Design and Implementation of DPFC for Power Quality Improvement and Harmonic Mitigation

ABSTRACT:

 According to growth of electricity demand and the increased number of non-linear loads in power grids, providing a high quality electrical power should be considered. In this paper, voltage sag and swell of the power quality issues are studied and distributed power flow controller (DPFC) is used to mitigate the voltage deviation and improve power quality. The DPFC is a new FACTS device, which its structure is similar to unified power flow controller (UPFC). In spite of UPFC, in DPFC the common dc-link between the shunt and series converters is eliminated and three-phase series converter is divided to several single-phase series distributed converters through the line. The case study contains a DPFC sited in a single-machine infinite bus power system including two parallel transmission lines, which simulated in MATLAB/Simulink environment. The presented simulation results validate the DPFC ability to improve the power quality.

KEYWORDS:

1.      FACTS

2.      Power Quality

3.      Sag and Swell Mitigation

4.      Distributed Power Flow Controller

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig.1. The DPFC Structure

EXPECTED SIMULATION RESULTS:

Fig.2. Three-phase load voltage sag waveform.

Fig.3. Mitigation of three-phase load voltage sag with DPFC.

Fig.4. Three-phase load current swell waveform without DPFC

Fig.5. Mitigation of three-phase load current swell with DPFC.

Fig.6. Total harmonic distortion of load voltage without DPFC.

Fig.7. Total harmonic distortion of load voltage with DPFC.

CONCLUSION:

To improve power quality in the power transmission system, there are some effective methods. In this paper, the voltage sag and swell mitigation, using a new FACTS device called distributed power flow controller (DPFC) is presented. The DPFC structure is similar to unified power flow controller (UPFC) and has a same control capability to balance the line parameters, i.e., line impedance, transmission angle, and bus voltage magnitude. However, the DPFC offers some advantages, in comparison with UPFC, such as high control capability, high reliability, and low cost. The DPFC is modeled and three control loops, i.e., central controller, series control, and shunt control are design. The system under study is a single machine infinite-bus system, with and without DPFC. To simulate the dynamic performance, a three-phase fault is considered near the load. It is shown that the DPFC gives an acceptable performance in power quality mitigation and power flow control.

REFERENCES:

[1] Ahmad Jamshidi, S. Masoud Barakati, and Mohammad Moradi Ghahderijani, “Power Quality Improvement and Mitigation Case Study Using Distributed Power Flow Controller”, IEEE 2012.

[2] S. Masoud Barakati, Arash Khoshkbar Sadigh and Ehsan Mokhtarpour, “Voltage Sag and Swell Compensation with DVR Based on Asymmetrical Cascade Multi-cell Converter”, North American Power Symposium (NAPS), pp.1 – 7, 2011.

[3] Alexander Eigels Emanuel, John A. McNeill “Electric Power Quality”. Annu. Rev. Energy Environ 1997, pp. 263- 303.

[4] I Nita R. Patne, Krishna L. Thakre “Factor Affecting Characteristics of Voltage Sag Due to Fault in the Power System” Serbian Journal of Electrical engineering. vol. 5, no.1, May2008, pp. 171-182.

[5] J. R. Enslin, “Unified approach to power quality mitigation,” in Proc. IEEE Int. Symp. Industrial Electronics (ISIE ‟98), vol. 1, 1998, pp. 8–20.

Compensation of Voltage Distribunces In SMIB System Using ANN Based DPFC Controller

ABSTRACT:

Since last decade, due to advancement in technology and increasing in the electrical loads and also due to complexity of the devices the quality of power distribution is decreases. A Power quality issue is nothing but distortions in current, voltage and frequency that affect the end user equipment or disoperation; these are main problems of power quality so compensation for these problems by DPFC is presented in this paper. The control circuits for DPFC are designed by using line currents, series reference voltages and these are controlled by conventional ANN controllers. The results are observed by MATLAB/SIMULINK model.

KEYWORDS:

1.      Power Quality

2.      Voltage Sag

3.      DPFC

4.      Voltage Swell

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

Figure 1: Schematic Diagram for DPFC

EXPECTED SIMULATION RESULTS:

Figure 2: Output Voltage during fault condition

Figure 3: Output Current during Fault Condition

Figure 4: Output voltage compensated by DPFC Controller

Figure 5: Compensated Output Current by DPFC Controller

Figure 6: Active and Reactive Power

Figure 7: THD value of system output voltage without DPFC

Figure 8: THD value of DPFC (pi controller) load Voltage

Figure 9: THD for output voltage under ANN Controller

CONCLUSION:

In this paper we implemented a concept to controlling the power quality issues i.e. DPFC. The proposed theory of this device is mathematical formulation and analysis of voltage dips and their mitigations for a three phase source with linear load. In this paper we also proposed a concept of Ann controller for better controlling action. As compared to all other facts devices the DPFC based ANN has effectively control all power quality problems and with this technique we get the THD as 3.65% and finally the simulation results are shown above.

REFERENCES:

1. Ahmad Jamshidi, S.Masoud Barakati, and M.Moradi Ghahderijani presented a paper on “Impact of Distributed Power Flow Controller to Improve Power Quality Based on Synchronous Reference Frame Method” at IACSIT International Journal of Engineering and Technology, Vol. 4, No. 5, October 2012.

2. Ahmad Jamshidi, S.Masoud Barakati, and Mohammad Moradi Ghahderijani posted a paper “Power Quality Improvement and Mitigation Case Study Using Distributed Power Flow Controller” on 978-1-4673-0158-9/12/$31.00 ©2012 IEEE.

3. Srinivasarao, Budi, G. Sreenivasan, and Swathi Sharma. "Comparison of Facts Controller for Power Quality Problems in Power System", Indian Journal of Science and Technology, 2015.

4. J.R.Enslin, “Power mitigation problems,” in Proc. IEEE Int. Symp. Industrial Electronics (ISIE ’98), vol. 1, 1998, pp. 8– 20.

5. Srinivasarao, Budi, G. Sreenivasan, and Swathi Sharma. "Mitigation of voltage sag for power quality improvement using DPFC system", 2015 International Conference on Electrical Electronics Signals Communication and Optimization (EESCO), 2015.

Mitigation of Voltage Sag and Swell in Transmission Line using DPFC with PI and Fuzzy Logic Control

ABSTRACT:

The Power Quality problems during the last two decades has been the major concern of the power companies. The operation of power systems has become complex due to growing consumption and increased number of non-linear loads because of which compensation of multiple power quality issues has become an compulsion. A new component within the flexible AC-transmission system (FACTS) family, called Distributed Power-flow controller (DPFC) is presented in this paper. DPFC is derived from the unified power-flow controller (UPFC). DPFC can be considered as a UPFC with an eliminated common dc link. The active power exchange between the shunt and series converters, which is through the common dc link in the UPFC, is now through the transmission lines at the third-harmonic frequency. The DPFC employs the distributed FACTS (D-FACTS) concept, which is to use multiple small-size single-phase converters instead of the one large-size three-phase series converter in the UPFC. Power quality issues are studied and DPFC is used to mitigate the voltage deviation and improve power quality. In this paper, the capability of DPFC is observed for the transmission line based on PI and fuzzy logic controllers (FLC). On comparing the two controllers performance, we can say that Fuzzy Logic Controller based DPFC gives better compensation than PI Controller based DPFC. Simulink models are developed with and without the controllers. The three phase fault is created near the load. Simulation results show the effectiveness between the two controllers.

KEYWORDS:

1.      Power Quality

2.      D-FACTS

3.      DPFC

4.      Voltage Sag

5.      Swell

6.      PI Controller

7.      Fuzzy Logic Controller

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig 1: The DPFC Structure

 EXPECTED SIMULATION RESULTS:

Fig 2: Voltage Sag without DPFC

Fig 3: Current Swell without DPFC

Fig 4: THD without DPFC

Fig 5: Voltage sag Compensation with DPFC using PI Controller

Fig 6: Current Swell Compensation with DPFC using PI Controller

Fig 7: THD with DPFC using PI Controller

Fig 8: Voltage Sag Compensation with DPFC using Fuzzy Logic Controller

Fig 9: Current Swell Compensation with DPFC using Fuzzy Logic Controller

Fig 10: THD with DPFC using Fuzzy Logic Controller

CONCLUSION:

In this study mitigation of power quality issues like voltage sag and swell are simulated in Matlab/Simulink environment employing a new FACTS device called Distributed Power Flow Controller(DPFC). The DPFC is emerged from the UPFC and inherits the control capability of the UPFC, which is the simultaneous adjustment of the line impedance, the transmission angle, and the bus voltage magnitude. The common dc link between the shunt and series converters, which is used for exchanging active power in the UPFC, is eliminated. This power is now transmitted through the transmission line at the third harmonic frequency. The series converter of the DPFC employs the D FACTS concept, which uses multiple small single phase converters instead of one large size converter. The reliability of the DPFC is greatly increased because of the redundancy of the series converters. The total cost of the DPFC is also much lower than the UPFC, because no high voltage isolation is required at the series converter part and the rating of the components of is low. It is proved that the shunt and series converters in the DPFC can exchange active power at the third harmonic frequency, and the series converters are able to inject controllable active and reactive power at the fundamental frequency .Also the performance of DPFC is simulated using two mechanisms i.e., with PI and Fuzzy Logic controllers.The results prove that the DPFC with Fuzzy controller gives better voltage compensation than DPFC with PI controller.

REFERENCES:

[1] Zhihui Yuan, Sjoerd W.H de Haan, Braham Frreira and Dalibor Cevoric “A FACTS Device: Distributed Power Flow Controller (DPFC)” IEEE Transaction on Power Electronics, vol.25, no.10,October 2010.

[2] Krishna Mohan Tatikonda,N.Swathi,K.Vijay Kumar"A Fuzzy Control scheme for damping of oscillations in multi machine system using UPFC" International trends for emerging trends in engineering and development on September 2012

[3] Y. H. Song and A. Johns. Flexible ac transmission systems (FACTS). Institution of Electrical Engineers, 1999.

[4] " Power quality improvement and Mitigation case study using Distributed Power Flow Controller "Ahmad Jamshidi ,S.Masoud Barakati and Mohammad Moradi Ghahderijani,IEEE Transactions on,2012

[5] N.G.Hingorani and L.Gyugyi, Understanding FACTS, Concepts and Technology of Flexible AC Transmission Systems. Piscataway, NJ: IEEE Press 2000