Wind tunnel experiments on the pollution characteristics of suspension insulators in an ion flow field

Abstract

Contamination particles in the air are charged by the ion flow field around a DC corona discharge wire. The electric force acting on the charged particle is associated with the ion flow field and affects the particle deposition on insulators. In this study, the pollution characteristics of the porcelain insulators in an ion flow field were investigated by pollution experiments in a wind tunnel. The conductor wire was applied a higher DC voltage than the corona onset voltage and connected to a test insulator string. As the test parameters, the DC voltage was variable, the contamination particle diameter was set at 20 μm, and the wind speed was 2 m/s. The nonsoluble deposit density (NSDD) and its distribution on test insulators were measured, compared, and analyzed. The relationship was discussed between insulator pollution characteristics, the electric force on dust particles, and the ion flow field. The pollution characteristics revealed that the pollution on the upper part of the string increased with the test voltage and corona current. The non-uniformity of pollution along the string and on the upper/lower insulator surfaces also increased. However, the non-uniformity of pollution on the windward/leeward of the insulators decreased. The discussions indicated that the spatial ion flow field around the conductor affected dust motion when the dust was away from the insulator. The direction and magnitude of the electric force on the charged particles impacted the pollution distribution. The pollution level of the strings in the unenergized test was considerably lower than that in energized tests. The pollution level could be reduced by increasing the conductor corona under a specific corona current range.