PICO-HYDRO POWER GENERATION USING DUAL PELTON TURBINES AND SINGLE GENERATOR 1 Ahmad Khusairee Yahya, 2 Wan Noraishah Wan Abdul Munim, IEEE, and 3 Zulkifli Othman, IEEE Centre for Electrical Power Engineering Studies (CEPES) Universiti Teknologi Mara, Shah Alam, Selangor, Malaysia 1 ahmadkhusairee@yahoo.com, 2 aishahmunim@salam.uitm.edu.my, 3 zulkifli_othman@salam.uitm.edu.my Abstract- Pico-hydro generation system is the effective way to help the remote communities by generates electricity using water as a main source. The main objective of this project is to introduce the green technology for the society in order to reduce the cost of fuel consumption. Green technology is an alternative energy whereas it is cheap, effective and reliable. It can reduce sources of fuel, capital costs and pollution. Furthermore, the idea of this project is to generate electricity by develop a prototype of picohydro generation system that produce low capacity to be used in rural communities. Generally, this project focused on designing and producing a pico-hydro system that can be used for small capacity equipments such as motor and bulb. Besides, this project able to analyze the output of generator based on the rotation of turbine. Water flow in the highpressure PVC pipe has potential to drive the turbine where it is connected with a generator to convert mechanical energy to electrical energy. In this project, it can be found that the pulley system can increase the efficiency of the turbine. The turbine that connected to the pulley system required lower speed compared to the turbine that connected directly to the generator. Keywords-component: pico-hydro generation system, penstock, Pelton turbine, pulley system, generator. I. INTRODUCTION Hydroelectricity is electricity using the energy from moving water. Hydroelectric power is a technology for generating electricity from the movement of water through rivers, streams, and tides. Water is passed through a conduit to turbine where it strikes the turbine blades and causes the shaft to rotate. To generate electricity, the shaft is connected to a generator that converts the mechanical energy into electrical energy. Pico-hydro is hydroelectric power which is capable of producing a maximum output of up to 5kW. Pico-hydro electricity is useful in small remote communities that require only a small amount of electricity such as for one or two fluorescent light bulbs and television or radio. Other than that, picohydro does not use fuel and free from pollution [10]. Furthermore, this system will invest less installation cost without the dam or reservoir. It also need less maintenance and replacement cost as well as environmental friendly for long term application [4]. However, hydro power generation also has disadvantages and losses. The main problem is about 30% losses of the total hydro power coming out of the nozzle that usually occur when the power in the water is converted into rotating mechanical power by hitting the turbine blades. Then, another 20% to 30% will be lost in the generator when the power is converted to mechanical energy [6]. Therefore, this pico-hydro project is developed to minimize the losses on turbine rotation and generator output. This project involves improving the green technology by using renewable energy such as water. It is also to help the remote communities to get their electricity with low cost of installation using green technology. II. PICO-HYDRO GENERATION Hydropower generation has several types such as large, medium, small, mini, micro and pico as shown in Table 1 [2]. This project focussed on pico-hydro. TABLE 1: TYPE OF HYDROPOWER GENERATION Hydro Power Capacity Description Large-hydro > 100MW Usually feeding a large electricity grid. Medium-hydro 15 100MW Usually feeding a grid Small-hydro 1 15MW Usually feeding into a grid Mini-hydro 100kW 1MW Stand alone scheme Micro-hydro Up to 100kW Provide power for small community or rural industry in remote area. Pico-hydro Under 5kW Require only small capacity
The process to generate electricity from pico-hydro generation is shown in Figure 1 whereas the main components of this system such as water, penstock pipe, turbines, pulley system, generator and load are required [12]. Besides that, the efficiency of the penstock depends on the material, length and diameter of the pipe. If large diameter pipeline, the less friction occurs and more power can be delivered to the turbine but the cost will be more expensive. The head of pipe for this project is 1m and the diameter of pipe is 15mm. In this case, the flow rate of water is calculated by using bucket method with the equation below: Flow Rate = (1) B. Pelton Turbine A. Penstock Pipe Figure 1: Process of Pico-Hydro Generation Penstock pipe plays an important role in the development of pico-hydro system whereas its purpose is to move the high pressure water to rotate the turbine [7]. Penstock pressure rating is critical because the pipe walls must be thick enough to withstand the maximum water pressure to avoid the risk of bursting pipe. This is because the pressure of the water in the penstock depends on the head where the higher the head, the higher the pressure. In this case, the un-plasticized polyvinyl chloride, upvc piping line as shown in Figure 2 will be used for the penstock because it is cheap and required less maintenance [6]. The upvc is better than mild steel and HPDE pipe in terms of friction, weight, corrosion, and cost, etc. The nozzle is required to maximize the amount of pressure in order to create the high speed of water to drive the turbine. Pelton turbine is a hydraulic turbine where it is rotate from the impulse of water jets on its bucket [8]. In this project, it is recommended to use Pelton turbine for the pico-hydro system because it is suitable for high head and low flow rate of water [6]. However, Alexander and Giddens said that a Pelton turbine is a universal turbine because it can be used for high head and low head [15]. Figure 3 shows Pelton turbine that has been developed. It consists of buckets mounted on the circular disk. Typically, the jets of water from nozzles with high velocity will hit the buckets to rotate the turbine [3].The important part when designing the Pelton turbine is the number of buckets on the disk. Figure 3: Pelton turbine The diameter of 0.16m, 12 buckets and the angle of 30 for each blade mounted together with shaft are used to give the smooth rotation and increase the capability of the turbine to rotate with the high speed. Figure 2: The piping system
C. Pulley System Pulley system is a method to change the speed of turbine. It consists of belt connected to two pulley wheels that called driver and driven each on a shaft. Furthermore, the speed of pulley wheel depends on the size of the wheel. The smaller wheel will spin faster than the larger wheel [14]. Figure 4 shows the pulley wheels for this project with diameter 0.12m and 0.06m. The output speed of this system is calculated using formula (2). it is connected with a bridge rectifier to convert AC output to DC output that can be operated on DC equipments. The layout of stator and rotor of the induction generator are shown in Figure 6 [13]. Output speed = (2) E. Electrical Circuit Figure 6: Stator and rotor layout. Figure 4: Driver and driven wheels Pico-hydro system generates an AC output from the induction generator. Therefore, the bridge rectifier is required to convert AC output into DC output as shown in Figure 7 whereby it can connected to the DC appliances such as DC motor, battery or LED. D. Generator Generator is a machine that used to convert the rotational energy from water turbine into electrical energy and at this stage there will be a reduction in efficiency [7]. The AC induction generator has been developed as in Figure 5 whereby the voltage produced by changing the magnetic field with the moving magnet. There are two parts when designing the generator such as stator and rotor where the stator consists of coil wire whilst the rotor consists of pole magnets. Figure 7: The electrical circuit of pico-hydro Generally, this project covers the entire engineering field which are electrical, civil and mechanical works must. Figure 8 shows the prototype of pico-hydro generation system that has been developed. Figure 5: Induction generator The generator is divided into two sides where 1600 number of turns of SWG26 coil and 4 pole magnets for each side are used. The output of the generator is depends on the magnetic field of magnet, the number of turn in a coil and the speed of rotor. Furthermore, the induction generator generates an AC output where Figure 8: Pico-hydro generation system
F. Power Estimation In theoretical, the amount of output power produced by pico-hydro system is depends on the flow rate of water (Q), the gravity (g), water flow head and the efficiency of the system (η) that presented in the equation (3). P = η (3) Where power is measure in watts, water flow rate is measure in l/s and gravity value is 9.81 m/ [8]. Normally, the efficiency is assumed 50% due to losses in penstock pipe, turbine and generator [9]. III. RESULTS AND DISCUSSION This section is focus on the testing, analyzing and troubleshooting the output of the pico-hydro generation system. Before that, the output power for this project is estimated as the following calculation. Flow rate of water (Q) = 10 l/10.53 s = 0.2 l/s Output power (W) A. AC Test = (0.5)(0.2 l/s)(9.81 m/ )(1m) = 0.981W TABLE 2: AC TEST ON TURBINE 1 WITHOUT PULLEY SYSTEM Current (ma) Voltage (Vac) 0 0 0 0 200 46.7 1.9 0.089 400 100 2.8 0.28 600 150.5 4.3 0.65 Table 2 shows the result for no load test on Turbine 1 whereby the turbine is directly connected to the generator on a single shaft without pulley system. From the result, the highest average speed which is 600rpm can generate 0.65W average output power. Table 3 shows the result for no load test on Turbine 2 whereby the turbine is connected to the pulley system. From the result obtained, the maximum average speed on Turbine 2 is 600rpm where it can generate 0.89W output power. 1 0.8 0.6 0.4 0.2 0 Figure 9: AC Power against speed characteristic. From the graph obtained on Figure 9, the average output power is increased proportionally to the average speed of turbines. It can be concluded that the Turbine 2 has more power than Turbine 1. T1(rpm) 0 500 1000 TABLE 4: AC TEST ON TURBINE 1 AND TURBINE 2 WITH NO LOAD T2(rpm) Power vs Current (ma) Voltage (Vac) Turbine 1 Turbine 2 0 0 0 0 0 200 112 120 3 0.36 400 220 175 4.8 0.84 600 342 220 8.3 1.83 Table 4 shows the result for no load test on Turbine 1 and Turbine 2. From the result, the highest average power obtained is 1.83W when average speed of Turbine 1 is 600rpm and Turbine 2 is 342rpm. In this case, Turbine 2 (T2) produces slower speed than Turbine (T1) due to change of speed by pulley system. 2 Power vs TABLE 3: AC TEST ON TURBINE 2 WITH PULLEY SYSTEM Current (ma) Voltage (Vac) 0 0 0 0 200 55.4 1.65 0.091 400 112 3.45 0.37 600 173 5.15 0.89 1.5 1 0.5 0 Turbine 1 Turbine 2 0 500 1000 Figure 10: AC power against speed characteristic.
From the graph obtained on Figure 10, the average output power is increased proportionally to the average speed of turbines. In this case, the speed of Turbine 1 is almost twice of Turbine 2. It can be concluded that Turbine 2 is more efficient compared with Turbine 1 due to slower speed required. Since the output power is in low capacity, the 5W AC bulb fails to light up. B. DC Test The rectifier was required to convert AC to DC output. In this case, the load of this test is LEDs. T1(rpm) TABLE 5: DC TEST ON TURBINE 1 AND TURBINE 2 T2(rpm) Current (ma) Voltage (Vdc) Power (W) 0 0 0 0 0 200 100 0.6 1.9 0.001 400 215 27.8 2.5 0.07 600 300 40 2.5 0.1 Table 5 shows the DC test for Turbine 1 and Turbine 2 where both turbines are operated simultaneously. From the result, the highest average power is 0.1W when average speed of Turbine 1 is 600rpm and Turbine 2 is 300rpm. 0.12 0.1 0.08 0.06 0.04 0.02 0 Figure 11: DC Power against speed characteristic Based on Figure 11, the DC output power is increased proportionally to the speed of turbines. In this case, the LEDs start to light up when the speed of the Turbine 1 reach at 300rpm. IV. Power vs 0 500 1000 CONCLUSION Turbine 1 Turbine 2 As a conclusion, this project is to understand the concept and process of generating electricity using pico-hydro generation system. Therefore, it can be concluded that this system is very efficient as an alternative way to produce electricity as the source is continually replenished and does not have limited supply. Other than that, the cost of designing this project is cheap compared with other technologies. The most important parts that need to be concerned when designing a pico-hydro system are the turbine and generator. Pelton turbine is a universal turbine where it can operate in low and high head. Moreover, this project able to analyze the output generator based on the rotation speed of the turbine. Based on this project, the pulley system is applicable in order to increase the efficiency of the turbine. The turbine that connected to the pulley system required lower speed compared to the turbine that connected directly to the generator. As a recommendation, this project can be further improved by proper design of the prototype. Increase the number of bucket on turbine will give the optimum rotation speed of the turbine. Furthermore, it is recommended to increase the number of turns in the coil and the magnetic field strength in the magnet on generator. For improvement, it is proposed to connect the DC output to the battery for charging purposes. V. ACKNOWLEDGEMENT This research was supported by the Universiti Teknologi MARA (UiTM) under the Research Intensive Faculty (RIF), 600-RMI/DANA 5/3/RIF (83/2012). The author(s) would like to acknowledge UiTM for the support and contributions VI. REFERENCES [1] Margeurite Rodger, Hydroelectricity Power: Power from Moving Water, in New York Crabtree, 2010. [2] Ahmad Maliki Omar, Renewable Energy, in Green Energy Resource Centre (GERC), Universiti Teknologi Mara, 2013 [3] I. Salhi, M. Chermani, S. Doubabi and N. Ezziani, Modelling and Regulation of a Micro Hydroelectric Power Plant, IEEE, 2008. [4] M. Musa, J. A. Razak, M. R. Ayob, M. A. Rosli, S. G. Herawan and K. Sopian, Development of Model System for Cost-Effective Pico-Hydro Turbine, in Sustainable Energy & Environment, 3 rd International Symposium & Exhibition, 2011. [5] S. J. William, B. H. Stark and J. D Booker, Modelling of a Multi-Source Low-Head Pico Hydropower Off-Grid Network, in IEEE ICSET, 2012. [6] H. Zainuddin, M. S. Yahaya, J. M. Lazi, M. F. M. Basar and Z. Ibrahim, Design and Development of Pico-Hydro Generation System for Energy Storage Using Consuming Water Distributed to Houses, in World Academy of Science, Engineering and Technology 59, p.p. 154-159, November 2009.
[7] M.F. Basar and M. Musa, An Overview of a Key Components in the Pico Hydro Power Generation System, in Renewable energy and Environmental Informatics, 2013. [8] Dr. R. K. Saket, Design, Development and Reliability Evaluation of Micro Hydro Generation System Based on Municipal Waste Water, IEEE Power & Energy Conference, 2008. [9] P.Maher and N.Smith, Pico hydro for village power: A practical manual for schemes up to 5kW in hilly area, 2nd ed, Intermediate Technology Publication, May 2001. [10] A.O.Tunde, Small Hydro Schemes Taking Nigeria s Energy Generation to the Next Level, Inaugural IEEE PES, 2005. [11] S. Nababan, E. Muljadi and F. Blaabjerg, An Overview of Power Topologies for Micro-hydro Turbines, 3rd IEEE International Symosium on Power Electronics for Distributed Generation Systems (PEDG), 2012. [12] M.F Basar, A. Ahmad, N. Hasim and K. Sopian, Introduction to the Pico Hydro Power and the Status of Implementation in Malaysia, in IEEE Student Conference on Research and Development (SCOReD), pp. 283-288, ISBN:978-1-4673-0099-5, Cyberjaya, Malaysia, December 2011. [13] The Pembina Institute, Build Your Own HydroElectric Generator. Available at: http://www.re-energy.ca/ Wan Noraishah Wan Abdul Munim was born in Malaysia, on July 10, 1982. She received her Diploma in Electrical Engineering (Telecommunication) from University Teknologi Malaysia (UTM), Bachelor of Engineering Technology in Electrical from Universiti Kuala Lumpur (UniKL), and M.Sc. in Electrical Power Engineering with Business from University of Strathclyde, Glascow, Scotland, UK in 2003, 2009 and 2009 respectively. She is currently a lecturer at Universiti Teknologi MARA (UiTM). Zulkifli Othman was born in Malaysia, on January 5, 1980. He received his Diploma and Bachelor of Electrical Power Engineering from Universiti Teknologi MARA (UiTM). He obtained his M.Sc. in University Malaya. He is currently a lecturer at UiTM. [14] GCSE Bitesize, Design & Technology. Available:http://www.bbc.co.uk/schools/gcsebite size/design/systemscontrol/mechanismsrev7.sht ml. [15] K.V. Alexander, and E.P Giddens, Optimum Penstock for Low Head Microhydro Schemes, Renewable Energy 33 (2008), Volume 33, Issue 3, p.p. 507-519, March 2008. VII. BIOGRAPHIES Ahmad Khusairee Bin Yahya was born on May 13, 1990 in Malaysia. He obtained his Diploma of Electrical and Electronic Engineering for fast track mode from Universiti Teknologi Mara (UiTM). He also received his Bachelor of Electrical Engineering (Power) from Universiti Teknologi Mara (UiTM). Currently, he works as Project Engineer at Pegasus Automation Sdn Bhd.