Prospects of constructing 20 kV asynchronous motors

Abstract

20 kV distribution networks with all its components, such as transformers, switches, cables etc., have existed and been operating safely for many decades. From an economic point of view, it would be convenient to replace the transformer-motor combination by just a single 20 kV asynchronous motor, even if the motor itself were more expensive. The cost of a transformer, facilities and maintenance gained in this way would easily cover the extra costs of a motor. Efficiency considerations also make elimination of the step-down transformer desirable. Furthermore, modern technological advances make the production of 20 kV asynchronous motors possible, which is proved by the existence of 32 kV generators. The main problem lies in overcoming the differences between the construction of the aforementioned network equipment and the high-voltage asynchronous motor. This paper analyzes the weak points in the insulation system of an asynchronous motor, and proposes improvements allowing motor supply voltage to be increased to 20 kV. © 2006 IEEE.