ISSBN, Electronic faculty of Niš, November 2010 1

Use of distortion power for side identification of the harmonic polution

Dejan Stevanović, Electronic faculty of Niš

Borisav Jovanović, Electronic faculty of Niš

Predrag Petković, Electronic faculty of Niš

ISSBN, Electronic faculty of Niš, November 2010 2

Summary

1. Introduction2. How harmonic distortion can affect to our equipment3. Harmonics Pollution Sources Identification4. The Definition of fundamental quantities 5. Function DSP block at IMPEG chips 6. Realization of circuit for identification nonlinear loads 7. Result of synthesis and simulation8. Conclusions

ISSBN, Electronic faculty of Niš, November 2010 3

Introductions

ac Electric Loads: Loads that draw sinusoidal currents, i.e., the current waveform is the

same as the voltage waveform, are defined as linear loads Electric loads that draw nonsinusoidal currents, i.e., the current

waveform differs from the voltage waveform, are defined as nonlinear loads

The magnitude and the frequency of the high frequency components is characteristic of the type of distorting load and can enable it to be identified

The distorting components flow through the power system and give addition high frequency voltage drops which modify the voltage waveform at all nearby customers

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How harmonic distortion can affect to our equipment

Equipment responds to harmonic differently depending on their method of operation.

Equipment respond to harmonic differently:– incandescent light, and most type household electrical heaters and stoves are not

affect adversely at all– induction motor windings are overheated by harmonic, which reduce their life– Operation of same equipment depends of accurate voltage waveform and they can

malfunction when harmonics are present

Also harmonic pollution can cause problems in the supply system:– distortion of current causes extra heating of transformers which reduces their life– distortion of voltage can cause overheating of dielectric of capacitors

ISSBN, Electronic faculty of Niš, November 2010 5

Harmonics Pollution Sources Identification

The IEEE Std. 519 and the IEC 1000-3 have proposed standard limits for harmonic currents and voltages generated by customers and utilities , in order to limit the amount of harmonics pollution present in a distribution system

These standards have been widely accepted in industry, so power systems are designed to operate within these limits

For correct identification nonlinear loads it is necessary to measuring the true RMS value rather than taking the fundamental peak value.

ISSBN, Electronic faculty of Niš, November 2010 6

The Definition of fundamental quantities

Instantaneous value for voltage and current when harmonic exist are given by following equation:

For a single-phase system where h is the harmonic number and H is the highest harmonic, RMS voltage and current, active, reactive, phase, apparent power is given by following equation:

hhh

H

hh IVP

cos1

hhh

H

hh IVQ

sin1

- active power

- reactive power

- phase power

- apparent power

N

h

ohhh tVtu

1

sin

N

h

ohhh tIti

1

sin

H

hhRMS VV

1

2RMS

H

hhII

1

2RMSRMS

- RMS voltage and current

22 QPS

RMSRMS IVDSU *22

ISSBN, Electronic faculty of Niš, November 2010 7

Function DSP block at IMPEG chips

DSP unit based on controller/datapath partition DSP block work at 4.194 MHz and with accuracy less than 0.1 % it calculates

all parameters

DSP block gets samples of voltage, current and phase shifted voltage, and calculates following power line parameters: current and voltage RMS values Irms and Vrms, apparent S, active P and reactive Q power, power factor cos(φ), frequency f, reactive Eq and active Ea energy

ISSBN, Electronic faculty of Niš, November 2010 8

Realization of circuit for identification nonlinear loads

Several techniques have been proposed to identify the source of harmonics pollution however, some of these techniques are based on new concepts that still need thorough investigation before confirming their validity

The most common method for harmonic source detection is the Total Harmonic Power (THP) method:

– If Ph > 0 then the source of harmonics is supply system – if Ph < 0 then the source of harmonics is customers

This paper suggest a new concept for harmonic source detection using Power Distortion

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Realization circuit for identification nonlinear loads

Power distortion : The term power distortion was first time mentioned in 1927 by C. Budeanu

The circuit calculation power distortion one time at every second

222 QPUD

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Results of Synthesis

• Active HDL

• RTL Compiler

• SoC Encounter

• Area of layout is 569 µm x 564µm.

Name of block

All circuit

Multiply circuit

Square circuit

FSM Register Add/Subtract

Area 4164 822 788 78 416 382

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Results of Simulation

a) b) c) d) e)IRMS(A) 42.8 41.84 42.13 41.78 41.78

VRMS(V) 125.33 125.33 125.33 125.33 125.33

P(W) 5275.16 5223.2 5223.2 5236.19 4533.62

Q(VAR) 0 0 0 0 2619.9

U(VA) 5364.32 5243.44 5279.88 5236.19 5236.19

D(VAR) 973.96 460.26 771 0 0

a) Typical current waveform and spectrum of Fluorescent lamp

b) Typical current waveform and spectrum of adjustable-speed drivers (ASD)

c) Typical current waveform and spectrum of IEEE 12 Pulse converter

d) Waveform of power supply voltage and spectrum

a)

b)

c)

d)

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Conclution

Using the value for power distortion we can easily find the source of distortion

Advantages of this solution are:

• Small area

• Potential for identification of all source of harmonics

• The value of power distortion can be used to create new bill for customers which cause harmonic pollution of system

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Thank you for your attention