Wide Frequency Response of Varistors and Coordination With Transient Voltage Suppression Diodes
Evangelos T. Staikos, Georgios D. Peppas, Thomas E. Tsovilis
Abstract
The voltage-current characteristic of metal-oxide varistors is experimentally investigated for a wide frequency range. Concave exponential and rectangular impulse currents that resemble lightning current field records are employed to investigate their energy coordination with transient voltage suppression diodes, commonly integrated into printed circuit boards to protect sensitive electronic components. Thus, the effective coordination is experimentally evaluated against high- and low-frequency surge events for components used in power, telecom, and automotive applications. Experimental results supported by ATP-EMTP simulations show that reliable coordination of conventional varistors with bidirectional diodes can be challenging; this finding reveals a risk for the uninterrupted operation and safety of equipment with built-in diodes. The satisfactory agreement of ATP-EMTP results with experimental data shows that electromagnetic transient simulations can be an effective tool for designing coordination circuits and evaluating the risk of failure in case of surge events and electromagnetic pulses.