Power system fundamentals - Wind Power Integration: Connection and System Operational Aspects - page 26

cables for the same power - would require voltage transformation. And this, in the
late nineteenth century, meant the use of AC supply and transformers.
Fortunately, the transformer is a very simple device that was invented by
Faraday in the course of his discovery of electromagnetic induction. The transfor-
mer can be used to transform a convenient alternator generation voltage to a much
higher transmission voltage. The high transmission voltage can then be stepped
down to an intermediate voltage for distribution, and finally to a suitable voltage
for consumption, currently 230 V in the United Kingdom.
The rapid growth of electrical energy in the twentieth century can be attrib-
uted, inter alia , to effective AC generation and supply. Paradoxically, though, DC
interconnectors are increasingly being deployed. This is possible as a result of
developments in power electronics. Power electronic devices are finding applica-
tions at various levels of electricity supply and utilisation. This is certainly true
of wind power generation, as will be seen in Chapter 3. However, we will focus on
AC systems for the moment. Our discussion will start with a look at the basic
principles of the transformer.

2.2.5 The transformer
A transformer consists essentially of an iron core on which are wound two coils -
referred to here for convenience as the primary (coil 1) and the secondary (coil 2).
This arrangement is shown in Figure 2.2. The primary and secondary have N 1 and
N 2 turns.
Assuming that the same flux links both windings, that is, no leakage flux, and
applying Faraday's Law (2.10), we obtain

N 1 d d t
v 2 ¼ N 2 d d t

v 1 ¼

Φ

i 1 i 2

v 1 v 2

N 1 N 2

Coil 1

Coil 2

Figure 2.2 Simple transformer