Effect of TiO ₂ coating on the surface condition and corona characteristics of positive DC conductors with particle matters

Abstract

Persistent severe smog and dust weather exists in many regions of China. Particles accumulate on the surface of high-voltage transmission lines, which affects the surface morphology of the transmission line and induces corona discharge. This work mainly studies the influence of electric field and photocatalysis on the corona characteristics of transmission lines. In this work, plasma spraying is used to prepare a dense, smooth and excellent photocatalytic TiO 2 coating on the surface of transmission wires. An electron microscope and a white light interference profilometer is used to study the surface condition of the samples. The variation in the surface condition of the samples is observed under different fouling, light time and electric field intensity. The corona characteristics of power transmission lines under different surface conditions are studied. The results show that light and applied electric field promote the photocatalytic effect of TiO 2, which helps to decompose the contamination on the surface of power transmission wires and thus reduce the corona discharge of transmission lines. The increase in corona inception voltage reduces the corona current pulse repetition rate and the ion current density during corona discharge.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

A review on mechanism and application of functional coatings for overhead transmission lines

“…In recent years, researchers have proposed many anti-corona coatings, which are expected to solve the corona problem. There are mainly hydrophobic coatings (Xu and Li, 2013;Yi et al, 2016;Zhang et al, 2019), TiO 2 coatings (Bian et al, 2018;Xu et al, 2022), and high dielectric coatings (Megala and Sugumaran, 2019;Megala and Pugazhendhi Sugumaran, 2020).…”

“…At the same time, because of the photoinduced superhydrophilic of TiO 2 , the contact angle will be further reduced under the condition of ultraviolet light. Xu et al (2022) prepared smooth and dense TiO 2 coatings on conductors by plasma spraying. The positive DC corona test demonstrates that under the catalysis of ultraviolet light or in the electric field of the DC circuit (typically about 20 kV/cm), the TiO 2 coating will generate many electron-hole pairs, which can promote to decompose the contamination on the surface of the DC transmission line.…”

The Role of Space Charge on Corona Inception Threshold Conditions in Rod-Plane Air Gaps at DC/AC Combined Voltages

“…Considering the adsorption process of electrons in air, the total number of positive ions produced by the electron is not equal to (7), it should be:…”

“…When the electric field on the electrode is above the corona inception, corona discharge will occur. Corona discharge can release a large of space charge [4] and lead to energy loss, audible noise, radio interference and insulation degradation [5][6][7][8][9]. Compared with a DC or AC transmission line, the electromagnetic environment of a DC-AC hybrid transmission is more complex [3], which makes it more challenging to ensure the safety of transmission lines and electrical components.…”

Audible noise evaluation for six‐phase overhead lines transformed from existing three‐phase double circuit infrastructures with uprated voltages

“…Under high voltage conditions, surface potential gradient of the conductor increases in magnitude, which causes corona discharges to occur. This causes energy loss, audible noise (AN), radio-frequency radiation and photon emission [15][16][17][18]. As a result, any increase of voltage level can produce excessive levels of acoustic noise, which may impact local communities, and this issue has thus become a significant concern for power utilities [19,20].…”