GC0076: Grid Code Limits on Rapid Voltage Changes

CC.6.1.7 sets a limit of 3% on voltage excursions other than step changes which are permissible at a Point of Common Coupling. It can be difficult to ensure connections to the Transmission System stay within this limit under all circumstances, particularly when designers consider the effect of very short lived voltage changes associated with actions such as transformer energisation for example. A number of connections to the transmission system have to be actively managed currently to meet CC.6.1.7 leading to operational restrictions for users. Therefore this requirement is under review.