摘要
为研究高压真空断路器触点分断电弧的产生机理,考虑触点表面微观形貌,建立真空环境下铜触点电接触的几何模型和数学模型。数值模拟真空断路器分断时金属液桥的形成过程,其中金属液桥的熔化电压与铜材料的熔化电压近似相等,证明建立仿真模型的正确性。得出金属液桥形成中的温度分布及熔化相变体积变化;探究触点初始分断电流、表面粗糙高度及初始接触压力对金属液桥形成的影响。数值计算结果表明:金属液桥的电势差由电接触位置向电极两边逐渐减小;模型最高温度出现在电接触位置;金属液桥的形变受热膨胀力与表面张力共同作用,随着熔化相变体积的增大,影响金属液桥形变的主导因素从热膨胀力逐渐过渡为表面张力,因此其形状由最初的圆柱形变为哑铃型;金属液桥熔化所需时间随触点初始分断电流和触点表面粗糙高度的增大而减小,随触点初始接触压力的增大而增大。为进一步研究真空金属蒸气电弧的形成机理及提高断路器的可靠性和寿命提供理论支持。
In order to study the generation mechanism of contact disconnected arc of high voltage vacuum circuit breaker,the geometry and mathematical models of electric contact with copper contacts in a vacuum environment are established considering the surface micro-morphology of the contact.The forming process of the metal bridge is simulated numerically when the vacuum circuit breaker is broken.It is pointed out that the melting voltage of the metal bridge is approximately equal to that of the copper,indicating the correctness of the proposed model.The temperature distribution and melting phase transition volume change are obtained in the formation of the metal bridge.The influence of initial disconnected current,surface roughness height and initial contact pressure of the contact on the formation of the metal bridge is investigated.The numerical results show that the potential difference of the metal bridge decreases gradually from the electric contact position to both sides of the electrode.The maximum temperature of the model occurs at the electric contact position.The deformation of the metal bridge is affected by the thermal expansion force and surface tension.With the increase of the melting phase transition volume,the dominant factor affecting the deformation of the metal bridge gradually is transferred from thermal expansion force to surface tension.Therefore,its shape changes from the initial cylindrical shape to the dumbbell shape.The melting time of metal bridge decreases with the increase of the initial disconnected current and the surface roughness height of the contact,and increases with the increase of the initial contact pressure.The result provides a theoretical support for further studying the formation mechanism of vacuum metal vapor arc and improving the reliability and life of circuit breakers.
作者
赵永秀
王瑶
王骑
田江晖
ZHAO Yongxiu;WANG Yao;WANG Qi;TIAN Jianghui(College of Electrical and Control Engineering,Xi’ an University of Science and Technology,Xi’ an 710054,China)
出处
《西安科技大学学报》
CAS
北大核心
2021年第1期172-178,共7页
Journal of Xi’an University of Science and Technology
基金
国家自然科学基金项目(51777167,51604217)
陕西省教育厅自然科学基金资助项目(19JK0529,19JK0545)。
关键词
真空断路器
金属液桥
熔化相变
初始分断电流
表面粗糙高度
初始接触压力
vacuum circuit breaker
metal bridge
melting phase transition
initial disconnected current
surface roughness height
initial contact pressure
