International Journal of Renewable Energy Technology (10 papers in press)
Corrective load shedding using fuzzy decision tree approach for real time voltage security enhancement of power system
by Sanjiv Kumar Jain, Narayan Prasad Patidar, Yogendra Kumar
Abstract: The paper proposes a novel algorithm for optimal load shedding using fuzzy decision tree. The presented algorithm is computationally efficient and can be utilised for on-line voltage security enhancement. It is based on Fuzzy Decision Tree. To avoid the voltage collapse condition and the system status is in non-correctable emergency, the final remedy is load shedding. Due to the feature selection approach of decision trees the method is fast enough for on-line load shedding of power system. The scheme is based on the notion of the static voltage stability margin. The vigorous classification of potential samples is simple due to the advantage of decision tree. The work presents the load shedding approach for all credible line outages. Classification of voltage security is done initially using test cases after the training of decision tree (DT). Which is further tested for secure and insecure status of the power system. The result shows the fast and accurate conversion of insecure cases to secure cases for a credible contingency condition. The initial database is prepared by wide variations of loading conditions at all the load buses using traditional approach of continuation power flow method. The effectiveness of the proposed algorithm of load shedding is tested using IEEE-30 bus system. The power management system applicability of the presented methodology is quite suitable for on-line control decisions to restore the power system in secure condition after disturbances.
Keywords: Continuation power flow (CPF),Credible contingencies; Fuzzy decision tree (FDT); Optimal Load shedding; Power system security; Voltage collapse,.
Interval Type-2 Fuzzy Logic Based MPPT Algorithm for Direct Drive PMSG Wind Turbine System
by Hanafy Hassan, Haitham Yassin, Mohab Hallouda
Abstract: This paper proposes a maximum power point tracking (MPPT) scheme for direct drive permanent magnet synchronous generator (PMSG) wind turbine system. In this scheme, the machine side converter (MSC) is controlled using the interval type-2 fuzzy logic control (IT2-FLC). The IT2-FLC is proposed owing to its ability to handle the uncertainties of the system parameters. The additional degree of freedom of type-2 fuzzy sets is due to the third dimension in the membership function which handles power oscillations damping and voltage recovery following parameter uncertainties in the network. The field oriented control is used to control the machine side and grid side converter. The design of the proposed control scheme of the MSC is presented in this paper.rnSimulation results, based on MATLAB-SIMULINK, for a 1.5 MW PMSG wind turbine are carried out to validate the proposed control scheme considering the various uncertainties. Also, experimental results, with hardware in loop (HIL) configuration, are obtained for reduced scale PMSG wind turbine to demonstrate the feasibility of the controller for real time applications. The results show a significant enhancement in speed regulation, mechanical stress reduction, and power harvest with the proposed control scheme.rn
Keywords: Interval type-2 fuzzy logic control (IT2-FLC); Permanent magnet synchronous generators (PMSG); Maximum Power Point Tracking (MPPT).
Experimental Investigation of the a Solar Cooker based on Evacuated Tube Collector with Phase Change Thermal Storage unit in Indian Climatic Conditions
by Avadhesh Yadav, Sanjeev Kumar, Ashish Kumar
Abstract: Solar cooker based on evacuated tube collector with phase change thermal storage unit is investigated. In this experimental setup, solar cooker with phase change thermal storage unit is attached with evacuated tube collector. The water is used as a working fluid, and it is filled in the evacuated tubes. During daytime, acetanilide (phase change material) stores solar energy throughout the sunshine hours. The energy stored by the phase change material during the daytime can be transferred to the cooking vessel entirely throughout the day up till the late evening time. Daytime and evening cooking processes are carried out separately at different loads. To enhance the performance of the solar cooker, the reflector is used beneath the evacuated tube collector. It is observed that in case of the high load, the solar cooker gives better performance with reflector as compared to without reflector. The maximum increase in the temperature of the working fluid, phase change material and cooking vessel with reflector is 18.3%, 20.4% and 20.8% respectively. Also, the cooking time is reduced to 30 minutes with the reflector. It is found that evening cooking using phase change material heat storage unit is faster than daytime cooking at low load.
Keywords: Thermal Performance; Evacuated tube collector; solar cooker; Phase change material.
Reliability assessment of a remote hybrid renewable energy system using Monte Carlo Simulation
by Sarangthem Sanajaoba, Eugene Fernadez
Abstract: Hybrid renewable energy systems have become a promising alternative for supplying power to remote locations because of the various negative environmental impacts caused by the conventional generating units. The reliability of power supply from such hybrid energy system is of prime concern owing to the stochastic power output from renewable energy sources. Unlike conventional generating units, the reliability aspects of a hybrid energy system are to be treated differently. System reliability depends on various factors such as the wind speed, solar radiation, load demand, wind turbine generator force outage rate (FOR) and hardware status of photovoltaic panels. In this context, a realistic simulation models for the reliability assessment of a remote hybrid energy system with battery storage is presented. The reliability analysis is conducted through Monte Carlo simulation to evaluate the loss of load expected (LOLE) reliability index. Finally, the proposed models are tested in a remote case study area.
Keywords: Hybrid energy system;Renewable energy; Solar photovoltaic; wind turbine generator; battery storage; Reliability; Monte Carlo simulation; Loss of load expected; Wind speed; Solar radiation.
Novel model for defining electricity tariffs using residential load profile characterisation
by Sima Davarzani, Ioana Pisica, Laurentiu Lipan
Abstract: In recent years, great attention towards enabling future smart grid functionalities in distribution networks creates significant changes in electricity load profiles. These changes require a new advanced paradigm in electricity pricing and tariffs definition aiming to increase the potential of responsiveness demand. This paper aims to propose a new model for designing residential electricity tariffs using their load profile clustering and characterization, taking into account social, technical and educational factors alongside the financial incentives. The methodology is based on estimation of the potential of demand responsiveness to dynamic pricing over time for different cluster of households with similar electricity consumption patterns. In this regard, different time of use pricing bands has been considered and compared with fixed price tariffs. Moreover, a baseline demand for each cluster of households has been determined based on the elasticity of demand to different static tariffs. The results show that the proposed model can provide distribution network operators (DNOs) and suppliers with a basic and general outline of defining more effective dynamic pricing schemes that reflect intermittent nature of residential demand.
Keywords: Demand response; electricity market; electricity tariffs; price elasticity; residential load profile.
Kinetic and Thermodynamic Modelling Studies of Enhanced Mixed Animal Wastes Biomethanization Co-digested with Pineapple Fruit Waste and Chicken Rumen
by Oluwafunmilayo A. Aworanti, Samuel E. Agarry, Oladipupo O. Ogunleye
Abstract: This work investigated the effects of feed/inoculums ratio, temperature and agitation speed on biomethanization of mixed animal wastes (cattle dung, pig dung, and poultry droppings) for enhanced biogas/biomethane production. The biomethanization experiments were carried out in anaerobic digesters at different process variables of feed/inoculums ratio (1:1, 1:2, 1:3, 2:1 and 3:1), temperature (25 - 60oC), and agitation speed (30 - 70 rpm). The digesters were incubated for 70 days. The results showed positive influence of feed/inoculum ratio, temperature and agitation speed on cumulative biogas yield, biomethane content and start-up time of biomethanization. Agitation speed of 30 to 70 rpm generally enhanced cumulative biogas yield in the range of 5.3 to 31.3% as well as the biomethane content in the range of 4.3 to 26.1% in comparison with biomethanization without agitation. Minimum cumulative biogas yield and biomethane content was respectively obtained with feed/inoculum ratio of 1:1, temperature of 25°C and agitation speed of 70 rpm; while maximum cumulative biogas yield with its biomethane content was attained with feed/inoculum ratios of 1:3 and 3:1, temperature of 60°C and agitation speed of 30 rpm, respectively. The biomethanization data were fitted to three kinetic growth models of Logistic, Exponential Rise to Maximum and Modified Gompertz, respectively. Modified Gompertz and Exponential Rise to Maximum kinetic models fitted very well to the data and thus showed better correlation of cumulative biogas production. The thermodynamic parameters of Gibbs free energy ( ), enthalpy ( ), entropy change ( ) and activation energy ( ) of biomethanization were estimated and evaluated and was found that the biomethanization process was thermodynamically feasible, spontaneous and endothermic in nature suggesting hydrogenotrophic methanogenesis pathway. The of the biomethanization process was found to be 3.324 kJ/ mol.
Keywords: Animal waste; Biogas; Biomethane Content; Process variables; Kinetics; Thermodynamics
Special Issue on: ECRES2017 Advances in Renewable Energy Systems
Optimal placement and sizing of DSTATCOM using Firefly Algorithm in the Distribution System
by Padmavathi K, Sudha K. R
Abstract: The electric power distribution system must be intended to operate and deliver acceptable level of electrical energy to consumers. Distribution Static Compensator (DSTATCOM) is a custom power device implemented in the distribution system to improve the power quality. This paper presents the optimal size and placement of DSTATCOM in the distribution system by using Firefly Algorithm (FA). Minimization of power loss and minimization of installation cost of DSTATCOM are considered as the Objective Function (OF), where the voltage and current limits of the buses are chosen as the optimization constraints. The performance of the proposed methodology using FA is demonstrated on IEEE 33 bus and 69 bus Radial Distribution Systems using MATLAB software. Backward/Forward sweep algorithm is used for load flow analysis of radial distribution system. The efficacy of the proposed methodology using Firefly algorithm (FA) is compared with the results obtained by using Immune Algorithm (IA).
Keywords: Backward/Forward load flow; DSTATCOM; Radial Distribution System; Firefly Algorithm (FA); Power Quality; Voltage Source Converter (VSC);.
Special Issue on: RESRB 2016 Research Development and Business of Renewable Energy Technologies
PERFORMANCE ANALYSIS OF DIFFERENT CONFIGURATIONS OF HEATING AND COOLING FOR A MULTIZONE BUILDING
by Saba Arif, Muzaffar Ali
Abstract: Multi zone HVAC designing is important as considerable amount of the worlds energy is used for heating, ventilation, and air conditioning (HVAC) systems used in multi zones. Hospitals are one of most critical multi zone buildings. So, proper designing of multi zone building will lead toward high savings in energy. Key step towards this goal is development of simulation based analysis approach for performance analysis of different air distribution systems. There is huge diversity in HVAC configurations used in commercial and residential sector which makes it difficult to model. Most common types of configurations are; constant volume with reheat, dual duct and Variable Air Volume (VAV) system, which is commonly found in large commercial buildings. Objective of this research is to investigate the impact of operational zoning and HVAC system operation strategies on energy performance of hospitals by maintaining comfort conditions. Load is calculated for each zone and optimized for creating multi zone building. Then after proper designing of central system, different HVAC configurations are designed for a hospital building. Afterwards, Energy simulation is used for forecasting best air distribution system for a multi zone building. Therefore; this research aims to simulate air distribution systems for energy saving potential for a hospital building in climate of Pakistan by developing different models in TRACE 700. Results show that COP of absorption chiller is highly dependent on components temperatures and out to be 0.78 in current research. Additionally, cooling capacities and NPV cash flow is determined for all three air distribution systems. According to results of economic analysis and cooling capacities, 52 ton load and required cfm in each zone is fulfilled by dual duct configuration in most efficient manner for multi zone buildings such as hospitals.
Keywords: Multi zone building; Air conditioning; energy; TRACE 700; NPV; Thermal comfort; VAV; CAV; dual duct.
Dome with dripping lateral pipe-fabricated solar water heater
by Mallikappa D.N, Vishwanath Nayak, Eshwa Raih
Abstract: This work deals with the design and fabrication of the semicircular solar water heater to use non-conventional energy to obtain hot water. The solar water heater has been made by using locally available materials like dripping lateral pipe, coconut coir, plastic drum, galvanized iron sheet, hose pipes etc. Work has been done on three types of set-ups. Experimentation has been carried out for the period two months. In the performance evaluation, inlet, outlet temperature of the water and the drum water temperature has been measured. Experimental investigation has been carried out by using three different trial setups, Semicircular setup without insulation and heat absorber plate, Semicircular setup with insulation and galvanized iron cover as a absorber, results are not favorable for getting hot water in both the cases. The setup with insulation blackened galvanized iron cover and transparent plastic cover which covers the pipes gives good amount of hot water. The maximum temperature attained in this set-up is 72 degrees. The water flow takes place due to thermo siphon effect.
Keywords: lateral pipe semicircular solar water heater; solar hour angle; instantaneous radiation; Dripping pipe.
Special Issue on: Sustainable Energy Technologies
STUDIES ON HYDROGEN FUELLED STATIONARY C. I. ENGINE OPERATED END-UTILITY SYSTEM
by Vinod Singh Yadav, Dilip Sharma, S.L. Soni
Abstract: The refineries turned in a better performance with their cumulative 181 million tones crude throughput, almost 7 per cent more than the previous fiscals achievement and a little over 2 percent of the planned target. The world is presently confronted with the twin crisis of fossil fuel depletion and environmental degradation. Combined residential and commercial energy demand is expected to increase in order to meet the expected increase in electricity demand as the worlds population shall grow and more people shall move to urban areas with access to electricity. The search for an alternative fuel, which promises a pleasant link with sustainable development, energy conservation, management, efficiency, and environmental safeguarding, has become highly noticeable in the present context. rnIn this investigation, fresh air with hydrogen enrichment was used as intake charge in a C. I. engine. Experiments were conducted on a 1-C, 4-S, air-cooled, stationary direct-injection diesel engine (Kirlosker TAF1) with maximum 1500 rpm and maximum 4.4 kW capacity coupled to an electrical generator. The injection timing (17
Keywords: Hydrogen-Enrichment; Injection timing; Flow rate of hydrogen; Performance.