Effects of electromagnetic radiation on equipment, with special reference to protection relays

A protection relay is an extreme example of electronic equipment being exposed to the effects of electromagnetic radiation. This is because relays employ microelectronic circuits and yet are used in very close proximity to the high voltages and currents of the power system plant which they protect. Relay circuits responding to fractions of a milliwatt control power measured in thousands of megawatts. The consequences of a maloperation or failure of a relay could lead to damage of plant, system shutdown and significant economic losses in the supply of power. The design of a protection relay must therefore take into account all possible sources and effects of electromagnetic interference in the power system