# Phase Risk Analysis of Overhead Lines Under Complex Icing Conditions
## 5 Conclusions  
In this study, the risk of phase-to-ground discharge of overhead lines under complex ice-covering conditions was analyzed in depth, in order to provide a theoretical basis for fault prevention and treatment. The finite element model of overhead lines was established, and the influence of different conditions on the discharge coefficient of the conductor-ground line of the overhead line and the discharge interval was studied. The following conclusions were drawn:  
The thickness of ice cover increases, the arc droop of the earth wire and the height of the conductor's de-icing jump increases significantly, the phase-to-ground distance decreases, and the phase-to-phase discharge coefficient appears to be equal to 1 when the thickness of ice cover reaches 20 mm. Especially when the thickness of ice cover reaches 30 mm, the risk interval expands to 49% of the total length of the line.  
Uneven ice cover leads to uneven local load of the overhead line, resulting in individual parts of the sag abnormally increasing, but also making the lowest sag position deviate from the middle point of the wire, and with the heavy ice cover position closer to the middle point of the wire, the greater is the risk area at close to 57%.  
Uneven de-icing caused by local vibration of the conductor, line side of the de-icing and de-icing area, is 300 m long when there is a discharge risk section--the section for the middle of the side near the de-icing area, accounting for 28.75% of the total length of the line.  
The cumulative effect of the long gear distance caused by the growth of the arc of the conductor and ground line after icing is more prominent--the gear distance increased from 200 m to 600 m, the increase in the arc of the conductor reached 19.4 m, the arc of the ground line increased to 23.7 m; the 600 m gear distance of the conductor de-icing bouncing risk area is as high as 73.667%.  
In strong wind conditions, the wind causes the arc droop of the conductor to decrease, the discharge easily occurs when the wind speed is small, and the horizontal displacement of the conductor increases while the risk of discharge decreases with larger wind speeds.  
This paper analyzed the risk zones between the conductors and the ground wire under different operating conditions, drawing several conclusions beneficial to engineering design. However, there was limited consideration of discharge risks between the conductors and ground wire in cases involving special terrains or split conductors.  
**Author Contributions:** [PERSON] was responsible for the overall design of the study and numerical simulation model. [PERSON] and [PERSON]. ([PERSON]) contributed to the interpretation of the data and the drafting of the manuscript. [PERSON]. ([PERSON]) was responsible for the analysis of the data, and the hydrodynamic model. All authors have read and agreed to the published version of the manuscript.  
**Funding:** Supported by the research project of State Grid Xinjiang Electric Power Co., Ltd. (Program No. 5230 DK240003).  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.  
**Conflicts of Interest:** Authors [PERSON] and [PERSON] were employed by the company Power Science Research Institute of State Grid Xinjiang Electric Power Co., Ltd. The funders participated in the design of the study, as well as in the analyses and interpretation of data, the writing of this article or the decision to submit it for publication. The remaining authors declare that the re-search was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.