An unconcealed struggle to optimise the operating cost of electricity can be easily witnessed when we refer contemporary researches based on load forecasting. Each of them has one primary aim in common, which is sustainable functioning of power system. Short term load forecasting (STLF) aims to predict system load over an interval of one day or one week. In power system the major operations like unit commitment, scheduling, load ow calculation and security assessments etc are mostly depends on STLF. An accurate electric load forecasting is an essential part in smart grid for smart generation scheduling. In this thesis six dierent models and their optimized models are presented, results shows that these models have great potential towards STLF.