A new method for modeling loss in distribution network

In this paper, a method is proposed for modeling the loss in power systems for the economic dispatch problem. It is based on the analysis of number of second order polynomial equations which model the loss so that by calculating the coefficients of these equations the loss relation is obtained which is the main objective. In order to determine these coefficients, first the loss curve for each unit is obtained while the real power output of the noted unit is changing and the output of the rest of units is constant. The same as this procedure is implemented mathematically and one second order polynomial equation for each unit is acquired. Using curve fitting between these curves and the equations, the coefficients are calculated. Two case studies are used to evaluate the proposed method and the results are compared with the results of conventional B-method and those obtained by the load flow. The accordance between the results of the proposed method and load flow shows the accuracy of the model. The method also enjoys simple equations and process and besides it is not as time consuming as some other methods.