economics of power utilization - 10th batch

8/3/2019 Economics of Power Utilization - 10th Batch

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EE 2802 Applied Electricity


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Cost of electric power

Tariffs

Factors influencing the costs and tariffs

Energy demand management

Power factor correction

2EE2802 - Applied Electricity


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Cost of electricity includes all the initial andcontinuousoperation costs

Alls

ho

uld be co

ns

idered befo

ref

ixing tariff

for consumers

Fixed costs

Running / operating costs



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FIXED COSTS OPERATING COSTS

Interest on capital

investment Allowance for

depreciation

Taxes and insurance

Most of the salaries

Small portion of thefuel cost

Most of the fuel cost

Small portion ofsalaries

Repair andmaintenance



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1. Fixed charge

For the portion of the plant that has beenallocated for the customer

2. Variable charge / Unit charge

For the units used by the customer (per kWh)

3. Maximum demand charge

Charge for the maximum demand (per kVA)



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Domestic purpose

Religious purpose

Industrial purpose

Hotel purpose

General purpose



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Fixed Charge(Rs/month)

Unit Charge(Rs/kWh)

Up to30 units 30.00 3.00

30 ~ 60 units 60.00 4.70

60 ~ 90 units 90.00 7.50

90 ~ 120 units 315.00 21.00

120 ~ 180 units 315.00 24.00

Above 180 units 315.00 36.00



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FixedCharge

(Rs/month)

UnitCharge

(Rs/kWh)

Demand Charge(Rs/kVA/month)

Industrial I1 240.00 10.50

Industrial I2 3000.00 850.00Peak 13.50

Off peak 7.35

Day 10.45

Industrial I3 3000.00 750.00

Peak 13.40

Off peak 7.15

Day 10.258EE2802 - Applied Electricity


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1. Demand

2. Diversity of demand

Maximum demand of various consumersnot occur simultaneously

This result in lower cost of electric energy



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3. Load factor

System is designed for maximum demand

Fully occupied or not, there are fixed charges

Poor load factor -> charge per kWh is high

To improve load factor -> accept off-peakloads at lower rates



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4. Power Factor

Productive power consumed on resistive loads

Non-productive power consumed oninductive loads

Low power factor -> greater non-productivepower



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Following information can be obtained

Daily operating schedule

Maximum lo

ad Size of generator units required

etc



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GENERATIONTRANSMISSION &

DISTRIBUTION

Plant loadfact

orimprovement

Clean fuel

Renewable

energy

Efficient

transfo

rmers

Transformerright sizing

END USE

Approaches

to

impro

veprocessefficiency

Efficient

appliances

Tariffregulations



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Customerbenefits

Societal benefits Utility benefits

Satisfy electricitydemands

Reduceenvironment

degradation

Lower cost ofservice

Reduce costs Conserveresources

Improveoperatingefficiency

Improve value ofservice

Protect globalenvironment

Reduce capitalneeds

Improve lifestyleand productivity

Maximizecustomer welfare

Improve customerservice

EE2802 - Applied Electricity 14

Benefits ???


15/19

Power factor of all AC motors &transformers is < 1

Majority of induction motors are inductionmotors

High p.f. at full load

Low p.f. at light loads

For a 3-phase balanced system

Low p.f. -> high current



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Disadvantages of low power factor

Line losses (I2R) are high

Large equipments are required

high capital cost

Large voltage drop

need extra regulation equipment

Low efficiency



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How to improve?

Inject a leading current into the circuit.

1. Installation of static capacitors

Capacitor may result in over correction

Toovercome automatic correction(control the no.of capacitors)



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How to improve?

Inject a leading current into the circuit.

2. Installation of synchronous motors

Employ instead of induction motors

Or use only for p.f. correction

3. Phase Advancers

Method of manipulating the phasecurrent



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economics of power utilization - 10th batch

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