Modeling and Simulation of a Distribution STATCOM (D-STATCOM) for Power Quality Problems-Voltage Sag and Swell Based on Sinusoidal Pulse Width Modulation (SPWM)


This paper presents the systematic procedure of the modeling and simulation of a Distribution STATCOM (DSTATCOM) for power quality problems, voltage sag and swell based on Sinusoidal Pulse Width Modulation (SPWM) technique. Power quality is an occurrence manifested as a nonstandard voltage, current or frequency that results in a failure of end use equipments. The major problems dealt here is the voltage sag and swell. To solve this problem, custom power devices are used. One of those devices is the Distribution STATCOM (D-STATCOM), which is the most efficient and effective modern custom power device used in power distribution networks. D-STATCOM injects a current in to the system to correct the voltage sag and swell.The control of the Voltage Source Converter (VSC) is done with the help of SPWM. The proposed D-STATCOM is modeled and simulated using MATLAB/SIMULINK software.


  1. Distribution STATCOM (D-STATCOM)
  3. Power quality problems
  4. Sinusoidal Pulse  Width Modulation (SPWM)
  5. Voltage sag and swell
  6. Voltage  Source Converter (VSC)



Fig. 1. Schematic representation of the D-STATECOM for a typical custom

power application.


 Fig. 2. Voltage Vrms at load point, with three-phase fault: (a) Without DSTATCOM and (b) With D-STATCOM, 750I-lf .

Fig. 3. Voltage vrms at load point, with three phase-ground fault: (a)

Without D-STATCOM and (b) With D-STATCOM.

Fig. 4. Voltage Vrms at load point, with line-ground fault: (a) Without DSTATCOM and (b) With D-STATCOM.

Fig. 5. Voltage vrms at load point, with line-line fault: (a) Without DSTATCOM and (b) With D-STATCOM.

Fig. 6. Voltage vrms at load point, with line-line-ground fault: (a) Without



This paper has presented the power quality problems such as voltage sags and swell. Compensation techniques of custom power electronic device D-ST ATCOM was presented. The   design and applications of D-STATCOM for voltage sags, swells and comprehensive results were presented. The Voltage Source Convert (VSC) was implemented with the help of Sinusoidal Pulse Width Modulation (SPWM). The control scheme was tested under a wide range of operating conditions, and it was observed to be very robust in every case. For modeling and simulation of a D-ST ATCOM by using the highly developed graphic facilities available in MA TLAB/SIMULINK were used. The simulations carried out here showed that the D-STATCOM provides relatively better voltage regulation capabilities.


[I] O. Anaya-Lara, E. Acha, “Modeling and analysis of custom power  systems by PSCAD/EMTDC,” IEEE Trans. Power Delivery, vol. 17, no .I, pp. 266-272, January 2002.

[2] S. Ravi Kumar, S. Sivanagaraju, “Simualgion of D-Statcom and DVR in  power system,” ARPN jornal of engineering and applied science, vol. 2,   no. 3, pp. 7-13, June 2007.

[3] H. Hingorani, “Introducing custom power”, IEEE Spectrum, vol. 32, no.6, pp. 41-48, June 1995.

[4] N. Hingorani, “FACTS-Flexible ac transmission systems,” in Proc. IEE 5th Int Conf AC DC Transmission, London, U.K., 1991, Conf Pub.  345, pp. 1-7.

[5] Mahesh Singh, Vaibhav Tiwari, “Modeling analysis and soltion to  power quality problems,” unpublished.

Three-Level 48-Pulse STATCOM with Pulse Width Modulation


 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.


  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)



Fig. 1 System configuration for simulation



 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


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].


  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)


Enhancement of Power Quality in Distribution System using D-Statcom


STATCOM (static synchronous compensator) as a shunt-link flexible AC transmission system(FACTS) controller has shown extensive feasibility in terms of cost-effectiveness in a wide range of problem solving abilities from transmission to distribution levels. Advances in power electronic technologies such as Voltage Source Converter (VSC) improves the reliability and functionality of power electronic based controllers hence resulting in increased applications of STATCOM. In this paper, design and implementation of a Distribution type, Voltage Source Converter (VSC) based static synchronous compensator (DSTATCOM) has been carried out. It presents the enhancement of power quality problems, such as voltage sag and swell using Distribution Static Compensator (D-STATCOM) in distribution system. The model is based on Sinusoidal Pulse Width Modulation (SPWM) technique. The control of the Voltage Source Converter (VSC) is done with the help of SPWM. The main focus of this paper is to compensate voltage sag and swell in a distribution system. To solve this problem custom power devices are used such as Fixed Compensators (FC, FR), Synchronous Condenser, SVC, SSSC, STATCOM etc. Among these devices Distribution STATCOM (DSTATCOM) is the most efficient and effective modern custom power device used in power distribution networks. DSTATCOM injects a current into the system to mitigate the voltage sag and swell. The work had been carried out in MATLAB environment using Simulink and SIM power system tool boxes. The proposed D-STATCOM model is very effective to enhance the power quality of an isolated distribution system feeding power to crucial equipment in remote areas. The simulations were performed and results were found to be satisfactory using MATLAB/SIMULINK.


  1. Statcom
  2. Facts Controllers
  3. D-Statcom
  4. Voltage Source Converter
  5. Total Harmonic Distortions



Fig.1 Schematic diagram of D-STATCOM



 Fig.2 Three Phase to Ground -Voltage at Load Point is 0.6600 p.u

Fig.3 Double Line to Ground- Voltage at Load Point is 0.7070 p.u

Fig.4 Line to Line- Voltage at Load Point is 0.7585

Fig.5 Single Line to Ground- Voltage at Load Point is 0.8257

Fig.6 The waveforms shows THD (41.31%) results of fixed load and variable inductive load.

Fig..7 The wave forms shows THD (21.28%) results of fixed load and variable capacitive load

Fig.8 Three Phase to Ground-Voltage at Load Point is 0.9367 p.u

Fig.9 Double Line to Ground- Voltage at Load Point is0.9800 p.u

Fig.10 Line to Line- Voltage at Load Point is 1.068

Fig.11 Single Line to Ground – Voltage at Load Point is 0.9837

Fig.12 The waveform for pure inductive,capacitive loads with statcom

Fig.13 The waveform for without filter THD results 41.31%

Fig.14 The above waveform for with filter THD results 1.11%


The simulation results show that the voltage sags can be mitigate by inserting D-STATCOM to the distribution system. By adding LCL Passive filter to D-STATCOM, the THD reduced. The power factors also increase close to unity. Thus, it can be concluded that by adding DSTATCOM with LCL filter the power quality is improved.


[1] A.E. Hammad, Comparing the Voltage source capability of Present and future Var Compensation Techniques in Transmission System, IEEE Trans, on Power Delivery. Volume 1. No.1 Jan 1995.

[2] G.Yalienkaya, M.H.J Bollen, P.A. Crossley, “Characterization of Voltage Sags in Industrial Distribution System”, IEEE transactions on industry applications, volume 34, No. 4, July/August, PP.682-688, 1999

[3] Haque, M.H., “Compensation of Distribution Systems Voltage sags by DVR and D STATCOM”, Power Tech Proceedings, 2001 IEEE Porto, Volume 1, PP.10-13, September 2001.

[4] Anaya-Lara O, Acha E., “Modeling and Analysis Of Custom Power Systems by PSCAD/EMTDC”, IEEE Transactions on Power Delivery, Volume 17, Issue: 2002, Pages: 266 272.

[5] Bollen, M.H.J.,”Voltage sags in Three Phase Systems”, Power Engineering Review, IEEE, Volume 21, Issue: 9, September 2001, PP: 11-


Offshore Wind Farm Power Control Using HVdc Link Control de puissance d’un parc éolien en mer utilisant la liaison CCHT


In this paper, a method is presented to control offshore wind farm output power. This method is able to fix the wind farm output power even during wind speed variations. In the proposed method, the offshore wind farm is connected to the onshore grid through the high-voltage dc (HVdc) cable. Moreover, the power control of the wind turbines is achieved by controlling the HVdc convertors. In the proposed system, the generator side convertors have to control the active power absorbed from the wind, and the grid side ones are obtained to control the HVdc link voltage. The control system is based on applying the appropriate modulation index to the voltage source converters. Two control strategies are proposed and analyzed to control wind farm output power. The simulation results illustrate that the proposed method is able to smooth the output power of the offshore wind farms appropriately. The proposed wind farm configuration and the control system are validated by simulations in the MATLAB/Simulink environment.


  1. Current source inverter (CSI)
  2. Offshore wind farm
  3. Permanent magnet synchronous generator (PMSG)
  4. PQ-bus
  5. Voltage source converter (VSC)



Fig. 1. Proposed configuration of wind turbines connection.



 Fig. 2. (a) Wind speed variations (m/s). (b) Turbine rotational speed (rad/s).

(c) Turbine efficiency.

Fig. 3. HVdc link voltage.

Fig. 4. Wind farm output power.


In this paper, the configuration and control methods have been proposed for the offshore wind turbines, connected to the onshore grid. This method is capable to control and smooth the wind farm output power, injected to the onshore grid. The proposed system can mitigate the fluctuations of wind farm output power, even during wind speed variations. In other words, the wind farm can operate such as a PQ-bus. Moreover, two strategies (fixed power and MPPT) have been analyzed and compared with each other. Finally, the proposed method is compared with other similar works to smooth the output power of the wind farm. The main result is that the proposed method can smooth the output power better than the TSR, PAC, and OTC methods. But it is a bit weaker than the KEC method in power smoothing issue. Moreover, using this method, the wind farm is able to cooperate in frequency control of the onshore grid by controlling the desired active power, to improve the power system operation, which is the future work of the authors.


[1] J. O. Dabiri, “Potential order-of-magnitude enhancement of wind farm power density via counter-rotating vertical-axis wind turbine arrays,” J. Renew. Sustain. Energy, vol. 3, no. 4, p. 043104, 2011.

[2] J. Hua, “A floating platform of concrete for offshore wind turbine,” J. Renew. Sustain. Energy, vol. 3, no. 6, p. 063103, 2011.

[3] A. Urtasun, P. Sanchis, I. S. Martín, J. López, and L. Marroyo, “Modeling of small wind turbines based on PMSG with diode bridge for sensorless maximum power tracking,” Renew. Energy, vol. 55, pp. 138–149, Jul. 2012.

[4] (2007). Global Wind and Energy Council, Market Forecast 2010- 2014. [Online]. Available: Publications/GlobalWind2007report/market/forecast%2020102014

[5] M. Kesraoui, N. Korichi, and A. Belkadi, “Maximum power point tracker of wind energy conversion system,” Renew. Energy, vol. 4, no. 10, pp. 2655–2662, 2011.

Multiconverter Unified Power-Quality Conditioning System: MC-UPQC



This paper presents a new unified power-quality conditioning system (MC-UPQC), capable of simultaneous compensation for voltage and current in multibus/multifeeder systems. In this configuration, one shunt voltage-source converter (shunt VSC) and two or more series VSCs exist. The system can be applied to adjacent feeders to compensate for supply-voltage and load current imperfections on the main feeder and full compensation of supply voltage imperfections on the other feeders. In the proposed configuration, all converters are connected back to back on the dc side and share a common dc-link capacitor. Therefore, power can be transferred from one feeder to adjacent feeders to compensate for sag/swell and interruption. The performance of the MC-UPQC as well as the adopted control algorithm is illustrated by simulation. The results obtained in PSCAD/EMTDC on a two-bus/two-feeder system show the effectiveness of the proposed configuration.


  1. Power quality (PQ)
  3. Unified power-quality conditioner (UPQC)
  4. Voltage-source converter (VSC)



Fig. 1. Typical MC-UPQC used in a distribution system.

Fig. 2. Control block diagram of the shunt VSC.

Fig. 3. Control block diagram of the series VSC.


Fig. 4. BUS2 voltage, series compensating voltage, and load voltage in Feeder2.

Fig. 5. Nonlinear load current, compensating current, Feeder1 current, and capacitor voltage.

Fig. 6. Simulation results for an upstream fault on Feeder2: BUS2 voltage, compensating voltage, and loads L1 and L2 voltages.

Fig. 7. Simulation results for load change: nonlinear load current, Feeder1 current, load L1 voltage, load L2 voltage, and dc-link capacitor voltage.

Fig. 8. BUS1 voltage, series compensating voltage, and load voltage in Feeder1 under unbalanced source voltage.


In this paper, a new configuration for simultaneous compensation of voltage and current in adjacent feeders has been proposed. The new configuration is named multi converter unified power-quality conditioner (MC-UPQC). Compared to a conventional UPQC, the proposed topology is capable of fully protecting critical and sensitive loads against distortions, sags/swell, and interruption in two-feeder systems. The idea can be theoretically extended to multibus/multifeeder systems by adding more series VSCs. The performance of the MC-UPQC is evaluated under various disturbance conditions and it is shown that the proposed MC-UPQC offers the following advantages:

1)  power transfer between two adjacent feeders for sag/swell and interruption compensation;

2) compensation for interruptions without the need for a battery storage system and, consequently, without storage capacity limitation;

3) sharing power compensation capabilities between two adjacent feeders which are not connected.


[1] D. D. Sabin and A. Sundaram, “Quality enhances reliability,” IEEE Spectr., vol. 33, no. 2, pp. 34–41, Feb. 1996.

[2] M. Rastogi, R. Naik, and N. Mohan, “A comparative evaluation of harmonic reduction techniques in three-phase utility interface of power electronic loads,” IEEE Trans. Ind. Appl., vol. 30, no. 5, pp. 1149–1155, Sep./Oct. 1994.

[3] F. Z. Peng, “Application issues of active power filters,” IEEE Ind. Appl. Mag., vol. 4, no. 5, pp. 21–30, Sep../Oct. 1998.

[4] H. Akagi, “New trends in active filters for power conditioning,” IEEE Trans. Ind. Appl., vol. 32, no. 6, pp. 1312–1322, Nov./Dec. 1996.

[5] L. Gyugyi, C. D. Schauder, S. L. Williams, T. R. Rietman, D. R. Torjerson, and A. Edris, “The unified power flow controller: A new approach to power transmission control,” IEEE Trans. Power Del., vol. 10, no. 2, pp. 1085–1097, Apr. 1995.

Implementation of Adaptive Filter in Distribution Static Compensator



This paper presents an implementation of an adaptive filter in a three-phase distribution static compensator (DSTATCOM) used for compensation of linear/nonlinear loads in a three-phase distorted voltage ac mains. The proposed filter, which is based on adaptive synchronous extraction, is used for extraction of fundamental active- and reactive-power components of load currents in estimating the reference supply currents. This control algorithm is implemented on a developed DSTATCOM for reactive-power compensation, harmonics elimination, load balancing, and voltage regulation under linear and nonlinear loads. The performance of DSTATCOM is observed satisfactory under unbalanced time-varying loads.


  1. Adaptive filter (AF)
  2. distribution static compensator (DSTATCOM)
  3. harmonics
  4. load balancing
  5. sinusoidal tracking algorithm
  6. voltage-source converter (VSC)



Fig.1. Schematic of three-leg DSTATCOM.





Fig. 2. (a), (b), and (c) Various intermediate signals of the control algorithm at load injection. (a) Ch. 1 and 2: 200 V/div; Ch. 3 and 4: 20 A/div; Time axis: 50 ms/div. (b) Ch. 1, 2, 3, and 4: 20 A/div; Time axis: 20 ms/div. (c) Ch. 1, 2,3, and 4: 20 A/div; Time axis: 20 ms/div.

 Fig. 3. Steady-state performance of DSTATCOM at linear lagging PF load in PFC mode. (a) Ps. (b) PL. (c) Pc. (d) vab, isa. (e) vbc, isb. (f) vca, isc.

Fig. 4. Steady-state performance of DSTATCOM at nonlinear loads in PFC mode. (a) vab, isa. (b) vbc, isb. (c) vca, isc. (d) Harmonic spectrum of isa. (e) vab, iLa. (f) Harmonic spectrum of iLa.

Fig. 5. Dynamic performance of DSTATCOM at unbalanced linear loads. (a) vab, isa, isb, isc. (b) vab, iLa, iLb, iLc. (c) vdc, isa, iCa, iLa.

Fig. 6. Dynamic performance of DSTATCOM at unbalanced nonlinear loads. (a) vab, isa, isb, isc. (b) vab, iLa, iLb, iLc. (c) vdc, isa, iCa, iLa

Fig. 7. Steady-state performance of DSTATCOM at linear lagging PF load in ZVR mode. (a) Ps. (b) PL. (c) Pc. (d) vab, isa. (e) vbc, isb. (f) vca, isc.

Fig. 8. Steady-state performance of DSTATCOM at nonlinear load in ZVR mode. (a) vab, isa. (b) vbc, isb. (c) vca, isc. (d) Harmonic spectrum of isa. (e) Harmonic spectrum of iLa. (f) iCa. (g) Ps. (h) PL.

Fig. 9. Variation of Vt, isa, and iLa with vdc under unbalanced linear loads.


 A DSTATCOM has been implemented for a three-phase distribution system. An AF has been used for control of DSTATCOM. This AF has been found simple and easy to implement, and its performance has been observed satisfactory with nonsinusoidal and distorted voltages of ac mains under load variation. The performance of DSTATCOM with its AF has been demonstrated for harmonics elimination, reactivepower compensation, and load balancing with self-supporting dc link in PFC and ZVR modes. The dc-link voltage of the DSTATCOM has been also regulated to a desired value under time-varying load conditions.


 [1] E. F. Fuchs and M. A. S. Mausoum, Power Quality in Power Systems and Electrical Machines. London, U.K.: Elsevier, 2008.

[2] H. Akagi, E. H. Watanabe, and M. Aredes, Instantaneous Power Theory and Applications to Power Conditioning. Hoboken, NJ, USA: Wiley, 2007.

[3] A. Emadi, A. Nasiri, and S. B. Bekiarov, Uninterruptible Power Supplies and Active Filters. Boca Raton, FL, USA: CRC Press, 2005.

[4] J. Jacobs, D. Detjen, C. U. Karipidis, and R. W. De Doncker, “Rapid prototyping tools for power electronic systems: Demonstration with shunt active power filters,” IEEE Trans. Power Electron., vol. 19, no. 2, pp. 500– 507, Mar. 2004.

[5] A. Ghosh and G. Ledwich, Power Quality Enhancement Using Custom Power Devices. New Delhi, India: Springer Int. Edition, 2009.

Dynamic Modeling of Microgrid for Grid Connected and Intentional Islanding Operation



 Microgrid is defined as the cluster of multiple distributed generators (DGs) such as renewable energy sources that supply electrical energy. The connection of microgrid is in parallel with the main grid. When microgrid is isolated from remainder of the utility system, it is said to be in intentional islanding mode. In this mode, DG inverter system operates in voltage control mode to provide constant voltage to the local load. During grid connected mode, the Microgrid operates  in constant current control mode to supply preset power to the main grid. The main contribution of this paper is summarized as

  • Design of a network based control scheme for inverter based sources, which provides proper current control during grid connected mode and voltage control during islanding
  • Development of an algorithm for intentional islanding detection and synchronization controller required during grid
  • Dynamic modeling and simulation are conducted to show system behavior under proposed method using

From the simulation results using Simulink dynamic models, it can be shown that these controllers provide the microgrid with a deterministic and reliable connection to the grid.


  1. Distributed generation (DG)
  2. grid connected operation
  3. intentional islanding operation and islanding detection
  4. Microgrid



Fig.1. Dynamic model of microgrid with controller.


Fig. 2. Line Current without current controller

Fig.3. Line Voltage without Voltage controller

Fig. 4. Line Voltage with voltage controller

Fig. 5. Phase voltage waveform (a) without re-closure controller (b) with re-closure controller

Fig. 6. Synchronization for grid reconnection (a) without re-closure algorithm (b) with re-closure algorithm


Current and voltage Control techniques have been developed for grid connected and intentional islanding modes of operation using PI controllers. An intentional islanding detection algorithm responsible for switching between current control and voltage control is developed using logical operations and proved to be effective. The reconnection algorithm coupled with the synchronization controller enabled the DG to synchronize itself with the grid during grid reconnection. The performance of the microgrid with the proposed controllers and algorithms  has been analyzed by conducting simulation on dynamic model using SIMULINK. The simulation results presented here confirms the effectiveness of the control scheme.


[1] L. Shi, M.Y. Lin Chew. “A review on sustainable design of renewable energy systems,” science direct journal present in Renewable and Sustainable Energy Reviews, Vol. 16, Issue 1, 2012, pp. 192–207.

[2] Q. Lei, Fang Zheng Peng, Shuitao Yang. “Multi loop control method for high performance microgrid inverter through load voltage and current decoupling with only output voltage feedback,” IEEE Trans. power. Electron, vol. 26, no. 3, 2011, pp. 953–960.

[3] J. Selvaraj and N. A. Rahim, “Multilevel inverter for grid-connected PV system employing digital PI controller,” IEEE Trans. Ind. Electron., vol. 56, no. 1, 2009, pp. 149–158.

[4] I. J. Balaguer, Fang Zheng Peng, Shuitao Yang, Uthane Supatti Qin Lei. “Control for grid connected and intentional islanding modes of operations of distributed power generation,” IEEE Trans. Ind. Electron., vol. 56, no. 3, 2009, pp. 726–736.

[5] R. J. Azevedo, G.I. Candela, R. Teodorescu, P.Rodriguez , I.E-Otadui “Microgrid connection management based on an intelligent connection agent,” 36th annual conference on IEEE industrial electronics society, 2010, pp. 3028–3033.

A Control Technique for Integration of DG Units to the Electrical Networks


This paper deals with a multi objective control technique for integration of distributed generation (DG) resources to the electrical power network. The proposed strategy provides compensation for active, reactive, and harmonic load current components during connection of DG link to the grid. The dynamic model of the proposed system is first elaborated in the stationary reference frame and then transformed into the synchronous orthogonal reference frame. The transformed variables are used in control of the voltage source converter as the heart of the interfacing system between DG resources and utility grid. By setting an appropriate compensation current references from the sensed load currents in control circuit loop of DG, the active, reactive, and harmonic load current components will be compensated with fast dynamic response, thereby achieving sinusoidal grid currents in phase with load voltages, while required power of the load is more than the maximum injected power of the DG to the grid. In addition, the proposed control method of this paper does not need a phase-locked loop in control circuit and has fast dynamic response in providing active and reactive power components of the grid-connected loads. The effectiveness of the proposed control technique in DG application is demonstrated with injection of maximum available power from the DG to the grid, increased power factor of the utility grid, and reduced total harmonic distortion of grid current through simulation and experimental results under steady-state and dynamic operating conditions.


  1. Digital signal processor
  2. Distributed generation (DG)
  3. Renewable energy sources
  4. Total harmonic distortion (THD)
  5. voltage source converter (VSC)




Fig. 1. General schematic diagram of the proposed control strategy for DG system.



Fig. 2. Load voltage, load, grid, and DG currents before and after connection of DG and before and after connection and disconnection of additional load into the grid.


Fig. 3. Grid, load, DG currents, and load voltage (a) before and after connection of additional load and (b) before and after disconnection of additional load.


Fig. 4. Phase-to-neutral voltage and grid current for phase (a).


Fig. 5. Reference currents track the load current (a) after interconnection of DG resources and (b) after additional load increment.


Fig. 6. Load voltage, load, grid, and DG currents during connection of DG link to the unbalanced grid voltage.


A multi objective control algorithm for the grid-connected converter-based DG interface has been proposed and presented in this paper. Flexibility of the proposed DG in both steady-state and transient operations has been verified through simulation and experimental results.

Due to sensitivity of phase-locked loop to noises and distortion, its elimination can bring benefits for robust control against distortions in DG applications. Also, the problems due to synchronization between DG and grid do not exist, and DG link can be connected to the power grid without any current overshoot. One other advantage of proposed control method is its fast dynamic response in tracking reactive power variations; the control loops of active and reactive power are considered independent. By the use of the proposed control method, DG system is introduced as a new alternative for distributed static compensator in distribution network. The results illustrate that, in all conditions, the load voltage and source current are in phase and so, by improvement of power factor at PCC, DG systems can act as power factor corrector devices. The results indicate that proposed DG system can provide required harmonic load currents in all situations. Thus, by reducing THD of source current, it can act as an active filter. The proposed control technique can be used for different types of DG resources as power quality improvement devices in a customer power distribution network.


[1] T. Zhou and B. François, “Energy management and power control of a hybrid active wind generator for distributed power generation and grid integration,” IEEE Trans. Ind. Electron., vol. 58, no. 1, pp. 95–104, Jan. 2011.

[2] M. Singh, V. Khadkikar, A. Chandra, and R. K. Varma, “Grid interconnection of renewable energy sources at the distribution level with power quality improvement features,” IEEE Trans. Power Del., vol. 26, no. 1, pp. 307–315, Jan. 2011.

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[4] C. Mozina, “Impact of green power distributed generation,” IEEE Ind. Appl. Mag., vol. 16, no. 4, pp. 55–62, Jun. 2010.

[5] B. Ramachandran, S. K. Srivastava, C. S. Edrington, and D. A. Cartes, “An intelligent auction scheme for smart grid market using a hybrid immune algorithm,” IEEE Trans. Ind. Electron., vol. 58, no. 10, pp. 4603–4611, Oct. 2011.


A New Control Strategy for Active and Reactive Power Control of Three-Level VSC Based HVDC System


This paper displays another control procedure no doubt and ready power control of three-level multipulse voltage source converter based High Voltage DC (HVDC) communication plan working at Fundamental Frequency Switching (FFS). A three-level voltage source converter change the regular two-level VSC and it is determined for the real and reactive power control is each of the four quarter task.


Another control method is created for produce the ready power control by changing the beat width and by keeping the dc connect voltage regular. The enduring state and dynamic showing of HVDC plan joining two unique density arrange are shown for dynamic and responsive forces control.


Complete capacity of motor apply in the plan are decreased in contrast with two dimension VSCs. The killing of the HVDC plan is also increase as far as decreased music level even at important frequenccy exchanging.


Fig. 1 A three-level 24-Pulse voltage source converter based HVDC system



Fig. 2 Control scheme of three-level VSC based HVDC system using dynamic dead angle (β) Control



Fig. 3 Performance of rectifier station during simultaneous real and reactive power control of three-level 24-pulse VSC based HVDC system


Fig. 4 Performance of inverter station during simultaneous real and reactive power control of three-level 24-pulse VSC based HVDC system


Fig. 5 Variation of angles (δ) and (β) values of three-level 24-pulse VSC based HVDC system during simultaneous real and reactive power control


Another control method for three-level 24-beat voltage source converter setup has been planned for HVDC plan. The execution of this 24-beat VSC based HVDC  plan apply the control method has been exhibited in dynamic power control in bidirectional, free control of the ready power and power quality improvement.


Another powerful dead point (β) control has been presented for three-level voltage source converter working at critical recurrence trade. In this control the HVDC plan activity is efficiently shown and furthermore an analysis of (β) esteem


for different responsive power necessity and symphonious execution has been completed in detail. In this way, the determination of converter task locale is more adaptable as indicated by the necessity of the responsive power and power quality.

Analysis and Design of Three-Level, 24-Pulse Double Bridge Voltage Source Converter Based HVDC System for Active and Reactive Power Control


This paper control the search, plan and control of a three-level 24-beat Voltage Source Converter (VSC) based High Voltage Direct Current (HVDC) framework. A three dimension VSC active at basic frequency exchanging (FFS) is proposed with 24-pulse VSC structure to improve the power quality and decrease the converter exchanging disaster for high power applications. The structure of three-level VSC converter and plan  parameters, for example, air conditioning inductor and dc capacitor is presented for the proposed VSC based HVDC plan. It comprises of two converter stations encouraged from two diverse air conditioning plan. The dynamic power is replaced between the stations in any case. The ready power is freely controlled in every converter station. The three-level VSC is worked at advanced dead edge (β). A planned control estimation for both the rectifier and an inverter stations for bidirectional dynamic power stream is created weak on FFS and neighborhood responsive power age. This outcomes in a serious decrease in exchanging disaster and maintaining a important distance from the responsive power plant. Recreation is conveyed to confirm the execution of the proposed control calculation of the VSC based HVDC plan for bidirectional dynamic power stream and their autonomous ready power control.



Fig. 1 Three-level 24-pulse double bridge VSC based HVDC system



Fig. 2a Performance of rectifier station during reactive power control of three level 24-pulse VSC HVDC system


Fig. 2b Performance of Inverter station during reactive power control at rectifier station of three-level 24 pulse VSC HVDC system


Fig. 2c Variation of (δ) and (α) values for rectifier and inverter Stations for reactive power variation of a three-level 24-pulse VSC HVDC system


Fig. 3a Rectifier station during active power reversal of three-level 24-pulse VSC HVDC system


Fig. 3b Inverter station during active power reversal of three-level 24-pulse VSC HVDC system


Fig. 3c Variation of (δ) and (α) values during active power reversal of three level 24-pulse VSC HVDC system.


Another three-level, 24-beat voltage source converter based HVDC plan working at important frequency trade has been planned and its model has been produced and it is efficiently tried for the autonomous control of dynamic and ready forces and suitable dimension consonant condition. The responsive power has been controlled free of the dynamic power at the two conditions.


The converter has been efficiently worked in each of the four quadrants of dynamic and responsive forces with the proposed control. The inversion of the dynamic power flow has been make real by switching the course of dc current without changing the limit of dc voltage which is unusuallly troublesome in traditional HVDC plan.


The power nature of the HVDC plan has additionally improve with three-level 24-beat converter task. The symphonious execution of this three-level, 24-beat VSC has been seen to an equal to two-level 48-beat voltage source converter.