Plasma Event TRiggering for Alarms (PETRA) is a flexible new system at JET for detecting plasma events to trigger exception handling responses. It provides a platform for all existing and new techniques which involve processing JET real-time data to identify when to change the trajectory of a plasma shot, and reduces the technical cost and risk in demonstrating new techniques. At the same time as providing a protection function to the machine, it still supports additions and modifications to the event detector library during the course of an experimental campaign. It has successfully demonstrated novel techniques, and has computational capacity to continue supporting research into further event detection triggers.