一种符合IEC标准的电压互感器保护用真空式限流熔断器

目前,国际上还没有能够完全保护电压互感器的熔断器,以及相应的IEC标准。笔者研究了一种新型的真空混合式全范围限流熔断器来保护电压互感器,为制定出相应的IEC标准提供技术支持,并指导该类产品的设计、制造、试验和运行。该产品是由真空熔断器和限流熔断器串联组成,采用环氧树脂工艺浇铸而成。根据熔断器的基本工作原理,利用真空熔断器具有特别陡的时间-电流特性,来开断小过载电流;利用限流熔断器来开断大过载电流和短路电流。试验结果验证该熔断器能够保证在额定电压因数波动范围为1～1.2时能够长期正常工作,额定电压因数为1.9时可以在30s内可靠动作,并且顺利开断了31.5kA的短路电流,实现了对电压互感器的妥贴保护。该产品具有结构新颖、性能安全可靠、性价比高等优点。

A new Type Vacuum Current-limiting Fuse for Voltage Transformer Protection

At present, there are no fuses that can protect the voltage transformer completely in the world, neither relevant IEC standards. This paper developed a new kind of vacuum hybrid full-range current-limiting fuse to protect voltage transformer. The fuse consists of a vacuum fuse in series with a current-limiting fuse, and is moulded by APG technique. In terms of the basic working principle of a fuse, it makes use of the very fast time-current characteristic of the vacuum fuse to break small overload current, and adopts the current-limiting fuse to break large overload current and short circuit current. The experimental results indicate that the new fuse can work normally when the rated voltage factor is within the range of 1～1.2, and work reliably in 30 seconds when the rated voltage factor is 1.9. It has successfully broken the short circuit current of 31.5 kA to provide a proper protection for the voltage transformer. This fuse is safe and reliable with a new structure and a high performance-cost ratio.