Voltage control by reactive current control in high-voltage power transformers

摘要

A voltage control device [1] that uses an enhanced reactive current control method whereby circulating current is calculated from measurements of transformer current [6] and voltage [7] and a bias applied to the voltage measurement such that the circulating current is minimised. The scheme discriminates between circulating current that flows between transformers that are in parallel at a site calculated using the summed load current on the common bus-bar, and that which flows between transformers that are paralleled across a network calculated from the deviation of measured power factor from an assumed network value. The scheme provides for voltage control in the event of network changes such as embedded generation or remotely paralleled transformers where existing reactive current control schemes are not accurate, and also monitors the bus-bar arrangement of the transformer site to allow for the calculation of summed load current.