The demand side management of electrical power systems is an issue of growing concern. In this study, annual load curves those have been obtained by field measurements on MV (31.5kV) feeders in an electricity distribution company in Turkey have been studied. Feeders supplying different type of customers (Agricultural irrigation, Commercial & Industrial and Residential) are classified through Peak and Night Ratio for the assessment of convenient incentive or price based methods. Statistical parameters, such as peak-to-average ratio, load factor and standard deviation are calculated. Active power deviations on annual and daily load curves are discussed.