introduction in recent years, harmonics are considered as one of the most essential problems in the...

IntroductionIntroductionIn recent years, harmonics are considered as one of the most In recent years, harmonics are considered as one of the most essential problems in the industrial power distribution networks. essential problems in the industrial power distribution networks. The problem of harmonics is increasing due to the use of the The problem of harmonics is increasing due to the use of the variable speed drives (VSDs), the uninterruptible power supplies variable speed drives (VSDs), the uninterruptible power supplies (UPS), and the solid-state devices. Harmonics current distortion (UPS), and the solid-state devices. Harmonics current distortion may produce negative effects on the power quality of the power may produce negative effects on the power quality of the power networks. The negative effects include malfunctioning of networks. The negative effects include malfunctioning of sensitive devices such as protective relays, motors overheating, sensitive devices such as protective relays, motors overheating, and transformer overheating. The current total harmonic and transformer overheating. The current total harmonic distortion (THD) can be reduced to the IEEE standards using distortion (THD) can be reduced to the IEEE standards using harmonics filters such as passive harmonic filters or active harmonics filters such as passive harmonic filters or active harmonic filters.harmonic filters.

Ahmad Hassan AlObaidly and Abdulaziz Abdulla AlshafaiSupervisor: Dr. Khaled Ellithy

Department of Electrical Engineering, College of EngineeringFALL 2008

ObjectivesObjectivesTo conduct a study on harmonics, harmonics sources, harmonics To conduct a study on harmonics, harmonics sources, harmonics

representation, harmonics effects, and harmonics indices.representation, harmonics effects, and harmonics indices.To study the recommended IEEE-519 standards for the current To study the recommended IEEE-519 standards for the current

and voltage harmonics distortion.and voltage harmonics distortion.To conduct a study on the types of harmonics filters.To conduct a study on the types of harmonics filters.To conduct a study on passive harmonics filters design.To conduct a study on passive harmonics filters design.To perform the harmonics analysis and harmonics filter design To perform the harmonics analysis and harmonics filter design

for a typical gas plant power network using EDSA power system for a typical gas plant power network using EDSA power system analysis software.analysis software.

Computer Simulation Results with the Designed Computer Simulation Results with the Designed Harmonics FiltersHarmonics Filters

HR-5343HR-5343 UPS-A UPS-A%THD%THDii=7.37%=7.37% %THD %THDii=2.98%=2.98%

The current total harmonic distortions (7.37% and 2.98%) are within the IEEE-519 standards.The current total harmonic distortions (7.37% and 2.98%) are within the IEEE-519 standards.

ConclusionsConclusions Harmonics sources, harmonics effects and harmonics representation Harmonics sources, harmonics effects and harmonics representation

have been presented.have been presented. An industrial power distribution network of a gas plant was chosen for An industrial power distribution network of a gas plant was chosen for

the study.the study. Measurements of the current and voltage harmonics distortions at the Measurements of the current and voltage harmonics distortions at the

Gas Plant were conducted using AEMC power quality analyzer. Gas Plant were conducted using AEMC power quality analyzer. The plant power distribution network for harmonics analysis was The plant power distribution network for harmonics analysis was

developed using EDSA power systems analysis software.developed using EDSA power systems analysis software. The harmonics filters were designed to eliminate the dominant The harmonics filters were designed to eliminate the dominant

harmonics orders to reduce the THD of the current and voltage to the harmonics orders to reduce the THD of the current and voltage to the allowable limits recommended by the IEEE 519 standards.allowable limits recommended by the IEEE 519 standards.

The maximum limits of voltage and kVAR of the harmonics filter The maximum limits of voltage and kVAR of the harmonics filter capacitor have been checked with the ANSI/IEEE 18 standards.capacitor have been checked with the ANSI/IEEE 18 standards.

Harmonics Indices and IEEE 510 StandardsHarmonics Indices and IEEE 510 Standards"Harmonics" term in an AC power system is defined as a sinusoidal component "Harmonics" term in an AC power system is defined as a sinusoidal component of a periodic waveform that has a frequency equal to an integer multiples of the of a periodic waveform that has a frequency equal to an integer multiples of the fundamental frequency (50 Hz) of the power network. fundamental frequency (50 Hz) of the power network. The Total harmonic distortion (THD) is a measure of the effective value of the The Total harmonic distortion (THD) is a measure of the effective value of the harmonic components of a distorted waveform.harmonic components of a distorted waveform.

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Maximum harmonic current distortion in percentage of the fundamental V ≤ 69 kV

ISC / IL h<11 11≤h<17 17≤h≤23 23≤h≤35 35≤hTDD%

%

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20-50 7.0 3.5 2.5 1.0 0.5 8.0

50-100 10.0 4.5 4.0 1.5 0.7 12.0

100-1000 12.0 5.5 5.0 2.0 1.0 15.0

>1000 15.0 7.0 6.0 2.5 1.4 20.0

Power Distribution Network Model for Harmonics Power Distribution Network Model for Harmonics Analysis of a Train in a Typical Gas PlantAnalysis of a Train in a Typical Gas Plant

Computer Simulation Results without Harmonics Computer Simulation Results without Harmonics FiltersFilters

HR-5343HR-5343 UPS-A UPS-A %THD%THDii= 42.55% = 42.55% %THD %THDii= 41.38%= 41.38%

The current total harmonic distortions (42.55% and 41.38%) exceed the IEEE-519 The current total harmonic distortions (42.55% and 41.38%) exceed the IEEE-519 standardsstandards

EDSA Harmonic Analysis

-150.0

-100.0

-50.0

0.0

50.0

100.0

150.0

Mag

nitu

de %

Angle in Degrees

0 80 160 240 320 400 480 560 640 720


0.0

16.7

33.3

50.0

66.7

83.3

100.0

Mag

nitu

de %

Harmonic

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0


-150.0

-100.0

-50.0

0.0

50.0

100.0

150.0

Mag

nitu

de %

Angle in Degrees

0 80 160 240 320 400 480 560 640 720


0.0

16.7

33.3

50.0

66.7

83.3

100.0

Mag

nitu

de %

Harmonic

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0

Harmonics Filter DesignHarmonics Filter DesignA passive harmonic filter is designed to eliminate the 11A passive harmonic filter is designed to eliminate the 11th th harmonic order for HR- harmonic order for HR-53435343

Passive harmonic filter to eliminate the 5th Passive harmonic filter to eliminate the 5th harmonic order for UPS-Aharmonic order for UPS-A

The voltage and kVAR of the harmonics filter capacitor have been checked with The voltage and kVAR of the harmonics filter capacitor have been checked with limits recommended by ANSI/IEEE 18-1980 standards.limits recommended by ANSI/IEEE 18-1980 standards.

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espo

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(Ohm

s)

Frequency (Hz)

0 111 222 333 444 556 667 778 889 1000


0.0

16.7

33.3

50.0

66.7

83.3

100.0

Mag

nitu

de %

Harmonic

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0


-150.0

-100.0

-50.0

0.0

50.0

100.0

150.0

Mag

nitu

de %

Angle in Degrees

0 80 160 240 320 400 480 560 640 720


0.0

16.7

33.3

50.0

66.7

83.3

100.0

Mag

nitu

de %

Harmonic

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0

Bus Voltage at PCC (KV)

Individual harmonic voltage

distortion (%)

Total Voltage Distortion, THD (%)

V < 69 3.0 5.0

69 < V < 161 1.5 2.5

V > 161 1.0 1.5


-150.0

-100.0

-50.0

0.0

50.0

100.0

150.0

Mag

nitu

de %

Angle in Degrees

0 80 160 240 320 400 480 560 640 720

IEEE 519 standard of current harmonicsIEEE 519 standard of current harmonics distortionsdistortions

IEEE 519 standard of voltage harmonics distortionsIEEE 519 standard of voltage harmonics distortions

The THD of voltage is given byThe THD of voltage is given by

The THD of current is given byThe THD of current is given by

Single-line diagram of power distribution network Including harmonics sources

introduction in recent years, harmonics are considered as one of the most essential problems in the...

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