MOV在液氮温区冲击响应特性的探讨

Research on Characteristics of MOV Under Pulse at Liquid Nitrogen Temperature

超导电力技术将为电力工业带来重大技术突破,其在脉冲功率技术上的应用也具有重大的意义。然而,低温下的保护技术是实现超导技术在电力和脉冲功率技术应用的重要基础。氧化锌避雷器,简称MOA,由金属氧化锌阀片(MOV)组成,是目前常温下理想的过电压保护装置,将MOV应用于超导系统的保护技术取决于MOV在低温下的响应特性。本文将MOV在常温和低温下进行了不同频率的冲击响应特性对比试验,通过分析,试验结果显示:相同频率下,同一样品在相同的冲击电压下,液氮温区的冲击电流最大值比常温下的小,并且低温下残压低;在相同温区下,样品加相同电压,频率越高,冲击电流越大,残压基本不变。并且MOV在常温和低温下的冲击响应速度都非常快,基本没有滞后效应,表明了MOV在低温和脉冲条件下有较好的保护特性。

The superconducting technology, which will greatly change the power industry, can also be used in pulse power technology. However, protective technology under low temperature is fundamental for superconducting technology and pulse power technology. Metal oxide arrestor, compose of MOV, is perfect protector for over-voltage. If MOV is used for protection in low temperature, pulse characteristics of MOV must be studied. An experiment on the pulse characteristics of MOV at liquid nitrogen temperature and in normal temperature has been done. It has found that the pulsed currents with the same frequency at liquid nitrogen temperature is lower than the corresponding values in normal temperature for the same MOV sample, and residual voltages of MOV at liquid nitrogen temperature are higher. Under same temperature and same charging voltage, the higher the frequency is, the bigger impulse current is, but residual voltage change slowly. The response speed of MOV to pulsed voltage is so swift that we can even ignore the effect of delay; all indicates that pulse characteristics of MOV are good at liquid nitrogen temperature.