Discharges in Air at UHV Technical Committee

When the electric field strength around an electrode is enough high, complex ionization processes take place in the air nearby, leading to the discharge phenomena known as corona [1]. The occurrence of discharge, as shown in Figure 1, can cause audible noise (AN), radio frequency interference (RFI), and corona loss (CL) which should be minimized for economic reasons [2-3]. Due to its adverse effects, it becomes an important consideration in the design and operation of ultra-high voltage (UHV) AC and DC transmission lines and other electrical devices [4]. On the other hand, when the discharge occurs, an ionic wind can be formed as air ions are accelerated by the electric field and exchange momentum with neutral air molecules. As there is no noise and in fact no moving parts at all, it offers an attractive method to cool down electronic devices such as the iPad [5-6]. The latest application of air discharge was achieved by MIT engineers who built and flew the first ever plane which was propelled only by the ionic wind instead of fossil fuels [7]. The study of discharge in air can date back to the middle of the 20th century by Meek, Raether, and Loeb [8-9]. However, because of the complexity of this problem, investigation of the discharge mechanism has continued up to the present day [10-12]. As a good understanding of the basic processes involved is essential to utilize or prevent the discharge, especially for the UHV projects which are being built in China, India, and many other countries, it is still of great importance to further investigate the discharge phenomena in air.

This Technical Committee has a mission to promote the development of knowledge concerning the phenomena and mechanisms involved in the initiation and propagation of discharges in air with respect to AC and DC UHV, as well as to propose appropriate solutions to reduce or suppress the discharges. Its purpose is also to identify test methods and available solutions currently proposed by various researchers and institutes, and to survey newly developed materials used on UHV systems to prevent discharges.

Figure 1. Corona discharge on an iced conductor

Past and Recent Committee Activities

Researchers in Tsinghua University have studied the air discharge for decades and notable achievements have been made. In 2012, Zhicheng Guan hosted the 19th International Conference on Gas Discharges and their Applications (GD 2012), September 2-7, Beijing, China, 2012. During the conference, a special session on discharges in air with respect to AC and DC UHV was organized. In 2013, Zhicheng Guan and Liming Wang organized the 2013 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP 2013), October 20-23, Shenzhen, China, 2013. This conference was a resounding success which attracted more than 330 participants from 27 countries [13]. In this conference, many papers related to air discharge were contributed by a number of Technical Committee members.

There is plenty of communication within the TC to exchange ideas on the topics that need to be addressed. In December 2017, Prof. Masoud Farzaneh was invited to Shenzhen for an academic exchange and he gave a lecture related to discharge in air. In September 2018, a special session was held at Graduate School at Shenzhen, China. Liming Wang, Jun Zhou, and Fuzeng Zhang made three presentations on “long-term operated conductors under rain weather in AC power transmission lines”, “Numerical simulation of the transition process from glow to streamer”, and “Recent progress and future development of external insulation for ultra-high voltage transmission system”, respectively. In October 2018, Prof. Simon Rowland was invited to Shenzhen. During his visit, Prof. Rowland gave a lecture and we took this occasion to exchange ideas especially on air discharge at low air pressure and discuss future cooperation in this field.

The Technical Committee is also seeking cooperation with other working groups dealing with the discharge in air. In August 2018, Liming Wang, Masoud Farzaneh, and Fanghui Yin attended the working group meeting of CIGRE B2.69 before the CIGRE Session 47 that was held in Paris. Several task forces were founded and we hope some research results can be escalated to IEEE Standards in the future. In October 2018, some Technical Committee members took part in a workshop titled “High Voltage Insulator Coating” organized by WG B2.69 in Italy. In this workshop, Liming Wang made a presentation on “RTV Silicone Coating Experience in China”. In the years ahead, all Committee members will be invited to participate more closely in the future activities.

In the past years, efforts were made to encourage young graduate students to be involved in this research field and IEEE DEIS. Currently, more than 10 graduate students from the Graduate School at Shenzhen, Tsinghua University have joined IEEE DEIS as student members.

Future Activities

Recently, some Technical Committee members are investigating the influence of forest fire on air discharge and flashover voltage as forest fire threatens the safety of the power grid and must be considered when building new EHV/UHV transmission lines. In addition, under high altitude or low pressure air conditions, air is more likely to be ionized. Therefore, the flow of large current between conductors can cause damage to the materials in aircraft electrical systems. To address this problem, some experiments and simulation on air discharge at high altitude or low air pressure are also being studied by Technical Committee members. When the research progresses, it will be shared with the DEIS community.

The Technical Committee is planning a workshop at the 2019 Conference on Electrical Insulation and Dielectric Phenomena which will take place from 20 – 23 October 2019, in Richland, Washington, USA. In this workshop, development of position papers and future workshops at DEIS-sponsored conferences will be discussed. Furthermore, after communication with Prof. Edward Cherney, the Editor-in-Chief of IEEE Transactions on Dielectrics and Electrical Insulation (TDEI), the Technical Committee is contacting Committee members and specialists in this field to prepare a special issue of TDEI in 2020. This special issue will be focused on the discharge phenomena in air. In the coming years, all Committee members will be invited to get more closely involved in the above activities.

More information about the DEIS Technical committees can be found on the IEEE DEIS page for Technical Activities. If you are interested in participating the future activities of Technical Committee on “Discharges in Air at UHV”, please contact the committee chair Dr. Liming Wang at wanglm@sz.tsinghua.edu.cn.


  1. P. S. Maruvada, Corona Performance of High-Voltage Transmission Lines, Research Studies Press: England, 2012.
  2. F. Yin, M. Farzaneh, and X. Jiang, “Corona investigation of an energized conductor under various weather conditions,” IEEE Trans. Dielectr. Electr. Insul., vol. 24, no. 1, pp. 462-470, 2017.
  3. I. Fofana, M. Farzaneh, H. Hemmatjou, and C. Volat, “Study of discharge in air from the tip of an icicle,” IEEE Trans. Dielectr. Electr. Insul., vol. 15, no. 3, pp. 730-740, 2008.
  4. M. Farzaneh, S. Farokhi, and W. A. Chisholm, Electrical Design of Overhead Power Transmission Lines, McGraw-Hill Press: New York, 2012.
  5. D. B. Go, R. A. Maturana, T. S. Fisher, and S. V. Garimella, “Enhanement of external forced convection by ionic wind,” Int. J. Heat Mass Transf., vol. 51, pp. 6047-6053, 2008.
  6. D. H. Shin, S. H. Baek, and H. S Ko, “Development of heat sink with ionic wind for LED cooling,” Int. J. Heat Mass Transf., vol. 93, pp. 516-528, 2016.
  7. H. Xu, Y. He, K. L. Strobel, C. K. Gilmore, S. P. Kelley, C. C. Hennick, T. Sebastian, M. R. Woolston, Da. J. Perreault, and S. R. H. Barrett, “Flight of an aeroplane with solid-state propulsion,” Nature, vol. 563, pp. 532-535, 2018. 
  8. J. M. Meek, “A theory of spark discharge,” Phys. Rev., vol. 57, no. 9, 1940.
  9. L. B. Loeb, Electrical Coronas, University of California Press: Berkeley, CA, USA, 1965.
  10. A. A. Masíud and B. Stewart, “An investigative study on the influence of correlation of PD statistical features on PD pattern recognition,” in 2nd IEEE Int. Conf. on Dielectr. (ICD), Budapest, Hungary, 2018. 
  11. X. Meng, H. Mei, L. Wang, Z. Guan, and J. Zhou, “Characteristics of streamer propagation along insulation surface: influence of shed configuration,” IEEE Trans. Dielectr. Electr. Insul., vol. 23, no. 4, pp. 2145-2155, 2016. 
  12. Y. Yuan, X. Jiang, S. Rowland, A. Xiao, Q. Li, and S. wang, “Calculations of breakdown voltage of rod-plane air gaps in the presence of water streams,” IEEE Trans. Dielectr. Electr. Insul., vol. 22, no. 3, pp. 1577-1587, 2015.
  13. A. Cavallini, “Report on CEIDP 2013,” IEEE Electrical Insulation Magazine, vol. 30, no. 1, pp. 46-48, 2014.

Committee Members & Affiliation

No.Member NameMember Affiliation
1Prof. Liming WangChair, Graduate School at Shenzhen, Tsinghua University, China
2Prof. Masoud FarzanehUniversité du Québec à Chicoutimi, Canada
3Prof. Zhicheng GuanGraduate School at Shenzhen, Tsinghua University, China
4Prof. Hulya KirkiciUniversity of South Alabama, USA
5Prof. Behzad KordiUniversity of Manitoba, Canada
6Prof. Jian LiChongqing University, China
7Prof. Azam NekahiGlasgow Caledonian University, UK
8Prof. Simon RowlandUniversity of Manchester, UK
9Prof. Brian StewartUniversity of Strathclyde, UK
10Prof. Zhongdong WangUniversity of Manchester, UK
11Dr. Fanghui YinGraduate School at Shenzhen, Tsinghua University , China
12Dr. Fuzeng ZhangElectric Power Research Institute of Southern Power, China
13Dr. Jun ZhouChina Electric Power Research Institute, China

For more information about this technical committee, please contact Prof. Liming Wang at wanglm@sz.tsinghua.edu.cn