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.

Digital Simulation of the Generalized Unified Power Flow Controller System with 60-Pulse GTO-Based Voltage Source Converter

 

ABSTRACT:

The Generalized Unified Power Flow Controller (GUPFC) is a Voltage Source Converter (VSC) based Flexible AC Transmission System (FACTS) controller for shunt and series compensation among the multiline transmission systems of a substation. The paper proposes a full model comprising of 60-pulse Gate Turn-Off thyristor VSC that is constructed becomes the GUPFC in digital simulation system and investigates the dynamic operation of control scheme for shunt and two series VSC for active and reactive power compensation and voltage stabilization of the electric grid network. The complete digital simulation of the shunt VSC operating as a Static Synchronous Compensator (STATCOM) controlling voltage at bus and two series VSC operating as a Static Synchronous Series Capacitor (SSSC) controlling injected voltage, while keeping injected voltage in quadrature with current within the power system is performed in the MATLAB/Simulink environment using the Power System Block set (PSB). The GUPFC, control system scheme and the electric grid network are modeled by specific electric blocks from the power system block set. The controllers for the shunt VSC and two series VSCs are presented in this paper based on the decoupled current control strategy. The performance of GUPFC scheme connected to the 500-kV grid is evaluated. The proposed GUPFC controller scheme is fully validated by digital simulation.

KEYWORDS:

60-Pulse GTO Thyristor Model VSC, UPFC, GUPFC,Active and Reactive Compensation, Voltage Stability

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

UPFC with 60-Pulse GTO-Based Voltage Source Converter

Figure 1. Three-bus system with the GUPFC at bus B5 and B2

EXPECTED SIMULATION RESULTS:

2

 Figure 2. Sixty-pulse VSC output voltage

3

Figure 3. Simulated results of the GUPFC .shunt converter operation for DC voltage with Qref = 0.3pu; 0.5 pu

4

Figure 4. Simulated results of the GUPFC series converter operation Pref=8.7pu; 10pu, Qref=-0.6pu; 0.7pu

5

Figure 5. Simulated results of the GUPFC series converter operation Pref=7.7pu; 9.0pu, Qref=-0.5pu; 0.9pu

6

Figure 6. Digital simulation results for the decoupled current controller schemes for the shunt VSC in a weak power system

 CONCLUSION:

The paper presents and proposes a novel full 60-pulse GTO voltage source converter that it constructed becomes GUPFC FACTS devices. It comprises the full 60-pulse VSC-cascade models connected to the grid network through the coupling transformer. These full descriptive digital models are validated for voltage stabilization, active and reactive compensation and dynamically power flow control using three decoupled current control strategies. The control strategies implement decoupled current control switching technique to ensure accountability, minimum oscillatory behavior, minimum inherent phase locked loop time delay as well as system instability reduced impact due to a weak interconnected ac system and ensures full dynamic regulation of the bus voltage (VB), the series voltage injected and the dc link voltage Vdc. The 60-pulse VSC generates less harmonic distortion and reduces power quality problems in comparison to other converters such as (6,12,24 and 36) pulse. In the synchronous reference frame, a complete model of a GUPFC has been presented and control circuits for the shunt and two series converters have been described. The simulated results presented confirm that the performance of the proposed GUPFC is satisfactory for active and reactive power flow control and independent shunt reactive compensation.

 REFERENCES:

[1] K. K. Sen, “SSSC-static synchronous series compensator. Theory, modeling and application”, IEEE Transactions on Power Delivery, Vol. 13, No. 1, pp. 241-246, January 1998.

[2] B. Fardanesh, B. Shperling, E. Uzunovic, and S. Zelingher, “Multi-Converter FACTS Devices: The Generalized Unified Power Flow Controller (GUPFC),” in IEEE 2000 PES Summer Meeting, Seattle, USA, July 2000.

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

[4] X. P. Zang, “Advanced Modeling of the Multicontrol Func-tional Static Synchronous Series Compensator (SSSC) in Newton Power Flow” , IEEE Transactions on Power Systems, Vol. 20, No. 4, pp. 1410-1416, November 2005,

[5] A. H. Norouzi and A. M. Sharaf, Two Control Schemes to Enhance the Dynamic Performance of the Statcom and Sssc”, IEEE Transactions on Power Delivery, Vol. 20, No. 1, pp. 435-442, January 2005.