Earthing for secondary and electronic equipment

Secondary and electronic systems include the control, protection and auxiliary power supply equipment in substations. The key feature of all this equipment is that they all use relatively low signal/voltage/current levels compared with those of the main power circuit and yet are connected directly and indirectly to high power equipment. Here, the author describes how earthing is important for a variety of reasons, including safety, prevention of damage to equipment and prevention of corruption to signals