Power Quality Improvement and Low Voltage Ride through Capability in Hybrid Wind-PV Farms Grid-Connected Using Dynamic Voltage Restorer

 ABSTRACT:  

The paper proposes the application of a Dynamic Voltage Restorer (DVR) to enhance the power quality and improve the low voltage ride through (LVRT) capability of a three-phase medium-voltage network connected to a hybrid distribution generation (DG) system. In this system, the photovoltaic (PV) plant and the wind turbine generator (WTG) are connected to the same point of common coupling (PCC) with a sensitive load. The WTG consists of a DFIG generator  connected to the network via a step-up transformer. The PV system is connected to the PCC via a two-stage energy conversion (DC-DC converter and DC-AC inverter). This topology allows, first, the extraction of maximum power based on the incremental inductance technique. Second, it allows the connection of the PV system to the public grid through a step-up transformer. In addition, the DVR based on Fuzzy Logic Controller (FLC) is connected to the same PCC. Different fault condition scenarios are tested for improving the efficiency and the quality of the power supply and compliance with the requirements of the LVRT grid code. The results of the LVRT capability, voltage stability, active power, reactive power, injected current, and DC link voltage, speed of turbine and power factor at the PCC are presented with and without the contribution of the DVR system.

KEYWORDS:

1.      Active power

2.      DC-link voltage DFIG

3.      Dynamic Voltage Restorer

4.      LVRT

5.      Power Factor

6.      Photovoltaic

7.      Voltage Stability

8.      Reactive Power

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Figure 1: PV-WTG Hybrid System With Dvr And A Load

Connected To Grid.

 EXPERIMENTAL RESULTS:

 

Figure 2: Voltage Phase Magnitude At Pcc During Faults With Typical Lvrt And Hvrt Characteristics Requirements Of Distributed Generation Code Of Germany As An Example.

Figure 3: Voltage Phase Magnitude At Pcc During Sag Fault.

Figure 4: Voltage Phase Magnitude At Pcc During Short Circuit Fault.

                                                           Figure 5: Phase Voltage At Pcc During Sag Fault.

Figure 6: Dvr Voltage Contribution At Pcc During Sag Fault.

Figure 7: Phase Voltage At Pcc During Short Circuit Fault.

Figure 8: Total Active Power Of Hybrid System At Pcc Injected To Grid.

Figure 9: Pv Active Power At Pcc Injected To Grid.

Figure 10: Wind Active Power At Pcc Injected To Grid.

Figure 11: Total Reactive Power Of Hybrid System At Pcc Injected

To Grid.

Figure 12: Pv Reactive Power At Pcc Injected To Grid.

Figure 13: Wind Reactive Power At Pcc Injected To Grid.

Figure 14: Total Pv-Wt Current Injected To Grid At Pcc.

Figure 15: Pv Current Injected At Pcc.

Figure 16: Wt Current Injected At Pcc To Grid.

Figure 17: Power Factor At Pcc.

Figure 18: Turbine Rotor Speed.

Figure 19: Vdc Link At Wtg Inverter.

Figure 20: Vdc Link Voltage At Pv Inverter.

CONCLUSION:

The simulation study was carried out using MATLAB to demonstrate the effectiveness of the proposed DVR control  system to improve the power quality and LVRT capability of the hybrid PV-WT power system. The system has been tested under different fault condition scenarios. The results have shown that the DVR connected to the PV-Wind hybrid system at the medium voltage grid is very effective and is able to mitigate voltage outages and short circuit failure  with improved voltage regulation capabilities and flexibility in the correction of the power factor.

The results of the simulation also prove that the system designed is secure since the required voltage ranges are respected correctly and the DG generators operate reliably. The main advantage of the proposed design is the rapid recovery of voltage; the power oscillations overshoot reduction, control of rotor speed and preventing the system from having a DC link overvoltage and thus increasing the stability of the power system in accordance with LVRT requirements.

REFERENCES:

[1] J. Hossain, H. Roy Pota, “Robust Control for Grid Voltage Stability High Penetration of Renewable Energy,” Springer ,1st ed., pp.1–11, 2014.

[2] S. Talari et al.,"Stochastic modelling of renewable energy sources from operators' point-of-view: A survey," Renewable and Sustainable Energy Reviews, Vol.81, no.2, , pp.1953-1965,Jan.2018.

[3] R. Teodorescu ,M. Liserre, P. Rodríguez, “Grid Converters For Photovoltaic And Wind Power Systems, “John Wiley & Sons Ltd.,1st ed.,2011.

[4] G. Romero Rey, L. M.Muneta, “Electrical Generation and Distribution Systems and Power Quality Disturbances,” InTech, 1^st ed., 2011.

[5] L.Ruiqi, G.Hua, Y.Geng, “Fault ride-through of renewable energy conversion systems during voltage recovery,” J. Mod. Power Syst. Clean Energy,vol. 4,no.1,pp:28-39, 2016.

Modeling, Control, and Performance Evaluation of Grid-Tied Hybrid PV/Wind Power Generation System: Case Study of Gabel El-Zeit Region, Egypt

ABSTRACT:  

The potential for utilizing clean energy technologies in Egypt is excellent given the abundant solar irradiation and wind resources. This paper provides detailed design, control strategy, and performance evaluation of a grid-connected large-scale PV/wind hybrid power system in Gabel El-Zeit region located along the coast of the Red Sea, Egypt. The proposed hybrid power system consists of 50 MW PV station and 200 MW wind farm and interconnected with the electrical grid through the main Point of Common Coupling (PCC) busbar to enhance the system performance. The hybrid power system is controlled to operate at the unity power factor and also the Maximum Power Point Tracking (MPPT) technique is applied to extract the maximum power during the climatic conditions changes. Modeling and simulation of the hybrid power system have been performed using MATLAB/SIMULINK environment. Moreover, the paper presented a comprehensive case study about the realistic monthly variations of solar irradiance and wind speed in the study region to validate the effectiveness of the proposed MPPT techniques and the used control strategy. The simulation results illustrate that the total annual electricity generation from the hybrid power system is 1509.85 GWh/year, where 118.15 GWh/year (7.83 %) generates from the PV station and 1391.7 GWh/year (92.17%) comes from the wind farm. Furthermore, the hybrid power system successfully operates at the unity power factor since the injected reactive power is kept at zero.

KEYWORDS:

1.      PV

2.      Wind

3.      Hybrid system

4.      Gamesa G80

5.      Gabel El-Zeit

6.      Egypt

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Figure 1. Configuration Of The Proposed Pv/Wind Hybrid System.

 EXPERIMENTAL RESULTS:

Figure 2. Pv Array Side Results.

Figure 3. Dynamic Action Of The Vsi Controller.

Figure 4. Dynamic Performance Of The Pv Station At The B1-Bus.

Figure 5. Gamesa Wind Turbine Results.

Figure 6. Dynamic Performance Of The Wind Speed At The B2-Bus.

Figure 7. Performance Of The Hybrid System At The Pcc Bus.

CONCLUSION:

This paper presented the detailed design, control strategy, and performance analysis of 250 MW grid-connected PV/wind hybrid power system in Gabel El-Zeit region, Egypt. This area is characterized by a good level of solar irradiation with an annual average value of 199.75 kWh/m2 and powerful wind speed with an average value of 14.08 m/s at 60 m hub height. The proposed hybrid power system consists of 50MW PV station based Sanyo HIP-200B PV module and 200 MW wind farm based Gamesa G80 wind turbine and it is inte- grated with the grid through the main PCC bus to support the system performance. The hybrid power system is adjusted to work at the unity power factor and also the MPPT algorithms are applied to capture the optimum power from the hybrid system under the changes of climatic conditions. Adaptive InCond MPPT technique based variable step-size is applied to the boost converter to extract the maximum power from the PV station during the solar irradiance variation. On the other 96540 VOLUME hand, a modied P&O MPPT strategy is implemented on the RSC of DFIG to obtain the maximum power from the wind farm during the change of wind speed.

Moreover, this paper analyzed the actual monthly changes of solar irradiance and wind speed in the study area to evaluate the dynamic performance of the hybrid system and validate the efciency of the proposed MPPT techniques and the control systems. The simulation results have illustrated that the proposed InCond MPPT algorithm tracks accurately the MPPs, where the PV station power increases signicantly from 8.9MWin January to its maximum value (17.9 MW) in June, then it falls drastically to the minimum value of 8.2MW in December. Also, the DC-link voltage controller of the VSI adjusts successfully the DC-link voltage at its reference value (500 V) regardless of the solar irradiance variation.

Furthermore, the proposed P&O MPPT strategy sustains the optimal value of the wind turbine performance coefcient, Cp D 0:48, to extract the maximum power from the wind farm during the change of wind speed. Therefore, the active power rises dramatically from 127.6 MW in January to the rated value (200 MW) in June, then it decreases gradually until reaching the minimum value of 112.4MWin November. Besides, the GSC controller has successfully stabilized the DC-bus voltage to the desired value (1150 V) regardless of the wind speed change.

Additionally, the simulation results have shown that the total annual electricity generation from the hybrid power system is 1509.85 GWh/year, where 118.15 GWh/year (7.83 %) generates from the PV station and 1391.7 GWh/year (92.17%) comes from the wind farm. Moreover, the control system always maintains the hybrid power system at the unity power factor as the injected reactive power is kept at zero. Also, the PCC bus voltage is sustained perfectly constant irrespective of the changes in climatic conditions and the magnitude of generated active power.

 REFERENCES: 

[1] K. D. Patlitzianas, ``Solar energy in Egypt: Signicant business opportunities,'' Renew. Energy, vol. 36, no. 9, pp. 23052311, Sep. 2011.

[2] H. M. Sultan, O. N. Kuznetsov, and A. A. Z. Diab, ``Site selection of large-scale grid-connected solar PV system in egypt,'' in Proc. IEEE Conf. Russian Young Researchers Electr. Electron. Eng. (EIConRus), Jan. 2018, pp. 813818.

[3] Ministry of Electricity and Renewable Energy. (2018). New and Renewable Energy Authority (NREA) Annual Report for the Egypt.[Online]. Available: http://www.nrea.gov.eg/Content/reports/Englishv 2AnnualReport.pdf

[4] M. EL-Shimy, ``Viability analysis of PV power plants in Egypt,'' Renew. Energy, vol. 34, no. 10, pp. 21872196, Oct. 2009.

[5] M. G. M. A. Y. Hatata and M. Rana Elmahdy, ``Analysis of wind data and assessing wind energy potentiality for selected locations in Egypt,'' Int. J. Sci. Eng. Res., vol. 6, p. 6, Mar. 2015.

Modeling, Simulation and Implementation of a Five-Phase Induction Motor Drive System

 ABSTRACT:  

This paper presents a comprehensive simulation model of a five-phase induction motor drive system. Both open loop and closed-loop control is elaborated. The complete component modeling is developed using ‘simpower system’ blocksets of Matlab/Simulink. To address the real time implementation issues, dead banding of the inverter switches are also incorporated in the simulation model. To validate the modeling procedure, experimental implementation is done in TMS320F2812 DSP platform with a custom built five-phase drive system. Excitation, acceleration and loading transients are investigated. The developed simulation model is fully verified by the real time implementation.

 KEYWORDS:

1.      Five-phase drive

2.      V/f control

3.      Induction motor

 SOFTWARE: MATLAB/SIMULINK

 BLOCK  DIAGRAM:

 

Fig. 1. Constant V/F control scheme for a five-phase drive.

   EXPERIMENTAL RESULTS:

 

Fig. 2. Speed response for open-loop constant v/f control at no-load.

Fig. 3. Speed response for constant v/f control at rated load operating at

1500rpm

Fig. 4.(a) Speed response of a five-phase IM for open loop constant v/f

control at no-load (three step rising and one step fall).

 

Fig. 4.(b) Speed response of a five-phase IM for open loop constant v/f

control at no-load(step rising)

Fig. 5. Speed response of a five-phase IM for open loop constant v/f

control at rated load operating at 1500rpm

 

Fig. 6. Speed response for closed-loop constant v/f control of a five-phase

Induction motor.

 

CONCLUSION:

This paper presents a complete simulation model to simulate a five-phase induction motor drive system for constant v/f speed control method. The simulation model is developed using simpower system block sets of the Matlab/Simulink software. Step by step model development is elaborated. Dead banding in the simulation procedure is presented. A detailed simulation results are presented to validate the modeling procedure. Experimental set up is discussed and the experimental results are provided to exactly match the results obtained using simulation. This proves the successful implementation of the control scheme.

 REFERENCES:

[1] D. Novotony, and T.A. Lipo, Vector control and dynamics of ac drives, Clarendon Press, Oxford, UK, 2000.

[2] A.M. Trzynadlowski, The field oriented Principle in Control of Induction motors, Kuluwer Press, 1994.

[3] I. Boldea and S.A. Nasar, Vector Control of AC Drives, CRC Press, London, 1992.

[4] D.C. White and H.H. Woodson, Electromechanical energy conversion, John Wiley and Sons, New York, 1959.

[5] S.A. Nasar and I. Boldea, The Induction Machine Handbook, CRC Press, London, 2002.

Control of Solar Photovoltaic Integrated Universal Active Filter Based on Discrete Adaptive Filter

ABSTRACT:  

In this work, a novel technique based on adaptive filtering is proposed for the control of three phase universal active power filter with a solar photovoltaic array integrated at its DC bus.  Two adaptive filters along with a zero crossing detection technique, are used to extract the magnitude of fundamental active component of distorted load currents, which is then used in estimation of reference signal for the shunt active filter. This technique enables extraction of active component of all three phases with reduced mathematical computation. The series active filter control is based on synchronous reference frame theory and it regulates load voltage and maintains it in-phase with voltage at point of common coupling under conditions of voltage sag and swell. The performance of the system is evaluated on an experimental prototype in the laboratory under various dynamic conditions such as sag and swell in voltage at point of common coupling, load unbalancing and change in solar irradiation intensity.

KEYWORDS:

1.      Power quality

2.      Universal active power filter

3.      Adaptive filtering

4.      Photovoltaic system

5.      Maximum power point tracking

6.      Quadrature signal generation

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig. 1. System Configuration of Solar Photovoltaic Integrated Unified Active

Power Filter

EXPERIMENTAL RESULTS:

Fig. 2. Salient Signals in Extraction of Fundamental Positive Sequence Load

Current using Adaptive Filter

Fig. 3. Salient Signals in Series Active Filter Control

Fig. 4. Steady State Per Phase Signals of PCC and Load Side in a PV-UAPF Compensated System

Fig. 5. PV-UAPF Response under Nominal Condition

Fig. 6. PV-UAPF Response under Sag Condition

Fig. 7. PV-UAPF Response under Swell Condition

Fig. 8. PV-UAPF Response under Voltage Sag/Swell Condition at PCC

Fig. 9. PV-UAPF Response under Load Unbalancing Condition

Fig. 10. PV-UAPF Operation During Change in Solar Irradiation

CONCLUSION:

The performance of adaptive filter based PV-UAPF system under both steady state and dynamic conditions, have been analyzed in detail. The method of sampling the fundamental component of load current obtained through adaptive filter enables fast extraction of fundamental active component of  nonlinear load currents for all phases in one sampling. Only two adaptive filters are required to extract magnitude of active component of three phase load currents. This technique requires reduced computational resources while achieving good dynamic and steady state performance in extraction of fundamental active component of nonlinear load current. The system performance has been found to be satisfactory under various disturbances in load current, PCC voltage and solar irradiation. The series active filter is able to regulate load voltage at 220 V under variations of PCC voltage from 170 V to 270 V. The grid  current THD is maintained at approximately 3% even though  the THD of load current is 28% thus meeting requirement of IEEE-519 standard. The PV-UAPF system has been able to maintain the grid currents balanced under unbalanced loading condition.

The proposed topology and algorithm are suited for employing in conditions where PCC voltage sags/swells and load current harmonics are major power quality issues. Certain power quality issues not addressed include voltage distortions, flicker, neutral current compensation etc. This power quality issues can be addressed by modification of topology and control algorithm according to the requirements in the distribution system.

The PV-UAPF system provides dual benefit of distributed generation as well as improving power quality of the distribution system.

 REFERENCES:

[1] N. R. Tummuru,M. K. Mishra, and S. Srinivas, “Dynamic energy management of hybrid energy storage system with high-gain pv converter,” IEEE Transactions on Energy Conversion, vol. 30, no. 1, pp. 150–160, March 2015.

[2] B. Singh, A. Chandra, K. A. Haddad, Power Quality: Problems and Mitigation Techniques. London: Wiley, 2015.

[3] S. Devassy and B. Singh, “Control of solar photovoltaic integrated upqc operating in polluted utility conditions,” IET Power Electronics, vol. 10, no. 12, pp. 1413–1421, Oct 2017.

[4] S. Devassy and B. Singh, “Performance analysis of proportional resonant and adaline-based solar photovoltaic-integrated unified active power filter,” IET Renewable Power Generation, vol. 11, no. 11, pp. 1382– 1391, 2017.

[5] L. Ramya and J. Pratheebha, “A novel control technique of solar farm inverter as pv-upfc for the enhancement of transient stability in  power grid,” in 2016 International Conference on Emerging Trends in Engineering, Technology and Science (ICETETS), Feb 2016, pp. 1–7.