Showing papers by "Kanzumba Kusakana published in 2015"

Optimal scheduled power flow for distributed photovoltaic/wind/diesel generators with battery storage system

Abstract: In this study, two control strategies involving ‘continuous’ and ‘ON/OFF’ operation of the diesel generator in the solar photovoltaic (PV)-wind-diesel-battery hybrid systems are modelled. The main purpose of these developed models is to minimise the hybrid system's operation cost while finding the optimal power flow considering the intermittent solar and wind resources, the battery state of charge and the fluctuating load demand . The non-linearity of the load demand, the non-linearity of the diesel generator fuel consumption curve as well as the battery operation limits have been considered in the development of the models. The simulations have been performed using ‘fmincon’ for the continuous operation and ‘intlinprog’ for the ON/OFF operation strategy implemented in Matlab. These models have been applied to two test examples; the simulation results are analysed and compared with the case where the diesel generator is used alone to supply the given load demand. The results show that using the developed PV-diesel-battery optimal operation control models, significant fuel saving can be achieved compared with the case where the diesel is used alone to supply the same load requirements.

Optimisation of battery-integrated diesel generator hybrid systems using an ON/OFF operating strategy

Abstract: This paper reports on the development of an optimisation algorithm based upon a genetic algorithm for the operation and control of battery-integrated diesel generator hybrid systems. The ON/OFF operating strategy has been applied to the diesel generator with the aim of minimizing the operation cost, subject to the load energy requirements as well as to the diesel generator and the battery operational constraints. The simulations have been performed using “Intlinprog” in MATLAB, and the results provide optimal generator setting and battery charging/discharging schedules for any given daily load profile. The model has been applied to two test examples and the simulation results shows that by using the hybrid system and taking into account the non-linearity in daily load demand and fuel consumption curve, more operation costs can be saved compared to the case where the diesel generator is used alone.

Optimal operation control of hybrid renewable energy systems

Abstract: Thesis (D. Tech. (Electrical Engineering)) -- Central University of Technology, Free State, 2014

Optimal energy management of an isolated electric Tuk-Tuk charging station powered by hybrid renewable systems

Abstract: Charging/discharging of a battery bank as well as its depth of discharge will influence its life span. Frequent discharge will contribute to a reduced life cycle; conversely minimal usage will prolong its life cycle. This paper investigates the possibilities of controlling and optimising the daily operation of a standalone hybrid renewable energy system by maximising the usage of the renewable resources whilst minimising the utilisation of the battery bank for supplying the required energy at an electric Tuk-Tuk charging station without any load rejection. The main objective is to develop an optimisation algorithm which will be employed to ensure that the energy stored in the battery banks is therefore utilised as a last resort when all means of supplying energy have been exhausted. The effectiveness and efficiency of the proposed control strategy is performed and simulated using fmincon in a Matlab environment. The results for different scenarios are presented and analysed for different potential sites in South Africa where the charging stations can be implemented.

Optimal Operation Control of Hydrokineticbased Hybrid Systems

Abstract: This chapter develops a mathematical programming model to optimize the operation of a hybrid energy system consisting of a hydrokinetic, photovoltaic, wind system, a battery bank, and diesel generator. The optimization approach is aimed at minimizing the cost function subject to the availability of renewable resources, total load energy requirements, as well as the diesel generator and the battery operational constraints. Furthermore, the mathematical models of all other components of hybrid, the proposed system, and the optimization control algorithm is also developed. The main purpose of the control algorithm proposed here is to minimize the use of the diesel generator in the electricity generation process, while maximizing the use of the hydrokinetic system and other available renewable energy sources. For simulation purpose, hourly water velocity, solar irradiation, wind data, and load demand data have been collected and used as an input data. The economic analysis has resulted in the calculation of optimized daily operation cost of the proposed hybrid system in summer and winter conditions. The obtained results represent also a helpful tool for energy planners and justify the consideration of hydrokinetic-based hybrid energy systems more seriously.

Pumped storage-based standalone hydrokinetic system: Feasibility and techno-economic study

Abstract: In this study, a pumped hydro storage is proposed to be used in conjunction with a standalone hydrokinetic system in off-grid power supply. The techno-economic feasibility of such combination is analyzed and compared to the option where batteries are considered as storage system. The system working principle is presented; the mathematical model and simulation model are also developed. Simulations are performed using two different types of loads in rural South Africa as case study to demonstrate the technical advantages as well as the cost effectiveness of the proposed supply option. The results reveal that the novel combination is a cost-effective, reliable and environmentally friendly solution to achieve 100% energy autonomy in remote and isolated communities.

Optimal operation scheduling of a hydrokinetic-diesel hybrid system with pumped hydro storage

Abstract: The present paper develops a model to optimize the daily operation of a hybrid energy system consisting of a hydrokinetic, a pumped hydro storage system and a diesel generator. The optimization approach is aimed at minimizing the cost function subject to the availability of water resource, the variable load requirements, and operational constraints of the hybrid system's components. The main purpose of the developed model is to minimize the daily amount of diesel fuel consumed to supply the load while maximizing the use of the hydrokinetic operating in conjunction with the pumped hydro storage. For simulation purposes, the hourly load demand, resource data for a selected rural area in South Africa have been collected and used as an input to the developed model. The economic analysis has resulted in the calculation of optimized daily operation cost of the proposed hybrid system in summer and winter conditions. The obtained results demonstrate that a substantial reduction in the daily operation cost can be achieved using the hybrid system compare to the case where the diesel generator is used alone.

Operation cost minimization of photovoltaic-wind-diesel-battery hybrid systems using “continuous” and “on-off” control strategies

Abstract: In this paper, two control strategies involving “continuous” and “ON/OFF” operation of the diesel generator in the solar photovoltaic-wind-diesel-battery hybrid systems are modeled. The objective of these proposed models is to minimize the system's daily operation cost while finding the optimal power flow considering the intermittent solar and wind resources, the battery state of charge and the fluctuating load demand. The non-linearity of the load demand, the non-linearity of the diesel generator fuel consumption curve as well as the battery operation limits have been considered in the development of the models. The simulations have been performed using “fmincon” for the continuous operation and “intlinprog” for the ON/OFF operation strategy implemented in Matlab. These models have been applied to two case studies; the results are compared to the scenario where the diesel generator is used alone to supply the same load demand. The results show that using the developed photovoltaic-wind-diesel-battery optimal operation control models, significant fuel saving can be achieved compared to the case where the diesel is used alone to supply the same load requirements.

Optimisation of the daily operation of a hydrokinetic-diesel generator power plant

Abstract: The present paper develops an optimization model for the operation of a hybrid energy system consisting of a hydrokinetic system, a battery bank and diesel generator. The optimization approach is aimed at minimizing the cost function subject to the availability of water resource, total load energy requirements as well as the diesel generator and the battery operational constraints. The main purpose of the control algorithm proposed here is to minimize the use of the diesel generator in the electricity generation process while maximizing the use of the hydrokinetic system. For simulation purpose, hourly water velocity, and load demand data for a selected rural area in South Africa have been collected and used as an input to the developed model. The economic analysis has resulted in the calculation of optimized daily operation cost of the proposed hybrid system in summer and winter conditions. The obtained results demonstrate that a substantial reduction up to 71% in the daily operation cost can be achieved using the hybrid system compared to the case where the diesel generator is used alone.

Daily operation cost minimization of photovoltaic-diesel-battery hybrid systems using different control strategies

Abstract: In this work, an optimal scheduling model is developed to minimize the operation cost of solar photovoltaic-diesel-battery hybrid systems. Furthermore, two operation modes of the diesel generator, namely the "ON-OFF" and the "CONTINUOUS", are modeled and integrated in the hybrid system operation mode. The principal objective of these developed models is to minimize the hybrid system's daily fuel expenses while optimizing the power flow from the different power sources and from the storage system. The variable character of the load demand, the efficient operation zone of the diesel generator as well as the charging and discharging constraints have been taken into account in the development of the models. These models have been applied to two test examples in South Africa; and the results are analyzed and compared to the case where the diesel generator is the only alternative of providing the load with electricity. Sensitivity analyses have been conducted on the diesel generator's size, and the battery control setting as key parameters. The results show that using the developed models, the daily operation cost can be significantly reduced compared to the case where the diesel is the only alternative of providing the load.