欠压脱扣器操动装置用复位弹簧的应力松弛分析

Stress Relaxation Analysis of the Reset Spring Used in the Operating Device of Underpressure Trip

摘要: 欠压脱扣器在高压断路器起着重要的保护作用。当断路器电压下降到额定工作电压35%时，欠压脱扣器闭合使断路器停止工作。欠压脱扣器的关键部件之一是安装于其外部的采用复位弹簧实现储能的操动装置，为评估长期服役下复位弹簧的储能性能，对复位弹簧在同一应力水平不同温度下的应力松弛进行有限元分析，建立复位弹簧的应力松弛模型；使用SCDM右旋方式建立不同结构参数复位弹簧的有限元模型，完成应力松弛仿真分析，得到200℃下复位弹簧的应力与时间的变化规律，拟合出负荷损失率与时间对数lnt关系图，确定复位弹簧的应力松弛率；基于不同的线径d，外径D，节距t等结构参数的复位弹簧模型，得到复位弹簧结构参数与应力松弛率间的对应关系，为提高复位弹簧使用寿命提供依据。

Abstract: The undervoltage release plays an important protective role in the high voltage circuit breaker. When the circuit breaker voltage drops to 35% of the rated operating voltage, the undervoltage trip is closed and the circuit breaker stops working. One of the key components of the undervoltage re-lease device is the operating device which uses the reset spring to realize energy storage. In order to evaluate the energy storage performance of the reset spring under long-term service, the stress relaxation of the reset spring under the same stress level and different temperatures was analyzed by finite element method, and the stress relaxation model of the reset spring was established. The finite element model of reset spring with different structural parameters was established by SCDM right rotation mode. The stress relaxation simulation analysis was completed to obtain the variation law of stress and time of the reset spring at 200˚C, and the relationship between load loss rate and time log lnt diagram was fitted to determine the stress relaxation rate of the reset spring. Based on different structural parameters such as wire diameter d, outer diameter D, pitch t and so on, the corresponding relationship between the structural parameters of the reset spring and the stress relaxation rate is obtained, which provides a basis for improving the service life of the reset spring.