Protection of TVSS Systems

摘要

Transient voltage surge suppressors (TVSSs) using MOV technology are widely used to protect power systems and components against the effects of transient overvoltages. However MOVs can fail explosively under certain conditions, and protection is needed. Thermal protectors provide protection against failure under sustained power-frequency overvoltages, and in the paper the requirements for and performance of a typical thermal protector are given. The role of a series fuse is discussed in detail, and alternative protection philosophies are compared, leading to recommendations for the fusing of TVSS systems. The development of a new range of fuses and thei key performance characteristics are described. Finally the performance of MOVs and fuses with repetitive surges is compared and it is shown how these two components can complement each other in an integrated TVSS system.