Abstract: An interface is disclosed for a self powered protection relay that uses mechanical switches for its configuration. The protection relay can include a base relay for measurement of line current and for generation of a trip signal, and a Human Machine Interface (HMI) unit for specifying, by a user, a base setting of an operating parameter of the protection relay. The base relay can be self-powered from the line and the HMI unit can include an auxiliary power supply. The protection relay is configured with mechanical switches provided in the protection relay. The HMI unit in the protection relay is designed to detect and alert the user of the relay of any change in the base setting carried out with one or more mechanical switches provided in the relay in powered and unpowered conditions of the base relay.

Abstract: A vacuum interrupter is disclosed with a fixed contact and a movable contact placed axially in a spaced apart relationship. The ceramic insulator cylinders each surround the fixed contact and the movable contact. A floating shield within the ceramic cylinders has a floating potential flange disposed between the two ceramic cylinders, and exposed to external ambient. Encapsulation for at least one contact terminal extends from a metallic end cap of the corresponding contacts to cover a respective ceramic cylinder by an overlapping distance.

Abstract: A device for controlling an electric field at a high voltage component including a resistive layer for field control, an insulating layer arranged on the resistive layer and a semi-conducting or conducting layer arranged on the insulating layer. The three layers meet at a triple point where the insulating layer ends. An interface between the resistive layer and the insulating layer makes in the triple point an angle to the semi-conducting or conducting layer of 60°-120°.