Study of Transient Voltages in Transit Systems

Data on transient-voltage environment are needed for the specification. and design of reliable transit-system electrical equipment, especially those containing semiconductor devices. Such data taken on the 600-V dc propulsion systems of the Chicago Transit. Authority (CTA) and the Long Island Railroad (LIRR) are presented. Transient-voltage counters, supplemented by an automatic cathode ray oscilloscope, were used to monitor transient voltages in substations, wayside switching stations and transit cars. The 37.5-V dc battery line was also monitored on board one transit car on the LIRR system. This program spanned a period of two and a half years. Theoretical analysis on the characteristics of transients caused by lightning and switching is also presented.