Determining the MOV Element Number of Surge Protective Device, Manufactured by Multi-Block MOV Technology

SPDs manufactured using multi-block MOV technology can indicate the remaining life (in %) of the SPD, thus helping users to plan appropriate replacement and maintenance. However, because the threshold voltage error of parallel-coupled MOV elements is not the same, the rated impulse current of the SPD manufactured by multi-block MOV technology is not equal to the total of the rated impulse current of parallel-coupled MOV elements. The paper presents the method of determining the number of parallel MOV elements of multi-block MOV according to the allowed dissipation energy method with the help of Matlab software and modelling and simulation technique.