Methodology for the implementation Of 20 KW Grid Tied Solar Photovoltaic Power Plant With Inverter

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1 Methodology for the implementation Of 20 KW Grid Tied Solar Photovoltaic Power Plant With Inverter ABSTRACT S.G.KADIRAVAN, B.E.,M.Tech., Lecturer(Selection Grade), EEE Department, Seshasayee Institute of Technology Trichy, Tamil Nadu, India Solar Photovoltaic power plant has gained much attention in recent years due to its advantages in high efficiency with very low maintenance. A 20 KW solar power plant requires 64 numbers of solar panels, each of 325 Watts. This paper presents a detailed implementation methodology to erect such a renewable energy power plantwith inverter on rooftop. Energy consumptionof Seshasayee Institute of Technology(S.I.T.), Trichy, during daytime (Institution working hours), and night time were monitored. Based on the requirement, to meet out onethird of energy, this plant is suggested. Various types of panels and inverters, suggested by Tamilnadu Energy Development Agency(TEDA) were compared and plant is constructed with Central Financial Assistance(CFA). Keywords : Photovoltaic Panel, Solar Inverter, AC & DC Distribution Boxes, Lightning Arrester, Earthing. 1.0 INTRODUCTION:- The Sun radiates 180 billion MW of energy over the earth. Just one hour of this energy could meet the power needs of the entire earth for one year. Renewable energy is naturally available and free from pollution and without any running expenses. There is a huge gap between supply and demand exists in the power supply. Working of solar power plant (On Grid Solar): When sunlight hits the solar photovoltaic (PV) panels, electricity (or 'solar energy') is produced. The electricity then runs from the solar panels through an inverter. The inverter turns the power from direct current (DC) into alternating current (AC), which you can then use for electronic appliances in your home. If the appliances in your home are turned on while solar power is being produced, the power runs through the switch board and the solar power is sent to your appliances. If electrical appliances are switched off, or if excess solar power is being produced, the power gets sent to the grid which is measured by the meter box. Your electricity retailer applies credits in exchange for the energy you produce. During the night, when your solar power system is not producing energy, you will draw power from the grid, which you can pay for with credits earned from exporting solar power during the day. 755

2 Grid-tied systems are the most common type of solar PV system. Grid-tied systems are connected to the electrical grid, and allow residents of a building to use solar energy as well as electricity from the grid. Grid-tied systems do not need to produce 100% of the electricity demand for a home or business. When there is no demand for energy, the solar panels send excess electricity back out into the grid for use elsewhere. When a home or business is using energy, but the solar panels aren't producing enough energy (at night, or on a stormy day), electricity from the grid supplements or replaces electricity from the panels. Owners of a grid-tied system complete a net metering agreement with their utility. This agreement allows utility customers to receive credit for the excess energy they generate, typically credited as a kilowatt-hour credit on the next month's bill. Net metering policies and agreements are different for each utility. Living with a grid-tied solar PV system is no different than living with utility electricity, except that some or all of the electricity you use comes from the sun. Grid-tied systems do not provide protection from power outages. When the electrical grid fails, gridtied systems will not continue to operate. This allows utility employees to fix the power lines safely without wasting time identifying solar energy systems that are still feeding electricity into the power lines. Tamil Nadu Energy Development Agency in its letter regarding Methodology for Implementation of Grid Connected Rooftop Solar Projects under open category, indicated the benchmark cost, which would be applicable for availing CFA under open category stated the following. S. No Capacity in kw Eligible CFA % of Rs.60,000/- (or) Benchmark cost for whichever is less % of Rs.57,100/- (or) Benchmark cost for whichever is less 3. Above % of Rs.56,482/- (or) Benchmark cost for whichever is less 756

3 The rules for availing CFA are, Minimum Capacity of project is 1 kwp and Maximum Capacity of project is 500 kwp at single beneficiary location. Only indigenously manufactured PV modules and Balance of System (BOS) as per MNRE specification and standards will be allowed for availing capital subsidy. The lowest project cost/ tariff discovered under the competitive bidding discovered by TEDA shall be applicable for all the proposals under open category. Various sectors were covered under this category, like, Schools, health institutions including medical college & hospitals, universities, educational institutions etc. [including those registered under the Societies Registration Act 1860 and the Indian Trust Act Initially the scheme was upto June 2018 only and it was extended till 30 th September, DEMAND MONITORING: ENERGY CONSUMPTION OF S.I.T. Seshasayee Institute of Technology(S.I.T.), Trichy, a Government Aided Polytechnic level Institution with a Low Tension Current Transformer(LTCT) service connection comes under Tariff II-B 1.As per our Electricity bill dated , number of units consumed was Kwhr and Electricity charges paid was Rs /. The Consumption pattern for the past two years was obtained from TANGEDCOwebsite and found that the peak was during August Number of units consumed at that time was and the charges were Rs.67928/ Assessment Date KWH Consumed TOTAL Reading Unit BILL 30/07/ /06/ /05/ /04/ /03/ /02/ /01/ /12/ /11/ /10/ /09/ /08/ /07/ /06/ /05/ /04/ /03/ /02/ /01/ /12/ /11/ /10/ /09/ /08/

4 Energy Consumption for 2 Years May-16Aug-16Nov-16Mar-17 Jun-17 Sep-17 Dec-17 Apr-18 Jul-18 Oct-18 Energy Consumed Tariff Energy Consumption for two weeks for various day orders and on weekends were measured and analysed. Day Order Consumption during College Hours Consumption from 5.15 pm to 9.30 am Total Consumption/ Day (Average) Week 1 Week 2 Week 1 Week 2 I II III IV V SATURDAY & SUNDAY (For 2 Days) Variation of load I Week Consumption during Day time Consumption during Night time Variation of load II Week Energy Consumption during Day time Energy Consumption during Night time Total Energy Daily Average = Kwhr 758

5 3.0 SOLAR PANEL POWER REQUIREMENT Based on the average daily requirement and actual monthly consumption, it was suggested to install a 20 KW Solar Photovoltaic Power Plant. In bright sunshine days, each KW capacity panel will produce 4 to 5 units. A 20 KW panel will produce a minimum of 80 Units and a maximum of 100 units per day. Cumulatively, 2400 to 3000 units will be generated per month, which meets about one-third of our demand. Case 1(Maximum Power generation, all days): Solar power proposed = 20 KW Number of units produced per KW per day = 5 Units Number of units produced for 20 KW per day = 20 X 5 =100 Units Number of units produced for 30 days = 100 X 30 =3000 Units Number of units generated in an year = Units Case 1I (Minimum Power generation, 300 days per year): Solar power proposed = 20 KW Number of units produced per KW per day = 4 Units Number of units produced for 20 KW per day = 20 X 4=80 Units Number of units produced for 30 days = 80 X 30 =2400 Units Number of units generated in an year(300 Days) = 24,000 Units Various makes offer different Wattage ratings per cell and panels. Capacities of mostly available Poly crystalline solar panels are, Wattage of solar cell Number of cells in one panel Total Wattage of panel Wattage of solar cell Number of cells in one panel Total Wattage of panel Various capacities of panels were analysed and 325 Watts panels of 64 numbers finalised, which would generate Watts. 4.0 Solar Panel Selection Five suppliers approved by TEDA were identified and requested to submit the bids. Parameters like Solar Panel details, Inverter details, Maximum power, balancing structures were compared. Panel Make, Voltage ratings, Power producing capacity per panel, Type of Crystalline structures, V-I characteristics of panels, Multistring technology, Integrated Grid Management functions and Reactive Power Provision, Web connect, Bluetooth provisions for Remote monitoring, 759

6 Inverter make, Mounting Structure Material, AC & DC Distribution Box details, Earthing Conductor material and Length of earth electrode, Type and size of Electrical Wiring Cables and Accessories, Lightning Arresters, Control Panel Box with ELCB & MCB, cost for Building Internal wiring, Cables from AC DB output to Grid point, All Civil works, additional Building Integrated SPV module Structure, Number of MPPTs, Weight of the installation, Warranty details, Operating temperature range, Resistance Against Hail, International Standards, Transportation charges, Roofing Structure cost, Accommodation for installation team, etc. were all collected and compared. 4.1 Selected items for the 20 KW Solar PV Grid Tied Power Generating System Multi Crystalline Solar PV Modules (Waaree), 20 KW Solar PV Modules 325Wp Poly. (Modules as per IEC Standards) -Nos. 64, Mounting Structure As per BIS, Solar PV Module mounting structure for Fixing Solar Modules,3 Solar PCU (Waaree), 20 KW Solar Grid Tied Inverter (As per IEC Standards), Remote Monitoringcombined in Inverter, Cables & Accessories, Accessories As per BIS Earthing Kit with Moisture Boost, Accessories As per BIS Lighting Arrestor, Cables As per BIS (4sq.mm. Copper Cable& 10sq.mm. Flexible Copper Cable), 16sq.mm. Armoured Aluminium Cable, As per BIS, GI Earthing Strip 25x3mm, DC DB As per BIS DC Distribution Box, AC DB As per BIS 4.2 Product Characteristics Model No. WS-325 Electrical Data at STC Maximum Power (Pmax) Voltage at Maximum Power (Vmpp) Current at Maximum Power (Impp) Open Circuit Voltage (Voc) Short Circuit Current (Isc) 325 Wp V 8.82 A V 9.55 A Panel Efficiency 16.75% Power Tolerance (Positive) +1.5% Standard Test Conditions (STC): air mass AM 1.5, irradiance 1000W/m 2, cell temperature 25 C 760

7 Electrical Data at NOCT Temperature Nominal Operating Cell Temperature (NOCT): 800W/m 2, AM 1.5, windspeed 1m/s,ambient temperature 20 C Operating Temperature Range -40~85 C Temperature Coefficient of Pmax Temperature Coefficient of Voc Temperature Coefficient of Isc %/ C %/ C %/ C Maximum Ratings Maximum System Voltage Maximum Reverse Current Series Fuse Rating 1000 V 15 A 15 A Material Data Panel Dimension (H/W/D) Weight Cell Type Cell Size 1960x990x40 mm 22.5 kg Polycrystalline mm Cell Number 72 Glass Type Tempered, Low Iron Glass Thickness Encapsulant Type 3.2 mm EVA Frame Type Anodized Alloy Aluminium 761

8 Junction Box Protection Class IP 67 Connector Type MC4 Cable Cross section 4 mm 2 Cable Length 1200 mm 5.0 Cash Flow Number of units produced for 300 days = 80 X 300 =2400 Units Under Tariff II B I, for Government Aided Educational Institutions, Cost/ Kwhr charged is Rs Cost of energy produced by 20 KW solar panel in an year = 24000X5.75 = Rs.1,38,000 Cost of 20 KW solar panel, Inverter, All Accessories and Commissioning = Rs.8,37,550 Pay back period = 8,37,550 /1,38,000 = 6.06 Years Expected life of solar panels is 25 Years. Minimum amount saved in remaining period = Rs.26,13,720(Provided, no hike in Energy bill) 5.1 Environmental & Other Benefits CO2 Reduction in 25 years 5,57,403 kgs. Equivalent Tree Plantations - 54,000 Nos. Water Saving in 25 years against Thermal Power - 32,64,789 kl Unlimited Ecological Benefits With Remote Monitoring & Data Logger with Mobile App. No Fuel Cost, Low Maintenance, Proven Technology. Can be compatible for Net-Metering and Grid Export. Carbon Credits/ REC - can be claimed based on energy generation. 6.0 RESULTS If there is no load in the system, generated units from solar will be included in the consumption without net metering. As an application for birectional Net metering is given to TANGEDCO, power production by solar panels is enabled only during college hours(from 9.30 am to 5.15 pm). This also for five days per week (Except on Saturdays& Sundays) only. Generation is isolated from distribution panel by disconnecting it from DB, using a switch provided in Inverter. Following table shows the quantity of energy generation for two weeks period since, installation is completed. 762

9 Days of the week Energy generated Energy generated during First during Second week(kwhr) Week(KWHr) Monday Tuesday Wednesday Thursday Friday Energy generated during First week(kwhr) Energy generated during Second Week(KWHr) 7.0 CONCLUSION The Earth receives an incredible, in-exhaustible supply of solar energy. The sun, is a fusion reactor that has been burning for more than 4 billion years. It provides sufficient energy in one minute to supply all the world's energy needs for one year. In one day, it provides more energy than our current population would consume in 27 years. In fact, "The amount of solar radiation striking the earth over a three-day period is equivalent to the energy stored in all fossil energy sources." By effectively harnessing this power using solar panel, energy crisis will not be a problem for our future. 8.0 FUTURE WORK Based on online monitoring data, generation will be compared during peak and off sunshine periods. A system to supply pressurised water, to clean the solar panels from dirt, dust and bird droppings is recommended. Periodical cleaning of panels will improve its efficiency. If needed, more panels will be added to existing system, to meet the increasing demand with high capacity inverter or with a new arrangement, at a different location. 763

10 9.0 REFERENCES 9.1 BOOK REFERENCES: [1].S.Rao, Dr.B.B.Parulekar - Energy Technology (Non Conventional, Renewable and Conventional) [2]. Ranjan Rakesh, Kothari D.P, Singal K.C- Renewable Energy Sources and Emerging Technologies, PHI [3]. D. Mukherjee, Fundamentals of Renewable Energy- New Age International Publishers [4]. O.P. Gupta, Energy Technology - Khanna Book Publishing House [5]. Solar Energy Utilisation- G.D.Rai Khanna Publishers 9.2 JOURNAL REFERENCES: [1] MNRE. 2010a. Report Available from ( [2] MNRE. 2010b. Typical Climatic Data for Selected Radiation Stations (The Data Period Covered: ), Solar Radiation Hand Book. Available from ( [3] Venkata Ramana, P. and Sinha, C Renewable energy technologies and climate change policies in India. International Journal of Environmental Technology and Management, 1(4): [4] J. Douglas, "Renewables on the Rise", EPRI Journal, vol. 16, no. 4, pp , June [5]R. Ramakumar, "Economic Aspects of Advanced Energy Technologies", Proceedings of the IEEE, vol. 81, no. 3, pp , March [6] E. S. Gavanidou, A. G. Bakirtzis, "Design of a Stand Alone System with Renewable Energy Sources Using Trade Off Methods", IEEE Trans. on Energy Conv., vol. 7, no. 1, pp , March [7].Fernandez-Infantes, A., Contreras, J. and Bernal-Agustin, J. L Design of grid connected PV systems considering electrical, economical and environmental aspects: a practical case. Renewable Energy, 31(13): [8] O. Ishihara, T. Hiyama, S. Kouzuma, S. Fujihiro, "Measurement and analysis of influence factors and efficiency of PV system Part 2: Analysis of results from annual measurements", presented at the Annual Meeting of the Japan Solar Energy Society, [9] M.G. Jaboori, M.S. Saied, A.A.R. Hanafy, "A contribution to the simulation and design optimization of photovoltaic systems", IEEE Trans. on Energy Conversion, vol. 6, no. 3, pp , [10] F. Stermole, J. Stermole, Economic Evaluation and Investment Decision Methods, Investment Evaluation Corporation,