Surges, transients and naval systems

A fighting platform such as a ship or submarine is bristling with electronic warfare systems, communications systems, radar, sonar and many electrical power systems-to name but a few. All of these can potentially emit high powered electromagnetic waves which can so easily interfere with other items of equipment fitted on board. These systems face a threat from another quarter-those of conducted transients, induced predominantly via cables, interfering with, and possibly causing damage to, all types of equipment. Sources of such transients are numerous and include lightning, electrostatic discharge (ESD), nuclear electromagnetic pulse (NEMP) and transients caused by load changes and inductive switching of 440 V 60 Hz and other main power supplies. DERA West Drayton have been instrumental in the long term monitoring and protection of naval systems against many conducted transient threats, particularly those on power supply lines. This experience has also led to the publishing of two specialist test techniques in the UK´s tri-service EMC Defence Standard 59-41 as test supplements DCS11 and DCS 12. This paper summarises experience gained during monitoring of shipboard supplies and EMC testing