The Evolution and Future of Electric Power Networks - Part 1: DC vs AC

Introduction

A typical Electric Power Network can be divided into three main parts, namely: generation, transmission and distribution. These have had many improvements since their emergence in 1880s. The first complete electric network (developed in 1882) was based on the DC theory. However, since electrical energy losses are dependent on the value the resistance times the square of the current, the voltage level has to be high to minimize losses. DC technology had not developed enough to transmit electric power over long distances at that time. The emergence of AC theory (mainly the AC transformer) allowed the transmission of electric energy over long distances, and as a consequence, the use of DC systems was gradually reduced, and for a long time more attention was paid to the developments of AC equipment. However, advances in power electronics and solid state technology gave the basis for the rise of DC equipment from the 1950’s onward, initially, for high power applications.