Design Installation and Testing of 1.6 kwp GPV System

Transcription

1 Design Installation and Testing of 1.6 kwp GPV System Napat Watjanatepin Rajamangala University of Technology Suvarnabhumi Nonthaburi Campus THAILAND Phone: , Fax: ABSTRACT This paper is to present the amorphous silicon (a- Si) solar cells that has the total power is 1.6 kwp. The solar panels installed on top of the Electrical Engineering Building at RMUTS is 23.7 m 2. This project has three important objectives. 1. Installation and testing results of 1.6 kwp Grid-Connected PV System (GPV), to find out the system efficiency by comparison with average test and peak test. 2. Measurement generating energy in one year and calculate generating cost, cost save and average energy generation 3. Comparison average electricity output by GPV system that installed in European countries, in Japan and in Malaysia The 1.6 kwp GPV System can potentially produce kwh of electricity per year and it can save electric cost of Bt per year. The cost for generated electric energy is Bt8.83 per kwh, average energy generation is kwh/m 2 /day. The overall efficiency of this system is 33./67.33% (average/peak), efficiency of PV arrays is 40.58/79.64% and efficiency of Grid-Connected inverter is 81.43/84.58%. The average electricity output per year is 1375 kwh/kwp higher than in Malaysia, Japan and Europe. Keywords : Amorphous silicon, GPV, Grid-Connected inverter 1. INTRODUCTION Between 1992 to 2001, 928MWp of solar PV had been installed in twenty of IEA-PVPS [8] participating countries. Almost 70% of these installations are connected to the grid. Since 1992,the growth rates of solar PV applications has risen from 20% to 40%. In 2001 alone, 257MWp of PVs were installed where 79% of which were in Japan and Germany. Thus, Japan recorded the highest PV power per capita of about 3.6 Wp/capita. Recently, the majority of the PV installations are as grid-connected PV system (GPV). This is due to various Government and utility supported programmes that drive the rapid rise of distributed GPV application in Japan, Germany, USA and Netherlands.[7] In 1983 the first GPV project of Thailand installed at Phuket province by Electricity Generating Authority of Thailand (EGAT), has generated electric power of kw. After that many solar projects about stand alone system, GPV and Hybrid system [1] were installed in Thailand. In 2000 The National Energy Policy Office (NEPO) of Thailand explored all of Solar (PV) project in Thailand, they found out that the total power is MWp. What was used for telecommunication system 36.5%, for battery charging system 32.5%, for GPV only 5.3% and another system 27.5%. However, Grid-Connected are interesting system because it cost lower than the stand-alone system. So, the Rooftop Grid-Connected PV system (RGPV) project in United States of America, Japan and Europe if to succeed can grow up to be the next project: For example in 1 million houses in USA, 100,000 houses in Europe and 70,000 houses in Japan. In 1987 Thailand had a PV project from EGAT and NEPO to cooperate for RGPV, this project installed 2.5 kwp kw of PV system at 10 houses and the next project was brought to the 50 houses during [3] This project we designed installed and tested using 1.6 kwp GPV on top of the Electrical Engineering Building at Rajamangala University of Technology Suvarnabhumi Nonthaburi Campus. We used amorphous silicon Kaneka Solar PV product of Japan and LEONICS 2.2 kw Single phase Grid-Connected Inverter model Apollo G-300 to convert DC power to AC power, all products of Thailand. 2. PRINCIPLE OF OPERATION 2.1 Design Procedure The design procedure conform to the GPV System Design review and approved procedures of Florida Solar Energy Center (FSEC-GP-70-01). This procedure comprise of six design processes.[5] 1. System design document 2. Electrical design 3. Mechanical design 4. Modules / Arrays 5. Inverter 6. Utility Interconnection

2 2.2 System Configuration The System block diagram of GPV System is shown in Fig 1. It consisted of 5 main parts; PV Array, Junction box,grid-connected Inverter, Production meter, protection system and Monitoring system Monitoring System 2.3 PV Array RS-232 DC AC Production meter & Protection system Junction box PV array (28 modules) Grid Connected Inverter Single phase utility grid Fig 1: The system block diagram The existing PV array is comprised of 28 Kaneka Solar PV amorphous silicon modules. The system consists of one set of PV array of 28 modules, arranged in four columns and seven rows, as seen in Fig 3. The modules are connected in series strings of four groups of seven parallel connected modules, for nominal voltage of 252 Volts dc as show in Fig 2. The output of PV array is connected to a LEONICS 2.2 kw Grid-connected Inverter. 2.4 Junction box The PV system has water proof junction box. The junction box used for connecting electric cable and install seven blocking diode rate is 3 A 1000 V to protect reverse current when there s shade on the top of PV array, as shown in Fig 4. We select the rating of diode by short circuit current of each PV panel is 1.12 A (manufactory data sheet), and chose safety factor is 200% the rating of diode need to more than 2.24 A Fig 4: Junction box and Blocking diode 2.5 Grid-connected Inverter The Grid connected Inverter used to convert DC power from PV array to AC power on grid. This project have LEONICS Inverter model G 300, its rate is 2.2 kw single phase output 220 V 50/60 Hz input voltage is VDC, Power factor > 0.98, low harmonic distortion <4% and MPPT control. The system was designed to generate power that would be injected directly to the MEA electric grid as show in Fig 5. Fig 2 : Single line diagram TO UTILITY GRID Fig 5: Single phase Grid Connected Inverter 2.6 Production meter and protection system Fig 3: The PV array has 28 PV panels The single phased kilowatt hour meter were installed for measuring electric energy from Grid Connected Inverter, we call it Production meter. The protection system consist of circuit breakers set in DC and AC part, set of surge protection devices were installed at output of inverter to bypass the high voltages induced by lightning. Those equipments were installed in the steel cabinet as show in Fig 6.

3 The electric cables were installed with rigid and EMT conduit between junction box and production meter box, approximately the distances are 30 meters from the control room. Fig 6: Production meter 2.7 Control and Monitoring System The control of Inverter operating function depends on the Inverter Specification. This means that the Inverter will be turned on in the morning and will automatically synchronize to the electric grid. After that it was operated all day until evening, it will just automatically shut down. So, the measurement system has current sensors, voltage sensors and data recorder that were include in the function of the Inverter, the data has been recorded after the set up of parameter by software. The monitoring system used LEONICS Apollo View software, it has local and Remote monitoring with PC,and display value of current, Voltage, Power and energy as shown in Fig 7. Fig 8: Galvanized Structure and grounding system The Grid-connected Inverter were installed in the control room and single phase output of Inverter were connected directly to distribution system, as show in Fig 9. Fig 9: Installation Inverter and Production meter 3.2 System Operating Fig 7: LEONICS Apollo View Software 3. INSTALLATION AND SYSTEM OPERATION 3.1 Installation 28 Solar panels were installed on the Galvanized Steel Structure. This structure has a slope of 15 degrees facing South. The area installed is 23.7 m 2, it uses stainless bolts fitting between PV panels and steel structure, and install Grounding System for thunderbolt safety, as show in Fig 8. Four workers and one technician worked for five days on May, 20. The system operating in this project single phase output of Grid connected Inverter will be connected to the electric grid, at sunrise. When the sunligth concentrate is enough to make the PV arrays, it can generate DC voltage approximately 165 V at 6.30 am to 7.00 am. The Inverters are operated until 6.00 pm (approximate), because the sunlight is low, it means that the PV voltage is less than 165 V, and then the Inverters are shut down. The Inverter output has the single phase kwh meter for measuring the electric energy generated. So, The GPV needed to have distribution system all the time. If the distribution system has a problem like shut down or unusual problem, the Grid Connected Inverter will stop operating for 1/50second. This operation is made for operator safety. The electrical data were measured by measurement function of Inverter and the examples are current and voltage. Those data sent to the Microcontroller for calculation and send all of data into the data logger. Its capacities can save data for 180 days. So, we can setup recording time and location of data text file by software. In

4 Energy (kwh) the same way when we want to load data from the Inverter, we can use local monitoring by RS-232 cable or remote monitoring function by modem, and save the data into text file. The details of data file and can take any data to make graph is found in the next step. 4. TESTING AND RESULTS 4.1 System testing This project has three objectives. 1.Installation and testing results of 1.6kWp GPV System, to find out the efficiency of the system. 2.Measurement generating energy in one year and calculate generating cost, cost save and average energy generation. 3.Comparision average electricity output by GPV system that installed in European countries in Japan and in Malaysia The tested period during June, 20 to May, 20. The way to find out the efficiency of 1.6 kwp GPV is random electrical data for 5 days (to be specific),october 20 th, 20, November 24 th, 20, December 19 th, 20, January 7 th, 20 and February 24 th, 20.These data in turm of average value and peak value. The measure electrical parameter thus, DC operating voltage, DC operating current, DC power, Inverter AC output (kw), Inverter AC voltage, Inverter AC current and Inverter AC output (kva). After that PV array-dc power efficient (Compare with kwp), Inverter-AC power efficiency and Overall efficiency is calculated. So, the energy data in 1 year was brought to calculate electric cost per year, cost for generated energy per kwh and average energy generation. 4.2 Results The results are maximum output kwh of electric energy on April, 20 and kwh on June, 20. So, the minimum output kwh of energy on January, 20 and kwh on September, 20, annual PV energy yield as show in Fig Ju Jul Au Se O t No De Ja Fe b M Apr il Fig 11: Annual PV Energy Yield (June Dec, 20 Jan May, 20) Ma In one year, a 1.6 kwp GPV can potentially produce 2, kwh of electric energy. The cost of investment for the production of electric energy is Bt8.83 per kwh (US$0.22 exchange rate US$1 per Bt40), it can save electric cost of Bt5, per year (US$134) and average energy generation of kwh/m 2 /day. The result of Inverter and System operating parameter and calculating efficiency for each PV system [4] and then average value calculated is PV array (DC power) efficiency is 40.58/79.64% (Average / Peak), Inverter (AC power) efficiency is 81.43/84.54% and the overall efficiency of this system is 33./67.33%. The investment cost of this project is Bt394,800 (US$9870), divided by the PV module cost is Bt308,560 (US$7714), the inverter cost is Bt60,000 (US$1500) and the installation cost is Bt26,240 (US$650). That means that the PV module cost is 78.15% the inverter cost is 15.19% and the installation cost is 6.66% of the projects total cost. Table 1: Inverter and Operation Parameter (Peak Test) Test Number Parameter DC Operating Voltage (V) DC Operating current (A) DC Power (kw) Inverter AC Output (kw) Inverter AC Voltage (V) Inverter AC Current (A) Inverter AC Output (kva) Power Factor Average PV array - DC Power efficency (%) Inverter - AC Power efficency (%) Overall efficency (%) Table2: Inverter and Operating Parameter (Average test) Test Number Parameter DC Operating Voltage (V) DC Operating current (A) DC Power (kw) Inverter AC Output (kw) Inverter AC Voltage (V) Inverter AC Current (A) Inverter AC Output (kva) Power Factor Average PV array - DC Power efficency (%) Inverter - AC Power efficency (%) Overall efficency (%) CONCLUSION The problem about energy supply and environmental pollution have always been great concerns to the world. Subsequently, the United Nation Frame work Convention on Climate Change (UNFCCC) and Kyoto Protocol were signed and ratified by many countries, as a sign of commitment to reduce greenhouse gasses (GHG) emission.

5 Electricity generation is one of the main contributors to GHG emissions. [7] Therefore, Solar energy is one of the solutions to combat the greenhouse effect. Solar PV technology is used to generate electricity and provides an effective solution to reduce GHG. This project is in agreement with the Thai government policy, and got budget on 20. The 1.6 kwp GPV was installed in May, 20 on top of the building of RMUTS Nonthaburi, Thailand. In one year, it can potentially produce 2, kwh of electricity (1,375 kwh/year per 1 kwp GPV). This output is higher than the average electricity output compared to the systems installed in European countries (800 kwh/year average), in Japan (1,000 kwh/year average) or Malaysia (1,200 kwh/year average). [7] In one year, the electricity savings is Bt 5, electricity production cost per kwh is Bt8.83 and average energy generation is kwh/m 2 /day. The PV array efficiency is 40.58%, the Inverter efficiency is 81.43% and the overall efficiency is 33.% Napat Watjanatepin received the B.S.Tech.Ed.(Electrical Engineering) from Institute of Technology Vocational Education,Thailand in 1985, and M.S.Tech.Ed (Electrical Technology) degree from King Mongkut s Institute of Technology North Bangkok, Thailand in His research interests include digital control system, power electronics drives and the PV system. 6. REFERENCES [1] Electricity Generating Authority of Thailand (EGAT), 1993, Solar and Wind Hybridge Generating System at Phuket, Research and Development Institute, Bangkok. [2] Chai Chewagate, 2000, Solar PV Generating Electricity, The National Energy Policy Office (NEPO), Jurnal 49 th (Jul-Sep 2000). [3] Electricity Generating Authority of Thailand (EGAT), 1997, Roof Top PV System Demonstration Project, Research and Development Institute, Bangkok. [4] Florida Power Corporation (FPC), 1998, Diagnostic Test Report on Florida Power Corporation s 15 kwp Amorphous Silicon Photovoltaic System. [5] Florida solar Energy Center, 20, Grid-Connected photovoltaic System Design Review and Approval. [6] Florida solar Energy Center, 1999, Evaluation of Grid-connected Photovoltaic System at the Nature Conservancy-Disney Wilderness Preserve. [7] Ahmad Hadri Haris, 20, Building Integrated Photovoltaic (BIPV) Applications in Malaysia : Current Status & Achievements, TNB Research Sdn Bhd. [8] IEA-PVPS, 2002, Trends in Photovoltaic Applications in Selected IEA Countries between 1992 and 2001, Task & Report IEA - PVPS T1 11 : 2002.