Harmonics supression

8/11/2019 Harmonics supression

1/38

HARMONIC SUPRESSION TECHNIQUES

IN POWER SYSTEM

PRESENTED BY :

KUMAR SATISH

ROLL NO.- 112224

01 SEPT 2014 NITW - EED 1


2/38

PLAN OF PRESENTATION

1. DEFINITIONS

2. CATEGORIES OF POWER QUALITY VARIATIONS

3. HARMONIC DISTORTION SOURCES IN INDUSTRIAL POWER SYSTEMS

4. EFFECTS OF HARMONICS ON ELECTRICAL EQUIPMENT

5. HARMONIC STANDARDS

6. HARMONIC MITIGATING TECHNIQUES

7. DESIGN EXAMPLES

8. CONCLUSIONS



3/38

WHY HARMONIC ANALYSIS ?

When a voltage and/or current waveform is distorted, it causes abnormaloperating conditions in a power system such as:

Voltage Harmonics can cause additional heating in induction and synchronousmotors and generators.

Voltage Harmonics with high peak values can weaken insulation in cables,windings, and capacitors.

Voltage Harmonics can cause malfunction of different electronic components andcircuits that utilize the voltage waveform for synchronization or timing.

Current Harmonics in motor windings can create Electromagnetic Interference(EMI).



4/38

Current Harmonics flowing through cables can cause higher heating over and

above the heating that is created from the fundamental component.

Current Harmonics flowing through a transformer can cause higher heating overand above the heating that is created by the fundamental component.

Current Harmonics flowing through circuit breakers and switch-gear can increasetheir heating losses.

RESONANT CURRENTS which are created by current harmonics and the differentfiltering topologies of the power system can cause capacitor failures and/or fusefailures in the capacitor or other electrical equipment.

False tripping of circuit breakers ad protective relays.



5/38


a) Current Source nonlinear load

Diode rectifier for ac drives,

electronic equipment, etc

HARMONIC SOURCES

Thyristor rectifier for dc drives,

heater drives, etc.

Per-phase equivalent circuit

of thyristor rectifier

b) Voltage source nonlinear load

Per-phase equivalent circuit

of diode rectifier


6/38


POWER QUALITY STANDARDS

IEEE 519-1992 STANDARDSTABLE I

CURRENT DISTORTION LIMITS FOR GENERAL DISTRIBUTION SYSTEMS

(120-69000 V)

Isc/IL


7/3801 SEPT 2014 NITW - EED 7

TABLE II

LOW VOLTAGE SYSTEM CLASSIFICATION AND DISTORTION LIMITS

IEEE 519-1992 STANDARTS

Special

Applications

General

System

Dedicated

System

Notch Depth 10% 20% 50%

THD (Voltage) 3% 5% 10%

Notch Area

(AN)*

16,400 22,800 36,500

Source: IEEE Standard 519-1992.

Note: The value AN for another than 480Volt systems should be

multiplied by V/480 .The notch depth, the total voltage distortion factor (THD) and

the notch area limits are specified for line to line voltage.

In the above table, special applications include hospitals and

airports. A dedicated system is exclusively dedicated to converter load.

*In volt-microseconds at rated voltage and current.


8/3801 SEPT 2014 NITW - EED 8

TABLE III

LIMITS OF THD%

IEEE 519-1992 STANDARDS

SYSTEM

Nominal Voltage

Special

Application

General

Systems

Dedicated

Systems120-600V 3.0 5.0 8.0

69KV and below - 5.0 -


9/3801 SEPT 2014 NITW - EED 9

1) Parallel-passive filter for current-source nonlinear loads

TYPES OF FILTERS

Harmonic Sinc

Low Impedance

Cheapest

VA ratings = VT(Load Harmonic current + reactive current of the filter)


10/3801 SEPT 2014 NITW - EED 10

2) Series-passive filter for voltage-source nonlinear loads

Harmonic damHigh-impedance

Cheapest

VA ratings = Load current (Fundamental drop across filter + Load Harmonic Voltage)


11/3801 SEPT 2014 NITW - EED 11

3) Basic parallel-active filter for current source in nonlinear loads


12/38


4) Basic series-active filter for voltage-source in nonlinear loads


13/38


5) Parallel combination of parallel active and parallel passive

6) Series combination of series active and series passive


14/38


7) Hybrid of series active and parallel passive

8) Hybrid of parallel active and series passive


15/38


9) Series combination of parallel-passive and parallel-active

10) Parallel combination of series-passive and series-active


16/38


11) Combined system of series-active and parallel-active

12) Combined system of parallel-active and series-active


17/38

POWER FACTOR CORRECTION ANDHARMONIC TREATMENTUSING TUNED FILTERS

- Basic configuration of a tuned 3-capacitor bank for power factor correction and

harmonic treatment.


Simple and cheap filter

Prevents of current harmonic magnification


18/38


ACTIVE FILTERING

Parallel type Series type


19/38


-2500

-1500

-500

500

1500

2500

0 5 10 15 20 25 30 35 40

I

[A]

Time [ms]

0

5

10

15

20

25

30

2 5 8 11 14 17 20 23

[%I

1]

Harmonics

-5000

-2500

0

2500

5000

0 10 20 30 40

Time [ms]

IDynac

omp[A]

0%

5%

10%

15%

20%

25%

30%

35%

2 5 8 11 14 17 20 23

Harmonics

[%I1]

RESULTS OF ACTIVE FILTERING

Input current of a 6-pulse Rectifier driving a DC machine without any input filtering

Input current with Active Filtering


20/38


-1000

-500

0

500

1000

0 5 10 15 20 25 30 35 40

U

[V]

Time [ms]

0

2

4

6

8

10

12

14

2 5 8 11 14 17 20 23

[%U

1]

Harmonics

-1000

-500

0

500

1000

0 5 10 15 20 25 30 35 40

U[

V]

Time [ms]

0

2

4

6

8

10

12

14

2 5 8 11 14 17 20 23

[%U

]

Harmonics

Typical 6-pulse drive voltage waveform

Voltage source improvement with active filtering


21/38

SHUNT ACTIVE FILTERS

By inserting a parallel active filter in a non-linear load location we can inject a

harmonic current component with the same amplitude as that of the load in to

the AC system.


C

FL

Equivalent circuit


22/38


Low implementation cost. Do not create displacement power factor problems and utility loading.

Supply inductance LS, does not affect the harmonic compensation ofparallel active filter system.

Simple control circuit.

Can damp harmonic propagation in a distribution feeder or betweentwo distribution feeders.

Easy to connect in parallel a number of active filter modules in order toachieve higher power requirements.

Easy protection and inexpensive isolation switchgear.

Easy to be installed.

Provides immunity from ambient harmonic loads.

ADVANTAGES OF THE SHUNT OR PARALLEL

ACTIVE FILTER


23/38


SHUNT ACTIVE FILTER CONTROL

a) Shunt active filter control based on voltage detection


24/38


3- HYBRID ACTIVE-PASSIVE FILTER

Compensation of current harmonics and displacement power

factor can be achieved simultaneously.


25/38


HARMONIC DETECTION METHODS

i) Load current detection iAF= iLh

It is suitable for shunt active filters which are installed near

one or more non-linear loads.

ii) Supply current detection iAF= KSiSh

Is the most basic harmonic detection method for series

active filters acting as a voltage source vAF.

iii) Voltage detection

It is suitable for shunt active filters which are used as

Unified Power Quality Conditioners. This type of ActiveFilter is installed in primary power distribution systems. The

Unified Power Quality Conditioner consists of a series and a

shunt active filter.


26/38


HYBRID ACTIVE-PASSIVE FILTER

Single-phase equivalent circuit Single-phase equivalent circuit

for 5thHarmonic


27/38


HYBRID SERIES AND SHUNT

ACTIVE FILTER

At the Point of Common Coupling provides:

Harmonic current isolation between the sub transmission and the

distribution system (shunt A.F)

Voltage regulation (series A.F)

Voltage flicker/imbalance compensation (series A.F)


28/38

HYBRID ACTIVE POWER FILTER USING FUZZYDIVIDING

FREQUENCY CONTROL METHOD> It shows great promise in reducingharmonics

> Improve the power factor with a relativelylow capacity active power filter

> Uses HAPF with injection circuit


Configuration of the adaptive


29/38

Configuration of the adaptivefuzzy dividing frequency

controller



30/38

Consists of two control

units:A generalized integrator control

unit

A fuzzy adjustor unit.



31/38

ADVANTAGE :The stability of the system is achieved by a proportional

controller, and the perfect dynamic state is received by thegeneralized integral controller. The fuzzy adjustor is set to adjust

the parameters of proportional control and generalized integralcontrol. Therefore, the proposed harmonic current trackingcontroller can decrease the tracking error of the harmonic

compensation current, and have better dynamic response androbustness



32/38

Block diagram of the fuzzy

adjustor unit.



33/38

Fuzzy AdjustorAdjust the parameters of proportional control gainand integral control gain , based on the error and

the change of error

Kp = Kp* + Kp

Ki = Ki* + Ki



34/38

Comparison without and

with IHAPFTHD pf

Without IHAPF 21.5% 0.69With IHAPF 1.9% 0.94



35/38

SELECTION OFAF S FOR SPECIFIC APPLICATION CONSIDERATIONS

AF Configuration with higher number of * is more preferredCompensation for

Specific Application

Active Filters

Active

Series

Active

Shunt

Hybrid of

Active Series

and Passive

Shunt

Hybrid of

Active Shunt

and Active

Series

Current Harmonics ** *** *

Reactive Power *** ** *

Load Balancing *

Neutral Current ** *

Voltage Harmonics *** ** *Voltage Regulation *** * ** *

Voltage Balancing *** ** *

Voltage Flicker ** *** *

Voltage Sag&Dips *** * ** *

01 SEPT 2014NITW - EED35


36/38

CONCLUSIONS

Solid State Power Control results in harmonic pollution above the tolerable limits.

Harmonic Pollution increases industrial plant downtimes and power losses.

Harmonic measurements should be made in industrial power systems in order (a) aid in the design of capacitoror filter banks, (b) verify the design and installation of capacitor or filter banks, (c) verify compliance with utilityharmonic distortion requirements, and (d) investigate suspected harmonic problems.

Computer software programs such as PSPICE and SIMULINK can be used in order to obtain the harmonicbehavior of an industrial power plant.

The series LC passive filter with resonance frequency at 4.7 is the most popular filter.

The disadvantages of the the tuned LC filter is its dynamic response because it cannot predict the loadrequirements.

The most popular Active Filter is the parallel or shunt type.

Active Filter technology is slowly used in industrial plants with passive filters as a hybrid filter. These filters canbe used locally at the inputs of different nonlinear loads.

Active Filter Technology is well developed and many manufactures are fabricating Active filters with largecapacities.

A large number of Active Filters configurations are available to compensate harmonic current, reactive power,neutral current, unbalance current, and harmonics.

The active filters can predict the load requirements and consequently they exhibit very good dynamic response.

LC tuned filters can be used at PCC and the same time active filters can be used locally at the input of nonlinearloads.



37/38

REFERENCES

[1] IEEE Std. 519-1992, IEEE Recommended Practices and Requirements forHarmonic Control in Electric Power Systems, 1993.

[2] IEC Sub-Committee 77B report, Compatibility Levels in Industrial Plants forLow Frequency Conducted Disturbances, 1990.

[3] IEC Sub-Committee 77A report, Disturbances Caused by EquipmentConnected to the Public Low-Voltage Supply System Part 2 : Harmonics ,1990 (Revised Draft of IEC 555-2).

[4] UK Engineering Recommendation G.5/3: Limits for Harmonics in the UKElectricity Supply System, 1976.

[5] CIRGE WG 36.05 Report, Equipment producing harmonics and ConditionsGoverning their Connection to the Mains power Supply, Electra, No. 123,March 1989, pp. 20-37.

[6] Fuzzy adjustor unit IEEE TRANSACTIONS ON POWER DELIVERY, VOL. 24, NO. 1,JANUARY 2009



38/38

DEFINITIONS

[7] J. Arriilaga, D.A. Bradley, and P.S. Bodger, Power System Harmonics,New York:Wiley, 1985.

[8] N. Shepherd and P. Zand, Energy flow and power factor in nonsinusoidal circuits ,Cambridge University Press, 1979.

EFFECTS OF HARMONICS

[9] J.M. Bowyer, Three-Part Harmony: System Interactions Leading to a DivergentResonant System, IEEE Trans. on Industry Applications, Vol. 31, No. 6, Nov/Dec1995, pp. 1341-1349.

[10] R.D. Hondenson and P.J. Rose, Harmonics: the Effects on power Quality andTransformers ,IEEE Trans. on Industry Applications, Vol. 30, No.3, May/June 1994,pp. 528-532.

[11] J.S. Subjak and J. S. McQuilkin, Harmonics-Causes, effects, Measurements andAnalysis: An Update, IEEE Trans. on Industry Applications, Vol. 26, No. 6, Nov/Dec1990, pp. 103-1042.

[12] P.Y. Keskar, Specification of Variable Frequency Drive Systems to Meet the NewIEEE 51 Standard, IEEE Trans. on Industry Applications, Vol.32, No.2, March/April1996, pp. 393-402.

Documents

Harmonics supression