Design and Simulation of Shunt Passive Filter. Design and Simulation of Shunt Passive Filter for Harmonics Mitigation of Non-Linear Loads

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1 Design and Simulation of Shunt Passive Filter for Harmonics Mitigation of Non-Linear Loads Design and Simulation of Shunt Passive Filter for Harmonics Dung Vo Tien, Mitigation Radomir Gono and ofzbigniew Non-Linear Leonowicz Loads FEECS, VSB- Technical University of Ostrava 7. Dung Listopadu Vo Tien 5/272,, Radomír Goňo Ostrava-Poruba,, ZbigniewCzech Leonowicz Republic 2 Faculty of Electrical Engineering, Wroclaw University of Science and Technology FEECS, WybrzeeVŠB Stanisawa Technical Wyspiaskiego University 27, of Ostrava, Wrocaw, CzechPoland Republic {dung.vo.tien.st, 2 Wroclawradomir.gono}@vsb.cz,{zbigniew.leonowicz}@pwr.edu.pl University of Science and Technology, Poland {dung.vo.tien, radomir.gono}@vsb.cz, zbigniew.leonowicz@pwr.edu.pl Abstract. This paper presents a study of shunt passive filter design procedure to mitigate harmonics of non-linear loads. There are some disadvantages of the passive filter, however, it is an economical choice for minimizing harmonics of large non-linear loads. The non-linear load considered in this paper is DC fed by a 2- pulse thyristor bridge converter. The passive filter is designed with reference to the IEEE standard for harmonic limits. The designed passive filter is modeled and tested by using MATLAB/SIMULINK. The results proved the effectiveness of filters and the correctness of the design procedure. Keywords: Harmonics, passive filter, single tuned filter, high- pass filter, power quality Introduction Harmonic is one of the most common events that affect power quality in the industrial power system. It can adversely affect the device including transformers, machines, circuit breaker, capacitor banks, electronic equipment, etc. Transformer and motors may excessive temperature and increased losses. Capacitors may prematurely fail because of increased dielectric stress and heating. The circuit breaker may incorrect operation due to sensitive electronic equipment malfunction. Therefore, harmonics mitigation is very important for both producers and customers. Filtering harmonics using passive filter is one of the earliest methods 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 and reduce power losses in the power system. In this paper, an investigation has been made to solve harmonic problem and improve the power factor due to nonlinear loads. The study procedure in analyzing harmonic is as follows. This research was partially supported by the SGS grant from VSB-TU Ostrava (No. SP207/54) and by the project TUCENET (No. LO404). c Radomír Goňo (Ed.): ELNET 207, pp. 34 4, ISBN VŠB Technical University of Ostrava, FEECS, 207.

2 Design and Simulation of Shunt Passive Filter for Harmonics 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 of DC motor for a rotary clinker kiln of Hoang Mai Cement factory (Viet Nam). The power system network is shown in Fig. and its parameters are shown in Tab.. The non-linear load is 490 kw DC motor fed by a phase controlled thyristor converter for a rotary clinker kiln. This converter is supplied from a 000kV A6300/675/675V, Y0/Y/D transformer. The 2- pulse thyristor bridge converter adjusts the armature voltage of the DC drive to maintain a constant speed irrespective of the load on the motor, the pulse firing angle variation from 0 to The details of the DC drive motor are as given follow Fig.. The single diagram of power system Voltage 0 750V, rated current 670A, rated speed 000 rpm, shunt field 300V dc, armature resistance R a = 0.024Ω, armature winding self inductance L aa = 9.4mH, mutual inductance between field and armature L af = 264mH, Rated Torque = 20, 37Nm, Moment of inertia J = 0kg.m 2, viscous friction co-efficient Bm = 0.052N.m.s and Coulomb friction torque T f = 52.9Nm. The Table. The system parameters. Components Details Source 250MVA, 220kV, 50Hz Transformer 25MVA, 230/5 kv, Y0/D Transformer 2 25MVA, 0/6,3/6,3 kv, Dd0, Dyn Line Transmission line, 8km, ACY 85 MATLAB/Simulink simulation of non-linear loads is presented in Fig. 2. Figures

3 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 simulation has a strong influence on the design procedure of the passive filters for mitigating harmonics. Therefore, the harmonic order in result simulation has been compared with 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 standards [9], but the THD of 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 th, 3th, 23th and 25th harmonics. The design procedure for shunt passive filters presented the choice of the passive filter type, the VAR rating and the values of the quality factor. Fig. 3. Voltage and current waveform of non-linear loads.

4 Design and Simulation of Shunt Passive Filter for Harmonics Fig. 4. FFT spectrum of current without passive filter. Table 2. The comparison order harmonic between simulation and measurement. Harmonics I % I3 % I23 % I25 % I35 % I37 % THD(%) Result simulation Real measurement Filter design Fig. 5 show common type of passive filters, their configuration and, R-X and Zplots []. 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 to design 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 (lowpass filter) for th and 3th harmonics and the second order high- pass filter for 23th and 25th harmonics. 3. 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 ) 2π.h.f.C () The impedance of the inductive and capacitive reactance are given by: XC = 2 Vph XC, XL = 2 QF.h h Where QF is reactive power requirement, h is harmonic number. The quality factor of single tuned filter is: (2)

5 38 Dung Vo Tien et al. Fig. 5. Common types of passive filters, configuration, R-X and Z-ω plots. The resonant frequency is given by: Q L = X L R f 0 = 2π LC (3) (4) 3.2 High Pass Filter [8] The impedance of the high- pass filter is given by: Z = The quality factor of the high- pass filter is: j2π.h.f.c + ( R + j2π.h.f.l ) (5) Q H = L R 2 C (6) The resonant frequency is given by: f 0 = 2π.h.C.R (7) 3.3 Parameters calculation With the single tuned filter:

6 Design and Simulation of Shunt Passive Filter for Harmonics With the high- pass filter: C = Q F 2π.f.Vph 2 (8) L h = C.(2π.h.f) 2 (9) R h = 2π.h.f.L h Q L (0) R h = 2π.C.h.f () R h = R2 h.c Q H (2) The filter is not only inductance and capacitance but also resistance. The values of R used to significantly alter the filter response, usually result in a significant increase in losses within the filter. The quality factor defines the sharpness of the filter. According to one research [2], the typical values of Q L range 25 to 00 and the typical values of Q H range 0.5 to 2. 4 Simulation results 4. Reactive power compensation The power factor is required to improve from 0.75 to The equation to get the reactive power is Q C = P (tanφ tanφ 2 ) = 490[tan(cos (0.75)) tan(cos (0.95))] = 270(kV Ar) (3) For this system, the passive filter has been designed for mitigating th, 3 th, 23 th, 25 th harmonic level with two low- pass filters and two high- pass filters and VAR 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 equations from Eq. 8 to Eq. 2 and shown in Tab. 3. The performance of passive filter has been analyzed in MATLAB/SIMULINK is presented in Fig. 6. The waveform of the current with and without passive filter is compared in Fig. 7. The FFT analysis 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 T HD I was originally worth 5.8% down to 2.96%, all the harmonic level is decreased. The T HD V 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 IEEE standard

7 40 Dung Vo Tien et al. Table 3. The system parameters. Filter C rating Low- pass Filter Q=50 (kvar) (µf) th harm. L R (mh) (Ω) Low- pass Filter Q=50 3th harm. L3 R3 (mh) (Ω) High-pass Filter Q= 23th harm. L23 R23 (mh) (Ω) High-pass Filter Q= 25th harm. L25 R25 (mh) (Ω) Fig. 6. MATLAB/SIMULINK model of the power system. 5 Concusion This paper presented a designed procedure of shunt passive filter for mitigating the harmonic filter in industrial power system. A real non-linear load has been taken for study. The design procedure, including the choice of the passive filters type, the VAR rating and the values of quality factor have been presented. Two types of passive filters, single tuned and high- pass filters were used. The designed passive filter is tested by using MATLAB/SIMULINK. The results proved the effectiveness of filters and the correctness of design procedure. References. J. C. Das. Passive Filter Potentialities and Limitations. IEEE Transactions on Industry Applications, Vol 40, No.. Jan /Feb D. A. Gonzalez and J. C. McCall. Design of filters to reduce harmonic distortion in industrial power systems. IEEE Transaction on Industry Application, vol. IA-23, pp May/June 987.

8 Design and Simulation of Shunt Passive Filter for Harmonics... 4 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 of Shunt Passive Harmonic Filters: Six Pulse Rectifier Load Power Factor Improvement and Harmonic Control. ACEEE Int. J. on Electrical and Power Engineering, Vol. 02, No. 0. Feb Subrata De, and G. Bhuvaneswari. Investigations on the impact of VAR rating and quality factor on the effectiveness of a shunt passive filter. Power India Conference, 2006 IEEE. India, June Khaled H. Ahmed, Stephen J. Finney and Barry W. Williams. Design, Application and Comparison of Passive Filters for Three-Phase Grid-connected Renewable Energy Systems. Electrical Power Quality and Utilisation, Journal Vol. XIII, No. 2, pp Mojgan Hojabri and Mehrdad Hojabri. Design, Application and Comparison of Passive Filters for Three-Phase Grid-connected Renewable Energy Systems. ARPN Journal of Engineering and Applied Sciences, vol. 0, no. 22. India, December, G. Bhuvaneswari. Investigations on the Impact of VAR Rating and Quality Factor on the Effectiveness of a Shunt Passive Filter IEEE Power India Conference. India, J. Arrillaga, D. A. Bradley, and P. S. Bodger. Power System Harmonics. New York: Wiley, 2003, ISBN Recommended Practice and Requirements for Harmonic Control in Electrical Systems. IEEE Std Guidance Notes for Control of Harmonics in Electrical Power Systems. New York 2006.