The performance improvement of the Internally-fused HV capacitors and comparison with fuse-less capacitors is discussed in this paper.It is insufficient that the internal fuse design only satisfied the existing standard.In order to optimize the fuse design

the fusing process of the internal fuse under the critical condition must be studied further and its current limiting performance be controlled and over-voltage be reduced.The reason of multi-explosion failures in the operated reactive power compensation installations is due to improper provision of expulsion fuses.