VIEWS: 49 PAGES: 13 CATEGORY: Emerging Technologies POSTED ON: 11/30/2012
International Journal of Electrical Engineering and Technology (IJEET), ISSN INTERNATIONAL JOURNAL OF ELECTRICAL0976 – 6545(Print), ISSN ENGINEERING 0976 – 6553(Online) Volume 3, Issue 3, October – December (2012), © IAEME & TECHNOLOGY (IJEET) ISSN 0976 – 6545(Print) ISSN 0976 – 6553(Online) Volume 3, Issue 3, October - December (2012), pp. 89-101 IJEET © IAEME: www.iaeme.com/ijeet.asp Journal Impact Factor (2012): 3.2031 (Calculated by GISI) ©IAEME www.jifactor.com SHUNT COMPENSATOR FOR INTEGRATION OF WIND FARM TO POLLUTED DISTRIBUTION SYSTEM T. NAGESWARA PRASAD1, V. CHANDRA JAGAN MOHAN2, DR. V.C. VEERA REDDY3 1 Research Scholar, Department of EEE, S.V.U. College of Engineering, Tirupati, India 2 Asst. Professor, Department of EEE, Vaishnavi Institute of Technology, Tirupati, India 3 Professor & Head, Department of EEE, S.V.U. College of Engineering, Tirupati, India E-mail:1np_thunga@yahoo.com, 2 veerareddyj1@rediffmail.com, 3 veerareddy_vc@yahoo.com ABSTRACT Greater concerns about rising fossil fuel prices, technical and environmental reasons, reliability of power and energy security increase are making the energy sector to incline towards installation of distributed resources or distributed generation (DG). DG is gearing-up now-a-days to serve local and distributed loads. Integration of DG to the distribution system is a hectic task as the present day Distribution systems are highly polluted due to non-linear loads. Integration of wind farm, employing squirrel cage induction generators, to distribution system is considered in this paper. In this paper challenges and opportunities arising from integration of wind power to polluted distribution system and viable measures to enable efficient, unity power factor operation at point of connection using shunt compensator are presented. The system is analyzed using MATLAB/SIMULINK. Keywords: Distributed Generation (DG), Polluted Distributed System, Wind Generation, Power Quality improvement, Shunt Compensator 1. INTRODUCTION The use of Distributed Energy Resource is gaining importance and is being pursued as a supplement and as alternative to large conventional power stations using fossil fuels. Out of the renewable energy resources like Wind, Biomass, Solar PV, Geothermal etc., wind is one of the most renewable resources found in nature available free of cost with zero hazardous effects. Harnessing power from wind through wind farms is given greater attention around the globe as it is one of the most mature technologies among all the renewable resources [1]. By the end of 2011, of the total renewable power capacity, 390 GW, across the world 61.1% of the renewable power is through Wind energy [2], [3]. Wind energy is a major source of 89 6545(Print), International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print ISSN 0976 – 6553(Online) Volume 3, Issue 3, October – December (2012), © IAEME ies world. Fig. 1 shows the increasing trend of the installed power in over 70 countries across the wo Renewable, capacity of Global Total Renewable, Wind, Biomass, Solar PV and Geothermal Powers cumulative installed capacity from 2005 to 2011. Fig. 1 A Global Renewable Power Cumulative installed capacity e Large percentage of wind energy conversion systems around the world is employing Squirrel Cage Induction Generators (SCIG). The operation of SCIG demands reactive power, usually provided from the grid and/or by shunt operated capacitor banks. Wind generation b based DG micro-grid o units can operate individually or in a micro grid which is formed by a cluster of DG units load . connected to a Distribution Network to serve local and distributed loads. This strengthens the Distribution system and improves the service reliability. 1.1 Polluted Distributed Systems 1 The advancements and ease of control of Power Electronic Devices made extensive usage of semiconductor technology in power industry [4]. This has led to deterioration of Power systems. non Quality in both Transmission and Distribution systems. The presence of non-linear loads injects harmonics into the power system and is becoming a serious concern not only to the consumers but also to the utility causing problems such as overheating and destruction of quality [ electrical equipment, voltage quali degradation, malfunctioning of meters etc., [5]. The non-linear non distribution system feeds different kinds of linear and non linear loads. The non-linear loads sinusoidal draw non-sinusoidal currents from ac mains and cause reactive power burden and excessive neigh neutral currents and are also responsible for lower efficiency and interfere with neighboring communication networks [6] - [9 9]. The power factor and efficiency can be improved by using capacitors and synchronous Filters condensers but they cannot eliminate harmonics. Passive Filters proved to be the solution for harmonic suppression, greater efficiency and power factor improvement in distribution systems. However, they have their own potentialities (more economical, maintenance free, synchronous condensers) [10] and limitations (not zero short circuit currents compared to synch ] suitable for changing system conditions, mistuning, fixed compensation, large size instability [5], and they may create new system resonance) [5 [10]. alternatives, To overcome these problems, many authors have proposed many alternatives, but Active harmonics Power Filters (APFs) proved to be a very effective alternative for suppression of harmonics. 90 International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 3, Issue 3, October – December (2012), © IAEME Shunt Active Power Filter (ShAPF) proves to be an attractive solution for reactive power compensation and suppression of current harmonics [5] and Series Active Power Filter (SeAPF) for suppression of voltage harmonics [6]. This paper emphasizes on suppression of current harmonics using shunt compensator. Shunt Compensator supplies harmonic current of same magnitude but opposite in phase of the current harmonics due to non-linear load. The main task in this compensator is the computation of reference current signal and generation of gate signals for Voltage Source Inverter (VSI). So many methods have been proposed by various authors for harmonic elimination [11] - [14]. But, the mathematical model and the control scheme given in [15] are simple and easy to implement. The control schemes used for the generation of gate signals for PWM inverter are compared and reported in [15], [16] and the Fuzzy Logic controller is found superior compared to the conventional PI controller. The Fuzzy Logic (FL) is closer in spirit to human thinking and natural language than conventional logical systems. This provides a means of converting a linguistic control strategy based on expert knowledge into an automatic control strategy. The ability of fuzzy logic to handle imprecise and inconsistent real-world data made it suitable for a wide variety of applications [17]. In particular, the methodology of the fuzzy logic controller (FLC) appears very useful when processes are too complex for analysis or when the available sources of information are interpreted qualitatively, inexactly or with certain uncertainty. Thus FLC may be viewed as a step towards a rapprochement between conventional precise mathematical control and human-like decision making. One of the major drawbacks of FLC that does not make wide spread use is the difficulty of choice and design of membership functions to suit to the given problem. Thorough understanding of the process to be controlled is very much essential for framing the rules for the fuzzy logic controller [18]. Thus, tuning of the fuzzy logic controller by trial and error is often necessary to get a satisfactory performance. However, the Neural Networks (NN) have the capability of identification of a system by which the characteristic features of a system can be extracted from the input and output data [19], [20]. The learning capabilities of NN can be combined with FL system resulting in a NFIS. ANFIS has proved to have very good prediction capabilities. An effort is made to overcome the integration barriers and help sustainable and clean DG technologies and make their contribution to the Power System in a way that enhances the overall grid performance. It is proved in this paper that the shunt compensator can effectively be utilized to perform the following functions in the event of integration of wind power generators to polluted distribution system. 1) Dynamic reactive power support to the wind farm and the load 2) Current harmonic compensation at the Point of connection 3) Unity power factor operation at Point of connection 4) Efficient operation of wind farms In addition to the above objectives, the power quality is strictly maintained within the standards prescribed by IEEE-519 [22] and IEC-61000 standards. 91 International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 3, Issue 3, October – December (2012), © IAEME 2. SYSTEM DESCRIPTION AND MODELING 2.1 SYSTEM DESCRIPTION The single line diagram of the power system under consideration is shown in Fig. 2. The network consists of a 33KV, 50 Hz, grid supply point, feeding a 33KV distribution system. There are four load centers in the system L1, L2, L3 and L4. The four load centers comprise of Linear and Non-Linear loads. The Wind farm comprises of 4 wind turbines using squirrel cage induction generators each rated 1.5MW, 690V, 50Hz. Each generator is provided 170 KVAr fixed reactive power compensation through a bank of capacitors to give necessary reactive power support at the time of starting. The total wind farm capacity 6MW is connected to the 33KV distribution system at MV7, Point of Common Coupling (PCC), through a 690V/33KV transformer. In this study a mean wind speed of 12 m/s is considered. The Squirrel Cage Induction Generator model available in Matlab / Simulink SimPowerSystem libraries is used. Fig. 2 one-line diagram of distribution system with wind farm integrated at PCC 2.2 COMPENSATION SCHEME In many cases, the power system design criterion is based on the current and its waveform. Hence, it is necessary that the rms value of the total current (current harmonics) be reduced as much as possible. This not only reduces the losses but also reduces the distortion in voltage at the point of connection. Fig. 3 shows the basic compensation scheme of compensator to make the source current free from harmonics and in phase with source voltage by drawing or supplying a filter current ic from or to the utility at point of connection. 92 International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 3, Issue 3, October – December (2012), © IAEME Fig. 3 Shunt Compensator basic compensation scheme 2.2.1. CALCULATION OF REFERENCE CURRENT The peak value of reference source current is calculated by regulating voltage across capacitor of the VSI. Source supplies two current components i. active and ii. loss (to meet losses in the VSI). The controller used in the VSI is supposed to generate the gating signals to maintain the required value of active current component by maintaining the DC voltage constant. The source voltage and source current are given by v s (t ) = Vsm sin ωt (1) i s (t ) = I sm sin ωt (2) As per Fig. 3, the load, source and compensator currents are related as i s (t ) = i L (t ) − iC (t ) (3) ∞ i L (t ) = ∑ I n sin(nωt + φ n ) n =1 ∞ = I 1 sin(ωt + φ f ) + ∑ I n sin(nωt + φ n ) n=2 = i Lf (t ) + i Lh (t ) (4) Where i Lf and i Lh are the fundamental and harmonic components of load current. I 1 and I n are the peak values of fundamental and nth harmonic component of load currents respectively. Assuming the voltage at load as v s (t ) , the instantaneous load power can be expressed as p Load (t ) = v s (t ) * i L (t ) = Vsm I 1 sin 2 ωt * cos φ f + Vsm I 1 sin ωt * cos ωt * sin φ f ∞ + Vsm sin ωt * ∑ I n sin(nωt + φ n ) n=2 93 International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 3, Issue 3, October – December (2012), © IAEME = p L (t ) + q L (t ) + p Lh (t ) (5) where p L (t ) , q L (t ) and p Lh (t ) are active, reactive and harmonic power of load. Out of these powers p L (t ) will be supplied by the source i.e., p L (t ) = Vsm I 1 sin 2 ωt * cos φ f = (Vsm sin ωt ).( I 1 cos φ f ) sin ωt = Vs (t ) * i s (t ) (6) From (2) and (6), the peak value of source current is given by I sm = I 1 cos φ f There are also some switching losses in the PWM converter and, hence, the utility must supply a small overhead for the capacitor leakage and converter switching losses in addition to the real power to the load. The total peak current to be supplied by the source is therefore * I sm = I sm + I sl (7) The peak value of the reference current I sm can be estimated by controlling the dc-side capacitor voltage. The ideal compensation requires the source current to be sinusoidal and in- phase with the source voltage irrespective of the nature of load current. The desired source currents after compensation can be given as ∗ ∗ i sa = I sm sin ωt , ∗ ∗ i sb = I sm sin(ωt − 120), ∗ ∗ i sc = I sm sin(ωt − 240) Hence, the magnitude of the source currents needs to be determined by controlling the dc side capacitor voltage. 2.2.2. DESIGN OF DC SIDE CAPACITOR Whenever the load changes not only a real power imbalance gets established between source and load but also a reactive power and harmonic real power imbalance between active filter and the load. The real power imbalance has to be compensated by the DC capacitor. This drives the DC capacitor voltage away from the reference value. For satisfactory operation of the compensator, the peak value of the reference current must be regulated to change in proportion to the real power drawn from the source. This real power charged or discharged by the capacitor compensates for the real power consumed by the load. Whenever the capacitor recovers from its transient state to its reference voltage, the real power imbalance gets vanished. Also the reactive power required at the point of connection will be compensated by the compensator. Thus the role of the DC side capacitor is (i) to absorb / supply real power demand of the load during transient period and (ii) maintain DC voltage in the steady state. The design of the DC side capacitor is based on the maximum possible variation in load and the required reduction in voltage ripple [11]. Thus the DC side capacitor can be found from π ∗ I Ci ,rated C DC = 3ωVdr , P − P (max) 94 International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 3, Issue 3, October – December (2012), © IAEME Where I Ci, rated is the rated filter current and Vdr , P − P (max) is the peak-to-peak voltage ripple. Therefore, for the system considered in Fig. 3, the parameters selected for simulation are LC = 1mH, V DC ,ref = 5000V and C DC = 300µF. 2.2.3. DESIGN OF COMPENSATOR CIRCUIT PARAMETERS SELECTION OF COMPENSATOR INDUCTOR LC AND REFERENCE VALUE OF DC LINK VOLTAGE V DCref : For of unity power factor operation, that is, the source fundamental current I s1 in-phase with the source voltage Vs , the compensator should compensate all the fundamental reactive power of the load. Thus the compensator current I C1 should be 900 out-of-phase to Vs as shown in Fig. 4 i s1 Vs VC1 iC 1 jωLC I C1 i L1 Fig. 4 Phasor representation of Shunt Compensator From Fig. 4, the compensator current I C1 is obtained as VC1 = Vs + jωLC I C1 VC 1 − V s V V I C1 = = C 1 1 − s V ωLC ωLC C1 and the 3-phase reactive power delivered by the compensator can be calculated as QC1 = 3Vs I C1 V V = 3Vs C1 1 − s ωL V (8) C C1 That is, the compensator works either as source of reactive power when VC1 > Vs (QC1 = + ve) or sink of reactive power when VC1 < Vs (QC = −ve) . The compensator inductor LC is used to filter out the ripples in the inverter current that occur due to switching of the inverter. Hence, the design of LC is based on the principle of harmonic current reduction. For the PWM inverter that operates in linear modulation mode 0 ≤ m a ≤ 1 ( ma = Vm 0.5V DC , the amplitude modulation factor), the maximum harmonic voltage occurs at the frequency m f ω , where m f is the frequency modulation of the inverter. The ripple current of the PWM inverter is given as VCh (m f ω ) I Ch (m f ω ) = (9) m f ωLC V DCref and LC can be obtained by solving equations (8) & (9) simultaneously. 95 International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 3, Issue 3, October – December (2012), © IAEME 3. PROPOSED SCHEME OF CONTROL System modeling based on conventional mathematical tools is not well suited for dealing with ill-defined and uncertain systems. By contrast, a fuzzy inference system employing fuzzy ‘if-then’ rules can model the qualitative aspects of human knowledge and reasoning processes without employing precise quantitative analysis. However, even today, no standard methods exist for transforming human knowledge or experience into the rule base and database of a fuzzy inference system. There is a need for effective methods for tuning the membership functions so as to minimize the output error measure. Recently, ANFIS architecture has proved to be an effective tool for tuning the membership functions. ANFIS can serve as basis for constructing a set of fuzzy ‘if-then’ rules with appropriate membership functions to generate the stipulated input-output data. An initial fuzzy inference system is taken from PI controller and is tuned with back propagation algorithm based on the collection of input-output data. The proposed control scheme is shown in Fig. 5. The system considered is a balanced three-phase system with a wind farm integrated to the system at MV6 and compensator is connected at MV1 as shown in Fig. 2. The scheme of generation of reference currents for the generation of gating signals of PWM inverter is also illustrated in Fig. 5. The shunt compensator employs a diode clamped PWM inverter. Fig. 5 Shunt Compensator control scheme The parameters for the ANFIS network used for the system under study are as detailed in Table 1. Table 1 Parameters used for ANFIS controller Parameter Value Number of training data pairs 500 Type of Membership function Triangular Number of input Membership functions 14 Number of epochs for training 50 96 International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 3, Issue 3, October – December (2012), © IAEME The rule base used for the TS-Fuzzy and ANFIS controller is shown in Table 2. Table 2 Rule base for Fuzzy & ANFIS controllers Input 2 (∫error (∫e)) NB NM NS ZE PS PM PB NB NB NB NB NB NM NS ZE Input 1 NM NB NB NB NM NS ZE PS (error (e)) NS NB NB NM NS ZE PS PM ZE NB NM NS ZE PS PM PB PS NM NS ZE PS PM PB PB PM NS ZE PS PM PB PB PB PB ZE PS PM PB PB PB PB 4. RESULTS & DISCUSSION The power system with wind farm integrated to it at MV6 along with the shunt compensator is illustrated in Fig. 2. Simulations are carried out using Matlab/Simulink to study the impact of the compensator on the operation of the system. The total simulation time considered is 0.5 Sec. Simulations are carried out to show that the filter eliminates the harmonics and also improves the power factor at the point of connection. The simulation was conducted with the following chronology: • at t = 0.0 sec, the simulation starts with shunt compensator not connected to the system • at t = 0.1 sec, the filter is turned ON • at t = 0.2 sec, the load is increased from 155 amps to 185 amps • at t = 0.3 sec, the load is decreased from 185 amps to 170 amps • at t = 0.4 sec, the load is increased from 170 amps to 185 amps Fig. 6 Load current in phase-a Fig. 6 depicts the non-sinusoidal nature of current due to non-linear loads. These non-linear currents have serious impact as detailed in section 1.1, on the operation of electrical 97 International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 3, Issue 3, October – December (2012), © IAEME equipment being operated. As a result of this harmonic current the performance and life span of the induction generators being operated in wind farm integrated to distribution system beyond MV1 at the Point of Common Coupling (PCC), MV7, gets deteriorated. To protect the wind farm from the adverse effects due to harmonics, the shunt compensator is turned ON at t = 0.1 sec. The instant the filter is switched ON, the current becomes sinusoidal. Fig. 7 illustrates the significance of compensator in making the current sinusoidal. Fig. 7 Current in phase-a at source (MV1) Comparison of Fig. 6 and Fig. 7 indicates that the current at MV1 continues to be sinusoidal after t = 0.1 sec for any load condition. The harmonic content in current and power factor at different load conditions is listed in Table 3. The Total Harmonic Distortion (THD) in current without the compensator is found as 31% and the power factor 0.7. Both are objectionable from the industry standards point of view. The Distortion Power Factor (DPF) is calculated at five different instants and tabulated in Table 3. The Distortion Power Factor describes how the harmonic distortion of load current decreases the average power transferred to the load. DPF is given by 1 DPF = 1 + THD 2 Table 3 THD and power factor for different load conditions Status of Instant Load THD Power Shunt DPF (sec) (amps) (%) factor Compensator 0.05 155 OFF 31.0 0.7 0.955 0.15 155 ON 1.80 1 0.999 0.25 185 ON 1.81 1 0.999 0.35 170 ON 1.80 1 0.999 0.45 185 ON 1.81 1 0.999 98 International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 3, Issue 3, October – December (2012), © IAEME Fig. 8 shows that the power factor at MV1 oscillates due to the starting of induction generators in wind farm and stabilizes finally to 0.7 at 0.015 sec. The power factor is low due to the reactive power drawn by the induction generators in the wind farm. The power factor 0.7 is a low value as per the IEEE-519 [22] and IEC-61000 standards. Fig. 8 Power factor at MV1 The compensator when turned ON not only generates harmonic power in such a way that it cancels the harmonic content in the current but also generates the reactive power needed at MV1. The reactive power needed for wind farm operation is met from the compensator. Thus the power factor is maintained unity by the compensator. For any load condition, the current is found to be sinusoidal and the power factor is unity. The steady state and dynamic performance of the shunt compensator is found satisfactory. The compensator current increases with the increase in load and is illustrated in Fig. 9. The current will be in opposition to the harmonic current to make the source current sinusoidal and unity power factor operation at the point of connection. Fig. 9 Compensator current 99 International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 3, Issue 3, October – December (2012), © IAEME The instant compensator is switched ON the current becomes sinusoidal i.e., free from harmonics and the power factor becomes unity. The improvement in the power factor from 0.7 to unity means that the filter supplies the required reactive power for the operation of induction generators in the wind farm. The performance of the proposed shunt compensator is much better in terms of THD and DPF. 5. CONCLUSION The role of shunt compensator for harmonic minimization and reactive power support for the wind farm is presented in this paper. The proposed compensator is found satisfactory for harmonics mitigation meeting the IEEE-519 standards. The average power transferred to load is increased. The mitigation of harmonics reduces the unnecessary heating and increase the life span of induction generators used in wind farm. Compensator is able to provide reactive power for the operation of induction generators in the wind farm, thus reducing the burden on the grid. The simulation results show that the Shunt Compensator can be used for satisfactory integration of wind farm to the distribution system. REFERENCES [1] Xia Chen, Haishun Sun, Jinyu Wen, Wei-Jen Lee, Xufeng Yuan, Naihu Li, “Integrating Wind Farm to the grid using Hybrid Multiterminal HVDC Technology”, IEEE Transactions on Industry applications, Vol. 47, No. 2, March/April, 2011. [2] REN21: Renewables (2012) Global status Report. [3] “Annual market update 2011”, Global Wind Energy Council (GWEC), March, 2012. [4] Mohan N, Undeland T and Robbins W. P., “Power Electronics – Converters, Applications and Design”, John Wiley and sons, 2003. [5] Juo, H. L., Wu, J. C., Chang, Y. J., and Feng, Y. T., “A novel active power filter for harmonic suppression”, IEEE Trans. Power Delivery, Vol. 20, No. 2, pp. 1507 – 1513, April, 2005. [6] Juo, H. L., Wu, J. C., Chang, Y. J., Feng, Y. T., and Hsu, W. P., “New active power filter and control method”, IEE Proc. Elect. Power Appl., Vol. 152, No. 2, pp. 175 – 181, March, 2006. [7] Cristian Lascu, Lucian Asiminoaei, Ion Boldea and Frede Blaabjerg, “High Performance Current Controller for selective Harmonic Compensation in Active Power Filters”, IEEE Trans. on Power Electronics, Vol. 22, No. 5, pp. 1826-1835, September, 2007. [8] J. Arillaga, D. A. Bradley and P. S. Bodger, “Power System Harmonics”, 1st Edition, Wiley, New York, 1985. [9] An Luo, Zhikang Shuai, Wenji Zu, Ruixiang Fan and Chunming Tu, “Development of hybrid active power filter based on the adaptive fuzzy dividing frequency-control method”, IEEE Trans. on Power Delivery, Vol. 24, No. 1, January, 2009. [10] J. C. Das, “Passive Filters-Potentialities and Limitations”, IEEE Trans. on Industry Applications, Vol. 40, No. 1, pp. 232-241, Jan./Feb., 2004. [11] Jiang Zeng, Chang Yu, Qingru Qi, Zheng Yan, Yixin Ni, B. L. Zhang, Shousun Chen, Felix F. Wu, “A novel hysterisis current control for active power filter with constant frequency”, Electric Power System Research, Vol. 68, pp. 75 – 82, 2004. [12] GYU-HA CHOE and MIN-HO PARK, “A New Injection method for AC Harmonic Elimination by Active Power Filter”, IEEE Trans. on Industrial Electronics, Vol. 35, No. 1, pp. 141-147, February, 1988. [13] Ambrish Chandra, Bhim Singh, B. N. Singh and Kamal Al-Haddad, “An Improved Control Algorithm of Shunt Active Filter for Voltage Regulation, Harmonic Elimination, Power-Factor Correction and Balancing of Nonlinear Loads”, IEEE Trans. on Power Electronics, Vol. 15, No. 3, pp. 495-507, May, 2000. [14] El-Habrouk .M, Darwish M. K. and Mehta .P, “Active Power Filters: A review”, IEE Proc. Electr. Power Appl., Vol. 147, No. 5, pp. 403 – 413, September, 2000. 100 International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 3, Issue 3, October – December (2012), © IAEME [15] C. N. Bhende, S. Mishra and S. K. Jain, “TS-Fuzzy-Controlled Active Power Filter for Load Compensation”, IEEE Trans. on Power Delivery, vol. 21, No. 3, pp. 1459-1465, July, 2006. [16] Nitin Gupta, Singh S. P. and Dubey S. P., “Fuzzy logic controlled shunt active power filter for reactive power compensation and harmonic elimination”, IEEE Int. Conference on Computer and Communication Technology (ICCCT), pp. 82 – 87, September, 2011. [17] Jhy-Shing Roger Jang, “ANFIS: Adaptive-Network-Based Fuzzy Inference System”, IEEE Trans. on Systems, Man and Cybernetics, Vol. 23, No. 3, pp. 665-685, May/June, 1993. [18] Ying H, “Fuzzy control and modeling: Analytical foundations and Applications, IEEE Press, 2000. [19] Vazquez J.R. and Salmeron P, “Active power filter control using neural network technologies”, IEE Proc. Electr. Power Appl., Vol. 150, No. 2, pp. 139 – 145, March, 2003. [20] Rukonuzzaman M and Nakaoka M, “An advanced active power filter with adaptive neural network based harmonic detection scheme”, IEEE Conference on Power Electronics Specialists Conference (PESC), Vol. 3, pp. 1602 – 1607, 2001. [21] Nitin Gupta, Singh S. P. and Dubey S. P., “Neural network based shunt active filter for harmonic and reactive power compensation under non-ideal mains voltage”, IEEE International Conference on Industrial electronics and applications (ICIEA), pp. 370 – 375, June, 2010. [22] “IEEE Recommended Practices and Requirements for Harmonic Control in Electrical Power Systems”, ANSI/IEEE Std. 519 – 1992, New York, 1993. AUTHORS PROFILE T. Nageswara Prasad is a Research Scholar at Sri Venkateswara University College of Engineering, Department of Electrical & Electronics Engineering, Tirupati, Andhra Pradesh, India. He obtained B.Tech. from Vellore Institute of Technology, Vellore and M.Tech. from JNTUCE, Anantapur. His area of interest is Power Quality, Power System Operation & Control, Microprocessors, Machines etc.,. He has more than a decade of teaching experience in engineering college. He is a Life member of ISTE. V. Chandra Jagan Mohan obtained B.Tech. degree from RMK Engineering College, Chennai and M.Tech. degree from Sree Vidyanikethan Engineering College, Tirupati. He is presently working as Assistant Professor, Department of EEE, Vaishnavi Institute of Technology, Tirupati, Andhra Pradesh, India. His areas of interest include Power Quality, Power System Operation & Control. Dr. V. C. Veera Reddy obtained his ME & Ph.D. degrees from Sri Venkateswara University, Tirupati, Andhra Pradesh, India in 1981 & 1999. He is presently working as Professor and Head, Department of EEE, S.V.U College of Engineering. He pursued research in the area of Power Systems. He has 31 years of teaching experience. He is a life member of CSE, IETE, and former member of IEEE. He has published 47 papers in the area of Power Systems in various journals. 101