Design and Power Quality Improvement of Photovoltaic Power

Design and Power Quality Improvement of Photovoltaic Power System 1

Design and Power Quality Improvement of Photovoltaic Power System Introduction and Previous Work 2

Design and Power Quality Improvement of Photovoltaic Power System Introduction ü This Lect presents a new approach for optimum design of rooftop grid-connected PV system installation on an institutional building at Minia University, Egypt as a case study. ü While the prices for fossil fuels are skyrocketing and the public acceptance of these sources of energy is declining, PV technology has become a truly sensible alternative. 3

Design and Power Quality Improvement of Photovoltaic Power System Thesis Objectives 1. A new approach for optimum design of rooftop grid-connected PV system is presented based on optimal configuration of PV modules and inverters according to not only MPP voltage range but also maximum DC input current of the inverter. 2. A comparative study between many configurations has been carried out taking into account PV modules and inverters specifications. 3. AEP, COE, SPBT and GHG emissions have been estimated using proposed MATLAB program. 4. A dynamic behavior of proposed grid-connected PV system is investigated using MATLAB/Simulink 5. Study the THD content in voltage and current waveforms at the PCC. 6. Develop a small-signal model of a buck converter in CCM and study the effects of load changes and input voltage variations on the proposed model. 4

Design and Power Quality Improvement of Photovoltaic Power System Background of PV Systems 5

Design and Power Quality Improvement of Photovoltaic Power System Introduction ü This chapter presents a background of PV systems. ü Firstly, the chapter study the energy situation in Egypt and discusses Egypt goals and policies regarding its RES especially solar energy resource. ü Secondly, solar PV energy applications share in Egypt are demonstrated and development of rooftop PV technologies is discussed. ü Finally, the chapter presents an overview of PV system types and its topologies 6

Design and Power Quality Improvement of Photovoltaic Power System Installation Examples Roof top of residence ( Grid connected ) Most popular installation style in Japan. (Almost 85% PV installations in Japan ) Owner can sell excess power to power utility. 7

Design and Power Quality Improvement of Photovoltaic Power System Installation Examples Roof top of school , hospitals and governmental buildings. (For education and emergency power) 8

Design and Power Quality Improvement of Photovoltaic Power System Optimum Design of Rooftop Grid-Connected PV System 9

Design and Power Quality Improvement of Photovoltaic Power System Introduction ü This chapter presents a new approach for optimum design of rooftop grid-connected PV system installation on an institutional building at Minia University, Egypt as a case study. ü The new approach proposed based on optimal configuration of PV modules and inverters according to not only MPP voltage range but also maximum DC input currents of the inverter. ü The study presented in this chapter includes two scenarios using different brands of commercially available PV modules and inverters. ü A comparative study between these configurations has been carried out taking into account PV modules and inverters specifications. ü AEP, COE, SPBT and GHG emissions have been estimated. 10

Design and Power Quality Improvement of Photovoltaic Power System Site Description Figure 3. 1: Google Earth™ image of Faculty of Engineering buildings’ layout 11

Design and Power Quality Improvement of Photovoltaic Power System Load Data Table 3. 1: Typical electrical appliances Load type Floor Lights (40 W) Fans (80 W) Total power / floor No. of units 565 36 34432 510 37 47978 435 33 26754 426 32 28552 416 20 22716 2352 158 94080 Total power 12640 W 53712 W 160432 W Table 3. 2: Typical energy consumption in the faculty for a recent year (2013) W Month Energy (MWh) Bills (EGP) Ground First Second Third Fourth Sum Airconditions (3 HP) 4 11 3 4 2 24 Marc Jun April May July Aug. Sept. Oct. h e 71. 8 54. 7 67. 4 62. 0 76. 2 80. 4 97. 4 110. 27 98. 4 50. 04 8 8 4 4 6 0 4 8 6 Jan. Feb. 2084 5 1588 6 14512 1849 4 1799 2 2211 5 2331 6 2825 8 29806 2855 3 Nov. Dec. 113. 7 6 105. 0 4 32990 30462 12

Design and Power Quality Improvement of Photovoltaic Power System Climate Data Table 3. 3: Monthly average climate data (k. W/m 2/day) for El-Minia, Egypt Month Radiation (k. Wh/m 2) Temp. , T (Co ) Jan. Feb. March April May June July Aug. Sept. Oct. Nov. Dec. 4. 7 5. 78 6. 58 7. 87 8. 03 8. 25 7. 9 7. 70 7. 20 6. 50 5. 59 14. 3 16. 9 17. 95 34. 3 23. 7 30. 15 33. 3 30. 6 31. 1 26. 7 21. 55 18. 2 Figure 3. 2: Hourly solar radiation on horizontal surfaces at El-Minia site 4. 77 13

Design and Power Quality Improvement of Photovoltaic Power System Methodology Radiation on tilted surfaces Mathematical modeling of PV module/array Calculation of optimal number of PV modules Optimal orientation and arrangement of PV modules Economic feasibility study & GHG emission analysis 14

Design and Power Quality Improvement of Photovoltaic Power System Methodology Radiation on Tilted Surfaces Estimation of monthly best tilt angle Calculation of radiation on tilted surfaces 15

Design and Power Quality Improvement of Photovoltaic Power System Methodology where; Mathematical modeling of PV module/array The performance of PV system is best described with usingle diode model or two-diode model Figure 3. 3: Equivalent circuit of a PV module 16

Design and Power Quality Improvement of Photovoltaic Power System Methodology Calculation of optimal number of PV modules 17

Design and Power Quality Improvement of Photovoltaic Power System Methodology 18

Design and Power Quality Improvement of Photovoltaic Power System Applications and Results Scenario No. 1 Four different types of PV modules with three different types of inverters have been used in this scenario. Figure 3. 5: Flowchart of proposed computer program in scenario No. 1 19

Design and Power Quality Improvement of Photovoltaic Power System Applications and Results Selected PV modules and inverters in scenario No. 1 Table 3. 6: Technical characteristics of selected PV modules in scenario No. 1 Module Item Mitsubishi PV-UD 190 MF 5 Suntech STP 270 S-24/Vb ET-P 672305 WB /WW 1 Sol Tech 1 STH-350 -WH 190 W 270 W 305 W 350 W 30. 8 V 44. 8 V 45. 12 V 51. 5 V 8. 23 A 8. 14 A 8. 78 A 8. 93 A 24. 7 V 35. 0 V 37. 18 V 43. 0 V 7. 71 A 8. 21 A 8. 13 A Dimensions, m 1. 658*0. 834 1. 956*0. 992 1. 652*1. 306 Efficiency 13. 7 % 15. 72 % 16. 2 % Number of cells 50 cell 72 cell 80 cell Cell type (Silicon) Polycrystalline Mono-crystalline Polycrystalline Mon-crystalline Table 3. 7: Characteristics of different used in scenario No. 1 Price/unit $340 $753 inverters $305 $525 Inverter Sunny Tripower HS 50 K 3 HS 100 K 3 Specification 20000 TL SMA Solar Han’s Inverter & Manufacturer Technology Grid Tech. co. Ltd. Pinverter 20. 45 k. W 55 k. W 110 k. W Max. DC current 36 A 122 A 245 A MPP voltage range 580~800 V 450~820 V Max. AC power 20 k. W 50 k. W 100 k. W Max. AC current 29 A 80 A 160 A Frequency 50 Hz Price/unit $3870 $8060 $14500 20

Design and Power Quality Improvement of Photovoltaic Power System Applications and Results Configurations of PV modules for each subsystem in scenario No. 1 Table 3. 8: Specifications for each subsystem in scenario No. 1 5 subsystem 2 subsystem 1 subsystem HS 100 K 3 HS 50 K 3 Sunny Tripower 20000 TL Inverter type Module Details Mitsubishi PVUD 190 MF 5 Suntech STP 270 S 24/Vb ETP 672305 WB /WW 1 Sol Tech 1 STH-350 WH 27 19 17 15 4 4 108 76 68 60 666. 9 V 665. 0 V 632. 06 V 645. 0 V 30. 84 A 32. 52 A 29 17 13 16 10 12 14 10 290 204 182 160 716. 3 V 595. 0 V 483. 34 V 688. 0 V 77. 1 A 92. 52 A 114. 94 A 81. 30 A 20 17 19 15 29 24 19 21 580 408 361 315 494. 0 V 595. 0 V 706. 42 V 645. 0 V 21

Design and Power Quality Improvement of Photovoltaic Power System Table 3. 9: AEP and COE results in scenario No. 1 COE ($/k. Wh) AEP (MWh/yr. ) Parameter Module Inverter Sunny Tripower 20000 TL HS 50 K 3 HS 100 K 3 Mitsubishi PV-UD 190 MF 5 Suntech STP 270 S-24/Vb ET-P 672305 WB /WW 1 Sol Tech 1 STH-350 -WH 228. 8893 228. 5928 195. 0641 238. 2875 245. 8443 245. 4365 208. 8333 254. 1732 245. 8443 245. 4365 207. 1121 250. 2018 0. 9565 1. 3988 0. 7017 0. 7984 0. 9370 0. 9304 1. 3793 1. 3727 0. 6792 0. 6725 0. 7804 0. 7756 Figure 3. 6: P-V characteristics of ET- 305 W PV module during a day in March Figure 3. 7: P-V characteristics of ET- 305 W PV module during a day in December 22

Design and Power Quality Improvement of Photovoltaic Power System Layout in Scenario No. 1 Figure 3. 8: Rooftop grid-connected PV system layout proposed in scenario No. 1

Design and Power Quality Improvement of Photovoltaic Power System Scenario No. 2 Five different types of PV modules with three different types of inverters have been used in this scenario. Figure 3. 9: Rooftop grid-connected PV system layout proposed in scenario No. 1 24

Design and Power Quality Improvement of Photovoltaic Power System Selected PV modules and inverters in scenario No. 2 Table 3. 11: Technical characteristics of selected PV modules in scenario No. 2 Module Item Mitsubishi PV-UD 190 MF 5 Suntech STP 270 S-24/Vb ET-P 672305 WB /WW 1 Sol Tech 1 STH-350 -WH Solar panel Heliene 96 M 420 190 W 270 W 305 W 350 W 420 W 30. 8 V 44. 8 V 45. 12 V 51. 5 V 60. 55 V 8. 23 A 8. 14 A 8. 78 A 8. 93 A 9. 0 A 24. 7 V 35. 0 V 37. 18 V 43. 0 V 49. 53 V 7. 71 A 8. 21 A 8. 13 A 8. 48 A Dimensions, m 1. 658*0. 834 1. 956*0. 992 1. 652*1. 306 1. 967*1. 310 Efficiency 13. 7 % 15. 72 % 16. 4 % Number of cells 50 cell 72 cell 80 cell 96 cell Cell type Polycrystalline Mono-crystalline Polycrystalline Mon-crystalline (Silicon) Table 3. 12: Characteristics of the different inverter ratings used in scenario No 2 Price/unit $340 $753 $305 $525 $420 Sunny Inverter GCI-10 k-LV Tripower ST 25000 TL HS 50 K 3 HS 100 K 3 Specification 20000 TL Han’s Inverter B&B SMA Solar B&B Manufacturer & Grid Tech. Power co. Ltd. Technology Power co. Ltd. Pinverter 10. 2 k. W 20. 45 k. W 26. 5 k. W 55 k. W 110 k. W Max. DC current 30 A 36 A 32 A 122 A 245 A MPP voltage 150~500 V 580~800 V 450~800 V 450~820 V range Max. AC power 10 k. W 25 k. W 50 k. W 100 k. W Max. AC current 25 A 29 A 40 A 80 A 160 A 25

Design and Power Quality Improvement of Photovoltaic Power System Configurations of PV modules for each subsystem in scenario No. 2 Table 3. 13: Specifications for each subsystem in scenario No. 2 Type Details 10 subsystem 5 subsystem 2 subsystem HS 50 K 3 Sunny Tripower 20000 TL GCI-10 k-LV Inverter type Mitsubishi PVUD 190 MF 5 Suntech STP 270 S 24/Vb ETP 672305 WB /WW 1 Sol Tech 1 STH-350 WH Solar panel Heliene 96 M 420 18 13 12 10 9 3 3 3 54 39 36 30 27 444. 6 V 455. 0 V 446. 16 V 430. 0 V 445. 77 V 23. 13 A 24. 63 A 24. 39 A 25. 44 A 27 19 17 15 17 4 4 3 108 76 68 60 51 666. 9 V 665. 0 V 632. 06 V 645. 0 V 842. 01 V 30. 84 A 32. 52 A 25. 44 A 29 17 13 16 11 10 12 14 10 12 290 204 182 160 132 716. 3 V 595. 0 V 483. 34 V 688. 0 V 544. 83 V 77. 1 A 92. 52 A 114. 94 A 81. 30 A 101. 76 A 26

Design and Power Quality Improvement of Photovoltaic Power System Figure 3. 10: Rooftop grid-connected PV system layout proposed in scenario No. 2 27

Design and Power Quality Improvement of Photovoltaic Power System Figure 3. 11: Rooftop grid-connected PV system layout proposed in scenario No. 1 28

Design and Power Quality Improvement of Photovoltaic Power System Chapter Modeling and Simulation Study of Grid. Connected PV System 29

Design and Power Quality Improvement of Photovoltaic Power System Introduction ü This chapter presents a simulation study, in steady state and transient conditions, for the PV system proposed in chapter three. ü A detailed dynamic mathematical model of a dual-stage, threephase rooftop grid-connected PV system is investigated. ü Also, the chapter presents a comparative study of THD content in voltage and current waveforms at the PCC for 2 L-VSI and 3 L-VSI topologies through Fast Fourier transform (FFT). ü A comprehensive set of simulation cases have been conducted. 30

Design and Power Quality Improvement of Photovoltaic Power System Description and Modelling Figure 4. 1: Schematic diagram of MATLAB/Simulink model for grid-connected PV system 31

Design and Power Quality Improvement of Photovoltaic Power System Modelling Modeling of PV module /array in MATLAB/Simulink Figure 4. 1: Equivalent circuit of PV array 32

Design and Power Quality Improvement of Photovoltaic Power System Modelling Three-Phase VSI Controller Scheme Figure 4. 1: Control scheme for three-phase grid-connected VSI 33

Design and Power Quality Improvement of Photovoltaic Power System Simulation Results Solar Radiation Profile Figure 4. 1: The hypothetical solar radiation distribution over the day 34

Design and Power Quality Improvement of Photovoltaic Power System Simulation Results PV Side Results Figure 4. 1: Simulated PV array voltage and current during a period represents a day Figure 4. 1: Duty cycle with and without MPPT algorithm Figure 4. 1: Simulated output power form PV array Figure 4. 1: Actual and reference DC voltage input to the inverter 35

Design and Power Quality Improvement of Photovoltaic Power System Simulation Results Grid Side Results Figure 4. 1: Simulated PV array voltage and current during a period represents a day Figure 4. 1: Simulated three-phase line current waveforms at bus B 2 Figure 4. 1: Zoom version of three-phase line voltage waveforms at bus B 2 Figure 4. 1: Zoom version of three-phase line current waveforms at bus B 2 36

Design and Power Quality Improvement of Photovoltaic Power System Simulation Results Grid Side Results Figure 4. 1: Simulated voltage and current waveforms of phase “A” at bus B 2 37

Design and Power Quality Improvement of Photovoltaic Power System Simulation Results Grid Side Results Figure 4. 1: Reference current and feedback current of the inverter in d-axis component Figure 4. 1: Simulated output voltage of 3 L-VSI before and after LC filter Figure 4. 1: Active and reactive power injected to UG Figure 4. 1: Zoom version of output voltage of 3 L-VSI before and after LC filter 38

Design and Power Quality Improvement of Photovoltaic Power System Simulation Results THD Content Analysis Figure 4. 1: THD content in phase “A” voltage waveform before LC filter for 2 L-VSI Figure 4. 1: THD content in phase “A” voltage waveform before LC filter for 3 L-VSI 39

Design and Power Quality Improvement of Photovoltaic Power System Simulation Results THD Content Analysis Figure 4. 1: THD content in phase “A” voltage waveform after LC filter for 2 L-VSI Figure 4. 1: THD content in phase “A” voltage waveform after LC filter for 3 L-VSI 40

Design and Power Quality Improvement of Photovoltaic Power System Simulation Results THD Content Analysis Table 4. 1: THD content in phase “A” voltage waveforms before and after LC filter for 2 L-VSI Time, hr. Radiation Before LC filter After LC filter (w/m 2) 08: 00 a. m. – 11: 00 a. m. 1000 362. 6 V 87. 25 % 359. 7 V 4. 03 % 11: 30 a. m. – 12: 00 p. m. 800 360. 5 V 87. 28 % 359. 3 V 3. 89 % 12: 30 p. m. – 01: 00 p. m. 1000 363. 8 V 86. 45 % 359. 7 V 4. 02 % 02: 00 p. m. – 03: 00 p. m. 500 355. 5 V 89. 01 % 358. 8 V 3. 93 % 04: 00 p. m. – 05: 00 p. m. 1000 363. 2 V 86. 81 % 359. 8 V 4. 00 % Table 4. 1: THD content in phase “A” voltage waveforms before and after LC filter for 3 L-VSI Time, hr. Radiation Before LC filter After LC filter (w/m 2) 08: 00 a. m. – 11: 00 a. m. 1000 363. 0 V 41. 13 % 359. 8 V 2. 08 % 11: 30 a. m. – 12: 00 p. m. 800 358. 9 V 41. 06 % 359. 5 V 2. 36 % 12: 30 p. m. – 01: 00 p. m. 1000 363. 7 V 40. 84 % 359. 9 V 2. 25 % 02: 00 p. m. – 03: 00 p. m. 500 355. 9 V 41. 63 % 358. 9 V 2. 14 % 04: 00 p. m. – 05: 00 p. m. 1000 363. 6 V 40. 94 % 359. 9 V 2. 13 % 41

Design and Power Quality Improvement of Photovoltaic Power System Simulation Results THD Content Analysis 4, 03% 4, 50% 4, 02% 3 Level VSI 3, 89% 3, 93%2 Level VSI 4, 00% THD 3, 50% 3, 00% 2, 36% 2, 25% 2, 08% 2, 50% 2, 14% 2, 13% 2, 00% 1, 50% 1, 00% 0, 50% 0, 00% 00 08: a. m . – 0 a. 0 11: m. 30 11: . – a. m . m. 0 p 0 12: 30 12: . – p. m . m. 0 p 0 01: 00 02: . – p. m . m. 0 p 0 03: 00 04: . – p. m 0 05: . m. 0 p Time, hr. Figure 4. 1: Comparison between THD content in both 2 L-VSI and 3 L-VSI 42

Design and Power Quality Improvement of Photovoltaic Power System Simulation Results THD Content Analysis Figure 4. 1: THD content in phase “A” voltage waveforms after LC filter for 2 L-VSI Figure 4. 1: THD content in phase “A” voltage waveforms after LC filter for 3 L-VSI 43

Design and Power Quality Improvement of Photovoltaic Power System Simulation Results THD Content Analysis Table 4. 1: THD content in each phase of current waveforms at bus B 2 for 2 L-VSI Time, hr. Radiation Phase A Phase B Phase C (w/m 2) 08: 00 a. m. – 11: 00 a. m. 1000 304. 4 A 2. 48 % 304. 4 A 2. 31 % 303. 3 A 2. 42 % 11: 30 a. m. – 12: 00 p. m. 800 252. 4 A 2. 74 % 252. 9 A 2. 62 % 251. 4 A 2. 98 % 12: 30 p. m. – 01: 00 p. m. 1000 319. 7 A 2. 31 % 319. 2 A 2. 22 % 318. 6 A 2. 28 % 02: 00 p. m. – 03: 00 p. m. 500 153. 1 A 4. 61 % 153. 3 A 4. 52 % 150. 2 A 4. 36 % 04: 00 p. m. – 05: 00 p. m. 1000 319. 3 A 2. 25 % 319. 1 A 2. 22 % 317. 5 A 2. 34 % Table 4. 1: THD content in each phase of current waveforms at bus B 2 for 3 L-VSI Time, hr. Radiation Phase A Phase B Phase C (w/m 2) 08: 00 a. m. – 11: 00 a. m. 1000 304. 3 A 1. 31 % 305. 7 A 1. 96 % 305. 2 A 2. 14 % 11: 30 a. m. – 12: 00 p. m. 800 251. 9 A 2. 61 % 253. 0 A 2. 63 % 253. 8 A 2. 50 % 12: 30 p. m. – 01: 00 p. m. 1000 319. 2 A 1. 94 % 319. 9 A 1. 96 % 320. 3 A 1. 96 % 02: 00 p. m. – 03: 00 p. m. 500 153. 1 A 3. 27 % 154. 0 A 3. 88 % 152. 4 A 3. 89 % 04: 00 p. m. – 05: 00 p. m. 1000 318. 9 A 1. 84 % 320. 7 A 1. 92 % 320. 0 A 1. 99 % 44

Design and Power Quality Improvement of Photovoltaic Power System Simulation Results THD Content Analysis Table 4. 1: THD content in each phase of voltage waveforms at bus B 2 for 2 L-VSI Time, hr. Radiation Phase A Phase B Phase C (w/m 2) 08: 00 a. m. – 11: 00 a. m. 1000 207. 6 V 4. 04 % 207. 7 V 4. 02 % 207. 7 V 4. 04 % 11: 30 a. m. – 12: 00 p. m. 800 207. 4 V 3. 94 % 207. 5 V 3. 89 % 207. 5 V 4. 00 % 12: 30 p. m. – 01: 00 p. m. 1000 207. 7 V 4. 02 % 207. 7 V 4. 00 % 02: 00 p. m. – 03: 00 p. m. 500 207. 1 V 3. 91 % 207. 2 V 3. 91 % 207. 1 V 3. 88 % 04: 00 p. m. – 05: 00 p. m. 1000 207. 7 V 4. 00 % 207. 8 V 4. 03 % 207. 7 V 4. 05 % Table 4. 1: THD content in each phase of voltage waveforms at bus B 2 for 3 L-VSI Time, hr. Radiation Phase A Phase B Phase C (w/m 2) 08: 00 a. m. – 11: 00 a. m. 1000 207. 8 V 2. 11 % 207. 7 V 2. 12 % 207. 8 V 2. 24 % 11: 30 a. m. – 12: 00 p. m. 800 207. 5 V 2. 30 % 207. 5 V 2. 37 % 207. 5 V 2. 26 % 12: 30 p. m. – 01: 00 p. m. 1000 207. 8 V 2. 24 % 207. 7 V 2. 23 % 207. 8 V 2. 22 % 02: 00 p. m. – 03: 00 p. m. 500 207. 2 V 2. 10 % 207. 2 V 2. 26 % 207. 2 V 2. 30 % 04: 00 p. m. – 05: 00 p. m. 1000 207. 8 V 2. 14 % 207. 7 V 2. 16 % 207. 8 V 2. 20 % 45

Design and Power Quality Improvement of Photovoltaic Power System 46