Influence of Metal Iron Dust Deposit on the AC Pollution Flashover Characteristics of Insulator

The contamination on the surface of insulators in metal industrial areas contains a significant amount of metal dust. The impact of insoluble metal dust on insulator pollution flashover is a matter of great concern for power grid operation departments. This paper takes U160B/155 porcelain insulators as the research object and experimentally investigates the influence of insoluble metal iron dust with different ratios and particle sizes in non-soluble deposit density (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">NSDD</i>) on their AC pollution flashover voltage. The mechanism of its influence on AC pollution flashover of insulators is analyzed in combination with the distribution of metal particles and leakage current. The results indicate that as the ratio of metal iron dust (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i>) in <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">NSDD</i> increases, the AC pollution flashover voltage of the insulator string decreases, and the critical leakage current increases. Compared with <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">NSDD</i> without metal dust, the pollution flashover voltage is approximately 5.3%~17.2% lower, and the critical leakage current increases by approximately 3.4%~20.0%. Under the same mass of metal dust, the smaller the metal particle size, the lower the pollution flashover voltage. The influence of metal dust on the pollution flashover voltage of insulator strings is similar to short-circuiting the creepage distance of the insulator strings. For areas with pollution sources containing metal dust, the impact of metal deposits on insulator pollution flashover should be considered separately. The findings of this paper can provide a reference for external insulation design and pollution flashover early warning in areas with pollution sources containing metal components.