真空开关全气压范围内激光诱导等离子体特性及其在真空度检测中的应用研究

Vacuum circuit breaker has many advantages, such as compact structure, convenient maintenance, no greenhouse gas emission, and strong interruption ability. Therefore, it is widely used in medium-voltage power grid. Vacuum interrupter is the core component of vacuum breaker, and its internal pressure (vacuum degree) is the key factor to reliably turn on and off the circuit. However, vacuum degree online detectionis still an international problem, and there is no effective vacuum degree online detection method for vacuum interrupter. This paper study the evolution of plasma under different pressures and different laser energies by plasma imaging. The experimental results show that the environmental pressure has a significant influence on the expansion dynamics of plasma, and there are obvious interval effect. At the same time, the evolution of plasma under different laser energy is similar. In order to quantify the change of plasma, this paper proposes three characteristic parameters of plasma: the distance from the plume barycenter to the target surface, the integral of plasma intensity, and the plume length of plasma. The experimental results show that the above three parameters can commendably extract the plasma characteristics at different vacuum degrees. This work can lay the foundation for the practical application of vacuum degree detection method based on laser-induced plasma technology.