ABSTRACT
This chapter expresses leakage reactance calculations that are applied to a single-phase unit or to one phase of a three-phase transformer. It is usually desirable to design some reactance into a transformer in order to limit any fault current. In addition, these reactances determine the voltage regulation of the unit. The chapter discusses the general theory of inductance calculations. Reactances are obtained from the inductances by multiplying the inductances by the angular frequency under sinusoidal conditions. Self- and mutual inductances are usually defined in terms of flux linkages between circuits. The chapter focuses on how the magnetic energy can be related to inductances or leakage inductances from circuit considerations. It explores the leakage reactance for a two-winding autotransformer. X-line taps are taps connected to the X terminal of an autotransformer. They are used to regulate the low voltage without affecting the volts per turn of the autotransformer.
