Prediction of switching impulse breakdown voltage of complex gap based on SVM

Abstract

Complex gaps may be formed when carrying out live working in substations, while the discharge characteristics of complex gaps are different from those of single gaps. This paper focuses on the prediction of critical 50% positive switching impulse breakdown voltage ( U 50–crit + of phase-to-phase complex gaps formed in 220 kV substations. Firstly, several electric field features were defined on the shortest discharge path of the complex gap to reflect the electric field distribution. Then support vector machine (SVM) prediction models were established according to the connection between electric field distribution and breakdown voltage. Finally, the U 50–crit¸+ data of the complex gap were obtained through twice electric field calculations and predictions. The prediction results show that the minimum U 50–crit + of phase-to-phase complex gaps is 1147 kV, and the critical position is 0.9 m away from the high voltage conductor, accounting for 27% of the whole gap. Both critical position and voltage are in good agreement with the values provided in IEC 61472.

Keywords

• complex gap
• electric field features
• svm