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

Harmonics Reduction And Power Quality Improvement By Using DPFC

 

ABSTRACT:

The DPFC is derived from the unified power-flow controller (UPFC). The 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 concept, in which the common dc-link between the shunt and series converters are eliminated and three-phase series converter is divided to several single-phase series distributed converters through the line. According to the growth of electricity demand and the increased number of non-linear loads in power grids harmonics, voltage sag and swell are the major power quality problems. DPFC is used to mitigate the voltage deviation and improve power quality. Simulations are carried out in MATLAB/Simulink environment. The presented simulation results validate the DPFC ability to improve the power quality.

KEYWORDS:

  1. Load flow control
  2. FACTS
  3. Power Quality
  4. Harmonics
  5. Sag and Swell Mitigation
  6. Distributed Power Flow Controller
  7. Y–Δ transformer

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1. DPFC configuration

EXPECTED SIMULATION RESULTS:

 

Fig 2. three phase voltage sag waveform without DPFC

 

Fig. 3 three phase voltage sag waveform with DPFC

Fig.4 3-ϕ load current swell waveform without DPFC

Fig.5 Mitigation of 3-ϕ 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:

This paper has presented a new concept called DPFC. The DPFC emerges 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 DFACTS 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. To improve power quality in the power transmission system, the harmonics due to nonlinear loads, voltage sag and swell are mitigated. 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 improvement and power flow control.

 

REFERENCES:

[1] S.Masoud Barakati Arash Khoshkbar sadigh and Mokhtarpour.Voltage Sag and Swell Compensation with DVR Based on Asymmetrical Cascade Multicell Converter North American Power Symposium (NAPS),pp.1-7,2011.

[2] 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.

[3] Zhihui Yuan, Sjoerd W.H de Haan and Braham Frreira “DPFC control during shunt converter failure” IEEE Transaction on Power Electronics 2009.

[4] M. D. Deepak, E. B. William, S. S. Robert, K. Bill, W. G. Randal, T. B. Dale, R. I. Michael, and S. G. Ian, “A distributed static series compensator system for realizing active power flow control on existing power lines,” IEEE Trans. Power Del., vol. 22, no. 1, pp. 642–649, Jan. 2007.

[5] D. Divan and H. Johal, “Distributed facts—A new concept for realizing grid power flow control,” in Proc. IEEE 36th Power Electron. Spec. Conf. (PESC), 2005, pp. 8–14.

Designing of Multilevel DPFC to Improve Power Quality

 

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, Enhancement of power quality by using fuzzy based multilevel power flow controller (DPFC) is proposed. 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. This eventually enables the DPFC to fully control all power system parameters. It, also, increases the reliability of the device and reduces its cost simultaneously. In recent years multi level inverters are used high power and high voltage applications .Multilevel inverter output voltage produce a staircase output waveform, this waveform look like a sinusoidal waveform leads to reduction in Harmonics. Fuzzy Logic is used for optimal designing of controller parameters. Application of Fuzzy Multilevel DPFC for reduction of Total Harmonic Distortion was presented. The simulation results show the improvement of power quality using DPFC with Fuzzy logic controller.

KEYWORDS:

  1. FACTS
  2. Power Quality
  3. Multi Level Inverters
  4. Fuzzy Logic
  5. Distributed Power Flow Controller component

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig.1: The DPFC Structure.

EXPECTED SIMULATION RESULTS:

 Fig.2: 5 Level Voltage Waveform

Fig.3: Three Phase output Voltage and Current Waveform

Fig.4: Supply Voltage and Current Waveform with unity PF

Fig.5: THD without fuzzy

Fig.6: THD with fuzzy

CONCLUSION:

In this paper Fuzzy Logic Controller technique based distributed power flow controller (DPFC) with multilevel voltage source converter (VSC) is proposed. The presented DPFC control system can regulate active and reactive power flow of the transmission line. We are reducing the THD value from 24.84% to 0.41% by using this technic as shown in fig’s (12) & (13).The series converter of the DPFC employs the DFACTS concept, which uses multiple 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 are low. Also results show the valid improvement in Power Quality using Fuzzy Logic based Multilevel DPFC.

 REFERENCES:

[1] K Chandrasekaran, P A Vengkatachalam, Mohd Noh Karsiti and K S Rama Rao, “Mitigation of Power Quality Disturbances”, Journal of Theoretical and Applied Information Technology, Vol.8, No.2, pp.105- 116, 2009

[2] Priyanka Chhabra, “Study of Different Methods for Enhancing Power Quality Problems”, International Journal of Current Engineering and Technology, Vol.3, No.2, pp.403-410, 2013

[3] Bindeshwar Singh, Indresh Yadav and Dilip Kumar, “Mitigation of Power Quality Problems Using FACTS Controllers in an Integrated Power System Environment: A Comprehensive Survey”, International Journal of Computer Science and Artificial Intelligence, Vol.1, No.1, pp.1-12, 2011

[4] Ganesh Prasad Reddy and K Ramesh Reddy, “Power Quality Improvement Using Neural Network Controller Based Cascaded HBridge Multilevel Inverter Type D-STATCOM”, International Conference on Computer Communication and Informatics, 2012

[5] Lin Xu and Yang Han, “Effective Controller Design for the Cascaded Hbridge Multilevel DSTATCOM for Reactive Compensation in Distribution Utilities”, Elektrotehniski Vestnik, Vol.78, No.4, pp.229- 235, 2011

Mitigation of Voltage Sag and Swell for Power Quality Improvement Using Distributed Power Flow Controller

 

 ABSTRACT:

During the last two decades, 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.

The DPFC is derived from the unified power-flow controller (UPFC). The 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 (DFACTS) 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. Matlab/Simulink is used to create the PI and FLC and to simulate DPFC model.

 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:

This paper has presented mitigation of various power quality issues like voltage sag and swell by 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 controllers Simulation is also carried without these two controllers.

In this case study three phase fault is injected into the system near the load and 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) L. Gyugyi, C. D. Schauder, S. L. Williams, T. R. Rietman, D. R. Torgerson,and A. Edris. “The unified power flow controller: a new approach to power transmission control”. Power Delivery, IEEE Transactions on, 1995.

(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

Mitigation of Voltage and Current Variations Due To Three Phase Fault in a Single machine system Using Distributed Power Flow Controller

 

ABSTRACT:

The Power quality issues like voltage variations and current variations presented in the electrical networks are due to the consumer’s utilities. Which are non – linear in nature. These non – linear loads inject increased flow of currents and reduced voltages with distortions. These voltage and current variations cause adverse effect on the consumer utilities. To overcome this problem we are using a modern Flexible Alternating Current Transmission System controller i.e. distributed power flow controller. This controller is also similar to any other series and shunt controllers like UPFC. In the present controller i.e. in DPFC, the common Dc link capacitor presented in UPFC is eliminated and three single phase converters are used in place of three phase series converter. In this paper we have implemented DPFC for a single machine connected to a three phase load under three phase fault environment. Observed the voltage and current variation suppression in a significant way. The control circuit is formulated using shunt currents and series referral voltages. The entire system is designed and analyzed using MATLAB/SIMULINK.

KEYWORDS:

  1. UPFC
  2. DPFC
  3. Decreased Voltage
  4. Increased current
  5. Power Quality

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1. Fundamental circuit of DPFC

EXPECTED SIMULATION RESULTS:

Fig. 2. Simulation results during three phase fault condition.

Fig 3 Voltage drop mitigated during 0.1 to 0.12 sec due to DPFC system

Fig. 4. Simulation results during fault (current swell) condition.

Fig. 5. Simulation results for mitigation of current swell between 0.1 to 0.12 sec using DPFC system.

Fig. 6. Simulation results for active and reactive powers.

Fig. 7. THD of load voltage without DPFC

Fig. 8. THD of load voltage with DPFC (pi controller)

 CONCLUSION:

In this paper we implemented a new concept for controlling power quality problems by Distributed Power Flow Controller device. The proposed concept of the DPFC approach is mathematically formulated and analyzed for voltage and current variations and their mitigations for a three phase source with linear load. The experimental results of DPFC shows the effectiveness of DPFC in power quality enhancement as compared to all other FACTS devices which are used for voltage drop mitigation process.

REFERENCES:

[1] Y.-H. Song and A. Johns, ‘‘Flexible ac Transmission Systems (FACTS)’’, (IEE Power and Energy Series), vol. 30. London, U.K.: Institution of Electrical Engineers, 1999.

[2] N. G. Hingorani and L. Gyugyi, Understanding FACTS : Concepts and Technology of Flexible AC Transmission Systems. New York: IEEE Press, 2000.

[3] L. Gyugyi, C. D. Schauder, S. L.Williams, T. R. Rietman,D. R. Torgerson and A. Edris, ‘‘The unified power flow controller: Anewapproach to power transmission control,’’ IEEE Trans. Power Del., vol. 10, no. 2, pp. 1085—1097, Apr. 1995.

[4] A. A. Edris, ‘‘Proposed terms and definitions for flexible ac transmission system (facts),’’ IEEE Trans. Power Del., vol. 12, no. 4, pp. 1848—1853, Oct. 1997.

[5] K. K. Sen, ‘‘Sssc-static synchronous series compensator: Theory, modeling, and application,’’ IEEE Trans. Power Del., vol. 13, no. 1, pp. 241—246, Jan. 1998.

 

Performance of Distributed Power Flow Controller on System Behavior under Unbalance Fault Condition

 

ABSTRACT:

Recently, within the family of FACTS, the distributed power flow controller is an additional device. This paper highlights on voltage sag mitigation which is one of the burgeoning power quality issues. It deals with the working concept of distributed power flow controller for compensating unbalanced three phase line currents in the transmission system. The single phase series converters of DPFC are able to compensate active as well as reactive, negative and zero sequence unbalanced currents. In this paper the performance of the DPFC has been studied by considering line to ground fault near the load end. The MATLAB/SIMULINK results obtained shows an improved performance in voltage sag mitigation, unbalance compensation, remarkable reduction in load voltage harmonics and also enhanced power flow control.

KEYWORDS:

  1. DPFC
  2. Power flow control
  3. Reduction of load voltage harmonics
  4. Reliability improvement
  5. Voltage sag mitigation
  6. Unbalance fault condition

 SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

Fig. 1. Basic DPFC structure.

EXPECTED SIMULATION RESULTS:

 Fig. 2. Load voltage sag waveform during unbalance fault.

Fig. 3. Mitigation of load voltage sag wave form during unbalance fault with DPFC.

(a)

(b)

Fig. 4. Load voltage. (a) Signal selected for calculating THD without DPFC.

(b) THD without DPFC.

(a)

(b)

Fig. 5. Load voltage. (a) Signal selected for calculating THD with DPFC.

(b) THD with DPFC.

Fig. 6. Capacitor dc voltage in dc side of shunt converter within DPFC.

CONCLUSION:

This paper introduces the unbalance compensation and the voltage sag mitigation during unbalance fault condition by utilizing a recent additional FACTS device which is distributed power flow controller (DPFC) adopting sequence analysis technique. The DPFC is designed by employing three control loops. The simulated system has two machine systems, in presence and absence of the DPFC in the system. To examine the capability of the DPFC, an unsymmetrical L-G fault is taken into account near the load end side. In this paper simulation done verifies that the adopted control is able to give unbalance compensation and mitigation of voltage sag.

REFERENCES:

[1] N. G. Hingorani and L. Gyugyi, Understanding FACTS : Concepts And Technology of Flexible AC Transmission Systems. New York: IEEE Press, 2000.

[2] L. Gyugyi, C. D. Schauder, S. L. Williams, T. R. Rietman, D. R. Torgerson, and A. Edris, “The Unified Power Flow Controller: A New Approach to Power Transmission Control,” IEEE Trans. Power Del., vol. 10, no. 2, pp. 1085–1097, April 1995.

[3] Y. H. Song, and A. Johns, “Flexible AC Transmission Systems (FACTS),” Institution of Electrical Engineers (IEE Power and Energy Series), London, U.K:, vol. 30, 1999.

[4] K. Ramya and C. Christober Asir Rajan, “Analysis And Regulation of System Parameters Using DPFC,” IEEE International Conference on Advances in Engineering, Science And Management (ICAESM), March 2012, pp. 505-509.

[5] M. D. Deepak, E. B. William, S. S. Robert, K. Bill, W. G. Randal, T. B. Dale, R. I. Michael, and S. G. Ian, “A Distributed Static Series Compensator System For Realizing Active Power Flow Control on Existing Power Lines,” IEEE Trans. Power Del., vol. 22, pp. 642-649, Jan. 2007.

Power Quality Improvement and Mitigation Case Study Using Distributed Power Flow Controller

 

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

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

[3] 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.

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

[5] B. Singh, K. Al-Haddad, and A. Chandra, “A review of active filters for power quality improvement,” IEEE Trans. Ind. Electron. vol. 46, no. 5, pp. 960–971, 1999.

Power Quality Improvement In Transmission Systems Using DPFC

 

ABSTRACT

The flexible ac-transmission system (FACTS) family called distributed power flow controller (DPFC). The DPFC is derived from the unified power flow controller (UPFC) with 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 is to use multiple small size single phase converters instead of large size three phase series converter in the UPFC. The large number of series converters provides redundancy, thereby increasing the system reliability. As the D-FACTS converters are single phase and floating with respect to the ground, there is no high voltage isolation required between the phases. The cost of the DPFC system is lower than the UPFC. The DPFC has the same control capability as the UPFC, which comprises the adjustment of the line impedance, the transmission angle, and the bus voltage. Due to the high control capability DPFC can also be used to improve the power quality and system stability, such as low frequency power oscillation damping, voltage sag restoration or balancing asymmetry.

KEYWORDS

  1. AC–DC power conversion
  2. Load flow control
  3. Power electronics
  4. Power semiconductor devices
  5. Power system control
  6. Power-transmission control

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Figure 1.DPFC configuration

 EXPECTED SIMULATION RESULTS

Figure 2.Supply voltage during sag condition

Figure 3. Injected voltage during sag condition

Figure 4. Elimination of sag voltage

Figure 5. Supply voltage during swell

Figure 6. Injected voltage for swell

Figure 7. Elimination of swell voltage

CONCLUSION

The series converter of the DPFC employs the DFACTS concept, which uses multiple small single-phase converters instead of one large-size converter. 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. The DPFC is also used to improving power quality problems such as sag and swell. 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.

REFERENCES

[1] D. Divan and H. Johal, “Distributed facts-A new concept for realizing grid power flow control,” in IEEE 36th Power Electron. Spec. Conf. (PESC), 2005, pp. 8–14.

[2] K K. Sen, “Sssc-static synchronous series compensator: Theory, modeling, and application”,IEEE Trans. Power Del., vol. 13, no. 1, pp 241–246, Jan. 1998.

[3] L.Gyugyi, C.D. Schauder, S. L.Williams, T. R. Rietman, D. R. Torgerson, and A. Edris, “The unified power flow controller: A new approach to power transmission control”, IEEE Trans. Power Del., vol. 10, no. 2, pp. 1085– 1097, Apr. 1995.

[4] M. D. Deepak, E. B. William, S. S. Robert, K. Bill, W. G. Randal, T. B. Dale, R. I. Michael, and S. G. Ian, “A distributed static series compensator system for realizing active power flow control on existing power lines”, IEEE Trans. Power Del., vol. 22, no. 1, pp. 642–649, Jan.2007.

[5] M. Mohaddes, A. M. Gole, and S. Elez, “Steady state frequency response of statcom”, IEEE Trans. Power Del., vol. 16, no. 1, pp. 18–23, Jan. 2001.

Mitigation of Voltage Sag For Power Quality Improvement Using DPFC System

ABSTRACT

A new control scheme to improve and maintain the power quality of an electrical power system by design of distributed power flow controller. Generally, In case of modern power utilities have problems like challenges in growth of electricity in case of non-linear loads in grid connected systems. In this paper, we introduced a new FACTS method i.e. distributed power flow controller which is similar to other series-shunt controller types. This DPFC method is also used like UPFC to mitigate voltage sag and swell as a power quality issue. In DPFC, we eliminate the common dc link capacitor and instead of single three phase series converter it has three individual single phase converters. In this paper the control circuit is designed by using series referral voltages, branch currents. The evaluated values are obtained by using MATLAB/SIMULINK.

KEYWORDS

  1. DPFC
  2. Voltage Sag and Swell
  3. Power Quality

 SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

Fig 1: Basic Configuration of DPFC

EXPECTED SIMULATION RESULTS

Fig 2: Simulation results for voltage sag condition

Fig 3: Simulation results for mitigation of Voltage sag with DPFC system

 

Fig 4: Simulation results for current swell condition

Fig 5: Simulation results for mitigation of current swell with DPFC system

Fig 6: simulation results for active and reactive powers

CONCLUSION

In this paper we implemented a new concept for controlling power quality problems by Distributed Power Flow Controller device. The proposed concept of the DPFC approach is mathematically formulated and analyzed for voltage dips and their mitigations for a three phase source with linear load. The experimental results of DPFC shows the effectiveness of DPFC in power quality enhancement as compared to all other FACTS devices.

REFERENCES

[1] J. Faiz, G. H. Shahgholian, and M. Torabian, “Design and simulation of UPFC for enhancement of power quality in transmission lines,” IEEE International Conference on Power System Technology, vol. 24, no. 4, 2010.

[2] A. E. Emanuel and J. A. McNeill, “Electric power quality,” Annu. Rev. Energy Environ, 1997.

[3] I. N. R. Patne and K. L. Thakre “Factor affecting characteristics of voltage sag due to fault in the power system,” Serbian Journal of Electrical engineering. vol. 5, no.1, 2008.

[4] B. Singh, K. Al-Haddad, and A. Chandra, “A review of active filters for power quality improvement,” IEEE Trans. Ind. Electron. vol. 46, no. 5, pp. 960–971, 1999.

[5] M. A. Hannan and A. Mohamed, member IEEE, “PSCAD/EMTDC simulation of unified series-shunt compensator for power quality improvement,” IEEE Transactions on Power Delivery, vol. 20, no. 2, 2005.