In our medium voltage capacitors, we are using the metallised polypropylene so well known from LV power factor correction. Instead of flat pack windings, our capacitance is formed by compact cylindrical windings, avoiding the mechanical stress at the edges of the ALLFILM flat packs. Dielectric breakdowns insulate and regenerate by themselves, domino-like failures of series-connected capacitor elements are impossible. The capacitance remains practically unchanged throughout the operating life which is of particular interest for applications with tuning or detuning reactors.
By that, phase asymmetries are impossible, and the costly star point monitoring by MV capacitor protection relais, typical for ALLFILM capacitors, becomes obsolete.
Unlike ALLFILM, they are manufactured without flammable liquid impregnants, and filled instead with eco-friendly solid, plant-oil-based resin. This offers advantages when using these capacitors in sensitive environment, in applications with high vibration stress, and during disposal at a later stage.