Search

Vacuum circuit breaker is a kind of power equipment widely used in the power system. It is developing toward the direction of high voltage and high current. How to design the contact to maximize the interrupting capacity of the contact system has been conducted by scholars. In this paper, the magnetic field simulation model of contact system is established, the magnetic field distribution characteristics of vacuum interrupters are studied, and the distribution characteristics of the magnetic field in the half cycle of the cup‐shaped axial magnetic field contact system are simulated and analyzed. On this basis, by changing the contact structure parameters, the effects of the number of slots in the cup, the slot angle, the center hole of the contacts, and the length of the slots on the distribution of the axial magnetic field were obtained. The results show that grooving the contact can reduce the eddy current, but it has a limited effect on reducing residual magnetic field. The increase of slot angle of contact cup can effectively reduce the residual axial magnetic field at the zero current moment and the axial magnetic field intensity at the peak current moment. Based on the above research results, a new embedded axial magnetic contact system with 12 slots embedded magnetic ring and reverse contact cup is designed. The embedded magnetic ring and reverse spiral slot increase the axial magnetic field at the peak current moment and reduce the residual axial magnetic field at the zero current moment. Finally, the characteristics of the magnetic field have been improved significantly compared with the magnetic field of traditional cup‐shaped axial magnetic field contact. © 2020 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Gas insulated metal enclosed switchgear (GIS) has been widely used in the world because of its compact structure and adaption to the environment. However, due to frequent operation and other reasons, GIS disconnector is prone to mechanical failure with poor contact, leading to abnormal vibration signals. In this paper, a GIS disconnector contact fault simulation platform is built to collect vibration signals in three states: normal contact, moderate poor contact and severe poor contact of disconnector contact. The Ensemble Empirical Mode Decomposition (EEMD) method is used to decompose the vibration signals, and the IMF decomposition signals are screened by Kurtosis criterion (a numerical statistic method). Finally, the vibration signal features of GIS under different conditions are obtained by reconstructing the screening signals. The results indicate that, under the normal contact, the frequency of GIS vibration signal mainly presents the distribution of 100 Hz and its integer multiple frequency component, when there is a contact defect, the high frequency component in the vibration signal spectrum increases significantly, and the tripling frequency component is present, and the amplitude of component will increase with the severity of the fault. Therefore, this study provides a theoretical reference for on‐line monitoring of GIS disconnecting switch contact fault. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]