Design and Simulation of Shunt Passive Filterfor Harmonics Mitigation of Non-Linear Loads

Dung Vo Tien1, Radomır Gono1, Zbigniew Leonowicz2

1 FEECS, VSB – Technical University of Ostrava, Czech Republic2 Wroclaw University of Science and Technology, Poland

dung.vo.tien, radomir.gono@vsb.cz, zbigniew.leonowicz@pwr.edu.pl

Design and Simulation of Shunt Passive Filterfor Harmonics Mitigation of Non-Linear Loads?

Dung Vo Tien, Radomir Gono and Zbigniew Leonowicz

FEECS, VSB- Technical University of Ostrava17. Listopadu 15/2172, 708 33 Ostrava-Poruba, Czech Republic

Faculty of Electrical Engineering, Wroclaw University of Science and TechnologyWybrzee Stanisawa Wyspiaskiego 27, 50-370 Wrocaw, Poland

dung.vo.tien.st, radomir.gono@vsb.cz,zbigniew.leonowicz@pwr.edu.pl

Abstract. This paper presents a study of shunt passive filter designprocedure to mitigate harmonics of non-linear loads. There are somedisadvantages of the passive filter, however, it is an economical choicefor minimizing harmonics of large non-linear loads. The non-linear loadconsidered in this paper is DC fed by a 12- pulse thyristor bridge con-verter. The passive filter is designed with reference to the IEEE 519-1992 standard for harmonic limits. The designed passive filter is mod-eled and tested by using MATLAB/SIMULINK. The results proved theeffectiveness of filters and the correctness of the design procedure.

Keywords: Harmonics, passive filter, single tuned filter, high- pass filter, power

quality

1 Introduction

Harmonic is one of the most common events that affect power quality in the in-dustrial power system. It can adversely affect the device including transformers,machines, circuit breaker, capacitor banks, electronic equipment, etc. Trans-former and motors may excessive temperature and increased losses. Capacitorsmay prematurely fail because of increased dielectric stress and heating. The cir-cuit breaker may incorrect operation due to sensitive electronic equipment mal-function. Therefore, harmonics mitigation is very important for both producersand customers. Filtering harmonics using passive filter is one of the earliest meth-ods and more widely used because of low cost, reliability and easy to maintain.The passive filter not only reduces harmonic but improve the power factor andreduce power losses in the power system.

In this paper, an investigation has been made to solve harmonic problemand improve the power factor due to nonlinear loads. The study procedure inanalyzing harmonic is as follows.

? This research was partially supported by the SGS grant from VSB-TU Ostrava (No.SP2017/54) and by the project TUCENET (No. LO1404).

c© Radomır Gono (Ed.): ELNET 2017, pp. 34–41, ISBN 978–80–248–4154–0.VSB – Technical University of Ostrava, FEECS, 2017.

Design and Simulation of Shunt Passive Filter for Harmonics ... 35

– Identification and simulation of a system with nonlinear load.– Design of shunt passive filter to provide reactive power compensation and

minimize harmonic problem.– Comparison of analytical solution of the designed filter and results obtained

from the simulation.

2 System configuration

Data collection was performed by measurements the real time operation ofDC motor for a rotary clinker kiln of Hoang Mai Cement factory (Viet Nam).The power system network is shown in Fig.1 and its parameters are shown inTab. 1. The non-linear load is 490 kW DC motor fed by a phase controlledthyristor converter for a rotary clinker kiln. This converter is supplied from a1000kV A6300/675/675V , Y0/Y/D1 transformer. The 12- pulse thyristor bridgeconverter adjusts the armature voltage of the DC drive to maintain a constantspeed irrespective of the load on the motor, the pulse firing angle variation from0 to 450. The details of the DC drive motor are as given follow

Fig. 1. The single diagram of power system

Voltage 0 − 750V , rated current 670A, rated speed 1000 rpm, shunt field300V dc, armature resistance Ra = 0.024Ω, armature winding self inductanceLaa = 9.41mH, mutual inductance between field and armature Laf = 264mH,Rated Torque = 20, 317Nm, Moment of inertia J = 10kg.m2, viscous frictionco-efficient Bm = 0.052N.m.s and Coulomb friction torque Tf = 52.9Nm. The

Table 1. The system parameters.

Components Details

Source 250MVA, 220kV, 50Hz

Transformer 1 125MVA, 230/115 kV, Y0/D11

Transformer 2 25MVA, 110/6,3/6,3 kV, Dd0, Dy11n

Line Transmission line, 118km, ACY 185

MATLAB/Simulink simulation of non-linear loads is presented in Fig. 2. Figures

36 Dung Vo Tien et al.

3 and 4 illustrate the voltage and current waveform of non-linear loads and FFT(Fast Fourier Transform) analysis of the current. The accuracy of the simulationhas a strong influence on the design procedure of the passive filters for mitigatingharmonics. Therefore, the harmonic order in result simulation has been comparedwith the real measurement is shown in Tab. 2, the error is very small. The THD(Total Harmonic Distortion) of voltage at PCC (the Point of Common Coupling)is 3.09%, it is acceptable according to IEEE 519-1992 standards [9], but the THDof the current is very high, exceed the standard harmonics limits.

Fig. 2. The MATLAB/Simulink simulation of non-linear loads.

The shunt passive filters have been designed for mitigating 11th, 13th, 23th

and 25th harmonics. The design procedure for shunt passive filters presented thechoice of the passive filter type, the VAR rating and the values of the qualityfactor.

Fig. 3. Voltage and current waveform of non-linear loads.

Design and Simulation of Shunt Passive Filter for Harmonics ... 37

Fig. 4. FFT spectrum of current without passive filter.

Table 2. The comparison order harmonic between simulation and measurement.

Harmonics I11% I13% I23% I25% I35% I37% THD(%)

Result simulation 10.10 6.67 4.50 3.72 2.91 2.61 15.18

Real measurement 10.3 6.8 4.7 3.6 2.8 2.5 15.8

3 Filter design

Fig. 5 show common type of passive filters, their configuration and, R-X and Z-plots [1]. The single tuned filter (also called low-pass filter or band-pass filter)and the high-pass filter are most commonly applied because the simplest todesign and the lowest price to implement.

The filter is designed to: (i) compensate the reactive power of the system, (ii)modifies, reshape or reject all the undesired frequencies of an electrical signal.In this case, the passive filter consists of the first order single tuned filter (low-pass filter) for 11th and 13th harmonics and the second order high- pass filter for23th and 25th harmonics.

3.1 Single Tuned Filter (or Low- Pass Filter)[8]

– The impedance of low- pass filter (or band-pass filter) is given by:

Z = R+ j(2π.h.f.L− 1

2π.h.f.C) (1)

– The impedance of the inductive and capacitive reactance are given by:

XC =V 2ph

QF .h,XL =

XC

h2(2)

Where QF is reactive power requirement, h is harmonic number.

– The quality factor of single tuned filter is:

38 Dung Vo Tien et al.

Fig. 5. Common types of passive filters, configuration, R-X and Z-ω plots.

QL =XL

R(3)

The resonant frequency is given by:

f0 =1

2π√LC

(4)

3.2 High Pass Filter [8]

– The impedance of the high- pass filter is given by:

Z =1

j2π.h.f.C+ (

1

R+

1

j2π.h.f.L)−1 (5)

– The quality factor of the high- pass filter is:

QH =L

R2C(6)

– The resonant frequency is given by:

f0 =1

2π.h.C.R(7)

3.3 Parameters calculation

– With the single tuned filter:

Design and Simulation of Shunt Passive Filter for Harmonics ... 39

C =QF

2π.f.V 2ph

(8)

Lh =1

C.(2π.h.f)2(9)

Rh =2π.h.f.Lh

QL(10)

– With the high- pass filter:

Rh =1

2π.C.h.f(11)

Rh =R2

h.C

QH(12)

The filter is not only inductance and capacitance but also resistance. Thevalues of R used to significantly alter the filter response, usually result in asignificant increase in losses within the filter. The quality factor defines thesharpness of the filter. According to one research [2], the typical values of QL

range 25 to 100 and the typical values of QH range 0.5 to 2.

4 Simulation results

4.1 Reactive power compensation

The power factor is required to improve from 0.75 to 0.95. The equation to getthe reactive power is

QC = P (tanφ1−tanφ2) = 490[tan(cos−1(0.75))−tan(cos−1(0.95))] = 270(kV Ar)(13)

For this system, the passive filter has been designed for mitigating 11th, 13th,23th, 25th harmonic level with two low- pass filters and two high- pass filters andVAR rating of the filter being 270 kVAr.

4.2 Parameters of designing passive filter and simulation results

The parameters of designing passive filter are calculated according to equationsfrom Eq. 8 to Eq. 12 and shown in Tab. 3. The performance of passive filter hasbeen analyzed in MATLAB/SIMULINK is presented in Fig. 6. The waveformof the current with and without passive filter is compared in Fig. 7. The FFTanalysis of the current with passive filter is shown in Fig. 8.

After the design procedure of the shunt passive filters and testing tools,results obtained from the simulation, it can be seen

– The THDI was originally worth 15.18% down to 2.96%, all the harmoniclevel is decreased.

– The THDV is reduced from 3.09% to 0.62% after using passive filters. Thus,the harmonic distortion at PCC is within the limit specified by the IEEEstandard 519− 1992.

40 Dung Vo Tien et al.

Table 3. The system parameters.

Filter C Low- pass Low- pass High-pass High-passrating Filter Filter Filter Filter

Q=50 Q=50 Q=1 Q=1(kVAr) (µF) 11th harm. 13th harm. 23th harm. 25th harm.

L11 R11 L13 R13 L23 R23 L25 R25

(mH) (Ω) (mH) (Ω) (mH) (Ω) (mH) (Ω)

500 5.42 15.460 1.068 11.069 0.765 3.540 25.550 2.990 23.500

Fig. 6. MATLAB/SIMULINK model of the power system.

5 Concusion

This paper presented a designed procedure of shunt passive filter for mitigatingthe harmonic filter in industrial power system. A real non-linear load has beentaken for study. The design procedure, including the choice of the passive filterstype, the VAR rating and the values of quality factor have been presented. Twotypes of passive filters, single tuned and high- pass filters were used. The designedpassive filter is tested by using MATLAB/SIMULINK. The results proved theeffectiveness of filters and the correctness of design procedure.

References

1. J. C. Das. Passive Filter Potentialities and Limitations. IEEE Transactions onIndustry Applications, Vol 40, No. 1. Jan /Feb 2004.

2. D. A. Gonzalez and J. C. McCall. Design of filters to reduce harmonic distortion inindustrial power systems. IEEE Transaction on Industry Application, vol. IA-23,pp. 504512. May/June 1987.

Design and Simulation of Shunt Passive Filter for Harmonics ... 41

Fig. 7. The waveform of current at PCC without and with passive filter.

Fig. 8. FFT spectrum of current when passive filter is installed.

3. Seema P. Diwan, Dr. H. P. Inamdar, and Dr. A. P. Vaidya. Simulation Studies ofShunt Passive Harmonic Filters: Six Pulse Rectifier Load Power Factor Improve-ment and Harmonic Control. ACEEE Int. J. on Electrical and Power Engineering,Vol. 02, No. 01. Feb 2011.

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