TRANSIENT ELECTROMAGNETIC-INTERFERENCE IN SUBSTATIONS

Electromagnetic interference levels on sensitive electronic equipment are quantified experimentally and theoretically in air and gas insulat ed substations of different voltages. Measurement techniques for recor ding interference voltages and currents and electric and magnetic fiel ds are reviewed and actual interference data are summarized. Conducted and radiated interference coupling mechanisms and levels in substatio n control wiring are described using both measurement results and elec tromagnetic models validated against measurements. The nominal maximum field and control wire interference levels expected in the switchyard and inside the control house from switching operations, faults, and a n average lightning strike are estimated using high frequency transien t coupling models. Comparisons with standards are made and recommendat ions given concerning equipment shielding and surge protection.