Study on long-term pollution characteristics of UHVDC lines under different environmental conditions

In order to fully obtain the contamination deposited characteristics of UHVDC transmission lines insulators under different meteorological conditions, this paper takes UHVDC transmission lines on four typical climatic conditions (extreme arid, arid, semi-arid, semi-humid and humid) as study objects to perform detailed layout scheme design and natural contamination deposited test, then obtains the characteristics and design parameters of contamination deposited of UHVDC insulators under four types of environmental conditions for many years and the influences of different umbrellas types, materials and voltage types (AC and DC) on the performance of contamination deposited on insulators. The results show that from the extremely arid region to the humid region, the saturated contamination deposited time, dust to salt ratio and the uneven contamination deposited ratio KE all decrease, ESDD of the outer umbrella and the bell jar-shaped insulators are 0.82 (humid), and those of the composite insulation and the hydrophilic surface on tension strings are 1.64 (extreme arid) and 1.84 (semi-arid).the degree of uneven contamination deposited of DC line is significantly higher than that of the AC line, and the ratio of contamination deposited on AC and DC lines under different meteorological conditions are different.