Kosuke Sasage

Vacuum arc behavior in transversal magnetic field electrode of Vacuum Interrupter

Vacuum Interrupters have been widely used for power distribution systems through the development of vacuum arc control technology by magnetic field. There are two major types of electrode: transversal magnetic field (TMF) type electrodes and axial magnetic field (AMF) type electrodes. In the first type of electrode, the vacuum arc column is rotated by the magnetic force generated by the transversal magnetic field, which is the radial direction to the electrode, and the current flowing in the arc. Transversal magnetic field electrodes are researched experimentally. To increase the interruption ability by preventing local heating of the electrode, the relationship among the arc behavior, the arc voltage waveform and the electrode structure was researched. The arc behavior and the arc voltage waveform are observed and measured by using a test circuit and a high speed video camcorder. The experimental results indicate the relationship among the arc behavior, the arc voltage waveform and the electrode structure.

Fundamental research of uniform vacuum arc control and its application to vacuum interrupter for high current interruption

The vacuum arc behavior and high current interruption ability of electrodes applied in the uniform vacuum arc control method are presented. The axial magnetic field distribution of this method is unlike that of the conventional AMF distribution. For extremely high interruption current, the arc of the conventional AMF electrode concentrates, causing local heating of the electrode, but the arc of this method diffuses over the whole contact area thus avoiding local heating. The relation among the electrode structure, the arc behavior and the magnetic field distribution between the electrodes is investigated, for applying this vacuum arc control method to the vacuum interrupter for the high current interruption. The vacuum interrupter applied this method can be made more compact and lighter than the conventional type.

Vacuum disconnectors an application study

The ageing of vacuum interrupters with combined functions of disconnector and circuit-breaker or switch is studied for compact shielded solid insulated switchgear. Different prototypes are manufactured to investigate the influence of contact materials and contact designs. A test program is presented that realistically represents the ageing as described in the standards. The feasibility to create vacuum disconnecting circuit-breakers, vacuum switch-disconnectors and vacuum earthing switches that respond reliably to the requirements of the standards is demonstrated. Most of the tested designs comply with the current IEC62271-1, −100, −103 and −102 requirements for combined disconnect functions. It is shown that all combined disconnector functions can be realised with suitably designed VIs in a compact and economical way even for environmental friendly, but dielectrically very constraint, shielded solid insulated switchgear.

The Arc Behavior and the Interruption Ability of the Transversal Magnetic Field Electrode in the Vacuum Interrupter

Vacuum interrupters have been widely used for power distribution systems with the development of vacuum arc control technology by magnetic field. There are two major electrode types: transversal magnetic field electrode and axial magnetic field (AMF) electrode. In the former, the vacuum arc column is rotated by the magnetic force generated by the transversal magnetic field, which is radial direction to the electrode, and the current flowing in the arc. In the latter, the vacuum arc is diffused and stabilized by the axial magnetic field, which is parallel to the arc current. Transversal magnetic field electrodes have been researched experimentally. To increase interruption ability by preventing local heating of the electrode, the relationship between the arc behavior and the interruption ability was researched. A high speed video camcorder was used to observe the arc behavior. The interruption ability of the transversal magnetic field electrode was evaluated using Weil test circuit. The arc observations and interruption test results indicate the relationship between the arc behavior, the magnetic field, and the interruption ability