PAPER OPTIMUM DISPATCH OF HYBRID SOLAR THERMAL (HSTP) ELECTRIC POWER PLANT USING NON-SMOOTH COST… Optimum Dispatch of Hybrid Solar Thermal (HSTP) Electric Power Plant Using Non-Smooth Cost Function and Emission Function for IEEE-30 Bus System http://dx.doi.org/10.3991/ijes.v4i2.5699 Dash Saroj Kumar, Ray Priyambada, Panda Chinmaya Kumar GITA, Bhubaneswar, Odessa, India Abstract—The basic objective of economic load dispatch (ELD) is to optimize the total fuel cost of hybrid solar ther- mal electric power plant (HSTP). In ELD problems the cost function for each generator has been approximated by a single quadratic cost equation. As cost of coal increases, it becomes even more important have a good model for the production cost of each generator for the solar thermal hybrid system. A more accurate formulation is obtained for the ELD problem by expressing the generation cost function as a piece wise quadratic cost function. However, the solu- tion methods for ELD problem with piece wise quadratic cost function requires much complicated algorithms such as the hierarchical structure approach along with evolutionary computations (ECs). A test system comprising of 10 units with 29 different fuel [7] cost equations is considered in this paper. The applied genetic algorithm method will provide optimal solution for the given load demand. Index Terms—Economic Load Dispatch (ELD),Combined Cycle Plant(CCP),Genetic Algorithm(GA),Hybrid Solar Thermal Power Plant(HSTP), Evolutionary Computa- tions(ECs),Multi-fuel Effects(MFE) I. INTRODUCTION The basic theme of economic dispatch is to determine the optimal combination of power outputs of the generat- ing units in electric power system so as to optimize the total fuel cost for a certain load demand satisfying opera- tional constraints. The economic load dispatch (ELD) problem is analyzed basically through the input output characteristic or through the heat rate input output charac- teristic by taking real power output of ith generating unit (PGi) in the X axis and Fuel input in rupees per hour in the Y axis. Input-Output characteristic is approximated as a single quadratic variation curve which gives sub-optimal solutions. Usually the nature of Input-Output characteris- tics of modern generating units is non-linear because of multi-fuel effects (M F E) using combined cycle power plants (CCPP) and valve loading effects, which may lead to multiple local minimum points of cost functions. Hence it is more realistic to represent the Input-Output character- istic as a piece wise quadratic cost function to avoid huge revenue loss over time problems. This project develops algorithm approach for solving the economic dispatch problem for a test system of 10 plants having 29 fuel cost options. A salient feature of proposed approach is that solution time grows approximately linear with problem size. More over the inclusion of solar power plant in tan- dem with the thermal power plant reduces the emission level so as to maximize the power generation for solar plant leading to minimum utility of the solar generation. The quadratic cost function so chosen is minimized fol- lowing the reduction in emission level of Sulphur dioxide (SO2), carbon monoxide (CO), nitrous oxide N2O and other greenhouse gasses. The quadratic programming approach so chosen for the hybrid solar thermal power system optimizes the cost of generation of solar thermal power plant and simulation time as well. II. ECONOMIC LOAD DISPATCH The ELD [3] problem is to determine the optimal com- bination of power outputs of all the generating units to minimize the total fuel cost while satisfying the load de- mand from the operational constraints. Minimum fuel costs are achieved by the economic load scheduling of different generating units. Here we mean to ascertain the generation of distinct generators so as to obtain the total fuel cost as minimum so that the load demand is met out by net generation. A. Economic Load Dispatch Problem However, economic load scheduling was not of rele- vance when there were small power generating plants for each locality, such as urban power system, but now with the growth in the power demand and at the same time guarantee regarding the continuity of power supply to the consumer under normal conditions have forced the power system engineers to develop grid system. For such system the economic dispatch problem has become increasingly important. The objective in the economic dispatch of power system is to minimize the cost of meeting the ener- gy requirements of the system over some appropriate period of time and in a manner consistent with reliable service. The appropriate period may be as short as few minutes or as long as a year or more depending on the nature of the energy sources available to the system. B. Problem Statement for ELD with Non-Smooth Cost Function Let N be the number of units. i PG be the power supplied by the th i unit. PD be the load demand in MW 46 http://www.i-jes.org