Power electronics applied to the distribution system

The concept of flexible AC transmission systems (FACTS), as the name implies, was originally developed for transmission networks but similar ideas are now starting to be applied in distribution systems. However, when considering the use of high power electronics on the distribution network it is important to recognise another strand of technology development which comes from uninterruptible power supplies (UPS), large variable speed machine drives and active filters. Thus, the new high power electronic systems now being applied to distribution systems owe something to the ideas of FACTS but also use concepts and techniques developed for power electronic systems with lower voltage and current ratings. In both cases, voltage source converters are used as the main component of the systems but the implementation and control of the power converters differs considerably.