Manual Pq Em

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PRACTICAL NO:-1

AIM :- INTRODUCTION OF POWER QUALITY.


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AIM:- INTRODUCTION OF POWER QUALITY.INTRODUCTION:

POWER QUALITY: Any power problem that results in failure or misoperation of customer equipment,

manifests itself as an economic burden to the user, or produces negative impacts onthe environment.

Issues Which Degrade Power Quality Include: Power Factor Harmonic Distortion Voltage Transients Voltage Sags or Dips Voltage SwellsPower Quality Can Be Improved Through: Power factor correction, Harmonic filtering, Special line notch filtering, Transient voltage surge suppression, Proper earthing systems. The Benefits Of Power Quality Economic Impact

Power Factor Penalties System Losses

Power Service Initial Capital Investments Equipment Reliability Power System Adequacy Power Factor Criteria Environment


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POWER QUALITY CRITERIAHarmonic Mitigation Criteria:

Guidelines for harmonic mitigation have beenestablished throughout the world. IEEEStd. 519-1992provides the guidelines for harmonic current and voltagedistortion at thepoint of common coupling.

This standard is accepted and applied in North America, andis referenced in many othercountries of the world where a similar local standard has not been created

Power Factor Criteria: If power factor correction is required due to contract or regulatory requirements, the

crane specification criteria should repeat the terms verbatim. However, it is important to

understand how the power factor is measured.

In most cases, the power factor is calculated as an average value over a demand period. Demand periods are commonly 5, 15, or 30 minutes. In other words, the customer is

penalized if the power factor dips below a given value over a sustained period of time.


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.

PRACTICAL NO:-2

AIM :- Analysis Of Harmonic Production In Three Phase Circuit Using

Matlab


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AIM:- Analysis Of Harmonic Production In Three Phase Circuit Using Matlab

Introduction:-

HarmonicsHarmonics Integer multiples of a fundamental -- added to

fundamental create distorted sinusoidal or non-sinusoidal

waveformHarmonics are caused by Non- linear load currents &

Non- linear voltage sourcesMeasurements of harmonic content

does not always indicate the presence of problems

Effects of HarmonicsCurrent Current flow without work (low power factor)

Transformer & wiring losses Negative sequence currents thatreduce torque in motorsExcessive neutral current

VoltagePeak voltage loss and "ride-through reduction Phasevoltage imbalance Motor plugging or cogging Zero voltage

cross distortion and frequency errors

SIMULINK MODEL:-


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Procedure:-

The model represent the harmonics production in three phasecircuit We will first open the breaker and we will genrate only the

harmonics due to three phase rlc load his harmonics will generate

current harmonics.

Then result is taken using scope .

Results:-


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PRACTICAL NO:-3

AIM:- Analysis Of Harmonic Reduction In Three Phase Circuit

Using Matlab

.


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AIM:- Analysis Of Harmonic Reduction In Three Phase Circuit Using Matlab

Introduction:-Harmonic Propagation

Harmonic effects increase with load/source interaction Odd harmonics develop naturally with rectangular waveforms Even harmonics develop with asymmetrical waveformsAsymmetry results in

direct voltages and currents (dc) DC conditions can adversely affect magnetic

devicesEven harmonics often indicate load problems Harmonic content normally decreases with increased frequency (1/3 of the third,

1/5 of the fifth...)

Harmonic Problems Summary Overheated, noisy transformers Overloaded or burned (hot) neutrals Timing

errors in logic controlled equipment Blown SCRs Capacitor failure

Variable speed drive (VSD) dropout Drift or hunting in electronic controls Rapid motor failure or insufficient

torque Insufficient distribution capacity Power factor or harmonic rate

penalties.

Mitigation methods Delta-wye transformers Eliminate shared neutrals Filtering Phase angle blending for control of harmonics Equipment redesign (linearize) Management of the environment


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Simulink model:-

Procedure:-

The model represent the harmonics reduction in three phase circuitWe will closed the breaker and we will genrate only the harmonics

due to three phase rlc load his harmonics will generate current

harmonicsthen using three phase harmonic filter.

Then result is taken using scope .


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Result:-


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PRACTICAL NO:-4

AIM:- Analysis Of Harmonic Reduction In Single Phase Circuit

Using 5th

And 3rd

Harmonic Filter In Matlab


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AIM:- Analysis Of Harmonic Reduction In Single Phase Circuit Using 5 th And 3rd HarmonicFilter In Matlab.

Introduction:-

Odd Harmonics Symmetrical90, 180, 270 Leading/trailing edgePositive/negative cycle Single phase loads3rd, 5th, 7th, 9th... Polyphase loadsFrequency doublets5th & 7th, 11th & 13th

Even Order Harmonics Asymmetrical90, 180, 270 Can shift the position of the fundamental causing loss of 120 phase shift

between phases Can cause dc bias problems in motors and transformers Can cause phase control problems for SCR/Triac loads

Simulink model:-


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Procedure:-A 5th harmonic filter is connected at a bus bar fed by a 60 Hz, 100 V inductive source. A 5th

harmonic (300 Hz, 1 A) current is injected at the bus bar.

This linear system consists of 3 states (2 inductor currents and 1 capacitor voltage), 2 inputs (Vs,

Is) and 2 outputs (Current and Voltage Measurement).

An Impedance Measurement block is used to compute the impedance versus frequency of the

circuit.

Results:-

Conclusion: - Thus we can see from result that one cycle of voltage is equal to five cycle of current


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PRACTICAL NO:-5

AIM:-Calculation Of IHD (individual harmonic distortion) AndTHD(total harmonic distortion) Of Harmonics Using

Matlab.


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AIM: Calculation Of IHD And THD Of Harmonics Using Matlab

Introduction:-

IHD:- Individual harmonic distortion (IHD) is the ratio between the root mean square (RMS)

value of the individual harmonic and the RMS value of the fundamental. IHDn = In/I1 For example, assume that the RMS value of the third harmonic current in a nonlinear load

is 20 A, the RMS value of the fifth harmonic current is 15 A, and the RMS value of thefundamental is 60 A. Then, the individual third harmonic distortion is:

IHD3 = 20/60 = 0.333, or 33.3% and the individual fifth harmonic distortion is:

IHD5 = 15/60 = 0.25, or 25.0%

THD:- Total harmonic distortion (THD) is a term used to describe the net deviation of a

nonlinear waveform from ideal sine waveform characteristics. Total harmonic distortionis the ratio between the RMS value of the harmonics and the RMS value of the

fundamental. For example, if a nonlinear current has a fundamental component of I1 and

harmonic components of I2, I3, I4, I5, I6, I7, , then the RMS value of the harmonics is:

IH = THD = (IH/I1) 100%

SIMULINK MODEL:-


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PROCEDURE: Here the model represent the harmonic in which we have calculated individual harmonic

distortion(IHD) and total harmonics distortion(THD) using thd block Then the result is taken from scope. RESULT:-

Manual Pq Em

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