# Reduction of Dust on Solar Panels through Unipolar Electrostatic Traveling Wave
## 1 Introduction
Varying the applied frequency from 0.5 to 10 Hz alters the transport distance of the loop, with the maximum transport distance being provided at a frequency of 1 Hz [28]. At low frequencies, the cleaning performance is increased because the particle motion can follow the polarity change [21]. In an alternative electrostatic cleaning method, the electrostatic cleaner produces a standing wave that does not move the particles in one direction, rather it causes a \"flip-flop\" movement of the particles on the surface of the plate and they are carried in the air and down by gravity [23]. An accumulation of dust of over 90% can be removed in 2 min by the moving wave generated by the applied electric field [11]. If the electrostatic cleaner is operated intermittently, dust that adheres to the glass of the solar panel is displaced. In the case of continuous operation, dust approaching the cover glass is also displaced [21]. The adhesion of dust particles is affected by the time of day, and water condensation at night will increase contamination on the solar panel [33]. When the plate surface is wet due to precipitation or dew, or when there is a sandstorm and precipitation together, the accumulated dust will adhere strongly to the plate [21]. This makes cleaning difficult. However, high performance in cleaning can be achieved after the plate has dried [21]. Poor performance was observed for extremely small dust particles [23]. It is suggested performance will be improved by applying a high voltage to reduce the adhesion force, using natural wind, and using frequent operations before dust accumulates [21]. Improving the cleaning of dust particles can be considered as improving the electrode configuration, adjusting the operational scheme, and using airflow [34]. The energy consumed in the cleaning system is proportional to the applied voltage, the number of working cycles, and the operating time of the system, although energy consumption can be extremely low with a simple and potentially cost-effective electrostatic cleaner [21]. It has been found that an electrodynamic cleaning system can achieve a reduction in dust pollution between 32.1% and 95.7% [35]. This can provide efficient operation for large-scale SSP built in deserts around the world [34] and may also be used to remove dust from solar visions, and surfaces such as solar panels on extra-terrestrial missions [26; 29; 30; 33; 36; 37; 38; 39]. The dust removal electrode is composed of an insulation material and a wire electrode, and dust removal performance is affected by the insulating material, the geometry of the copper electrode [33]. The efficiency of electrodes with the same copper area but different design (planar, thick-toothed comb, and thin-toothed comb) to remove powder has been investigated [33]. The comb-shaped dust removal electrode was found to provide better cleaning performance compared to the planar electrode [33]. It has also been shown that under electrostatic and hydrophobic conditions, not only are environmental dust particles removed but, by reducing the adhesion of dust particles on the surface on the hydrophobic surface, more dust particles are removed [32]. The Electrodynamic Screen (EDS) will be one of the particle removal technologies used for space travel (Moon, Mars, etc.) [26; 29; 36; 37]. The Electrodynamic Shield is to be used to clean particle from the surface of the solar panels on Mars [29]. It has been shown how uncharged particle can be lifted and extracted from solar panels under the environmental conditions of Mars, with an average power consumption under various dust loads and on a screen with an active surface area of 59 cm\({}^{2}\) that was found to be 1.02 to 2.87 mW [37]. The power loss in the solar panel increased by 15% before the dust was removed [37]. The technology has other potential benefits for removing dust from sun visors, sight fields, and many other surfaces such as sun strings [38].