DC and AC coupling: which one is the best solution?

Transcription

1 DC and AC coupling: which one is the best solution? 1W. Suponthana, 2V. Salas and 3W. Pokakul 1Leonics Co., Ltd. Thailand. 2UC3M PV-Lab, Universidad Carlos III de Madrid, Spain 3SERT, Naresuan University, Thailand Phone: / wuthipong@leonics.com/vicente.salas@uc3m.es/wilailuk@leonics.com

2 Agendas - DC and AC coupling PV energy of systems - Efficiency of each type - Which one is better, DC or AC coupling? - Load profile impact performance and energy cost - What is the best solution? - Real performance from system in operation - Conclusion

3 Agendas - DC and AC coupling PV energy of systems - Efficiency of each type - Which one is better, DC or AC coupling? - Load profile impact performance and energy cost - What is the best solution? - Real performance from system in operation - Conclusion

4 Stand-Alone PV system Design Concept using DC Coupling : PV energy goes into system at DC Bus

5 Stand-Alone PV system Design Concept using AC Coupling : PV energy goes into system at AC Bus AC coupling Stand Alone PV-WT Hybrid System Grid Connect Inverter AC Bus Bi-Directional Inverter AC Load

6 Agendas - DC and AC coupling PV energy of systems - Efficiency of each type - Which one is better, DC or AC coupling? - Load profile impact performance and energy cost - What is the best solution? - Real performance from system in operation - Conclusion

7 AC Coupling VS DC Coupling Day time system efficiency when PV supply Load Efficiency from PV to supply load = 96% Efficiency from PV to supply load = 93.1% AC coupling Stand Alone PV-WT Hybrid System DC coupling Stand Alone PV-WT Hybrid System Grid Connect Inverter Charge Controller Inverter 96% 95% AC Load Bi-Directional Inverter AC Load 98% Real Load = Load + BDI Loss

8 AC Coupling VS DC Coupling Day time system efficiency when PV charge battery Efficiency of PV energy path to charge Battery = 82.08% AC coupling Stand Alone PV-WT Hybrid System Efficiency of PV energy path to charge Battery = 88.2% DC coupling Stand Alone PV-WT Hybrid System Grid Connect Inverter Charge Controller 96% 98% Inverter AC Load Bi-Directional Inverter AC Load 95% 90% 90% 82.08% from 100% of PV output 88.20% from 100% of PV output

9 AC Coupling VS DC Coupling Night time system overall efficiency when battery supply load Efficiency from PV to battery and Back to supply load = 74.07% AC coupling Stand Alone PV-WT Hybrid System Efficiency from PV to battery and Back to supply load = 79.6% DC coupling Stand Alone PV-WT Hybrid System Grid Connect Inverter Charge Controller 98% Inverter 95% AC Load Bi-Directional Inverter AC Load 95% 95% 88.20% from 100% of PV output 95% 82.08% from 100% of PV output

10 Agendas - DC and AC coupling PV energy of systems - Efficiency of each type - Which one is better, DC or AC coupling? - Load profile impact performance and energy cost - What is the best solution? - Real performance from system in operation - Conclusion

11 - Both of them are good in different times - DC coupling is better when PV is used to charge battery - AC coupling is better when PV is used to direct supply load System Efficiency Day time charge in to Battery Day time supply to Load Night time round trip supply load DC Coupling 88.20% 93.1% 79.60% AC Coupling 82.08% 96.0% 74.07% - DC or AC coupling which one is better should be effected by Load profile that the PV system operates.

12 Agendas - DC and AC coupling PV energy of systems - Efficiency of each type - Which one is better, DC or AC coupling? - Load profile impact performance and energy cost - What is the best solution? - Real performance from system in operation - Conclusion

13 Cost of Energy from using DC or AC Coupling when Load Profiles are different Simulated by using HOMER

14 1. Uses HOMER to simulate cost of energy 2. Same load energy consumption per day 3. Same PV power, Converter, Battery capacity 4. Change Load Profile - Flat Load, - High Day time Load, - High Night time Load 5. Change PV configuration - PV on AC bus - PV on DC bus

15 PV AC Coupling PV DC Coupling Cost of Energy (USD/kWh) PV AC coupling PV DC coupling Flat Load 0.217USD/kWh USD/kWh High Nigh time load 0.425USD/kWh USD/kWh High Day time load USD/kWh USD/kWh

16 HOMER simulation with DC and AC coupling with real village load profile

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18 Agendas - DC and AC coupling PV energy of systems - Efficiency of each type - Which one is better, DC or AC coupling? - Load profile impact performance and energy cost - What is the best solution? - Real performance from system in operation - Conclusion

19 The Hybrid DC and AC coupling can benefit by using better point of both PV at DC and AC coupling. Balance fluctuation of the Sun 96% Direct Supply load 96% form AC Coupling 98% Direct Charge Battery 98% From DC Coupling

20 The Hybrid DC and AC coupling can benefit by using better point of both PV at DC and AC coupling. Supply Night time Load With efficiency 95% form Battery 95%

21 Agendas - DC and AC coupling PV energy of systems - Efficiency of each type - Which one is better, DC or AC coupling? - Load profile impact performance and energy cost - What is the best solution? - Real performance from system in operation - Conclusion

22 Grid Connect Inverter MPPT Charge Controller Bidirectional Inverter

23 Grid Connect Inverter MPPT Charge Controller Bidirectional Inverter

24 MPPT Charge Controller Bidirectional Inverter

25 A performance evaluation experiment on a Hybrid DC and AC coupling to comparing system efficiency using IEC concept has result as follow η load = E use E in = E frompce +E to_battt E A_tobatt +E A(DC) +E from_batt PR = Y f Y r = (E A toload +E AtoBatt.η BDI +E A(DC).η load )/P o Y r E A(AC) E frompce E L(AC) E A(DC) E A_toBatt E A_toLoad E to_batt E from_batt

26 E A(AC) η= 89%, PR = 69.64% E L(AC) E to_batt E from_batt

27 η = 90%, PR = 74.78% E L(AC) E A(DC) E to_batt E from_batt

28 E A(AC) η = 92%, PR = 75.54% E L(AC) E A(DC) E to_batt E from_batt

29 New design approach Hybrid DC-AC Coupling can improve system efficient 3-7% by Use AC Coupling for Day time Load Use DC Coupling to Charge Battery for Night time Load

30 Design DC Couple side by using nigh time energy consumption and AC Coupling side using day time energy consumption Load Profile of haminadhoo Night Day Pattern load Real load 0: : : : : : : : : : : : : : : : : : : : : : : : kwh 2, , Ratio 70.20% 29.80% Peak power Average Load/h Add Increase factory 40% Cal Average kwh per hours

31 kw Real load Profile % pf PV % of Fuel Produce CO % 0.00% - kg/day Irradiation Ambient Temp kwh/m2.day 31.8 o C 0.00 Peak Load kw Aver. Load kw/h Total Load kwh/day Bidirectiona Inverter Grid Connected Inverter # of Inverter 250 kw 3 Units Units units Back Up DG Power rating kw AC Coupling PV kwp Consume Diesel Fuel - Liters/day Installation Area m 2 Fuel Consumption rate 0.28 Liter/kWh MPPT charger Battery Ah Vdc Units Cells Annual Load Energy consumption 1,408,608 kwh Annual Energy generated form PV 1,901,181 kwh Expect Batt Life 5.95 Years Annual Diesel fuel consumption - Liters Replace Energy Price IPP USD/kWh DC Coupling PV kwp Annual Diesel fuel reduction 0 Liters Installation Area m 2 Annual Diesel fuel amount saving 0 USD Total Investment 2,747,641 USD Simple Pay back period 5.62 Years Project Life 18 Year Confidential information, this hybrid minigrid design is property of Leonics Co., Ltd., may not reproduce without prio notice to Leonics Co., Project IRR reduce use of fuel 10.19% IPP 9.69% % Averag daily system operation condition and consumptions Site Name : TG. Labian Project Owner : Site Location (Lat./Long.) : 5.18 o N o E Design by Wuthipong S. Version/Rev. : 1A Date 16-Sep-14 Altitude : Meter (ASL)

32 MW scale Stand-Alone Hybrid Mini-Grid System (PV) = Photovoltaic Module, (I) = BDI + GCI, (B) = Battery, (DG) = Diesel Generator X.xx MW Total Power of INV+DG+PV T&C 14-Nov MW Kema 850 kwp (PV) 850 kw (I) 4,800 kwh (B) 1600 kw (DG) 3.45 MW T&C 25-Jan-14 Bario 906 kwp (PV) 1,100 kw (I) 3,860 kwh (B) 1,443 kva (DG) 4.93 MW Banggi 1,200 kwp (PV) 2,075 kw (I) 2,880 kwh (B) 1,650 kva (DG) 4.45 MW T&C 19-Nov-12 Tanjung Labian 1,212 kwp (PV) 1,650 kw (I) 4,320 kwh (B) 1250 kw (DG)

33 4.45 MW Tg. Labian Grid Connect Inverter 250kW x 3 = 750kW Bi-directional Battery Inverter 300kW x 3 = 900kW Diesel Generator 350kW 500kW 500kW GS GS GS MPPT Charge Controller 70 kw x9 = 630kW PV on AC Coupling Remote Station 255 kwp (Phase 2) PV on AC Coupling 750 kwp Battery 480Vdc 4,320 kwh PV on DC Coupling 512 kwp

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36 Grid Connect Inverter 75kW x 3 = 225kW Grid Connect Inverter 250kW x 3 = 750kW Bi-directional Battery Inverter 300kW x 3 = 900kW Diesel Generator 350kW 500kW 500kW GS GS GS PV on AC Coupling Remote Station 4.93 MW Banggi Battery 480Vdc 720 kwh Battery 480Vdc 2,880 kwh MPPT Charge Controller 70 kw x3 = 210kW

37 Main Contractor : USAHA SIRIMAS SDN. BHD. COD on : 25 January 2014

38 BDI 3 BDI 2 BDI 1 Charge Controller

39 GCI 1 GCI 2 GCI 3

40 SMU 1 HCCU ISC DC Combiner

41 Battery Bank 1 Battery Bank 2 Battery Bank 3

42 AC Bus Combiner

43 MV TF 1 MV TF 2

44 Agendas - DC and AC coupling PV energy of systems - Efficiency of each type - Which one is better, DC or AC coupling? - Load profile impact performance and energy cost - What is the best solution? - Real performance from system in operation - Conclusion

45 Conclusions - Both DC and AC coupling are good in different time - DC coupling is better when using with high nigh time load - AC coupling is better when using directly supply load at day time - The best performance is using both DC and AC coupling together in a PV system. - Load profile is useful in determining portion of DC and AC coupling to supply energy to PV system - The performance of Hybrid DC and AC coupling is higher than DC or AC coupling only in a PV system - Real plant performance designed by using Hybrid DC and AC coupling confirm the calculation and simulation.

46 Thank you for bring us electricity Children in Papua, Indonesia at the moment that they have electricity, Dec 2012