Improved voltage quality through advances in voltage control techniques

It is incumbent upon power utilities to maintain customers´ supplies within specified parameters under varying conditions of load. In the vast majority of cases, the last point at which the power utility can influence the voltage is the on-load tap-changer (OLTC). A number of factors influence the optimum tap change operating point: the power system voltage level; loading; power factor; and, for parallel transformers, the magnitude of any inter-transformer circulating current. As power systems have developed and become more complex, the potential efficiency savings of comprehensive voltage control system cannot be realised by the majority of existing automatic voltage control (AVC) relays. Indeed their complexity has often resulted in voltage control not being implemented. This paper describes a simple solution to remove the unneeded complexity, based upon the fundamental requirements of the power system. It then shows how AVC relays can be used to collect data to for power quality analysis. Since AVC relays exist throughout the electricity network, this leads to new possibilities for improving network power quality