THE REQUIREMENTS FOR EFFICIENT OVERVOLTAGE PROTECTION OF ELECTRONIC DEVICES IN LOW-VOLTAGE POWER SYSTEMS

The increasing sensitivity of electronic devices widely used in low-voltage AC systems requires an appropriate protection against voltage and current surges. Protection of the equipment against the prospective surges is based on application of surge protection devices (SPDs). Most common situation, especially in residential buildings, is application of only one SPD at distribution board. In the paper, comprehensive analysis of this type of overvoltage protection system with wide ranges of influencing parameters is performed through experimental measurements and number of simulations. Obtained results show that existence of built-in varistors within electronic devices, with low protection voltages causes their thermal destruction due to inadequate distribution of surge energy between SPD and varistors. The requirements for efficient protection system which will provide survival of built-in varistors, as well as proper overvoltage protection characteristics are described and discussed in the paper.