lower if the frequency is high, and higher if the frequency is low

UI Charge

Taken on 21 Aug, 2012 at 20:43

Load Frequency

Load Frequency

Both High and low frequencies are dangerous for machines and power lines

Load Frequency Relationship

Load Frequency

UI Rate increasesIncentive for

Power plant to generate more

Unscheduled Load Management

• Inventory does not comprise semi-finished or finished goods as in case of

most manufacturing plants

• Electricity can not be stored nor is it generated in stages. It is a continuous

non-stop process.

• The place of raw material is taken by the fuel used in generation viz. coal, gas

etc.

• Thermal power generation involves considerable plant and machinery, the

operation and maintenance of which require an inventory of requisite spares

and components to be regularly maintained

• Thus inventory comprises fuel and spares and components, loose tools,

chemicals and consumables

INVENTORY MANAGEMENT

With the introduction of Computerized Stores Accounting System, all information/reports can be generated either item wise or by any required group under the NTPC, Materials codification System (MCS). NTPC has codified the stores & spares under 100 main groups (from 00 to 99)

A) Construction Stores1. Cement2. Steel3. Others (viz. pipe, pipe fitting, cables etc.)

B) O&M Stores1. Coal2. Fuel (Excluding coal)3. Spares (Excluding insurance spares)4. Loose Tools5. Chemical, Gases & Explosives6. Oil & Lubricants7. Stores other than spares (consumables & Gen. Stores)8. Scrap

GROUPING OF ITEMS FOR REPORTING & CONTROL

•Spare parts which are not normally required for routine maintenance but would cause long shut down of vital equipment or entire plant in case of non-availability

Insurance Spares(I)

•Assemblies/sub-assemblies which are replaced as complete units to release defective assemblies for repair in order to cut down on costly idle time of equipment

Unit Assembly (U )

•All spares which require replacement due to wear & tear on their inherently short life

Consumables(C )

IUC Classification

•very tight control and accurate records

•Annual consumption value more than Rs 100000

A Items

•less tightly controlled and good records

•Annual consumption value between Rs 10000 to Rs 100000

B Items

•simplest controls possible and minimal records

•Annual consumption value less than Rs. 10000

C Items

ABC Classification

INVENTORY NORMS FOR STORES & SPARESConstruction store

Cement 2-3 months

Steel 9 months

Others (viz. pipe, pipe fittings, cables) 9 months

Operation and Maintenance StoresCoal 15 days

Fuel (excluding coal) OS shall fix the inventory

Spares (Excluding insurance spares) 18 moths usage indigenous24 month imported

24 month imported

Loose Tools 6 months

Chemical, Gases & Explosives 3 months

Oil & Lubricants 3 months

Consumables & Gen. Stores 6 months

Scrap At least 2 disposals in a year

Maintenance & Protection of Power Plants

• Start-up & shut-down operations more frequent

• Independent management of facilities important

• Preservation of global environment

• Improved generation efficiency

• Enhancing fuel conversion in existing facilities

• Technology to meet the trends

• Life cycle cost minimization

This makes Preventive Maintenance important

Background

Preventive & Predictive Maintenance :

• Non destructive inspection

• Life assessment technology

• Rationalization technology for scheduled inspections

All this improves the efficiency of maintenance

Methodology

• Monitor operation during transition

• Knowledge of deterioration state of equipment

• Regular monitoring of operations

• Performance evaluation for LCC minimization

• Operation Management for efficiency

• Operation data management services

Quantitative State of Facilities

• NDT :– Liquid Penetrant Testing– Magnetic particle testing– Ultrasonic testing

• Problems :– Narrow gap area inspection– Large amount of associated work– Difficulty of life time diagnosis

PM for Boilers

• Prevention of Stress Corrosion Cracking

• Analysis of vibratory response in grouped blades

• Overhauling by removing bucket

• Rationalization technology for scheduled inspection

• Facility Diagnosis Technology (Leak Diagnosis)

• Asset Management Technology (Trend)

PM for Steam Turbines

• Bucket : – Oxidation resistance coating : Ni Based Super alloy– Bucket tip coating for erosion prevention– Low current welding to prevent tip weld build up

• Nozzle : – Welding to cure thermal fatigue cracking– Diffusion Brazing to avoid nozzle deformation

PM for Bucket & Nozzle

• OIL : – Oil level checking. Leakages to be attended.– Oil BDV & acidity checking at regular intervals. If acidity

is between 0.5 to 1mg KOH, oil should be kept under observation.

– BDV, Color and smell of oil are indicative.

• BUSHINGS : – Cleaned and inspected for any cracks.– Note Deposition : Dust, dirt, Salt, chemical, cement, acid

fumes.

PM for Transformers

Condition MonitoringCondition monitoring is the process of monitoring a parameter

of condition in machinery, such that a significant change is indicative of a developing failure.

Fault Diagnosis Fault PredictionAvoid cascading damage to other

machines

Better Spare Management

Enhance machine endurance limit

Lesser Downtime: Increased

Productivity

Greater safety of workforce

Objectives Techniques

Vibration Monitoring

Lubricant Analysis

Noise Analysis

Thermography

DGA

Vibration Analysis•PdM (Predictive Maintenance) technique

• Uses instruments to monitor and analyze machine vibration to determine if the machine is working properly. •Vibration analysis is of the most common techniques used in PdM.

Vibration Spectrum AnalyzerUsed For

Turbines

Generators

Pumps

Motors

Fans

Compressors

Gears• Tooth meshing• Worn teeth• Misalignment• Mechanical looseness

Shaft & Motors• Unbalanced• Bent• Misalignment

Bearings• Damages• Distortion• Lubricant loss

Reasons

Lube Oil Analysis•Performed during routine Preventive Maintenance

• Provides meaningful and accurate information on lubricant and machine condition

OA – 3 Parts

Analysis of Oil Properties

• Moisture• Density• Viscosity• Acidity

Analysis of contaminates

Analysis of wear debris from machines

Contaminated Lube Oil

Measuring moisture content

Thermography•Identification of hot spots•Used for monitoring of switchyard equipment•Routine monitoring of motors/pumps•Monitoring of drain pipes to detect choking•To monitor condition of insulation on pipe and equipments

OA – 3 Parts

The hottest parts are depicted in bright

Yellow Color

Schedules & Standards

Sample Schedules

Vibration Monitoring Daily / Weekly / MonthlyOil Analysis Quarterly

Thermography Quarterly

ISO 17359

Condition monitoring & diagnostics of machine, general guidelines

ISO 13373

Mechanical vibrations and shock vibration monitoring of machines

Standards

Thanks

Power Generation - Video