University of South Wales Master of Sciences Thesis
Standalone hybrid generation system for the remote area of Thar, Pakistan
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Standalone hybrid generation system for the remote area of Thar, Pakistan In this paragraph a brief review of some of the published work on the hybrid generating systems. Reference [1, 2] presents a hybrid configuration comprising of a wind–diesel system originally developed by the Hydro-Quebec, aimed at reducing the cost of electricity supply in remote areas. The two main blocks of the system presented are, diesel- driven synchronous generator and the wind turbine driven by the asynchronous (induction) generator. The wind turbine block uses a 2- dimensional lookup table to compute the turbine torque output as a function of wind speed and turbine speed. At low wind speeds both the induction generator and the diesel-driven synchronous generator are required to feed the load. When the wind power exceeds the load demand, it is possible to shut down the diesel-generator. In this all-wind mode, the synchronous machine is used as a synchronous condenser and its excitation system controls the grid voltage at its nominal value. A secondary load bank is used to regulate the system frequency by absorbing the wind power exceeding consumer demand. In comparison to the system the system proposed here will be more reliable and economical to provide electricity to the remote areas as it include other renewable resources as well hence system will not only depend on wind energy and fossil fuel to run the system, in most of the cases when there is no enough wind energy the system uses sun irradiation to store the electricity to the batteries. [4] While if both of the resources is not available and consumer load requirement is high the system can use diesel generator to charge the batteries and also to provide electricity hence use of Genset will be less making it more economical and environment friendly system and also in the published design the system is using mixed coupling system which is more complicated and requires more DC and AC links hence make it more costly as well while In my project I will be adopting DC coupled topology to make it simple and also DC coupled are more efficient then AC, below is the block diagram of the published system design. [1] In the literature, most of the models used to represent a wind turbine are based on a non-linear relationship between rotor power coefficient and linear tip speed of the rotor blade [1, 4] Muljadi and Butterfield mention the advantages of employing a variable speed wind turbine and present a model of it with pitch control. In his model, during low to medium wind speeds, the generator and the power converter control the wind turbine to maximize the energy capture by maintaining the rotor speed at a predetermined optimum value. For high wind speeds the wind turbine is controlled to maintain the aerodynamic power produced by the wind turbine either by pitch control or by generator load control. However, generator load control in the high wind regions, in some cases suffers from the disadvantage of exceeding the rated current values of the stator windings of the generator. Care should be taken not to exceed the rated values of the current. |