7.1 Introduction

7.1 Introduction

Power transformers adjust voltage levels between different parts of the Electric Power System. We need power transformers to increase, and decrease voltage levels (Fig. 7.1).

! Diagram illustrating the flow of electrical power from a power station through various stages. It starts with a generator labeled "G" at the power station, followed by two transport stages at 15/220 kV and 220/400 kV. This is followed by a distribution stage at 400/66 kV, and finally, a consumption stage at 66/3 kV. Each stage is represented by interconnected circles.

Fig. 7.1 Electrical power system. Source Own elaboration

The transformer comprises a magnetic circuit and two electrical windings, as described above. The different configurations of a transformer include the laminated iron core (Fig. 7.2).

! Two electrical coils with visible wire windings are positioned side by side. Each coil is mounted on a rectangular base with holes for mounting. The coils are dark in color, and the wire is tightly wound around the core. The image is in grayscale, highlighting the texture and structure of the coils.

Fig. 7.2 Electrical transformer. Source From wikicommons under free to use license [1]

The primary winding is the one through which the power enters the transformer, the side through which it receives the energy. In contrast, the secondary winding is the one to which we connect the load, that is, the side through which it delivers the energy. We find real power transformers in the facilities of the electricity Network (Fig. 7.3).

! A black and white photo of an electrical transformer. The transformer has a ribbed metal casing and several insulators on top. It is positioned on a flat surface, and the background is plain, emphasizing the industrial design and components of the transformer.

Fig. 7.3 Power transformer. Original Source From wikicommons under 3.0 CC use license [2]

A step-up transformer is a device that has a lower input voltage than its output voltage. In such a transformer, the low voltage (LV) side is the primary, while the high voltage (HV) side is the secondary. In contrast, we classify a transformer as a step-down transformer when the input voltage is greater than the output voltage. In this configuration, the high-voltage side is the primary and the low-voltage side is the secondary.