NONTYPICAL LOAD MODELLIN G IN LOAD FLOW CALCULATIONS

In this paper, the loads are considered into two categories, we call them typical and nontypical loads.Typical loads can be modelled as a constant active and reactive model in load flow calcuations. That Means, the power consumption of this kind of loads in independent of the voltage. In distribution systems, however some of the loads can not be exactly considered as a typical load such as, constant current loads This type of nontypical loads.The objective of this are called paper is special modelling of such kind of loads for the purpose of load flow calculations. Normally, we have not any mathematical information about the functional behavior of such loads, but we can obtain (V,I) through measurements, at many different points. We propose to use a cubic spline approximation to find a proper mathematical model in different intervals. i.e. each nontypical load which can be defined as I=f(v) is approximated by a proper cubic function in each interval.We then preform the power consumption calculation.This kind of modelling is combined with fast decoupled load flow program, and it has been tested in a typical distribution system.