Abstract: The design of a functional measuring group for a medium-voltage substation has been optimized to make the product compact and robust in terms of internal arc, and also to favour complete accessibility to the measurement sensors. In particular, the voltage sensors are located in a vertical plane directly accessible via the front panel of the group, and the current sensors are located in the rear housing of the group, being directly accessible via the top of the group. In addition to being placed in an insulated compartment, the voltage sensors are insulated and shielded, and their connection terminals are designed for connection by cable with a flat interface.

Abstract: The Rogowski type current measuring device comprises at least three coils electrically connected in series and forming a closed polygonal outline designed to surround a conductor to perform current measurement. The local inductance of at least one of the ends of said coils is greater than the local inductance towards the central part of said coils.

Abstract: The invention relates to an electrical fixing terminal for an electrical switchgear apparatus being disconnected by an axial withdrawal motion. In particular, an extractable circuit breaker, comprising a protruding part extending parallel to an axis of withdrawal and, defined by its external surface on the side where its free end is located a contact surface designed to cooperate with fixing jaws of a plug-in contact whose plug-in jaws are designed to cooperate by plug-in with an electrical plug-in terminal. The contact surface follows the outline of a cylinder sector of axis perpendicular to the axis of the protruding part, of opening angle greater than 180.degree. and is designed to form a pivot for rotation of the plug-in contact around the axis of the cylinder. An application is plug-in multipole circuit breakers.