基于超声透射法的盆式绝缘子紧固螺栓松动检测方法

Detection Method of Fastening Bolt Looseness of Basin-Insulator Based on Ultrasonic Transmission Method

盆式绝缘子是GIS中重要的支撑部件,当固定它的法兰螺栓松动后,盆体会因受力不均而破裂,引起重大安全事故。文中提出一种盆式绝缘子螺栓松动检测方法,将压电传感器以一发一收的方式布置在待检测螺栓附近,通过超声信号仪激励一侧压电传感器发射超声波,并在另一侧对压电传感器接收到的信号分别进行互相关和自相关计算,获得表征螺栓松动的超声信号声时差和能量。通过实验研究了螺栓不同松动程度下信号能量和声时差的变化规律,结果表明,随着螺栓扭矩增加,超声透射信号的声时差逐渐减小、信号能量逐渐增大;当螺栓扭矩增大到一定程度后,超声透射信号的声时差不再变化而能量继续增大。可见,能量相比声时差对螺栓松动更敏感,所以可以通过计算超声信号能量来实现盆式绝缘子固定螺栓的松动检测。

Basin insulator is an important support component in GIS.If the flange bolt fixing the insulator is loose,the basin will break due to uneven stress,which will cause big accidents.In order to realize the bolt looseness detection of basin insulator,a bolt looseness detection method is proposed.The piezoelectric plates are regularly arranged near the bolts.The ultrasonic signal instrument is used to excite the piezoelectric plates on one side to emit ultrasonic waves,and the signals received by the piezoelectric plates on the other side are calculated respectively to obtain the acoustic time difference and energy of the ultrasonic signals characterizing the bolt looseness.The results show that with the increase of bolt torque,the acoustic time difference of ultrasonic transmission signal decreases and the signal energy increases;When the bolt torque increases to a certain extent,the acoustic time difference of the ultrasonic transmission signal does not change and the energy continues to increase.Therefore,the looseness detection of the fixed bolt of the basin insulator can be realized by calculating the ultrasonic signal energy.