The reliable design of PCB Rogowski Coil current transformer

PCB Rogowski coil has a particular structure that interconnects the conductive imprints on the upper and lower sides of the each printed circuit board by plated through holes and connects printed circuit boards in series by soldering points. Once a plated through hole or a soldering point falls, PCB Rogowski coil opens and outputs incorrect signal, which causes current measurement unreliable and misoperation of protecting relays. Thus, This paper focuses on the reliability study of PCB Rogowski coil: failure modes and failure mechanism of plated through holes are presented; failure criterion of PCB Rogowski coil is proposed; reliability model of PCB Rogowski coil is established; and the relationship between coil failure rate and plated through holes as well as soldering points is quantificationally deduced. Finally, mean time to failure of PCB Rogowski coil for 300 A current measurement is predicted about 27 years based on GJB/Z299B-98.