Performance comparison of PI & ANN based STATCOM for 132 KV transmission line

ABSTRACT:

This paper presents simulation model of the 132KV transmission line with comparison of ANN based STATCOM and conventional PI based STATCOM. The STATCOM being the state-of-the-art VSC based dynamic shunt compensator in FACTS family is used now a days in transmission system for reactive power control, increase of power transfer capacity, voltage regulation etc. Such type of controller is applied at the middle of the transmission line to enhance the power transmission capacity of the line. The simulation result shows that the STATCOM is effective improve the power factor and voltage regulation for the 132kV line loading.

KEYWORDS:

1.      STATCOM

2.       PI

3.      ANN control strategy

4.      MatLab simulink

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig 1: Schematic Representation of the Control Circuit.

EXPECTED SIMULATION RESULTS:

Fig 2 1-phase current and voltage waveform using STATCOM

Fig3 Phase Current and Voltage waveform when the STATCOM is ON

Fig 4Phase Current and Voltage waveform when Load is Varied in the system

Fig 5 Phase Current and Voltage waveform when suddenly a Load is remove from the system at 0.4sec

Fig 6 3-phase current and voltage waveform using STATCOM

Fig 7 Active and Reactive power flow in Transmission system using STATCOM

Fig8 1-phase current and voltage waveform for STATCOM using ANN

Fig 9 Phase Current and Voltage waveform when the STATCOM is ON

Fig 10 1 Phase Current and Voltage waveform when Load is Varied in the System

Fig11 3-phase voltage and current waveform for STATCOM using ANN

CONCLUSION:

The paper present that the STATCOM bring the power factor to the unity thereby enhancing the power transfer capability by supplying or absorbing controllable amount of reactive power. By using a STATCOM with ANN controller and the Response time is faster comparing to the PI Controller because of this voltage regulation maintained within a limit. More over ANN Controlled STATCOM will improve the stability of the system and improve the dynamic performance of the system.

REFERENCES:

[1] B.Sing ,R.saha, A.Chandra “Static Synchronous Compensator (STATCOM): a review” IET Power Electronic 2008

[2] N.G Hingroni and I Gyugyi. “Understanding FACTS: Concepts and Technology of flexible AC Transmission System”, IEEE Press, New York, 2000.

[3] D.J Hanson, M.L.Woodhouse, C.Horwill “STATCOM: a new era of Reactive Compensation” Power Engineering Journal June 2002

[4] Mustapha Benghanem — Azeddine Draou” A NEW MODELLING AND CONTROL ANALYSIS OF AN ADVANCED STATIC VAR COMPENSATOR USING A THREE–LEVEL (NPC) INVERTER TOPOLOGY” Journal of ELECTRICAL ENGINEERING, VOL. 57, NO. 5, 2006, 285–290

[5] Jagdish Kumar, Biswarup Das, and Pramod Agarwal “ Modeling of 11- Level Cascade Multilevel STATCOM” International Journal of Recent Trends in Engineering, Vol 2, No. 5, November 2009

An Interline Dynamic Voltage Restoring and Displacement Factor Controlling Device (IVDFC)

 ABSTRACT:

An interline dynamic voltage restorer (IDVR) is invariably employed in distribution systems to mitigate voltage sag/swell problems. An IDVR merely consists of several dynamic voltage restorers (DVRs) sharing a common dc link connecting independent feeders to secure electric power to critical loads. While one of the DVRs compensates for the local voltage sag in its feeder, the other DVRs replenish the common dc-link voltage. For normal voltage levels, the DVRs should be bypassed. Instead of bypassing the DVRs in normal conditions, this paper proposes operating the DVRs, if needed, to improve the displacement factor (DF) of one of the involved feeders. DF improvement can be achieved via active and reactive power exchange (PQ sharing) between different feeders. To successfully apply this concept, several constraints are addressed throughout the paper. Simulation and experimental results elucidate and substantiate the proposed concept.

KEYWORDS:

1.      Displacement factor improvement

2.      Interline dynamic voltage restorer (IDVR)

3.      Interline dynamic voltage restoring and displacement factor controlling (IVDFC)

4.      PQ sharing mode

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

 Fig. 1. Single line diagram of an IPFC in transmission system.

EXPECTED SIMULATION RESULTS:

Fig. 2. Per-phase PQ sharing mode simulation results: (a)–(c) for first case and (d)–(f) for the second case.

Fig. 3. Per-phase simulation results for voltage sag condition at: (a) feeder 1 and (b) feeder 2.

Fig. 4. Per-phase experimental and corresponding simulation results for DF improvement case: (a) and (b) receiving feeder; (c) and (d) sourcing feeder (time/div= 10 ms/div).

Fig. 5 Per-phase experimental results and corresponding simulation results for voltage sag case: (a) and (b) at feeder 1 and (c) and (d) at feeder 2 (time/div = 10 ms/div).

Fig. 6 Per-phase experimental results and corresponding simulation results for voltage swell case at: (a) and (b) feeder 1 and (c) and (d) at feeder 2 (time/div = 10 ms/div).

CONCLUSION

This paper proposes a new operational mode for the IDVR to improve the DF of different feeders under normal operation. In this mode, theDFof one of the feeders is improved via active and reactive power exchange (PQ sharing) between feeders through the common dc link.

The same system can also be used under abnormal conditions for voltage sag/swell mitigation. The main conclusions of this work can be summarized as follows:

1) Under PQ sharing mode, the injected voltage in any feeder does not affect its load voltage/current magnitude, however, it affects the DFs of both sourcing and receiving feeders. The DF of the sourcing feeder increases while the DF of the receiving feeder decreases.

2) When applying the proposed concept, some constraints should be satisfied to maintain the DF of both sourcing and receiving feeders within acceptable limits imposed by the utility companies. These operational constraints have been identified and considered.

3) The proposed mode is highly beneficial if the active power rating of the receiving feeder is higher than the sourcing feeder. In this case, the DF of the sourcing feeder will have a notable improvement with only a slight variation in DF of the receiving feeder.

The proposed concept has been supported with simulation and experimental results.

REFERENCES:

[1] S. A. Qureshi and N. Aslam, “Efficient power factor improvement technique and energy conservation of power system,” Int. Conf. Energy Manage. Power Del., vol. 2, pp. 749–752, Nov. 21–23, 1995.

[2] J. J. Grainger and S. H. Lee, “Optimum size and location of shunt capacitors for reduction of losses on distribution feeders,” IEEE Trans. Power App. Syst., vol. PAS-100, no. 3, pp. 1105–1118, Mar. 1981.

[3] S. M. Kannan, P. Renuga, and A. R. Grace, “Application of fuzzy logic and particle swarm optimization for reactive power compensation of radial distribution systems,” J. Electr. Syst., 6-3, vol. 6, no. 3, pp. 407–425, 2010.

[4] L. Ramesh, S. P. Chowdhury, S. Chowdhury, A. A. Natarajan, and C. T. Gaunt, “Minimization of power loss in distribution networks by different techniques,” Int. J. Electr. Power Energy Syst. Eng., vol. 3, no. 9, pp. 521–527, 2009.

[5] T. P.Wagner, A. Y. Chikhani, and R. Hackam, “Feeder reconfiguration for loss reduction: An application of distribution automation,” IEEE Trans. Power Del., vol. 6, no. 4, pp. 1922–1933, Oct. 1991.

Three-Level 48-Pulse STATCOM with Pulse Width Modulation

 ABSTRACT:

In this paper, a new control strategy of a three level 48-pulse static synchronous compensator (STATCOM) is proposed with a constant dc link voltage and pulse width modulation at fundamental frequency switching. The proposed STATCOM is realized using eight units of three-level voltage source converters (VSCs) to form a three-level 48-pulse STATCOM. The conduction angle of each three-level VSC is modulated to control the ac converter output voltage, which controls the reactive power of the STATCOM. A fuzzy logic controller is used to control the STATCOM. The dynamic performance of the STATCOM is studied for the control of the reference reactive power, the reference terminal voltage and under the switching of inductive and capacitive loads.

KEYWORDS:

1.      Fuzzy logic control (FLC)

2.      Static synchronous compensator (STATCOM)

3.      Voltage source converter (VSC)

4.      Flexible ac transmission system (FACTS)

5.      Power frequency switching (PFS)

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

Fig. 1 System configuration for simulation

 EXPECTED SIMULATION RESULTS:

Fig. 2 a Dynamic performance of STATCOM for varying the reference reactive power. b Zoomed-in waveforms of the STATCOM ac current as well the dc current during a floating, b capacitive and c inductive operations

Fig. 3 Dynamic performance of STATCOM for varying the reference terminal voltage

Fig. 4 Dynamic performance of STATCOM by switching on inductive and capacitive loads

Fig. 5 a ac terminal voltage without STATCOM on switching non-linear load. b Dynamic performance of STATCOM and ac terminal voltage by switching on switching non-linear load

Fig. 6 Dynamic performance of STATCOM by switching on large value of apparent power

Fig. 7 Dynamic performance of STATCOM under short circuit of the upper half of the dc bus capacitance

Fig. 8 Dynamic performance of STATCOM under short circuit of the complete dc bus capacitance

Fig. 9 a Variation of the dc voltage with sudden load change using a PI and an FLC. b Variation of the ac terminal voltage with sudden load change using a PI and an FLC

CONCLUSION:

A new control strategy of a three-level 48-pulse STATCOM has been proposed with a constant dc link voltage and pulse width modulation at fundamental frequency switching. Its performance has been validated using MATLAB/Simulink. Simulation results have validated the satisfactory dynamic and steady performances of the proposed STATCOM operation. The harmonic content of the STATCOM current is found well below 5 % as per IEEE 519 standard [27].

REFERENCES:

1. T. Johns, A. Ter-Gazarian, D.F. Warne, Flexible ac transmission systems (FACTS), IEE Power Energy Series, the Institute of Electrical Engineers, London, UK, 1999

2. N.G. Hingorani, L. Gyugyi, Understanding FACTS: Concepts and Technology of Flexible ac Transmission Systems (IEEE Press, 2000)

3. R.M. Mathur, R.K. Verma, Thyristor-Based FACTS Controllers for Electrical Transmission Systems (Wiley-IEEE Press, 2002)

4. K.R. Padiyar, FACTS Controllers in Power Transmission and Distribution (New Age International (P) Limited Publishers, India, 2007)

5. K.K. Sen, Introduction to FACTS Controllers: Theory, Modeling and Applications (Wiley-IEEE Press, 2009)

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

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-V_M for 6, 12 and 48 pulse STATCOM respectively.

Fig. 3: q-axis STATCOM current-i_shq 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-V_dc       

                                        


                                                                           b: Active power of loads-P_L

    

c: Reactive power-Q_stat         

                                


d: Active power-P_stat

Fig. 5: V_dc, P_L, Q_stat and P_stat 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.