Power System Stability Enhancement Using Static Synchronous Series Compensator (SSSC)

ABSTRACT:  

In this study, a static synchronous series compensator (SSSC) is used to investigate the effect of this device in controlling active and reactive powers as well as damping power system oscillations in transient mode. The SSSC equipped with a source of energy in the DC link can supply or absorb the reactive and active power to or from the line. Simulations have been done in MATLAB/SIMULINK environment. Simulation results obtained for selected bus-2 in two machine power system shows the efficacy of this compensator as one of the FACTS devices member in controlling power flows, achieving the desired value for active and reactive powers, and damping oscillations appropriately.

 KEYWORDS:

  1. Static synchronous series compensator (SSSC)
  2. FACTS
  3. Two machine power system
  4. Active and reactive powers

 SOFTWARE: MATLAB/SIMULINK

 SINGLE LINE DIAGRAM:

 Figure 1. Two machines system with SSSC

EXPECTED SIMULATION RESULTS:

 Figure 2. Active power of bus-2 without the installation of SSSC

.Figure 3. Reactive power of bus-2 without the installation of SSSC

Figure 4. Current of bus-2 without the installation of SSSC

Figure 5. Voltage of bus-2 without the installation of SSSC

Figure 6. Active power of bus-2 in the presence of SSSC

Figure 7. Reactive power of bus-2 in the presence of SSSC

Fig.8.Current of Bus-2 In The Presence Of SSSC

CONCLUSION:

 It has been found that the SSSC is capable of controlling the flow of power at a desired point on the transmission line. It is also observed that the SSSC injects a fast changing voltage in series with the line irrespective of the magnitude and phase of the line current.  Based on obtained simulation results the performance of the SSSC has been examined in a simple two-machine system simply on the selected bus-2, and applications of the SSSC will be extended in future to a complex and multimachine system to investigate the problems related to the various modes of power oscillation in the power systems.

REFERENCES:

 [1] Gyugyi, L. (1989). “Solid-state control of AC power transmission.” International Symposium on Electric Energy Conversion in Power System, Capri, Italy, (paper No. T-IP.4).

[2] Sen, K.K. (1998). “SSSC-static synchronous series compensator: theory, modeling and publications.” IEEE Trans. Power Delivery. Vol. 13, No.1, January, PP. 241-246.

[3] L. Gyugyi, 1994, “Dynamic Compensation of AC Transmission Line by Solid State Synchronous Voltage Sources,” IEEE Transactions on Power Delivery, 9(22), pp. 904-911.

[4] Muhammad Harunur Rashid, “Power Electronics – Circuits, Devices, and Applications, “PRENTICE HALL, Englewood Cliffs, New  Jersey.07632, 1988.

[5] Amany E L – Zonkoly, “Optimal sizing of SSSC Controllers to minimize transmission loss and a novel model of SSSC to study transient response, “Electric power Systems research 78 (2008) 1856 – 1864.

Powеr Quality Improvement In Powеr Systеm By Using SVPWM Based Static Synchronous Sеriеs Compеnsator

ABSTRACT:  

 Power quality improvement is an important issue in power system. Flexible AC Transmission (FACTS) devices are commonly used for solving problems related to power quality and improving it. In this paper a synchronous static series compensator (SSSC) is used for control and modulation of power flow in a transmission line. The Pulse Width Modulation (PWM) and SVPWM control techniques are employed in SSSC. The active performance of SSSC is evaluated using Matlab/Simulink environment. The simulation results validate that the power quality is enhanced properly using SSSC.

 KEYWORDS:

  1. Power Quality
  2. FACTS
  3. PWM
  4. SVPWM
  5. SSSC

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

 

 Figure 1. Functional model of SSSC.

 EXPECTED SIMULATION RESULTS:

 

 Figure 2. (a) Source voltage (b) Source current without SSSC.

Figure 3. (a) Load voltage (b) Load current without SSSC.

Figure 4. (a) Source voltage (b) Source current with SSSC.

Figure 5. (a) Load voltage (b) Load current with SSSC.

Figure 6. (a) Source voltage (b) Source current with SVPWM SSSC.

Figure 7. (a) Load voltage (b) Load current with SVPWM SSSC.

Figure 8. FFT analysis of (a) Source voltage (b) Source current-without SSSC.

Figure 9. FFT analysis of (a) Load voltage (b) Load current –without SSSC.

Figure 10. FFT analysis of (a) Source voltage (b) Source current with SSSC.

Figure 11. FFT analysis of (a) Load voltage (b) Load current with SSSC.

Figure 12. FFT analysis of (a) source voltage and (b) source current using SVPWM SSSC.

Figure 13. FFT analysis of (a) Load voltage and (b) Load current using SVPWM SSSC.

 CONCLUSION:

 In this paper the problem of modulation and control of power flow in transmission line is carried out by using SSSC with PWM and SVPWM techniques. The performance of SSSC is validated using Matlab/Simulink software. Thus, simulation results and THD analysis shows that by using SVPWM based SSSC power quality gets improved more as compared to the SPWM based SSSC. Hence SVPWM technique proves better as compared to that of the SPWM technique for power quality improvement.

REFERENCES:

[1] N.G. Hingorani and L. Gyugyi, “Undеrstanding FATCS concеpts andtеchnology of flеxiblе ac transmission systеm”,Nеw York, NY: IЕЕЕ prеss, 2000.

[2] “Static Synchronous Compensator,” CIGRE, Working group 14.19, 1998.

[3] Laszlo Gyugyi, Colin D. Schaudеr, and Kalyan K. Sеn, “static synchronous sеriеs compеnsator: a solid-statе approach to thе sеriеs compеnsation of transmission linеs”, IЕЕЕ Transactions on powеr dеlivеry, Vol. 12, No. 1, January 1997.

[4] Vaishali M. Morе, V.K. Chandrakar, “Powеr systеm pеrformancеs improvеmеnt by using static synchronous sеriеs compеnsator”, intеrnational confеrеncе on Advancеs in Еlеctrical, Еlеctronics,Informantion, Communication and Bio-Informatics 978-1-4673-9745-2©2016 IЕЕЕ.

[5] M. Farhani, “Damping of subsynchronous oscillations in powеr systеm by using static synchronous sеriеs compеnsator”,IЕT Gеnr. Distrib.vol.6.Iss.6.pp.539-544,2012.

Comparative Analysis of 6, 12 and 48 Pulse T-STATCOM

2016, IEEE 

ABSTRACT: This paper presents the performance and comparative analysis of Static Synchronous Compensator (STATCOM) based on 6, 12 and 48-pulse VSC configuration. STATCOM is implemented for regulation of the voltage at the Point of Common Coupling (PCC) bus which has time-variable loads. The dq decoupled current control strategy is used for implementation of STATCOM, where modulation index M and phase angle ø are varied for achieving voltage regulation at the PCC bus. The 6, 12 and 48-pulse configurations are compared and analyzed on the basis of Total Harmonic Distortion (THD) and time response parameters such as rise time, maximum overshoot and settling time. The simulation of various configurations of STATCOM is carried out using power system block-set in MATLAB/Simulink platform.

KEYWORDS:

  1. FACTS
  2. STATCOM
  3. Decoupled current control system
  4. Voltage Sourced Converter
  5. Total Harmonic Distortion

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

 

Fig.1:Single line diagram of STATCOM.

 EXPECTED SIMULATION RESULTS:

 

 

Fig. 2: PCC bus voltage-VM for 6, 12 and 48 pulse STATCOM respectively.

Fig. 3: q-axis STATCOM current-ishq for PI controller of 6, 12 and 48 pulse STATCOM respectively.

Fig. 4: d-axis STATCOM current-ishd for PI controller of 6, 12 and 48 pulse STATCOM respectively.

a: Dc capacitor voltage-Vdc

b: Active power of loads-PL

c: Reactive power-Qstat

                                d: Active power-Pstat

Fig. 5: Vdc, PL, Qstat and Pstat for 48 pulse STATCOM respectively.

CONCLUSION:

In this paper, for voltage regulation and dynamic power flow control a 48-pulse ±100 MVA two-level GTO STATCOM has been modeled and simulated using decoupled current control strategy. By varying the modulation index (M) and phase angle (ɸ) between PCC bus voltage and STATCOM voltage, voltage regulation at the PCC bus is achieved. The THD and various time response parameters of 6, 12 and 48 pulse STATCOM are compared. The results show that THD of output voltage of 48 pulse STATCOM is less than 5%, which satisfies the IEEE 519 standard. Hence, there is no need of active filter. Also, 48 pulse STATCOM has better transient response as compared to 6, 12 pulse STATCOM.

REFERENCES:

[1] K. Padiyar, FACTS controllers in power transmission and distribution. New Age International, 2007.

[2] K. K. Sen and M. L. Sen, Introduction to FACTS controllers: theory, modeling, and applications. John Wiley & Sons, 2009, vol. 54.

[3] A. Edris, “Facts technology development: an update,” IEEE Power engineering review, vol. 20, no. 3, pp. 4–9, 2000.

[4] El-Moursi and A.M. Sharaf, “Novel controllers for the 48-pulse vscstatcom and ssscfor voltage regulation and reactive power compensation,” IEEE Transactions on Powersystems, vol. 20, no. 4, pp. 1985–1997, 2005.

[5] N. G. Hingorani and L. Gyugyi, Understanding FACTS: concepts and technology of flexible AC transmission systems. Wiley-IEEE press, 2000.

Final year projects in hyderabad,academic projects..

Final year projects

Final year projects In this post, we are listing out some good Final Year EEE Projects ideas as many people are searching for this kind of post on internet for many days. So, here we have included various projects in different categories like  electrical,FACTs by SVC (flexible ac transmission) , solar, matlab,FACTs (flexible ac transmission) by TSR ,UPFC Unified Power Factor Control etc. I hope these eee projects for final year students would be more helpful for many engineering students in completing their B.Tech successfully.

final year projects

Nonlinear Control of Single-PhasePWM Rectifiers With InherentCurrent-Limiting Capability

Impact of SFCL on the Four Types of HVDC Circuit Breakers by Simulation

An Adaptive SPWM Technique for Cascaded Multilevel Converters with Time-Variant DC Sources

Model-Based Control for a Three-Phase ShuntActive Power Filter

Design of a multi-level inverter with reactive power control ability for connecting PV cells to the grid

DSTATCOM supported induction generator for improving power quality

Improved equal current approach for reference current generation in shunt applications underunbalanced and distorted source and load conditions

A Hybrid-STATCOM With Wide Compensation Range and Low DC-Link Voltage

Design of External Inductor for Improving Performance of Voltage-Controlled DSTATCOM

Full-Bridge Reactive Power Compensator With Minimized-Equipped Capacitor and Its Application to Static Var Compensator

A New Cascaded Switched-Capacitor Multilevel Inverter Based on Improved Series–Parallel Conversion With Less Number of Components

Efficient Implicit Model Predictive Control of Three Phase Inverter with an Output LC Filter

Single-stage Three-phase Differential-mode Buck-Boost Inverters with Continuous Input Current for PV Applications

Soft-start control strategy for the three phase grid-connected inverter with LCL filter

High-Gain Single-Stage Boosting Inverter For Photovoltaic Applications

Multilevel Inverter Topologies With Reduced Device Count: A Review

Cascaded Control of Multilevel Converter based STATCOM for Power System Compensation of Load Variation

ABSTRACT:

The static synchronous compensator (STATCOM) is used in power system network for improving the voltage of a particular bus and compensate the reactive power.It can be connected to particular bus as compensating device to improve the voltage profile and reactive power compensation. In this paper, a multi function controller is proposed and discussed. The control concept is based on a linearization of the d-q components with cascaded controller methods. The fundamental parameters are controlled with using of proportional and integral controller. In closed loop method seven level cascaded multilevel converter (CMC) is proposed to ensure the stable operation for damping of power system oscillations and load variation.

KEYWORDS:

  1. FACTS
  2. PWM
  3. CMC
  4. STATCOM

 SOFTWARE: MATLAB/SIMULINK

TEST SYSTEM:

 Figure 1.STATCOM network connection.

 EXPECTED SIMULATION RESULTS:

Figure 2. Load terminal dq0 Currents with Load variation

Figure 3. Source terminal dq0 Currents with Load variation.

Figure 4. Iqref output for load rejection.

Figure 5. Source Voltage for load rejection with AGC.

Figure 6. THD of output Voltage of Cascaded Multilevel converter.

Figure 7. THD of output Current of Cascaded Multilevel Converter

Figure 8.Source Active and Reactive power.

Figure 9. Power factor in Load and Source Bus

Figure 10.Three phase Supply Voltage of multilevel converter.

 CONCLUSION:

The cascaded controller is designed for seven level CMC based STATCOM. This control scheme regulates the capacitor voltage of the STATCOM and maintain rated supply voltage for any load variation with in the rated value. It has been shown that the CMC is able to reduce the THD values of output voltage and current effectively. The CMC based STATCOM ensures that compensate the reactive power and reduce the harmonics in output of STATCOM.

 REFERENCES:

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

[2] P. Lehn and M. Iravani, Oct.1998, “Experimental evaluation of STATCOM closed loop dynamics”, IEEE Trans. Power Delivery, vol.13, pp.1378-1384.

[3] Mahesh K.Mishra and Arindam Ghosh, Jan 2003, ”Operation of a D-STATCOM in Voltage Control Mode”, IEEE Trans. Power Delivery, vol.18, pp.258-264.

[4] Arindam Ghosh, Avinash Joshi, Jan 2000, ”A New Approach to Load Balancing and Power Factor Correction in Power Distribution System”, IEEE Trans. Power Delivery, vol.15, No.1, pp. 417-422.

[5] Arindam Ghosh, Gerard Ledwich, Oct 2003,”Load Compensating DSTATCOM in Weak AC Systems”, IEEE Trans. Power Delivery, vol.18, No.4, pp.1302-1309.

 

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

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.

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.

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