DC Overload Behavior of Low-Voltage Varistor-Based Surge Protective Devices

This letter provides evidence of a peculiar behavior of metal-oxide varistors under DC overvoltages. It stresses the need for extending the V-I characteristic of varistors in the time domain so as to accurately predict the dynamic performance of varistor-based surge protective devices under temporary overvoltages. Observations and mathematical formulation of DC overload behavior of metal-oxide varistors may have significant implications in energy absorption requirements for low-voltage surge protective devices and unlocks possible monitoring strategies in emerging DC distribution smart grids.