Single Phase Dynamic Voltage Restorer Topology Based on Five-level Ground point Shifting Inverter

ABSTRACT

A Single Phase Dynamic Voltage Restorer (DVR) based on five-level ground point shifting multilevel inverter topology has been proposed in this paper. The proposed inverter has a floating ground point. Therefore, by shifting the ground point, it is observed that the inverter circuit gives five output voltage levels from single DC voltage source. This configuration uses less number of switches compared to the existing multilevel inverter topologies. A fast sag swell identification technique using d-q reference frame is also discussed in this paper. This proposed topology of the DVR can compensate voltage sag, swell, flicker and maintain the required voltage at the load bus. The detailed simulation study is carried out using MATLAB/Simulink to validate the result.

 KEYWORDS

  1. Voltage sag
  2. Swell
  3. Ground Point Shifting Multilevel Inverter (GPSMI)
  4. Topology
  5. DVR

 SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM


Fig. 1. General structure of the proposed DVR.

EXPECTED SIMULATION RESULTS

Fig. 2. (a) Grid terminal voltage (vt) and (b) load voltage (vl) during sag

mitigation.

Fig. 3. direct axis value of the d-q reference frame which is used to detect

sag in the system.

Fig. 4. During voltage sag (a) grid terminal voltage (vt), (b) series injected

voltage (vinj) and (c) inverter terminal voltage (vinv).

Fig. 5. FFT analysis of the series injected voltage (vinj).

Fig. 6. (a) Grid terminal voltage and (b) load voltage during Voltage flicker

 CONCLUSION

This paper proposes dynamic voltage restorer based on the ground point shifting multilevel Inverter topology (GPSMI). And explained  the operation of the multilevel inverter and the power circuit diagram. The inverter topology requires less number of switches than conventional multi-level inverter. In this inverter topology, only two switches are active at any instant of time that reduce switch conduction loss. Using this multi-level inverter, reduced the passive filter requirement in the DVR topology. Proper PWM for this proposed inverter has been explained. Instantaneous sag identification technique using d-q reference frame has also been explained. This proposed DVR can mitigate the power quality problem like sag/swell and voltage flicker.

REFERENCES

 [1] IEEE Guide for Voltage Sag Indices,” in IEEE Std 1564-2014 , vol., no., pp.1-59, June 20 2014

[2] IEEE Guide for Identifying and Improving Voltage Quality in Power Systems,” in IEEE Std 1250-2011 (Revision of IEEE Std 1250-1995) , vol., no., pp.1-70, March 31 2011

[3] A. G ho sh and G. Led w i ch, ”Structures and control of a dynamic voltage regulator (DVR),” Power Engineering Society Winter Meeting, 2001. IEEE, Columbus, OH, 2001, pp. 1027-1032 vol.3. do i: 10.1109/PE  S W.2001.917209

[4] Hui wen Li u, Bowen Z hen g and X  ion  g Z h an, ”A comparison of two types of storage less DVR with a passive shunt converter,” 2016 IEEE 8th International Power Electronics and Motion Control Conference (I P EM C-EC CE Asia), He f e i, 2016, pp. 1280-1284.

[5] P. C. Lo h, D. M. Vi lath g  a m  u  w  a , S. K. tang, H. L. Long, ”Multilevel dynamic voltage restorer”, IEEE Power Electronic Letters, vol. 2, no. 4, pp. 125-130, Dec. 2004.

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

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