Active earthing system to optimise power quality in MV networks

Neutral treatment is a key issue when a MV network is designed. Requirements of insulation and safety have to be met whilst guaranteeing rapid fault detection, location, arc suppression and tripping -if necessary- within a proper timing. The values of overvoltages and fault currents expected in the network are crucial, since they affect Power Quality parameters, namely interruptions and voltage dips. A new technical solution has been developed which, in addition to the power quality improvements of the resonant earthing, overcomes is limitations by injecting controlled current, as desired, into the neutral of the network. Being able to inject current of different frequencies, it chooses the most appropriate one for performing each specific function. This active operation is the feature that provides added functionality, reducing interruption time and even prevents faults from appearing.