摘要:The object of the research is a mathematical model of the active part of the high-voltage instrument autotransformer with several output windings. The most challenging task in this model is leakage inductance calculation of single winding turns or groups of autotransformer winding turns. Also, a significant problem when calculating the parameters of the autotransformer are those operating conditions, that are close to no-load conditions.To create a mathematical model of the active part of a high-voltage autotransformer, taking into account the leakage inductance of each single winding turn (or groups of winding turns), and also the magnitude and type of the load, it is proposed to modify the known system of transformer equations detailed to the level of single turns (or groups of turns) and use the proposed method for determining the partial self- and mutual- leakage inductances by numerical methods.With a help of the developed mathematical model of the active part of a high-voltage autotransformer, a prototype of a 10 kV autotransformer with high metrological characteristics was designed and manufactured. Positive results of metrological certification of the created high-voltage autotransformer confirmed the possibility of calculating the parameters of such primary high-voltage transformers that can be used in Smart Grid networks in conjunction with analog-to-digital converters, thus unifying the electromagnetic primary high-voltage transformers.It is shown that the operating conditions of high-voltage autotransformers, close to no-load conditions, allow easily achieve high accuracy of high voltage transformation.