Simulation Analysis of Arc Interruption Characteristics in Disconnector

Wind and solar energy are examples of clean energy that are widely developed and utilized in order to achieve the goal of carbon neutrality. Higher requirements for the safety and reliability of the power grid are put forward after they are connected to it. In the case of disconnectors, as the power system’s protection equipment, their arc interruption characteristics are closely tied to the safety and reliability of the power system. In addition, a disconnector is required to be able to break the DC arc in the photovoltaic power generation system. Therefore, this paper focuses on the arc evolution characteristics in disconnectors. A magnetohydrodynamics (MHD) model of disconnectors was built. In this model, not only are the coupling of the electromagnetic field and the airflow field considered, but also the characteristics of the external circuit. Therefore, not only can arc evolution characteristics be obtained through this simulation model, but the breaking performance will also be directly obtained. The temperature, pressure and velocity distribution are obtained to analyze the evolution process. The curve of current versus time is calculated to analyze the breaking performance. The evolution characteristics of AC and DC arcs in the disconnector are analyzed by calculation and comparison. This provides theoretical guidance for the optimal design of DC disconnectors through simulation analysis.

Preparation of Silver Nanopowders and Its Application in Low Temperature Electrically Conductive Adhesive

Printable electrically conductive adhesive with high electrical conductivity and good mechanical properties has wide application prospect in electronic device. In order to explore new conductive fillers of interconnecting materials in electronic circuit and electronic packaging industries, silver nanopowders were prepared by DC arc plasma method with high pure. The silver nanopowders present a spherical structure, the particle’s diameter range from 15 to 220 nm. In this paper, a high performance electrically conductive adhesive (ECA) was prepared. This ECA was fabricated by mixing silver nanopowders with epoxy resin and was screen-printed to a required shape. It was found that the ECA can be solidified through a low temperature sintering method in the air at 150 ℃ for 10 min. The electrical and mechanical of above ECA were investigated and characterized. The ECA filled with 75% silver nanopowders exhibits excellent performances, including high electrical conductivity (9.5×10-4 Ω·cm), high bonding strength ( 8.3 MPa). Based on the performance characteristics, the ECA applications in flexible printed electrodes and interconnecting materials are demonstrated.

New Laboratory and Pilot Techniques Applied at Mintek in Aid of Furnace Containment System Designs

The Pyrometallurgy Division at Mintek is known internationally for the development of applications of direct current (DC) arc furnace technology in smelting applications, more specifically in the smelting of primary resources, i.e., chromite, ilmenite, titanomagnetite, nickel laterite and ores containing precious group metals, and secondary resources, i.e., furnace slag or dust. From a furnace containment perspective, either an insulating or a conductive design philosophy can be applied, irrespective of the raw material being processed. In the initial stages of a project, desktop studies are typically conducted which include the selection of a furnace containment design philosophy, specific to the application. To lower the risk associated with incorrect selection of a design philosophy and/or furnace containment system components, it is prudent to conduct tests on laboratory and pilot scale and to transfer the knowledge gained to industrial applications. The paper presents examples of the laboratory and pilot techniques utilized.