Power quality improvement in distribution network using DSTATCOM with battery energy storage system

ABSTRACT

The distribution static compensator (DSTATCOM) provides fast control of active and reactive powers to enable load compensation, harmonics current elimination, voltage flicker mitigation, voltage and frequency regulation. This paper presents power quality improvement technique in the presence of grid disturbances and wind energy penetration using DSTATCOM with battery energy storage system. DSTATCOM control is provided based on synchronous reference frame theory. A modified IEEE 13 bus test feeder with DSTATCOM and wind generator is used for the study. Power quality events during grid disturbances such as feeder tripping and re-closing, voltage sag, swell and load switching have been studied in association with DSTATCOM. The power quality disturbances due to wind generator outage, synchronization and wind speed variations have also been investigated. The study has been carried out using MATLAB/SIMULINK and the simulation results are compared with real time results obtained by the use of real time digital simulator (RTDS) for validating the effectiveness of proposed methodology. The proposed method has been proved to be effective in improvement of power quality with all disturbances stated above.

 

KEYWORDS

  1. Battery energy storage system
  2. Radial distribution feeder
  3. DSTATCOM
  4. Synchronous reference frame theory

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig.1. Proposed DSTATCOM with BESS.

 

SIMULATION RESULTS

Fig.2. Feeder tripping and re-closing without DSTATCOM in the network (a) RMS voltage at bus 632, (b) active power flow and (c) reactive power flow

Fig.3. Feeder tripping and re-closing with DSTATCOM in the network (a) RMS voltage at bus 632, (b) active power flow and (c) reactive power flow

Fig.4. Load switching without DSTATCOM in the network (a) RMS voltage at bus 632, (b) active power flow and (c) reactive power flow

Fig.5. Load switching with DSTATCOM in the network (a) RMS voltage at bus 632, (b) active power flow and (c) reactive power flow.

Fig.6. Voltage sag and swell (a) without DSTATCOM, (b) with DSTATCOM and (c) reactive power flow during voltage sag and swell.

Fig. 7 Wind synchronization (a) voltage without DSTATCOM, (b) voltage with DSTATCOM, (c) active power flow with DSTATCOM and (d) reactive power flow with DSTATCOM.

Fig. 8. Wind outage (a) voltage without DSTATCOM, (b) voltage with DSTATCOM, (c) active power flow with DSTATCOM and (d) reactive power flow with DSTATCOM

Fig. 9. Wind speed variation.

 

CONCLUSION

The proposed research work investigates into PQ events associated with distribution network due to grid disturbances such as voltage sag, swell, load switching, feeder tripping and re-closing. The DSTATCOM has been proposed to improve the power quality in the above events. The proposed DSTATCOM with SRF based control has been proved to be effective in improving the power quality in these events at grid level. The power quality events associated with wind operations such as wind generator outage, grid synchronization of wind generator and wind speed variations have been improved by the use of proposed DSTATCOM in the distribution network. From, these studies it has been established that the DSTATCOM can effectively be used to improve the power quality in the distribution network with wind generation and during grid disturbances. The results have been validated in real time utilizing RTDS. The real time results are very close to the simulation results which shows the effectiveness of proposed DSTATCOM with BESS for improvement of PQ in the distribution system.

 

REFERENCES

  • Ibrahim W, Morcos M. A power quality perspective to system operational diagnosis using fuzzy logic and adaptive techniques. IEEE Trans Power Deliv 2003;18(3):903–9. http://dx.doi.org/10.1109/TPWRD.2003.813885.
  • Ray P, Mohanty S, Kishor N. Classification of power quality disturbances due to environmental characteristics in distributed generation system. IEEE TransSust Energy 2013;4(2):302–13. http://dx.doi.org/10.1109/TSTE.2012.2224678.
  • Tascikaraoglu A, Uzunoglu M, Vural B, Erdinc O. Power quality assessment of wind turbines and comparison with conventional legal regulations: a case study in turkey. Appl Energy 2011;88(5):1864–72. http://dx.doi.org/10.1016/j. apenergy.2010.12.001.
  • Dash P, Padhee M, Barik S. Estimation of power quality indices in distributed generation systems during power islanding conditions. Int J Electr Power Energy Syst 2012;36(1):18–30. http://dx.doi.org/10.1016/j.ijepes.2011.10.019.
  • Mahela OP, Shaik AG, Gupta N. A critical review of detection and classification of power quality events. Renew Sust Energy Rev 2015;41(0):495–505. http:// dx.doi.org/10.1016/j.rser.2014.08.070.

final year eee in ieee electrical projects in mancherial

final year eee in ieee electrical projects in mancherial. 
Software Used: Matlab/Simulink
Areas : Power Electronics and Drives, Power Systems, Renewable Energy and sources, etc
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ELECTRICAL ENGINEERING is a field of engineering that generally deals with the study and application of electricity, electronics, and electro magnetism. This field first became an identifiable occupation in the later half of the 19th century after commercialization of the electric telegraph, the telephone, and electric power distribution and use. Subsequently, broad casting and recording media made electronics part of daily life. The invention of the transistor, and later the integrated circuit, brought down the cost of electronics to the point they can be used in almost any household object.
Electrical engineering has now subdivided into a wide range of sub fields including electronics, digital computers, power engineering, tele communications, control systems, radio-frequency engineering, signal processing, instrumentation, and microelectronics. Many of these sub disciplines overlap and also overlap with other engineering branches, spanning a huge number of specializations such as hardware engineering, power electronics, electro magnetics & waves, microwave engineering, nanotechnology, electro chemistry, renewable energies, mechatronics, electrical materials science, and many more.

Design and Performance Analysis of Three-Phase Solar PV Integrated UPQC

2016 IEEE

ABSTRACT: In this paper, the design and performance of a threephase solar PV (photovoltaic) integrated UPQC (PV-UPQC) are presented. The proposed system combines both the benefits of distributed generation and active power filtering. The shunt compensator of the PV-UPQC compensates for the load current harmonics and reactive power. The shunt compensator is also extracting maximum power from solar PV array by operating it at its maximum power point (MPP). The series compensator compensates for the grid side power quality problems such as grid voltage sags/swells by injecting appropriate voltage in phase with the grid voltage. The dynamic performance of the proposed system is simulated in Matlab-Simulink under a nonlinear load consisting of a bridge rectifier with voltage-fed load.

KEYWORDS:

  1. Power Quality
  2. DSTATCOM
  3. DVR
  4. UPQC
  5. Solar PV
  6. MPPT

SOFTWARE: MATLAB/SIMULINK

 CIRCUIT DIAGRAM:

Fig. 1. System Configuration PV-UPQC

EXPECTED SIMULATION RESULTS:

 Fig. 2. Performance PV-UPQC at steady state condition

Fig. 3. PCC Voltage Harmonic Spectrum and THD

Fig. 4. Load Voltage Harmonic Spectrum and THD

Fig. 5. Load Current Harmonic Spectrum and THD

Fig. 6. Grid Current Harmonic Spectrum and THD

Fig. 7. Performance PV-UPQC at varying irradiation condition

Fig. 8. Performance of PV-UPQC under voltage sag and swell conditions

CONCLUSION:

The dynamic performance of three-phase PV-UPQC has been analyzed under conditions of variable irradiation and grid voltage sags/swells. It is observed that PV-UPQC mitigates the harmonics caused by nonlinear and maintains the THD of grid voltage, load voltage and grid current under limits of IEEE-519 standard. The system is found to be stable under variation of irradiation from 1000𝑊/𝑚2 to 600𝑊/𝑚2. It can be seen that PV-UPQC is a good solution for modern distribution system by integrating distributed generation with power quality improvement.

REFERENCES:

[1] Y. Yang, P. Enjeti, F. Blaabjerg, and H. Wang, “Wide-scale adoption of photovoltaic energy: Grid code modifications are explored in the distribution grid,” IEEE Ind. Appl. Mag., vol. 21, no. 5, pp. 21–31, Sept 2015.

[2] B. Singh, A. Chandra and K. A. Haddad, Power Quality: Problems and Mitigation Techniques. London: Wiley, 2015.

[3] M. Bollen and I. Guo, Signal Processing of Power Quality Disturbances. Hoboken: Johm Wiley, 2006.

[4] P. Jayaprakash, B. Singh, D. Kothari, A. Chandra, and K. Al-Haddad, “Control of reduced-rating dynamic voltage restorer with a battery energy storage system,” IEEE Trans. Ind. Appl., vol. 50, no. 2, pp. 1295– 1303, March 2014.

[5] M. Badoni, A. Singh, and B. Singh, “Variable forgetting factor recursive least square control algorithm for DSTATCOM,” IEEE Trans. Power Del., vol. 30, no. 5, pp. 2353–2361, Oct 2015.

A Voltage Regulator for Power Quality Improvement in Low-Voltage Distribution Grids

ABSTRACT:

This paper presents a voltage-controlled DSTATCOM-based voltage regulator for low voltage distribution grids. The voltage regulator is designed to temporarily meet the grid code, postponing unplanned investments while a definitive solution could be planned to solve regulation issues. The power stage is composed of a three-phase four-wire Voltage Source Inverter (VSI) and a second order low-pass filter. The control strategy has three output voltage loops with active damping and two dc bus voltage loops. In addition, two loops are included to the proposed control strategy: the concept of Minimum Power Point Tracking (mPPT) and the frequency loop. The mPPT allows the voltage regulator to operate at the Minimum Power Point (mPP), avoiding the circulation of unnecessary reactive compensation. The frequency loop allows the voltage regulator to be independent of the grid voltage information, especially the grid angle, using only the information available at the Point of Common Coupling (PCC). Experimental results show the regulation capacity, the features of the mPPT algorithm for linear and nonlinear loads and the frequency stability.

KEYWORDS:

  1. DSTATCOM, Frequency Compensation
  2. Minimum Power Point Tracker
  3. Power Quality
  4. Static VAR Compensators
  5. Voltage Control
  6. Voltage Regulation

 SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1. Low voltage distribution grid under analysis with the voltage regulator

EXPECTED SIMULATION RESULTS:

Fig. 2. Dc bus voltages during the DSTATCOM initialization

Fig. 3. PCC voltages without compensation for linear loads

Fig. 4. PCC voltages with compensation for linear loads

Fig. 5. Voltage regulator currents for linear loads

Fig. 6. Grid, load and voltage regulator currents for linear loads

Fig. 7. PCC voltages without compensation for nonlinear loads

Fig. 8. PCC voltages with compensation for nonlinear loads

Fig. 9. Voltage regulator currents for nonlinear loads

Fig. 10. Grid, load and voltage regulator currents for nonlinear loads

Fig. 11. PCC rms value with linear loads

Fig. 12. Processed apparent power with linear loads

Fig. 13. Voltage regulator currents with mPPT enabled for linear loads

Fig. 14. PCC rms value with nonlinear loads

Fig. 15. Processed apparent power with nonlinear loads

Fig. 16. Voltage regulator currents with mPPT enabled for nonlinear loads

Fig. 17. Total dc bus voltage, PCC voltage, grid voltage and voltage regulator current waveforms of a-phase with mPPT enabled with grid swell

Fig. 18. (a) Total dc bus voltage, PCC voltage, grid voltage and voltage regulator current waveforms of a-phase and (b) detail of total dc bus voltage performance with mPPT enabled with grid sag

CONCLUSION:

This paper presents a three phase DSTATCOM as a voltage regulator and its control strategy, composed of the conventional loops, output voltage and dc bus regulation loops, including the voltage amplitude and the frequency loops. Experimental results demonstrate the voltage regulation capability, supplying three balanced voltages at the PCC, even under nonlinear loads.

The proposed amplitude loop was able to reduce the voltage regulator processed apparent power about 51 % with nonlinear load and even more with linear load (80%). The mPPT algorithm tracked the minimum power point within the allowable voltage range when reactive power compensation is not necessary. With grid voltage sag and swell, the amplitude loop meets the grid code. The mPPT can also be implemented in current-controlled DSTATCOMs, achieving similar results. The frequency loop kept the compensation angle within the analog limits, increasing the autonomy of the voltage regulator, and the dc bus voltage regulated at nominal value, thus minimizing the dc bus voltage steady state error. Simultaneous operation of the mPPT and the frequency loop was verified. The proposed voltage regulator is a shunt connected solution, which is tied to low voltage distribution grids without any power interruption to the loads, without any grid voltage and impedance information, and provides balanced and low-THD voltages to the customers.

REFERENCES:

[1] D. O. Koval and C. Carter, “Power quality characteristics of computer loads,” IEEE Trans. on Industry Applications, vol. 33, no. 3, pp. 613- 621, May/June1997.

[2] Abraham I. Pressman, Keith Billings and Taylor Morey, “Switching Power Supply Design,” 3rd ed., McGraw Hill, New York, 2009.

[3] B. Singh, B.N. Singh, A. Chandra, K. Al-Haddad, A. Pandey and D.P. Kothari, “A review of single-phase improved power quality AC-DC converters” IEEE Trans. on Industrial Electronics, vol.50, no.5, pp.962- 981, Oct. 2003.

[4] K. Mino, H. Matsumoto, Y. Nemoto, S. Fujita, D. Kawasaki, Ryuji Yamada, and N. Tawada, “A front-end converter with high reliability and high efficiency,” in IEEE Conf. on Energy Conversion Congress and Exposition (ECCE),2010, pp. 3216-3223.

[5] Jih-Sheng Lai, D. Hurst and T. Key, Switch-mode supply power factor improvement via harmonic elimination methods,” in 6th Annual IEEE Proc. on Applied Power Electronics Conference and Exposition, APEC’91, 1991, pp. 415-422.

 

 

Voltage Sag and Swell Mitigation Using DSTATCOM in Renewable Energy Based Distributed Generation Systems

Voltage Sag and Swell Mitigation Using DSTATCOM

in Renewable Energy Based Distributed Generation Systems

ABSTRACT:

Renewable distributed generation systems are an alternative solution to provide energy locally near customers. However, the supplying of power without disturbance is the main challenge for utilities, especially for systems that integrate fluctuating renewable sources which can cause voltage sag and swell. In this paper, voltage sag and swell issues are investigated. The first studied scenario is related to the disturbance of the energy source and the second one is due to the installation of a heavy load with a sensitive load at the same supplying bus. A D-STATCOM is connected at the point of common coupling (pCC) to mitigate the voltage sag and sell problems. An energy storage battery has been installed at the DC-side of the compensator that gives the possibility to control the voltage at the PCC and exchange the active and reactive power with the grid. A linear proportional integral (PI) feed-forward controller supervises the compensator. The obtained results show that the D-STATCOM compensator behaves as a good solution to mitigate the voltage sag and swell in distribution grid.

 

KEYWORDS:

  1. Voltage sag, Voltage swell
  2. DSTATCOM
  3. Distributed generation
  4. FACTS
  5. Feed forward control
  6. Power quality.

 

SOFTWARE: MATLAB/SIMULINK

 

BLOCK DIAGRAM:

Fig. 1: Proposed power system

Proposed micro-grid schema

Fig. 2: Proposed micro-grid schema

 

EXPECTED SIMULATION RESULTS:

Grid side voltage of D-STATCOM

Fig. 3: Grid side voltage of D-STATCOM

Voltage at PCC point

Fig. 4: Voltage at PCC point

DG output voltage without D-STATCOM

Fig. 5: DG output voltage without D-STATCOM

PCC voltage with D-STATCOM

Fig. 6: PCC voltage with D-STATCOM

 Voltage at PCC

Fig. 7: Voltage at PCC

 Voltage at PCC point

Fig. 8: Voltage at PCC point

 

CONCLUSION:

Voltage sag and swell issues are important for energy suppliers, because of the awareness of customers toward the lack of power service quality and its consequences. A D-ST ACOM can be connected at the PCC in order to mitigate these issues. An energy storage battery can be installed at DC-side of the compensator to control voltage magnitude at the PCC. The performance of compensator using a feed-forward PI controller was investigated. Based on the obtained results, the compensator behaves as a good solution for the voltage sag and swell mitigation.

 

REFERENCES:

  • Lineweber and S. McNulty, ” The cost of power disturbances to industrial & digital economy companies,” EPRl, Palo Alto, Calif., 2001.
  • K. Rao, T. Ganeshkumar, and P. Puthra, “Mitigation of Voltage Sag and Voltage Swell by Using D-STATCOM and PWM Switched Autotransformer.”
  • Peterson, “Distributed renewable energy generation impacts on microgrid operation and reliability,” EPRl, Palo Alto, CA: 2002. 1004045.
  • Hatziargyriou, H. Asano, R. Iravani, and C. Marnay, “Microgrids,” Power and Energy Magazine, IEEE, vol. 5, pp. 78- 94,2007.
  • Khodaei, “Provisional Microgrids,” Smart Grid, IEEE Transactions on, vol. 6, pp. 1107 1115,2015.

Comparative Simulation Results of DVR and D-STATCOM to Improve Voltage Quality in Distributed Power System

ABSTRACT:

This paper presents the comparative improvement of the voltage profile of the distributed power system using a Dynamic Voltage Restorer (DVR) and a Distributed Static Synchronous Compensator (D-STATCOM). The IEEE benchmark 13-bus distributed power system is used to present the distributed power grid. A proposed DVR is connected in series with bus 632 while a D-STATCOM is connected in parallel with bus 632. Comparative simulation results of the system with DVR and D-STATCOM are performed by using commercial MATLAB software. It can be concluded from the simulation results that DVR is suitable to mitigate the voltage sag of the load side while D-STATCOM can enhance the voltage stability margin of the buses that are located near the connected bus of the proposed D-STATCOM in the distributed grid.

 

KEYWORDS:

  1. Distributed Power System
  2. Dynamic Voltage Restorer (DVR)
  3. Distributed Static Synchronous Compensator (D-STATCOM)
  4. Voltage Quality.

 

SOFTWARE: MATLAB/SIMULINK

 

DVR AND STATCOM MODELS:

Figure 1. Basic DVR Model

Figure 2. Basic D-ST ATCOM Model

 

EXPECTED SIMULATION RESULTS:

Voltage at bus 633 without DVRlD-STATCOM

Voltage at bus 646 with D-STATCOM

Voltage at bus 633 with D-STATCOM

Voltage at bus 684 with D-STATCOM

Voltage at bus 646 with DVR

Voltage at bus 633 with DVR

Voltage at bus 684 with DVR

Figure 3. Simulation results of the studied system when a three-phase short-circuit fault happened at bus 633.

 

CONCLUSION:

In this paper, the voltage stability improvement of an IEEE I3-bus distributed power system has been presented. A DVR and a D-STATCOM have been proposed and integrated to the studied system. Based on the results from the simulation, it can be concluded that the proposed DSTATCOM is better than DVR for improving the voltage quality of the distributed power system under a severe fault happened.

 

 REFERENCES:

  • Bollen, “Understanding Power Quality Problems – Voltage Sags and Interruptions”, IEEE Press Series on Power Engineering – John Wiley and Sons, Piscataway, USA, 2000.
  • Math H.J. Bollen, Understanding power quality problems: voltage sags and interruptions, IEEE Press, New York, 2000.
  • FACTS controllers in power transmission and distribution by K. R. Padiyar ISBN: 978-81-224-2541-3.
  • Singh, A. Adya, A. P. Mittal and J. R. P. Gupta, “Modeling, Design and Analysis of Different Controllers for DSTATCOM,” 2008 Joint International Conference on Power System Technology and IEEE Power india Conference, New Delhi, 2008, pp. 1-8.
  • Devaraju, V. C. Reddy and M. Vijaya Kumar, “Performance of DVR under different voltage sag and swell conditions”, ARPN Journal of Engineering and Applied Sciences, Vol. 5, No. 10,2010, pp. 56-64.

A Voltage Regulator for Power Quality Improvement in Low-Voltage Distribution Grids

ABSTRACT:

This paper presents a voltage-controlled DSTATCOM-based voltage regulator for low voltage distribution grids. The voltage regulator is designed to temporarily meet the grid code, postponing unplanned investments while a definitive solution could be planned to solve regulation issues. The power stage is composed of a three-phase four-wire Voltage Source Inverter (VSI) and a second order low-pass filter. The control strategy has three output voltage loops with active damping and two dc bus voltage loops. In addition, two loops are included to the proposed control strategy: the concept of Minimum Power Point Tracking (mPPT) and the frequency loop. The mPPT allows the voltage regulator to operate at the Minimum Power Point (mPP), avoiding the circulation of unnecessary reactive compensation. The frequency loop allows the voltage regulator to be independent of the grid voltage information, especially the grid angle, using only the information available at the Point of Common Coupling (PCC). Experimental results show the regulation capacity, the features of the mPPT algorithm for linear and nonlinear loads and the frequency stability.

KEYWORDS:

  1. DSTATCOM
  2. Frequency compensation
  3. Minimum power point tracker
  4. Power quality
  5.  Static VAR compensators
  6. Voltage control
  7. Voltage regulation

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

 Fig. 1. Low voltage distribution grid under analysis with the voltage regulator

 EXPECTED SIMULATION RESULTS:

 

 Fig. 2. Dc bus voltages during the DSTATCOM initialization

 

Fig. 3. PCC voltages without compensation for linear loads

Fig. 4. PCC voltages with compensation for linear loads

Fig. 5. Voltage regulator currents for linear loads

Fig. 6. Grid, load and voltage regulator currents for linear loads

Fig. 7. PCC voltages without compensation for nonlinear loads

Fig. 8. PCC voltages with compensation for nonlinear loads

Fig. 9. Voltage regulator currents for nonlinear loads

Fig. 10. Grid, load and voltage regulator currents for nonlinear loads

Fig. 11. PCC rms value with linear loads

Fig. 12. Processed apparent power with linear loads

Fig. 13. Voltage regulator currents with mPPT enabled for linear loads

Fig. 14. PCC rms value with nonlinear loads

Fig. 15. Processed apparent power with nonlinear loads

Fig. 16. Voltage regulator currents with mPPT enabled for nonlinear loads

Fig. 17. Total dc bus voltage, PCC voltage, grid voltage and voltage regulator current waveforms of a-phase with mPPT enabled with grid swell

Fig. 18. (a) Total dc bus voltage, PCC voltage, grid voltage and voltage regulator current waveforms of a-phase and (b) detail of total dc bus voltage performance with mPPT enabled with grid sag

CONCLUSION:

This paper presents a three phase DSTATCOM as a voltage regulator and its control strategy, composed of the conventional loops, output voltage and dc bus regulation loops, including the voltage amplitude and the frequency loops.

Experimental results demonstrate the voltage regulation capability, supplying three balanced voltages at the PCC, even under nonlinear loads.

The proposed amplitude loop was able to reduce the voltage regulator processed apparent power about 51 % with nonlinear load and even more with linear load (80%). The mPPT algorithm tracked the minimum power point within the allowable voltage range when reactive power compensation is not necessary. With grid voltage sag and swell, the amplitude loop meets the grid code. The mPPT can also be implemented in current-controlled DSTATCOMs, achieving similar results.

The frequency loop kept the compensation angle within the analog limits, increasing the autonomy of the voltage regulator, and the dc bus voltage regulated at nominal value, thus minimizing the dc bus voltage steady state error. Simultaneous operation of the mPPT and the frequency loop was verified.

The proposed voltage regulator is a shunt connected solution, which is tied to low voltage distribution grids without any power interruption to the loads, without any grid voltage and impedance information, and provides balanced and low-THD voltages to the customers.

REFERENCES:

[1] ANEEL National Electric Power Distribution System Procedures – PRODIST, Module 8: Energy Quality. Revision 07, 2014.

[2] M. Mishra, A. Ghosh and A. Joshi, “Operation of a DSTATCOM in voltage control mode,” IEEE Trans. Power Del., vol. 18, no. 1, pp. 258-264, Jan. 2003.

[3] G. Ledwich and A. Ghosh, “A flexible DSTATCOM operating in voltage or current control mode,” IEE Proc.-Gener., Transmiss. Distrib., vol. 149, n. 2, pp. 215-224, Mar. 2002.

[4] T. P. Enderle, G. da Silva, C. Fischer, R. C. Beltrame, L. Schuch, V. F. Montagner and C. Rech, “D-STATCOM applied to single-phase distribution networks: Modeling and control,” in Proc. IEEE Ind. Electron. Soc. Annu. Conf., Oct. 2012, pp. 321 – 326.

[5] C. Kumar and M. Mishra, “Energy conservation and power quality improvement with voltage controlled DSTATCOM,” in Proc. Annu. IEEE India Conf., Dec. 2013 pp. 1-6.

 

DSTATCOM supported induction generator for improving power quality

 

ABSTRACT

This paper presents an implementation of sliding mode controller (SMC) along with a proportional and integral (PI) controller for a DSTATCOM (Distribution STATic COMpensator) for improving current induced power quality issues and voltage regulation of three-phase self-excited induction generator (SEIG). The use of SMC for regulating the DC link voltage of DSTATCOM offers various advantages such as reduction in number of sensors for estimating reference currents and the stable DC link voltage during transient conditions. The use of PI controller for terminal voltage control gives the error free voltage regulation in steady state conditions. The voltage regulation feature of DSTATCOM offers the advantages of single point voltage operation at the generator terminals with the reactive power compensation which avoids the saturation in the generator. Other offered advantages are balanced generator currents under any loading condition, harmonic currents mitigation, stable DC link voltage and the reduced number of sensors. The SMC algorithm is successfully implemented on a DSTATCOM employed with a three-phase SEIG feeding single phase or three phase loads. The performance of the proposed control algorithm is found satisfactory for voltage regulation and mitigation of power quality problems like reactive power compensation, harmonics elimination, and load balancing under nonlinear/linear loads.

 SOFTWARE: MATLAB/SIMULINK

 SCHEMATIC DIAGRAM:

Fig. 1 Configuration of DSTATCOM supported induction generator

a Schematic diagram of induction generator supported by VSC-based DSTATCOM

CONTROL DIAGRAM:

b Control algorithm of DSTATCOM for estimation of reference currents using SMC

with PI controller

EXPECTED SIMULATION RESULTS

Fig. 2 Simulation results of DSTATCOM

a Performance of DSTATCOM under three-phase and single-phase non-linear load

b, c Harmonic content of load current ila and generator current

 CONCLUSION

A DSTATCOM supported induction generator has been implemented with the SMC with PI control algorithm for mitigating the power quality problems and it has enhanced the active power capability of the generator. The SMC has been verified for the dynamics in the DC-link voltage and found robust and acceptably fast to avoid large variations in DC-link voltage. Moreover, from the experimental results it has been inferred that the sliding mode control with PI controller algorithm has been found capable of meeting various functionalities of DSTATCOM such as voltage regulation, source currents balancing, harmonics mitigation, and reactive power compensation.

REFERENCES

1 Bansal, R.C.: ‘Three phase self-excited induction generators: an overview’, IEEE Trans. Energy Convers., 2005, 20, (2), pp. 292–299

2 Murthy, S.S., Singh, B., Gupta, S., et al.: ‘General steady-state analysis of three-phase self-excited induction generator feeding three-phase unbalanced load/ single-phase load for stand-alone applications’, IEE Proc. Gener. Transm. Distrib., 2003, 150, (1), pp. 49–55

3 Rai, H., Tandan, A., Murthy, S.S., et al.: ‘Voltage regulation of self-excited induction generator using passive elements’. Proc. IEEE Int. Conf. Electric Machines and Drives, September 1993, pp. 240–245

4 Singh, B., Shilpakar, L.: ‘Analysis of a novel solid state voltage regulator for a self-excited induction generator’, IEE Proc. Gener. Transm. Distrib., 1998, 145, (6), pp. 647–655

5 Singh, B., Murthy, S.S., Gupta, S.: ‘A solid state controller for self-excited induction generator for voltage regulation, harmonic compensation and load balancing’, J. Power Electron., 2005, 5, (2), pp. 109–119

Control of Cascaded H-Bridge Converter based DSTATCOM for High Power Applications

 

ABSTRACT

This paper presents the simulation studies on a Cascaded H-Bridge converter based Distribution Static Synchronous Compensator (DSTATCOM) for improving the power quality of a distribution system. Voltage source converter based DSTATCOM has been established as the most preferred solution for management of reactive power in distribution utilities and for improving voltage regulation, power factor and power quality in industries. For high power applications, cascaded H-Bridge converter is the most ideal choice compared to two-level inverter with series connected power devices. In the present work DSTATCOM controller is designed using DQO modelling for reactive power management and thereby improving the power factor in distribution systems. The dc link voltage and the three phase load currents are used as feedback signals for the controller and it is designed in such a way that DSTATCOM is able to supply the reactive current demanded by the load both during steady state and transient conditions using sinusoidal pulse width modulation control.

KEYWORDS

  1. Cascaded H-Bridge Converter
  2. DSTATCOM
  3. Reactive power compensation
  4. Sinusoidal PWM

 SOFTWARE: MATLAB/SIMULINK

SIMULINK BLOCK DIAGRAM:

Fig. 1. The cascade H-bridge converter based DSTATCOM.

 

EXPECTED SIMULATION RESULTS

Fig. 2. The phase voltage (top trace ) and line-to-line voltages of H-bridge cascaded inverter.

Fig. 3. Source phase voltage (top trace) and source phase Current (bottom trace) with DSTATCOM in closed loop power factor control mode.

Fig. 4. DC link voltage (Vd,) (Top or First Trace), direct and quadrature axis source currents (Second Trace) ,inverter currents Id and Iq (Third Trace) and load reactive current (Bottom Trace).

Fig 5. Individual Capacitor voltages of three level Cascaded H-Bridge Inverter.

CONCLUSION

The paper presents the principle of operation of cascaded H-bridge converter and simulation studies on cascaded converter based DSTATCOM using Sinusoidal PWM control. It is observed that the DSTATCOM is capable of supplying the reactive power demanded by the load both during steady state and transient operating conditions. The harmonics in cascaded H-bridge three-level inverter current are less compared to two-level inverter operating at same switching frequency.

REFERENCES

[1] Jih-Sheng Lal, Fang Zheng Peng,” Multilevel Converters – A New Breed of Power Converters”, IEEE Transactions on Industry Applications, Vol.32, no.3, pp.509,1996.

[2] Muni B.P., Rao S.E., Vithal J.V.R., Saxena S.N., Lakshminarayana S., Das R.L., Lal G., Arunachalam M., “DSTATCOM for Distribution Utility and Industrial Applications”, Conference Proceedings, IEEE, Region Tenth Annual Conference, TENCON-03. Page(s): 278- 282 Vol. 1

[3] Bishnu P. Muni, S.Eswar Rao, JVR Vithal and SN Saxena, “Development of Distribution STATCOM for power Distribution Network” Conference Records, International conference on “Present and Future Trends in Transmission and Convergence”, New Delhi, Dec.2002,pp. VII_26-33.

[4] F.Z. Peng, J. S. Lai, J.W. Mckeever, J. Van Coevering, “A Multilevel Voltage – Source inverter with Separate dc sources for Static Var Generation” IEEE Transactions on Industry Applications, Vol. 32, No. 5, Sep 1996, ppl 130-1138.

[5] K.Anuradha, B.P.Muni, A.D.Rajkumar,” Simulation of Cascaded HBridge Converter Based DSTATCOM” First IEEE Conference on Industrial Electronics and Applications, May 2006, pp 501-505.

Design and Simulation of Cascaded H-Bridge Multilevel Inverter Based DSTATCOM for Compensation of Reactive Power and Harmonics

ABSTRACT:

This paper presents an investigation of five-Level Cascaded H – bridge (CHB) Inverter as Distribution Static Compensator (DSTATCOM) in Power System (PS) for compensation of reactive power and harmonics. The advantages of CHB inverter are low harmonic distortion, reduced number of switches and suppression of switching losses. The DST ATCOM helps to improve the power factor and eliminate the Total Harmonics Distortion (THD) drawn from a Non-Liner Diode Rectifier Load (NLDRL). The D-Q reference frame theory is used to generate the reference compensating currents for DSTATCOM while Proportional and Integral (PI) control is used for capacitor dc voltage regulation. A CHB Inverter is considered for shunt compensation of a 11 kV distribution system. Finally a level shifted PWM (LSPWM) and phase shifted PWM (PSPWM) techniques are adopted to investigate the performance of CHB Inverter. The results are obtained through Matlab/Simulink software package.

KEYWORDS:

  1. DSTATCOM
  2. Level shifted Pulse width modulation (LSPWM)
  3. Phase shifted Pulse width modulation (PSPWM)
  4. Proportional-Integral (PI) control
  5. CRB multilevel inverter
  6. D-Q reference frame theory

SOFTWARE: MATLAB/SIMULINK

SCHEMATIC DIAGRAM:

 image001

Fig. 1 Schematic Diagram of a DST ATCOM

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Fig. 2 Block diagram of 5-level CHB inverter model

EXPECTED SIMULATION RESULTS:

 image003

Fig. 3 five level PSCPWM output

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Fig. 4 Source voltage, current and load current without DSTATCOM

 image005

Fig. 5 DC Bus Vooltage

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Fig. 6 Phase-A source voltage and current

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Fig. 7 Harmonic spectrum of Phase-A Source current without DSTATCOM

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Fig. 8 Harmonic spectrum of Phase-A Source current with DSTATCOM

 CONCLUSION:

A DSTATCOM with five level CHB inverter is investigated. Mathematical model for single H-Bridge inverter is developed which can be extended to multi H Bridge. The source voltage , load voltage , source current, load current, power factor simulation results under nonlinear loads are presented. Finally Matlab/Simulink based model is developed and simulation results are presented.

REFERENCES:

[ I ] K.A Corzine. and Y.L Familiant, “A New Cascaded Multi-level HBridge Drive:’ IEEE Trans. Power.Electron .• vol. I 7. no. I. pp. I 25-I 3 I . Jan 2002.

[2] J.S.Lai. and F.Z.Peng “Multilevel converters – A new bread of converters, “IEEE Trans. Ind.Appli .• vo1.32. no.3. pp.S09-S17. May/ Jun. 1996.

[3] T.A.Maynard. M.Fadel and N.Aouda. “Modelling of multilevel converter:’ IEEE Trans. Ind.Electron .• vo1.44. pp.3S6-364. Jun. I 997.

[4] P.Bhagwat. and V.R.Stefanovic. “Generalized structure of a multilevel PWM Inverter:’ IEEE Trans. Ind. Appln, VoI.IA-19. no.6, pp. I OS7-1069, Nov.!Dec .. 1983.

[5] J.Rodriguez. Jih-sheng Lai, and F Zheng peng, “Multilevel Inverters; A Survey of Topologies, Controls, and Applications,” IEEE Trans. Ind. Electron., vol.49 , n04., pp.724-738. Aug.2002.