Factors affecting corona on twin-point gaps under DC and AC HV

I. A. Metwally*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


The factors affecting corona formation on twin-point/plane gaps are investigated both theoretically and experimentally. In the theoretical analysis, an electrostatic field computation program based on the charge simulation method was used to get the electric field profile on the plate for different gap lengths and interspacings between the two points. Also, the effect of voltage level, air pressure and gap length on the number of axial streamers occurring across the critical field line was introduced for a constant time duration. The variation of the integral of the ionization coefficient with the axial length from the point was studied. Finally, a study of the effect of air pressure and gap length on both the corona inception voltage and critical length was presented. Corona formation in single and twin-point/plane gaps also was investigated experimentally under both high direct and alternating voltages. There are many factors affecting such corona formation. The investigated factors were the interspacing between the two points, gap length between the point and the plane, ambient temperature, relative humidity, polarity or frequency of the applied voltage, and electrode material. In order to study and explain such phenomena, a photographic investigation together with a simultaneous measurement of both the applied voltage and the corona current were introduced. Curve fitting of the dc corona current vs. gap length and voltage for both single and twin-point/plane gaps gave the conventional relationship, but in case of twin point the power of the gap length varies between 1.2 and 1.3.

Original languageEnglish
Pages (from-to)544-553
Number of pages10
JournalIEEE Transactions on Dielectrics and Electrical Insulation
Issue number4
Publication statusPublished - 1996
Externally publishedYes

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


Dive into the research topics of 'Factors affecting corona on twin-point gaps under DC and AC HV'. Together they form a unique fingerprint.

Cite this