Abstract: A diagnostic measuring system (20) for gas insulated electrical substations having UHF couplers (11) fitted to bus chambers (12) monitors for partial discharge events within the chamber (12) to identify the nature and location of an emergent breakdown condition. The system (20) identifies each partial discharge event but characterizes it by amplitude and its time of occurrence with respect to the start of the 50 Hz power frequency wave. The characterized events are communicated over an optical fiber link (13) configured as a token passing ring to an analyzer (25) where a comparison is made with stored historic data characterizing known events. The analyzer (25) provides a self checking routine for the system (20). A microprocessor (36) forming part of a unit (21) associated with a plurality of couplers (11) provides data compression of events identified from these couplers.

Abstract: A hand-grippable device having hanger loops at its opposite ends for detachably hanging keys, an alarm whistle, identification tags and the like. The device also includes provision for releasably securing a selected set of keys, preferably three, thereto in such spaced positions along its length as to project outwardly from between the fingers of a gripping hand whereby they can be used to strike or be twisted with force into the person of an attacker.