Investigation of transformer's reactive power consumption for different operational voltages

Inhalt:
Transformers are an essential part of any power network allowing for the stepping-up and stepping-down of voltages in order to transmit power and minimise network losses. Ideally, a transformer would have zero resistance on both its primary and secondary windings, whilst the iron core would provide infinite permeability allowing for no internal losses and an efficiency of 100%. In practice this is never the case. This paper investigates the reactive power consumption of a single phase 200 VA, 220 V / 69 V transformer and a 5 kVA, 11 kV / 240 V transformer. Basic background information on the transformers is given. Open-circuit and short-circuit testing is applied to the transformer in order to determine their characteristics. The transformer's operation with regards to consumption of reactive power is investigated and discussed for varying voltage levels and loading conditions.