28 Efficient Electrical Energy Management (2)

7/29/2019 28 Efficient Electrical Energy Management (2)

http://slidepdf.com/reader/full/28-efficient-electrical-energy-management-2 1/13

EFFICIENT ELECTRICAL ENERGY MANAGEMENT-An ultimate solution to power crisis.

By N.Mounika & G.N.S.Ramya

[email protected] [email protected]

Ph.no:9290084414 ph.no:08643224881

BAPATLA ENGINEERING COLLEGE

¾ EEE

ABSTRACT: Power is the engine of growth of any developing economy, and as

the time is running out for reforms for power crisis, this paper tries to show some

effective solutions to reduce losses in electrical equipment which are widely used in

Industrial, Commercial , Agricultural , Domestic and Power Sectors so that electrical

energy can be effectively managed to overcome present situation of power crisis. In this

paper we are going to give a brief scenario of saving electrical energy by the following

methods in various electrical equipment.

Energy Efficient Motors

Energy Saving in Transformers

Saving Energy with Electric Resistance Heating

Loss Reduction using Capacitor Control Concepts

Increasing Lightning Efficiency

Energy Management in Power Systems

mailto:[email protected]

mailto:[email protected]



INTRODUCTION:

Energy management is defined as the scientific

investigation , analysis, optimization and control of the use of energy and it is very

much concerned with instructing and training people to conserve energy.

The Need For Energy Management:

“ As one unit saved is equivalent to two units generated due to

various losses”, And as the consumption of electrical energy is a universally accepted

indicator of progress in agriculture, industrial and commercial sectors, So the energy

need to be managed efficiently so that energy shortages can be overcome. There is an

urgence of energy conservation because the demand for power has been outstripping the

growth of availability. And the India’s power sector is plagued by capacity shortages,

resulting in frequent black outs, poor reliability and deteriorating physical and financial

conditions.

Energy management or Energy conservation means

avoiding all power waste, through the use of energy efficient equipment and

processes.So efficient energy management is the ultimate weapon to outgrow the



situation of energy and peaking shortages and make the country free from power crisis

so that the entire system is reliable.

ENERGY EFFICIENT MOTORS:

As motors occupy a lion’s share in all industrial ,

commercial , agriculture and domestic loads ,Energy conservation in motors is need of

the hour. And energy saving in motors can be done in the following ways.

1. Switching off the Motor: The simplest way of reducing energy consumption in

Motors is to switch off the motors when it is not needed. These are some of the ways of

controlling the switching operation .

Time switch: Fit a time switch to ensure the equipment is on only when it is

needed.

Sequencing of multiple loads: The optimum selection of machines in a multiple

installation is selected to achieve the desired pressure or temperature.

Load sensing : Many motors spend long periods of time running with no useful

load but they may still have to overcome significant losses in gear boxes coupling.

Interlocking:An extract or fan only switched on when a woodworking centre or

welding equipment is switched on.



2. Motor Energy Controls: Induction motors have distinct inefficiencies in that they

cannot effectively adjust the amount of electricity they consume for the work they do;

when they operate under less than full load, substantial power is wasted.

By having control over energy consumption, energy saving is between 15% and 40%

of electricity costs without any loss of power or detriment to motor.

Fig. 1 : Motor Consumption of 0.5kW Single Phase Motor

3. Higher Efficiency Motors: These higher efficiency motors contain smaller, more

efficient cooling fans and have lower magnetic loading. And these motors also have a

better power factor, which can give saving through the reduction in the KVA

maximum demand charge. Some of the features of these motors are

• High quality stampings

• High quality of stator winding

• Copper die cast rotor

4. Higher efficiency Geared Motors:

In India the prevailing trend is buying motor, gear box and

coupling separately. The more the mechanical gadgets the less is the efficiency. So



the need of the hour is the standardization of Geared Motors as a product rather than

buying each of them separately. Some of the benefits of these geared motors are…..

• No coupling in between , so more efficiency.

• Need not do the assembly of motor , gearbox and coupling and thereby

saving money and energy.

• Energy optimizing controls.

ENERGY SAVING IN TRANSFORMERS:

Thoughtful selection of transformers can greatly reduce electricity

consumption. Small efficiency improvements are very effective. Typical efficiencies

range from 95% to 99% ; a 1% improvement can reduce waste by one-half , When

selecting transformers, consider the load factor; with high load variation, transformers are

mostly lightly loaded, and should be selected for low core losses. with higher load

factor, transformers with low winding losses save more.

It is estimated that present energy wastage on account of

transformer no load loss in India is about 4billion Kwh per year. Such a loss is

equivalent to the generation capacity of a large power plant. So there is a need of a

Energy Efficient Transformer which will have reduced no load loss.

Energy Efficient Transformer:

Reduction of no load loss depends on reduction of Hysterisis

loss and Eddycurrent loss . By using the CRGO steel and silicon steel hysterisis and

eddycurrent losses are reduced respectively.Eventhough In order to achieve significant



improvement in efficiency , Amorphous Metal is used to make the transformer cores.

Amorphous metal exhibits a unique random molecular structure unlike rigid grain

structure of silicon steel ,which enables easy magnetization and demagnetization, thereby

reducing hysterisis loss. Further processing of Amorphous metal in very thin

laminations enables significant reduction in eddycurrent losses.

Comparing with typical silicon steel transformer cores the no load

loss reduction in AMDT cores will be about from 70% to 80%. And it is estimated that

2.5 million silicon steel core transformers of Indian distribution system currently in

operation if were replaced with AMDT’S about 3.0 billion kwh energy would be saved

annually which is equal to financial impact of Rs.1080 crores.

SAVING ENERGY WITH ELECTRIC RESISTANCE HEATING:

Electric resistance heating converts nearly 100% of the energy

in the electricity to heat. However, most electricity is produced from oil, gas, or coal

generators that convert only about 30% of the fuel's energy into electricity. Electric

resistance heat can be supplied by centralized forced-air furnaces or by zonal heaters in

each room, both of which can be composed of a variety of heater types. Zonal heaters

distribute electric resistance heat more efficiently than electric furnaces because you set

room temperatures according to occupancy. In addition, zonal heaters have no ducts that

can lose heat before it reaches the room.



Energy-Saving Measures:

Whatever the electric heating system we use, there are steps to be taken to reduce

energy consumption. These methods include maximizing insulation, installing quality

windows, reducing air leakage, using zone heating, and regularly replacing or cleaning

filters in forced-air systems.Some of the methods are discussed below.

1.Insulation:To keep heating costs reasonable, electrical heaters should be very well-

insulated. Insulation's ability to slow heat flow is measured by R-value ("R" stands for

thermal "resistance"). The higher the R-value, the better the insulation restricts heat

flow.However an adequate R-value does not necessarily mean that it is well-insulated.

The insulation must be properly installed as well. Gaps and voids in the insulation—even

small ones—create air convection or air leakage that markedly reduce rated R-values.

2 .Zone Heating:Zone heating cuts costs by heating the rooms occupied while allowing

unoccupied sections to remain cooler.Zone heating can produce energy savings of more

than 20% compared to heating both occupied and unoccupied areas . Of course, the

amount of savings we achieve depends on how the portable or built-in zone heaters are

combined with centralized heating system.One recommended zone heating strategy

involves controlling the centralized heating system with an automatic setback thermostat.

During the times when everyone is at home and active, the automatic setback thermostat

provides a comfortable temperature throughout the house..



3.Furnace Filters:Furnace filters are designed to keep the blower, heat exchanger, and

ductwork clean.Furnace cannot run as efficiently if the filters, blowers, and heating coils

are dirty. Plus, it is much easier to change or clean filters than to clean blowers, heating

coils, and ductwork.

LOSS REDUCTION USING CAPACITOR CONTROL CONCEPTS :

Sources of losses: The energy losses in the transmission lines are of two kinds :

Resistive and Reactive . The former are caused by resistive component of the load and

cannot be avoided. The latter, coming from reactive component of the load, can be

avoided. Reactive losses come from circuit capacitance (negative), and circuit inductance

(positive). When a heavy inductive load is connected to the power grid, a large positive

reactive power component is added, thereby increasing observed power load. This

increases losses due to reactive load current, increases kVA demand, increases customer

energy consumption, usually degrades voltage profiles.



Process of reduction:

More than one half of system energy loss is caused by the resistance of the

feeders. To minimize energy losses it is, therefore, important to locate feeder capacitors

as close to the loads as possible. Substation capacitors can not do the job - the reactive

load current has already heated feeder conductors downstream from the substation.

Reducing reactive current at the substation can not recover energy losses in the feeders.

Another way to minimize energy losses is to use capacitor banks that are not too large.

This makes it possible to put the banks on-line early in the load cycle. Since energy saved

is the product of power reduction and the time the banks are on-line, the overall energy

reduction is usually greater than when using large banks which are turned on for shorter



amounts of time .As shown in Fig. 2 the reactive component of current can be reduced by

using the capacitor and due to which there will be reduction in losses , decreased

energy consumption and decreased KVA demand. Improved voltage profile.

Increasing Lighting Efficiency:

Increasing lighting efficiency is one of the fastest ways to decrease energy

consumption. If we replace 25% of total lights in high-use areas with fluorescents, we can

save about 50% of energy wastage. Following are the two areas where we can save

lighting energy.

Indoor Lighting : Using linear fluorescent and energy-efficient compact fluorescent

lamps (CFLs) in fixtures to provide high-quality and high efficiency lighting.

Fluorescent lamps are much more efficient than incandescent bulbs and last 6 to 10 times

longer. Although fluorescent and compact fluorescent lamps are more expensive than

incandescent bulbs, they pay for themselves by saving energy over their lifetime.

Outdoor Lighting: When selecting outdoor lights, we have lights from low voltage

pathway lighting to high-sodium motion-detector floodlights. Instead of using Torchiere

halogen lamps if we use compact halogen lamps in the light fixtures there will be

substantial saving of energy .Some lights are powered by small photovoltaic (PV)

modules that convert sunlight directly into electricity.Using outdoor lights with a

photocell unit or a timer so they will turn off during the day.

ENERGY MANAGEMENT IN POWER SYSTEMS:

As Power system is the basic building block of the phenomena

like Generation , Transmission and Distribution , Saving of energy in power systems



play a major role in energy conservation and Following are some of the methods by

which we can save energy considerably.

Power Factor Improvement: As power factor decides the amount of reactive power

drawn by the load.And lower the power factor , higher is the reactive power and higher is

the current drawn and so higher are the losses. So it is of utmost importance to improve

the power factor and following are the methods to improve the powerfactor.

1.Use of Static capacitors: These are connected in parallel with equipment whose p.f is

to be improved and take the current leading by 90 degrees from supply which neutralizes

the reactive lagging component of the load current and improves the power factor.

2.Using synchronus condensers: Synchronus condenser also called as synchronus motor

is the only motor which can be made to run at leading powerfactor at the same time of

supplying mechanical power. It is connected in parallel with the equipment whose

power factor is to be improved.

3.Using phase advancers: These are the special commutator machines which improve

the power factor of Induction motors.



CONCLUSION :

As every sector is worst hit by power shortage and as energy conservation

is the only solution to the power crisis this paper has tried to throw light on some of the

methods of energy saving and they are as follows..

• In Motors by employing higher efficient geared motors.

• In Transformers by using AMDT core as transformer core.

• By employing Zone heating in Electric Resistance Heating .

• Loss reduction by capacitor controls.

• Compact fluorescent bulbs to replace Incandescent bulbs.

• Power factor improvement in power systems.

References:

1.Paper on “Use of Energy Efficient Transformers in Asia“By Jerry CF Li.

2.Journals: IEEMA , Electrical India.

28 Efficient Electrical Energy Management (2)

Documents

Transcript of 28 Efficient Electrical Energy Management (2)