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.