Article
Economic Load Dispatch of Distributed Generation – An analysis of Thermal units with and without integration of PV units.
The means of distributing the everchanging load by properly scheduling the available units, both thermal and solar photovoltaic(PV) units of distributed generation so as to obtain the most economic operating cost, reducing the valve point loading effects, minimizing the emissions and making the maintenance of the units simpler is proposed in this paper. The analysis carried out on 6,15,31Thermal units without and with integration of solar PV units distributed at uniform geographical locations in the state of Telangana, India. The unique cost -per -hour characteristics of thermal generating units(TG), their emissions, valve point loading effects, ramp rate limits, prohibited operating zones and capacity constraints make the cost equation more complex also the cost of operation of thermal units is more.To supply for reliable, sustainable,ever increasing load requirements in most economical way, solar power plants have to be installed and integrated them to the grid evenly across various geographical locations in addition to the already existing ones. The allocation of the load i.e the Load Dispatch to the generating units both Solar PV and TG considering their various parameters which effect their cost of operation are evaluated for different load demands to obtain the most economical operating costs using the 3 algorithms, viz., Non-linear Generalized reduced gradient (GRG) algorithm, Evolutionary algorithm(EA) and Moth flame optimization algorithm (MFA) and the results are compared. While calculating ELD,the various parameters such as the fuel cost coefficients, valve point loading effects, penalty due to emissions, transmission losses, minimum and maximum capacities, ramp rate limits and prohibited operating zones of thermal power units and the parameters such as the minimum, maximum and average power capacities of a solar PV units placed at that particular location,which in turn depend on the solar irradiance values for the peak solar hours in any day of the year at that location and a factor of overestimation, underestimation of available solar power of PV units are considered. By integrating PV units with Thermal units, the transmission line losses, the cost incurred due to valve point loading effects, the penalties due to emissions, and mainly cost of load dispatch which is associated to all the aboveare greatly reduced more so in case of systems having lager number of units and with greater power demand.Even the maintenance of TG units becomes simpler as the loads are distributed to PV units. Non-Linear GRG and Evolutionary algorithm are simpler and can be evaluated in Solver an add-in ofMicrosoft Excel inMSOffice2010 version and above systems and consume less time and needs only a minimum coding knowledge.Also,the results obtained from MFA are more economical compared to Evolutionary algorithm and GRG algorithm andthe time taken for convergence to arrive at Global optima is also very less.
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