Targeted Current Conditioning Technology for Vacuum Interrupters

Accurately pinpointing the weak insulation area on the electrode surface and effectively regulating the arc energy exerted on the area are key problems in optimizing conditioning performance. In this study, high-voltage pulses with relatively low energy were adopted to cause breakdown in the vacuum gap. Furthermore, the weak insulation area on the electrode surface can be positioned successively. During the breakdown period, a specific current with a certain amplitude and time constant was injected into the weak insulation area, and conditioning on the identified area was performed subsequently. Regarding the aforementioned conditioning principles, the performance of targeting the insulation weaknesses on the electrode surface and the regulation of the conditioning energy in a quantitative style are both achieved, which is called the targeted current conditioning (TCC) method in this study. To optimize the energy exerted on the electrode surface and monitor the conditioning status, the field emission current was explored, and the corresponding measurement system was researched and established consequently. Experimental results show that the insulation level can be improved significantly using the TCC method compared with the traditional method. In addition, the field emission current was measured in sequence during the conditioning process, which is in accordance with the conditioning status at the current moment and can be adopted as a criterion for the subsequent optimization of the conditioning energy.