Normally, loads are a function of frequency. For example, a fan driven by an induction machine slows down and consumes lesser power if frequency is reduced. In the previous lecture we saw that a system will settle to a frequency at which load(+losses) and generation is balanced. Therefore it is instructive to examine the load behavior as a function of frequency.

For simplicity, let's assume voltage and frequency changes are small. In such a case, load can be represented (in steady state) as follows: