Factors influencing the selection and installation of surge protective devices for low voltage systems

The present paper aims to illustrate the influence of the main factors which affect the selection and installation of an SPD for the protection of electrical and electronic systems against overcurrent and overvoltage due to direct lightning flash to a structure. The two most typical SPDs are considered, namely switching and limiting type. Simple rules are established for the selection of effective SPD with regard to the discharge current, its protection level and location.