electrical energy conservation

7/29/2019 Electrical Energy conservation

1/105

ELECTRICLAL ENERGY GENERATIOCONSERVATION AND UTILISATION

UNIT-IICONSERVATION


2/105

DEFINITION:The rate of charging for electrical energy

supplied by the utility company to its consumer.Tariff= total actual charges(fixed+running)

Total energy supplied to the consumer


3/105

OBJECTIVES1. ACCESSIBILITY

It must be such that it does not become a barrierto the effective use of, and derivation of benefitsfrom, electricity for ALL.

2. QUALITY OF LIFEIt should promote continual improvementin quality of life for ALL.

3. SUSTAINABILITY The tariff should be determined such that the

sustainability of electricity supply is assured, as

well the sustained promotion of access and quality


4/105

OBJECTIVES

A tariff must cover the following items (i) capital investment in generating, transmitting

and distributing equipment(ii) operation, supplies and maintenance of equipment and

(iii) metering equipment, billing, collection andmiscellaneous services(iv) a satisfactory return on the total capitalinvestment.


5/105

TYPES OF TARIFF (i) Flat Demand Tariff (ii) Simple Tariff (iii) Flat Rate Tariff (iv)Step Rate Tariff (v) Block Rate Tariff (vi) Hopkinson Demand Rate or Two Part Tariff (vii) Maximum Demand Tariff (viii) KVA Maximum Demand Tariff (ix) Doherty Rate or Three Part Tariff (x) Off Peak Tariff


6/105

1. Flat Demand Tariff This is one of the earliest forms of tariffs This tariff is expressed as energy charges, y = Rs.

Ax A is the rate per lamp or kw of connected load x is the number of lamps or load connected in kw In these types of tariff the metering equipment,

meter reading, billing, and accounting costs areeliminated

Now-a-days such a tariff is restricted to use such as

in street lighting, signal systems, sign lightings etc.


7/105

2.Simple Tariff/Uniform ratetariff

This is the simplest type of tariff according to which the cost o energy is charged on the basis of units consumed (energy meter)It can be expressed in the form y = Rs Ax

A is charges in rupees per unitx is the total electrical energy consumed in units orkwh.


8/105

Draw backsThe cost per unit delivered is highThere is no discrimination between different typesof consumers since every consumer has to pay equally for the fixed charges.


9/105

3. Flat Rate Tariff The different types of consumers are charged atdifferent rates.

i.e. the flat rate for light and fan loads is slightly higher than that for power load.The rate for each category of consumers is arrivedat by taking into account its load factor anddiversity factor.


10/105

Draw backs

Separate meters are required for different types of supply.Difficult to derive the load factor and diversity factor for various types of loads to be employed indeciding tariff.

A particular class of consumers is charged at thesame rate irrespective of the magnitude of energy consumed.


11/105

4.Step Rate Tariff

The step rate tariff is a group of flat rate tariffs of decreasing unit charges for higher range of

consumption.EX:Rs.4.00 per unit if consumption50KWh200KWh etc..


12/105

Draw back

By increasing the energy consumption so as just toenter the next range from the final stage of previous range, the total energy cost is reduced.


13/105

5.Block Rate Tariff In this type of tariff a given block of energy is

charged at higher rate and succeeding blocks of energy are charged at progressively reduced rates.

EX:

The first 25 units charged at Rs.5 per unit, the next40 units charged at Rs.4 per unit , consumptionexceeds 65 units at Rs.3 per unit etc.


14/105

Draw backIt lacks the measure of consumers demand.


15/105

6.Hopkinson Demand Rate /Two Part Tariff.

The total energy charge to be made to theconsumer is split into two components namely fixed charge and runign charge

tariff is expressed as Y = Rs a kw + b kwh Rs a is the charge per kw of maximum demand

assessed. Rs b is the charge per kwh of energy consumed. This tariff is mostly applicable to medium

industrial consumers.


16/105

Draw back The consumer has to pay the fixed chargesirrespective of the fact whether he has consumedor not consumed the electrical energy.There is always error in assessing the maximum

demand of the consumer.


17/105

7.Maximum Demand Tariff This tariff is similar to that of two part tariff except

that in this case maximum demand is actually measured by a maximum demand indicatorinstead of merely assessing it on the basis of rateable value.


18/105

8.KVA Maximum Demand Tariff It is a modified form of two part tariff.

In tis case maximum demand is measured in Kvainstead of in kw.This type of tariff encourages the consumers tooperate their machines/equipment at improvedpower factor because low power factor will causemore demand charges


19/105

9.Doherty Rate/Three PartTariff

In this tariff total energy charge is split into threeelements namely fixed charge, semi-fixed chargeand variable charge.

Such a tariff is expressed as y = Rs a + bkw + c kwh. a' is a constant charge. b is unit charge in Rs per kw of maximum demand

in kw during billing period (in some case it is also

charged in Rs per kva instead of Rs per kw) c is the unit charge for energy in Rs per kwh of

energy consumed. This type of tariff is usually applicable to bulk

su lies.


20/105

10.Off Peak Tariff The load on the power station usually has

pronounced peak loads in the morning and early evening and a very low load during the night (from10 P.M. to 6 A.M.).

During the night, therefore, and other off-peakperiod which may occur, a large proportion of thegenerating and distribution equipment will belying idle.


21/105

In case the consumers are encouraged to useelectricity during off peak hours by giving a special

discount, the energy can be supplied withoutincurring an additional capital cost and shouldtherefore prove very profitable.

This type of tariff is very advantageous for certain

processes such as water heating by thermalstorage, pumping, refrigeration etc.

10.Off Peak Tariff


22/105

The Importance of SavingEnergy

What does ' energy conservation' mean ? We use electrical energy in our homes for cooking,

heating, TV. etc. We also use fuel energy in ourcars, and we may also use energy by burning woodor coal in our homes. The main ways most of uscan save energy are by:

using less electricity in the house, and by

using less fuel in cars.


23/105

Why should we save energy ?


24/105

Energy conservation 1.Save money : Typical mid-income households

spend R 150 to R 200 per month on electricity --500 to 800 kilowatt-hours (kWh). Mosthouseholds could save 20 - 30 % of this easily.

2. Reduce 'Greenhouse Gas' emissions : InSouth Africa electricity is generated from the coal-burning industries in Gauteng, which produces

carbon dioxide (CO2) when burnt. This iscontributing to Global Warming, which ispotentially catastrophic. Fuel combustion in cars isalso responsible for substantial CO2 emissions.


25/105

Contd;3. Reduce air pollution caused by burning coal togenerate electricity, and from car fumes.4. Save water : Power stations use 2 litres of water forevery unit of electricity (kWh) generated.


26/105

How does one use lesselectricity ?

There are several ways to use less electricity withlittle effort.

Priority 1: Your Geyser Your household geyser uses about 40 % or more of

the total electricity consumption, as is shown inthe following pie chart:


27/105

Typical household electricityuse


28/105

TO REDUCE ENERGYCONSUMPTION

Insulate the geyser and hot water pipes by wrapping a blanket or other material around them.

Install a timer on the geyser to avoid heating up water when you don't need it. A timer unit may cost R 150, but the estimated saving can be up to 10

% of your electricity bill. Install a solar water heater. If you are building anew house, this will be a sound economic choiceand can save up to 15-25 % of your total electricity

bill.


29/105

Priority 2: Your Lighting


30/105

Priority 2: Your Lighting Use 'compact fluorenscent' lights rather than

normal incandescent 'bulb' lights for any lights which stay on longer than about 4 hours per day.

These are especially good for outside fittings whichstay on all night.

CFLs are expensive (up to R 60 each), but they usually end up costing you half of what you wouldhave paid if you used a normal light bulb, because

they last much longer and use much less electricity for the same light output.

Each CFL installed saves about 500 kg of CO2 emissions over its lifetime by using lesselectricity.


31/105

Priority 3: Heating

Heating is generally the third major cause of highenergy consumption in your household.

Insulate your ceiling. It is estimated that you cansave half of your heating electricity bill by doingthis.Include 'passive solar' features if you are designinga new house.Install roof hangings. These keep the summer sunout but let the winter sun in.


32/105

ENERGY SAVING TIPS1. Turn off unnecessary lights, TVs, computers and

other electrical appliances when not in use.

2. When possible, replace older appliances withnewer, high-efficiency models.

3. Run only full (but not overloaded) loads in yourdishwasher.

4. Set the temperature in your refrigerator between37F and 40F.5. Keep your freezer section at 5F. If you have a

separate freezer for longer-term storage, itshould be kept at 0F.


33/105

contd6. Unplug extra or unused appliances.

7. Get rid of that second refrigerator.8. Vacuum your refrigerators condenser coils (for

most models, once a year will do the job.)

9. Use small electric appliances or a microwave forcooking instead of your stove or oven.10. Do dishes and wash and dry clothes after 8pm.


34/105

ENERGY CONSERVATIONFOR HT INDUSTRY


35/105

ENERGY MANAGEMENT INHOSPITALS Energy use in Hospitals Hospitals and hospital

buildings are large consumers of energy Per square

meter, hospitals are the second highest energy intensive space type in the US In this part of the world it is the highest . They have an energy intensity nearly twice that of average building

Energy use in hospitals Energy has always been anessential element to the delivery of quality servicesExplosion in the use of technology by healthcarefacilities - increased energy demand


36/105

contd Explosion ..Ten fold Lighting Lifts Laundry Air

conditioning ,refrigeration Advanced imagingsystems Diagnostic equipments

5. Hospital energy balance Air conditioning - 45%Hot water - 5% Lighting - 20% Kitchen - 5% Other- 20%

Power consumption daily SCT(250 beds) 15,000 units -60units/bed/day Rs.22 lakhs. pm -SUT(150 beds) - 5000 units 30units/bed/day. Rs 7.5lakhs /pm


37/105

Contd;

Consumption Say 25 units /bed/day Keralahas more than 1,20,000 hospital beds >30,00,000units of electricity per day > Rs 1 crore a day

Kerala Scenario Healthcare facilities spend morethan Rs.380 crores annually.

10% Energy savings 25,000 tonnes of greenhousegases 750 acres of forest preserved from

deforestation Healthcare and Energy Impact Importance of

addressing climate changes Encouraging hospitalsto cut their Carbon emission Healthcare shouldnot create health problems


38/105

Air Conditioning Minimize Energy Use Turn off AC right after use affix Save Energy

sticker near the exit Use natural ventilation or fan where possible Set AC at 24oC and suitable fan speed. Check

temperature regularly Air Conditioning Use Energy Efficiently


39/105

contd Set up maintenance programme to ensure efficientoperation

Clean AC and dust filter Replace room coolers with more energy efficient

models Keep windows and doors closed to minimize air

infiltration when AC is running curtains to reduce direct sunlight during summer

time


40/105

Air Conditioning Install Fresh Air Heat Exchanger Fresh Air Heat Exchanger Energy saving about 10 ~

15% Increase every 1oC of set point temperature will

save about 1.5% of electricity Use evaporative water-cooling for condensers

Energy saving about 10~15% Avoid pre-cooling. If pre-cooling is necessary,

switch on AC not more than 15 minutes in advance


41/105

Lighting Turn off unnecessary lighting for area not in use

affix Save Energy sticker near the switch Turn off or dim lighting in perimeter area Set all computers and office equipment to energy

saving mode, and turn them off after use Screen Saver is actually Energy Waster &

should not be used when computer is idle Unplug equipment chargers and adapters when

these electronic equipment are not in use Arrange for last-man-out to turn off all equipment


42/105

Lighting Lighting Replace tungsten lamps with fluorescent

tubes or compact fluorescent lamps (CFLs) Energy saving up to 80%

Lighting Replace conventional magnetic ballasts with electronic type Energy saving about 20~40%

Lighting Install separate control for lighting at

window perimeter to allow switch off duringbright days Energy saving about 10~15% Lighting LED is gradually replacing some

conventional lighting technologies


43/105

LIFTS Use the stairs for 1 or 2 floors up or down affix SaveEnergy sticker near the lift

Shut down some of the lifts and escalators during non-peak hours

Switch off the lighting and ventilation fan inside the liftcar when the lift is in standby/idle mode


44/105

Get People Into ActionGet support from all staff Explain energy policy and housekeeping practices

(and incentive scheme) through staff briefings, emails,newsletters or notice boards Affix Save Energy stickers at switches, doors, exits,lifts and escalators as a reminderKeep track of organizational performance in energy saving, and benchmark against targets.


45/105

ENERGY MANAGEMENT/ENERGY AUDIT


46/105

Definition An energy audit is an inspection, survey andanalysis of energy flows for energy conservation ina building, process or system to reduce the amountof energy input into the system without negatively affecting the output(s).


47/105


48/105

Energy audit: DefinitionEnergy audit is a systematic study or survey to

identify how energy is being used in a building or plant, and identifies energy savingsopportunities. Using proper audit methods andequipment, an energy audit provides the energymanager with essential information on howmuch, where and how energy is used within anorganization (factory or building).


49/105

Main issues of an audit

process The analysis of building and utility data, includingstudy of the installed equipment and analysis of energy bills

The survey of the real operating conditions; The understanding of the building behavior and of

the interactions with weather, occupancy andoperating schedules;

The estimation of energy saving potential; The identification of customer concerns and

needs.


50/105

LAYOUT OF EEGCTU


51/105


52/105

Stages of Energy Audit


53/105

Energy audit-stages

Energy audit can be categorized into two types,1.walk-through or preliminary2. detail audit.


54/105

Walk-through / preliminary audit

Walk-through or preliminary audit comprises oneday or half-day visit to a plant and the output is asimple report based on observation and historicaldata provided during the visit. The findings will

be a general comment based on rule-of-thumbs,energy best practices or the manufacturer's data.


55/105

Preliminary Energy Survey Quick overview of energy use patterns

Provides guidance for energy accounting system

Provides personnel with perspectives of processes and equipment

Identify energy intensive processes andequipment

Identify energy inefficiency ,if any

Set the stage for detailed energy survey


56/105

Detail audit Detail audit is carried out for the energy savingsproposal recommended in walk-through or

preliminary audit.It will provide technical solution options andeconomic analysis for the factory management todecide project implementation or priority.A feasibility study will be required to determinethe viability of each option.


57/105

Contd;

It covers the estimation of energy input for different processes,losses,collection of past dataon production level and specific energyconsumption.

Review of equipment operatingcharacteristics

Evaluation of efficiencies


58/105

Scope:

To formulate a detailed plan on the basis of qualitative and control evaluation, to reducetotal energy consumption for the productmanufactured.It should aim at 8 to 10% savings.


59/105

Inputs and Outputs of Energy audit


60/105

Benefits of energy auditThere is a lot of potential for energy savings fromenergy audits..

Technical solutions proposed in the energyaudits show massive potential for energy savingsin every sub-sector with an average of almost tenpercent of the energy usage.However, this can only materialize throughreplication at other factories within the respectivesub-sector.


61/105

It also includes Energy savings Avoiding power factor penalties and

environmental compliance costs Quality improvements Productivity improvements Reduced maintenance Fewer breakdowns Better safety and protection A process for repeatable improvements


62/105

Efficiency oportunities


63/105

Process VS. EquipmentEquipment efficiency improvement : Max. 5%

Process efficiency improvement : 15% to30%

Focus on Processes


64/105

Energy intensive

processes and equipmentExamples of processes Electrical furnace Rolling mills Gas furnace

Steam generation Feed water system Condensate return system Steam distribution s stem

Examples of equipment Electrical motor Pump Fan

Heater (gas,..,electric) Dryer (steam/electric) Motor / generator Com ressor


65/105

Energy conservationopportunities

Electrical Reduce demand by load management

Electrical / thermal Reduce consumption by improving energy use

efficiency (reducing losses ,utilizing waste heat,etc..)


66/105

Examples of conservationopportunities - processes

1.Electric furnaceAutomation of energy supply controlSubstitute electricity by thermal energy( mazout/solar/gas )Reduce radiation losses

2 S i


67/105

2. Steam generation system

- Combustion efficiency improvement

- Waste heat recovery from flue gases

- Heat loss reduction from boiler surfaces

- Reduce leakage3. Condensate return system

4. Steam distribution system

- Pipe insulation

- Steam traps

- Steam leaks

Examples of conservation


68/105

Examples of conservationopportunities equipment

1. Gas/air compression system

pre-cooling the gas/air

2. High efficiency motors

3. High efficiency lamps

4. High efficiency pump/fan

5. Change electric dryer and heater to oil/gas fuel

6. Replace motor/generator set with silicon

controlled rectifier (SCR)


69/105

Energy Audit / step by step


70/105


71/105

What is Power Factor?

Power Factor is an index used to compute theefficiency level of electricity usage. The index is

measured from 0 to 1. A higher index shows efficient usage of electricity and vice versa.Low power factor shortens the lifespan of electricalappliances and causes power system losses to TNB.

Basic terms


72/105

Basic terms KW Working Power (also called Actual Power, Active

Power or Real Power).It is the power that powers equipment andperforms useful work.

KVAR Reactive Power.It is the power which magnetic equipment such astransformers, motors and relays need to producethe magnetizing flux.

KVA Apparent Power. It is the vectorial summation of KVAR and KW.


73/105


74/105

Simple analogy Lets say you are at a park and it is a hot day. You

order a glass of a carbonated drink. The thirst-quenching portion of the drink is represented by KW.

Unfortunately, along with your drink comes a littlebit of foam. The foam does not quench your thirst.

This foam is represented by KVAR. The total content of your glass, KVA , is this

summation of KW (the carbonated drink)and KVAR (the foam).


75/105

Power factor

Power Factor is the ratio of Working Power to Apparent Power.Power Factor = KW / KVA Looking at our carbonated drink analogy, powerfactor is the ratio of carbonated drink (KW) to thecarbonated drink plus foam (KVA).

Power Factor = KW / (KW + KVAR) = Carbonated drink / (Carbonated drink + foam)


76/105

Contd;

Thus, for a given KVA:- i. The more foam you have, the lower your powerfactor.

ii. The less foam you have, the higher your powerfactor.

For efficient usage of electricity, power factor mustapproach 1.0. Power factor that is less than 0.85

shows inefficient use of electricity. Calculation for Power Factor =

KWh _(KWh 2 + KVARh2)


77/105


78/105

Macs analogy Mac here is dragging a heavy load .Macs WorkingPower (or Actual Power) in the forward direction, where he most wants his load to travel, is KW.

Unfortunately, Mac cant drag his load on a perfecthorizontal (he would get a tremendous backache), sohis shoulder height adds a little Reactive Power, orKVAR.

The Apparent Power Mac is dragging, KVA, is thisvectorial summation of KVAR and KW.


79/105

The effects of powerfactor.


80/105

Consider a canal boat being pulled by a horse. If the horse could walk on water then the angle (Phi) would be zero and COSINE =1.

Meaning all the horse power is being used to pullthe load.However the relative position of the horseinfluences the power.

As the horse gets closer to the barge, angle 1

increases and power is wasted.But, as the horse is positioned further away, thenangle 2 gets closer to zero and less power iswasted


81/105

Causes of Low Power Factor In our carbonated drink analogy, low power factor

resulted when the foam is large. Low power factoris caused by inductive loads, which are sources of

reactive power. Examples of inductive loads are:- Transformers Induction motors High Intensity Discharge (HID) lighting Inductive loads constitute a major portion of

power consumed by commercial and industrialsectors.


82/105

Why to Avoid Low Power

Factor A system load with a low P.F. will draw morecurrent than a system with a higher P.F.. A systemdesigner considers the following:

A Low P.F. draws a higher internal current and theexcessive heat generated will damage and/orshorten equipment life

Increased reactive loads can reduce output voltageand damage equipment sensitive to reduced voltage


83/105

contd Low P.F. requires equipment to be constructed

heavier to absorb internal energy requirements Low P.F. will result in a more expensive system

with equipment able to absorb internal loads andlarger load requirements A system designer looks to increase P.F. to lower

system costs, increase reliability and increase thesystems life cycle

Utilities will charge a higher cost to industrial andcommercial clients having a low P.F.


84/105

How to Improve Power Factor?

Customers are advised to follow these steps:- Install capacitors (KVAR Generators) Capacitor Corrector Synchronous generators Synchronous motors

Minimize operations of idling or lightly loadedmotors.

Avoid operating equipment above its rated voltage. Replace standard motors as they burn out with

energy efficient motors.

f f


85/105

Benefits of Improving Power

Factor Benefit 1: Reducing KW billing demand Low Power Factor requires high reactive

power (KVAR) and apparent power (KVA), whichis the power that TNB supplies. Therefore, afacilitys low power factor forces TNB to increaseits generation and transmission capacity in order

to handle this extra demand. By increasing power factor, customers use less

KVAR. This results in less KW, which equates toRM savings for TNB.


86/105

Benefit 2: Eliminating power factor surcharge:

Utility companies all around the world chargecustomers an additional surcharge when theirpower factor is less than 0.95. In fact, some utilitiesare not obliged to deliver electricity to their

customers at any time the customers power factorfalls below 0.85. Thus, customer can avoid this additional surcharge

by increasing power factor. In Malaysia, TNB isallowed through the Malaysian Grid Code and theMalaysian Electricity Distribution Code, to imposea surcharge to the customer if the power factor is


87/105

Benefit 3: Increased system capacity and reduced

system losses in your electrical system Low power factor causes power system losses inthe customers electrical system.By improving power factor, these losses can bereduced. With the current rise in the cost of energy,increased facility efficiency is important.

Moreover, with lower system losses, customers areable to add additional load in their electricalsystem.


88/105

Benefit 4: Increased voltage level in yourelectrical system, resulting in more efficient

motors As mentioned before, low power factor causes

power system losses in customers electricalsystem. As power losses increase, customer may experience a voltage drop. Excessive voltage dropscan cause overheating and premature failure of motors and other inductive equipment.

Therefore, by raising the power factor, customerscan minimize these voltage drops along feedercables and avoid related problems. Motors willrun more efficiently, with a slight increase in

capacity and starting torque.


89/105

Why Apply PFCs? Power Factor Correction Saves Money! Reduces Power Bills Reduces I 2R losses in conductors Reduces loading on transformers Improves voltage drop

Wh d I t ll


90/105

Why do we Install

Capacitors? Capacitors supply, for free, the reactive energy required by inductive loads. You only have to pay for the capacitor ! Since the utility doesnt supply it (kVAR), you

dont pay for it!


91/105

Other Benefits: Released system capacity: The effect of PF on current drawn is shown below:

Decreasing size of conductors requiredto carry the same 100kW load at P.F.ranging from 70% to 100%


92/105

Reduced Power Losses:

As current flows through conductors, the conductorsheat. This heating is power loss Power loss is proportional to current squared

(PLoss=I2R)

Current is proportional to P.F.: Conductor loss can account for as much as 2-5% of

total load

Capacitors can reduce losses by 1-2% of the totalload


93/105

Low Voltage Capacitor Unit Low Voltage Capacitor

Cubicle-type automaticcapacitor banks are

modular in structure.


94/105

High Voltage Capacitor Unit High Voltage Capacitor Units

There are two types of fuses used for

capacitors; internal andexternal.


95/105

High Voltage Capacitor High Voltage

Capacitors

High Voltage CapacitorsOne-Phase Units have all-film dielectric and areimpregnated with

dielectric liquid which isenvironmentally safe.

P F t C t ll


96/105

Power Factor Controller

Power Factor Controllers

Power Factor controllers 6step or 12 step models aremanufactured for the controlof the automatic capacitorbanks.

P F t C ti


97/105

Power Factor Correction

Capacitor PFC

Automatic capacitor banksare used for central powerfactor correction at main

and group distributionboards.

ff f


98/105

Different Locations of

capacitor banks


99/105

POWER FACTOR IMPROVEMENT

Improving power factor by reducing the kVAr load

requires the use of power factor equipment whichoperate at a leading power factor such as: Static capacitors Synchronous motors


100/105

Synchronous motors which are either over-excitedor under loaded with full excitation so they will

supply kVAr to the electrical system.

Static capacitors which are electrical devices without

moving parts that have the ability to providemagnetizing current to the load. Their efficiency ishigh since losses are less than one-half of 1 percentof their kVAC (or kVAR) rating.

In the past two other types of equipment were usedto supply kVAr to a system: synchronous condensersand synchronous converters.


101/105

Static Capacitors Static capacitors are the cheapest and the simplest

means for reactive power compensation . They areinstalled by power utilities in the transmission anddistribution network and also at the consumerspremises on to different loads such as motors,transformers, incoming supply, etc. In present daysautomatic switching of the capacitors enableskeeping a high power factor for heavily fluctuatingloads as well.


102/105

connecting capacitor in parralel improves pf andconnecting series improves voltage profile. in somecases connecting capacitor increases the output voltage i.e. voltage acroos load may be greater than voltage accross source


103/105

SYNCHRONOUS MACHINESBy Use of : Synchronous machines are excited by dc, and the power factor may be controlled by controlling the field excitation. The varioussynchronous machines available for power factorcorrection comprise synchronous motors,synchronous condensers, synchronous converters,synchronous phase modifiers, phase advancers,and synchronous-induction motors.


104/105

Synchronous CondensersBy use of : An over-excited synchronous motorrunning on no load is called the synchronouscondenser or synchronous phase advancer andbehaves like a capacitor, the capacitive reactance of which depends upon the motor excitation.Power factor can be improved by using

synchronous condensers like shunt capacitorsconnected across the supply.


105/105

Synchronous converters are used where dc supply is

needed. The pf of induction motor of rating exceeding 150kw may be improved by equipping the set with ac exciter orphase advancer which supplies the exciting current to therotor circuit at slip frequency.

electrical energy conservation

Documents