Reactive power compensation

IntroductionLiterature SurveyProblem IdentificationObjective Of The ProjectProject Analysis And DesignProject ImplementationConclusionFuture Work SuggestedReference

CONTENTS

INTRODUCTIONINTRODUCTION

•Power Factor correction (PFC) is applied to electric circuits as a means of minimizing the inductive component of the current and thereby reducing the losses in the supply.

•Power factor (PF) is the name given to the ratio of the active or usable power measured in kilowatts (KW), to the total power (active and reactive) measured in kilovolt amperes (KVA).ie: Power Factor = KW / KVA.

POWER TRIANGLE

Electrical power in an AC circuit has three components: real power (P), reactive power (Q) and apparent power (S).

Real power is considered to be the work producing power measured in watts (W), or kilowatts (kW). Real power produces the mechanical output of a motor.

Reactive power is not used to do work but is needed to operate equipment and is measured in volt‐amperes‐reactive (VAR) or kilovar (kVAR)

Apparent power (also known as demand power) is comprised of (vectorial sum) both real and reactive power and is measured in units of volt‐amps (VA) or kilovolt‐amps (kVA).

DISADVANTAGES OF LOW POWER DISADVANTAGES OF LOW POWER FACTORFACTOR

Increases heating losses in the transformers and distribution equipment.Reduce plant life.Upgrade costly equipment.Decrease energy efficiency.Increase electricity costs by paying penalties.

Power factor correction capacitors; Essentials & Cautions- M.H.Shwehdi, M.R.SultanDept. of Electr. Eng., King Fahd Univ. of Pet. & Miner., DhahranDate of Current Version :   06 August 2002Page(s): 1317 - 1322 vol. 3

Optimal selection of capacitors-IEEE: S.Sudehararajan & A PahwaDept. of Electr. & Comput. Eng., Kansas State Univ., Manhattan, KSDate of Current Version :   06 August 2002Page(s): 1499 - 1507

Optimal Reactive Power Planning and Compensation Effects on Transmission Loss ComponentsK. Barot; H. Bhattacharya, Power & Energy Syst. Group, Univ. of Waterloo.Date of Current Version :   23 July 2007Page(s): 1 - 7

Universal input single-phase single-stage power supply with power factor correction and automatic voltage clampingChongming Qiao; Smedley, K.M. Dept. of Electr. & Comput. Eng., California Univ., Irvine, CA Date of Current Version :   07 August 2002Page(s): 907 - 913 vol.2

High-capacity hybrid power filter for harmonic suppression and reactive compensation in the power substationLina Wang An Luo Dept. of Electr. Eng., Tsinghua Univ., BeijingDate of Current Version :   10 January 2005Page(s): 215 - 220 Vol.1

LPF is a main problem that our industries face in today’s world. There are many factors that leads to LPF.The aim of our project is reactive power compensation using automatic capacitor banks.

We using automatic capacitor PFC, because fixed capacitor has following disadvantages……

•Manual operation(on/off)•Not meet the require kVAr under varying loads.•Can result leading power factor •Cause over voltage•Penalty by electricity authority

Types of PFC

The choice of the correct power factor correction equipment depends on the type of loads present and by their way of working

• Individual compensation is most effective if the majority of the reactive power is concentrated on few loads with high power and that work for long period of time.

• Central compensation is best suited for systems where the load fluctuates through out the day. If the absorption of reactive power is variable, it is advisable the use of automatic regulation than fixed capacitors.

INDIVIDUAL COMPENSATIONINDIVIDUAL COMPENSATION

CENTRAL COMPENSATIONCENTRAL COMPENSATION

PROJECT ANALYSIS & DESIGN

AREA OF FOCUS

As a part of our project, we did a case study on Cochin Port Trust and

found that the power factor was below 0.9. as per our calculation, at 0.85

pf, the total cost including penalty was Rs. 3,51,394.25 per month. It’s

noticed that the total cost got reduced to Rs. 3,32,653.25 per month,

after the installation of the capacitor bank that increased the PF to 0.94.

The cost of capacitor was found to be Rs.200/kVAR and the cost of

capacitor installation could be replaced in a period of 1 year and 2

months.

SITES MOTORS RATING WORKING PERIOD(hrs) TRUE POWER(kW) TOTAL kWh

PUMP HOUSE 1 MOTOR 1 52 HP 3

MOTOR 2 52 HP 3 76.5 229.5

PUMP HOUSE 2 MOTOR 1 37 Kw 3

MOTOR 2 37 Kw 3 74 222

RAIN WATER PURIFING PUMP 5 HP 3 3.8 11.4

AD BLOCK INDUCTION MOTOR 60 HP 6

INDUCTION MOTOR 3.7 Kw 6 47.83 287

FIRE HOUSE PUMP 60 HP 10 44.13 441.3

TELEPHONE EXCHANGE MOTOR 20 HP 24 14.71

353

BELT DRIVE MOTOR 1 7.5 HP

MOTOR 2 7.5 HP 6 11 66.2

SUPPLY MOTOR 5 HP 6 3.68 22.1

NORTH END MOTOR 12 Kw 12 12 144

CT CANTEEN MOTOR 12 Kw 16 12 192

12th CROSS ROAD MOTOR 12 Kw 16 12 192

RNAS MOTOR 1 12 Kw 12

MOTOR 2 12 Kw 12 24 288

CLUB MOTOR 12 Kw 14 12 168

HOSPITAL MOTOR 1 12 Kw 24

MOTOR 2 12 Kw 24

MOTOR 3 12 Kw 24 36 864

CISF MOTOR 1 12 Kw 24

MOTOR 2 12 Kw 24 24 576

• Total load demand =405.65kW• Total kWh =4056.50kWh• Total kW in 1 month =12169.50kW/month• Total kWh in 1 month =121695.00kWh/month• Total amount in 1 month =Rs 334661.25/month

TARIFFTARIFF

Cost of energy per unit=2.75Rs/kWh/month

•At 0.85pf

Penalty = 5%*334661.25 =Rs 16733.00 Total cost including penalty

=Rs(334661.25+16733.00)/month =Rs 351394.25/month •At 0.94pf

Incentive = 0.6%*334661.25 = Rs 2008.00/month

Total cost = Rs(334661.25-2008.00)/month =Rs332653.25/month

Selection of capacitor for 0.85 Selection of capacitor for 0.85 pfpf

PFold = 0.85PFnew= 0.94

M =0.367

kVARcap =165.81kVARCost of capacitor= Rs 200 per kVAR

Total cost of capacitor, kVARcap =165.81 kVAR * Rs 200 = Rs 33,162.Incentive = Rs 2008.00/month.The capacitor installation cost will be compensated in 33162/2008 =16.51 months =1 year & 2 months.

Here our hardware is of passive…….

BecausePassive components are those that do not require electrical power to operate.

Guaranteed stability

Passive filters scale better to large signals (tens of amperes, hundreds of volts), where active devices are often impractical

No power consumption.

Inexpensive (unless large coils are required)

POWER FACTOR CORRECTION: Advantages

• Reduced demand charges• Reduction in size of transformers, cables and switchgear in

new installations• Less total plant KVA for the same KW working power• Automatically switch on/off relevant capacitors steps for

consistent power factor• Continuously sense and monitors the load

CONCLUSION

Raising power factor is a proven way of increasing the efficient use of electricity by utilities & end users. Economic benefits for end users may include reduced energy bills, lower cable, transformer losses & improved voltage conditions, while utilities benefit from released system capacity.

FUTURE SCOPE

In our project, we have not considered harmonics. In future, we can improve the power factor by adding a reactor circuit with the capacitor bank to eliminate harmonics. As a result, especially the 3rd harmonic component can be detected and suppressed and power factor in whole can be raised up to a value of 0.99.

REFERENCES

• Ferreira,A.J.M(2009).MATLAB Codes for finite Element Analysis Springer.

• Optimal selection of capacitors-IEEE: S.Sudehararajan & A Pahwa

• Power Factor Correction Capacitors: Essentials and Caution, M.H.Shwhdi.

• Reactive Power Compensation, T.J.E.Miller.• Power System, J.B.Gupta