The great advances in technology and industry have brought about an increase in the demand for energy in electrical power systems. In order to meet this increased demand, planning the operation of power systems and optimum operation of those systems are required. To obtain it, optimal power flow, reactive power optimization and solutions of the economic dispatch problem are required. The problem of Economical Dispatch (ED) is one of the limited non-linear optimization problems of electrical power systems. Operation of generators with minimum cost by being held in certain limit values is required. Intuitional methods resulting in better conclusions have been used in solving this complicated non-linear problem so far. In this study, the conclusions obtained on conditions with line loss and without line loss of 3 and 6 switchboards with thermal fuel were compared with each other by using different crossover operators of genetic algorithm (GA).