Compensation of Voltage Distribunces In SMIB System Using ANN Based DPFC Controller

International conference on Signal Processing, Communication, Power and Embedded System (SCOPES)-2016, IEEE

ABSTRACT: Since last decade, due to advancement in technology and increasing in the electrical loads and also due to complexity of the devices the quality of power distribution is decreases. A Power quality issue is nothing but distortions in current, voltage and frequency that affect the end user equipment or disoperation; these are main problems of power quality so compensation for these problems by DPFC is presented in this paper. The control circuits for DPFC are designed by using line currents, series reference voltages and these are controlled by conventional ANN controllers. The results are observed by MATLAB/SIMULINK model.

 KEYWORDS:

  1. Power Quality
  2. Voltage Sag
  3. DPFC
  4. Voltage Swell

 SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Figure 1: Schematic Diagram for DPFC

EXPECTED SIMULATION RESULTS:

Figure 2: Output Voltage during fault condition

Figure 3: Output Current during Fault Condition

Figure 4: Output voltage compensated by DPFC Controller

Figure 5: Compensated Output Current by DPFC Controller

Figure 6: Active and Reactive Power

Figure 7: THD value of system output voltage without DPFC

Figure 8: THD value of DPFC (pi controller) load Voltage

Figure 9: THD for output voltage under ANN Controller

 CONCLUSION:

In this paper we implemented a concept to controlling the power quality issues i.e. DPFC. The proposed theory of this device is mathematical formulation and analysis of voltage dips and their mitigations for a three phase source with linear load. In this paper we also proposed a concept of Ann controller for better controlling action. As compared to all other facts devices the DPFC based ANN has effectively control all power quality problems and with this technique we get the THD as 3.65% and finally the simulation results are shown above.

 REFERENCES:

  1. Ahmad Jamshidi, S.Masoud Barakati, and M.Moradi Ghahderijani presented a paper on “Impact of Distributed Power Flow Controller to Improve Power Quality Based on Synchronous Reference Frame Method” at IACSIT International Journal of Engineering and Technology, Vol. 4, No. 5, October 2012.
  2. Ahmad Jamshidi, S.Masoud Barakati, and Mohammad Moradi Ghahderijani posted a paper “Power Quality Improvement and Mitigation Case Study Using Distributed Power Flow Controller” on 978-1-4673-0158-9/12/$31.00 ©2012 IEEE.
  3. Srinivasarao, Budi, G. Sreenivasan, and Swathi Sharma. “Comparison of Facts Controller for Power Quality Problems in Power System”, Indian Journal of Science and Technology, 2015.
  4. J.R.Enslin, “Power mitigation problems,” in Proc. IEEE Int. Symp. Industrial Electronics (ISIE ’98), vol. 1, 1998, pp. 8– 20.
  5. Srinivasarao, Budi, G. Sreenivasan, and Swathi Sharma. “Mitigation of voltage sag for power quality improvement using DPFC system”, 2015 International Conference on Electrical Electronics Signals Communication and Optimization (EESCO), 2015.

Modeling and Control of Multi-Terminal HVDC with Offshore Wind Farm Integration and DC Chopper Based Protection Strategies

2013, IEEE

ABSTRACT: Multi-Terminal HVDC based on three-level neutral-clamped voltage source converters (VSC) is an ideal approach for the integration of DFIG wind farms to the power grid. However, dc-link faults and ac faults are major concerns for the safety and consistency of VSC-HVDC system. This paper demonstrates methods employing both full bridge and half bridge DC-DC converters for the fast clearance and protection of dc and ac ground faults respectively. In addition, control strategies incorporating decoupling control and feed-forward compensation on both grid side and wind farm side VSCs are also presented. Normal operations are observed to examine the performance of the MT-HVDC system, and also dc-link fault and three-phase ground fault at inverter side are simulated to verify the effectiveness of the approach employing DC-DC converters to suppress dc current overshoot in case of dc-link fault and mitigate dc voltage overshoot during three-phase ac ground fault. This proposed MT-HVDC transmission system and the fault-ride through capabilities provided by the dc choppers is validated by the simulation studies using detailed Matlab/Simulink model for normal operation, dc and ac ground faults.

KEYWORDS:

  1. VSC-HVDC
  2. DFIG
  3. DC chopper
  4. Faults

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

 Fig. 1 Topology of the proposed multi-terminal VSC-HVDC system.

 EXPECTED SIMULATION RESULTS:

 

 Fig. 2 Simulation results of MT-HVDC during normal operation: (a) active power of wind farm, (b) dc voltage, and (c) ac rms current.

Fig. 3 Simulation results of 6 DFIG units during normal operation: (a) active power, (b) reactive power, (c) ac rms voltage, and (d) back-to-back dc-link voltage of DFIG unit.

Fig. 4 Simulation results of MT-HVDC during dc pole-to-pole fault with and without full bridge dc chopper protection: (a) dc voltage, and (b) dc current.

Fig. 5 Simulation results of MT-HVDC during three-phase ac ground fault at inverter side with and without half bridge dc chopper protection: (a) ac rms voltage at inverter side, (b) dc voltage overshoot without protection measures, and (c) dc voltage with protection measures.

CONCLUSION:

This paper investigates a multi-terminal VSC-HVDC system, which integrates two DFIG wind farms to the ac grid. The control strategies of both WFVSC and GSVSC stations are discussed in detail, and two approaches employing both full bridge and half bridge dc choppers are extended and displayed. Simulation studies are carried out in normal, dc pole-to-pole and ac ground fault operations, and the result verifies the effectiveness of the proposed MT-HVDC system in both the performance of wind power delivery and the protection measures for various fault conditions. Specifically, the dc voltage drop and dc current overshoot are eliminated during dc fault with full bridge dc choppers, while only a 8% voltage overshoot is observed with the implementation of half bridge dc choppers in case of three-phase ac ground fault.

REFERENCES:

[1] S. G. Hernandez, E. M. Goytia and O. A. Lara, “Analysis of wide area integration of dispersed wind farms using multiple VSC-HVDC links,” in Proc. of EPE, Sevilla, pp. 17-26, 2008.

[2] S. Towito, M. Berman, G. Yehuda and R. Rabinvici, “Distribution generation case study: electric wind farm doubly fed induction generators”, in Proc. Convention of Electrical and Electronics Engineering(CEEE), Israel, pp. 393-397, Nov. 2006.

[3] N. Flourentzou, V. G. Agelidis, and G. D. Demetriades, “VSC-based HVDC power transmission systems: an overview,” IEEE Trans. Power Electron., vol. 24, no. 3, pp. 592-602, Mar. 2009.

[4] L. Xu, L. Yao, and C. Sasse, “Grid integration of large DFIG-based wind farms ssing VSC transmission,” IEEE Trans. Power Syst., vol. 22, no. 3, pp.976-984, Aug. 2007.

 

A Combination of Shunt Hybrid Power Filter and Thyristor-Controlled Reactor for Power Quality

IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 61, NO. 5, MAY 2014

ABSTRACT: This paper proposes a combined system of a thyristor-controlled reactor (TCR) and a shunt hybrid power filter (SHPF) for harmonic and reactive power compensation. The SHPF is the combination of a small-rating active power filter (APF) and a fifth-harmonic-tuned LC passive filter. The tuned passive filter and the TCR form a shunt passive filter (SPF) to compensate reactive power. The small-rating APF is used to improve the filtering characteristics of SPF and to suppress the possibility of resonance between the SPF and line inductances. A proportional–integral controller was used, and a triggering alpha was extracted using a lookup table to control the TCR. A nonlinear control of APF was developed for current tracking and voltage regulation. The latter is based on a decoupled control strategy, which considers that the controlled system may be divided into an inner fast loop and an outer slow one. Thus, an exact linearization control was applied to the inner loop, and a nonlinear feedback control law was used for the outer voltage loop. Integral compensators were added in both current and voltage loops in order to eliminate the steady-state errors due to system parameter uncertainty. The simulation and experimental results are found to be quite satisfactory to mitigate harmonic distortions and reactive power compensation.

KEYWORDS:

  1. Harmonic suppression
  2. Hybrid power filter
  3. Modeling
  4. Nonlinear control
  5. Reactive power compensation
  6. Shunt hybrid power filter and thyristor-controlled reactor (SHPF-TCRcompensator)
  7. Thyristor-controlled reactor (TCR)

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1. Basic circuit of the proposed SHPF-TCR compensator.

EXPECTED SIMULATION RESULTS:

Fig. 2. Steady-state response of the SHPF-TCR compensator with harmonic generated load.

Fig. 3. Harmonic spectrum of source current in phase 1. (a) Before compensation. (b) After compensation

Fig. 4. Dynamic response of SHPF-TCR compensator under varying distorted harmonic type of load conditions.

Fig. 5. Dynamic response of SHPF-TCR compensator under the harmonic and reactive power type of loads.

Fig. 6. Harmonic spectrum of source current in phase 1. (a) Before compensation. (b) After compensation.

Fig. 7. Steady-state response of the SHPF-TCR compensator with harmonic produced load.

CONCLUSION:

In this paper, a SHPF-TCR compensator of a TCR and a SHPF has been proposed to achieve harmonic elimination and reactive power compensation. A proposed nonlinear control scheme of a SHPF-TCR compensator has been established, simulated, and implemented by using the DS1104 digital realtime controller board of dSPACE. The shunt active filter and SPF have a complementary function to improve the performance of filtering and to reduce the power rating requirements of an active filter. It has been found that the SHPF-TCR compensator can effectively eliminate current harmonic and reactive power compensation during steady and transient operating conditions for a variety of loads. It has been shown that the system has a fast dynamic response, has good performance in both steady-state and transient operations, and is able to reduce the THD of supply currents well below the limit of 5% of the IEEE-519 standard.

REFERENCES:

[1] A. Hamadi, S. Rahmani, and K. Al-Haddad, “A hybrid passive filter configuration for VAR control and harmonic compensation,” IEEE Trans. Ind. Electron., vol. 57, no. 7, pp. 2419–2434, Jul. 2010.

[2] P. Flores, J. Dixon, M. Ortuzar, R. Carmi, P. Barriuso, and L. Moran, “Static Var compensator and active power filter with power injection capability, using 27-level inverters and photovoltaic cells,” IEEE Trans. Ind. Electron., vol. 56, no. 1, pp. 130–138, Jan. 2009.

[3] H. Hu, W. Shi, Y. Lu, and Y. Xing, “Design considerations for DSPcontrolled 400 Hz shunt active power filter in an aircraft power system,” IEEE Trans. Ind. Electron., vol. 59, no. 9, pp. 3624–3634, Sep. 2012.

[4] X. Du, L. Zhou, H. Lu, and H.-M. Tai, “DC link active power filter for three-phase diode rectifier,” IEEE Trans. Ind. Electron., vol. 59, no. 3, pp. 1430–1442, Mar. 2012.

[5] M. Angulo, D. A. Ruiz-Caballero, J. Lago, M. L. Heldwein, and S. A. Mussa, “Active power filter control strategy with implicit closedloop current control and resonant controller,” IEEE Trans. Ind. Electron., vol. 60, no. 7, pp. 2721–2730, Jul. 2013.