Patent ID: 8476526

Claim:
A device for controlling an electric field at a high voltage component, said device comprising: a resistive layer arranged along said component and which at a first end is configured to be electrically connected to a live high voltage part of the component and, at a second end, configured to be electrically connected to ground potential, an insulating layer arranged on said resistive layer and extending outside thereof from said first end towards said second end, the insulating layer terminated by a tapering field controlling geometry without reaching the second end and at a distance to said second end, and a semi-conducting or conducting layer arranged on the insulating layer and extending outside thereof past an end of the insulating layer towards said second end of the resistive layer, so that said resistive layer, said insulating layer and said semi-conducting or conducting layer meet at a triple point at said end of the insulating layer, wherein said insulating layer ends in an extension thereof from said first end towards said second end by a substantially sharp edge forming a transversal surface continuing into the re-sistive layer for forming a step in said resistive layer and making the resistive layer thinner in a direction towards said second end.