During the long-term operation of electrical equipment, under the conditions of high voltage and strong current, the contact area decreases and the contact resistance increases due to the pollution of gas dust, oxidation of contact, electrochemical reaction, aging and loosening of mechanical structure, which leads to the high temperature of contact and forms a vicious circle, Serious accidents that will lead to fire and even explosion are likely to cause huge economic losses and even personal injury, and have a serious negative impact on the corporate image. Therefore, accurate, real-time and on-line monitoring of key conductor connection parts in electrical equipment has strong necessity, high economic value and social significance.