Research on surface electric field of parallel gap

Abstract

With parallel gap, by controlling the motion path of the electric arc, effectively avoid burning and damaging the insulator during lightning strike so that the effect to reduce the accident rate of line is obvious. Because of simple structure, convenient installation and good economical efficiency, its importance in measures of lightning protection for transmitting line is continually improved. Electric field characteristics on the surface of parallel gap electrode have obvious influence on corona generation and the gap breakdown position and are the key parameters that must be considered in the design. Based on the finite element method, this paper sets up the analysis model of electric field of parallel gap including the tower, the conductor and the insulator, uses ANSOFT software for simulation, studies the surface electric field characteristics of parallel gap electrode, compares the electric field of four types of parallel gap put forward in the paper and analyzes the law of influence of parallel gap electrode parameters on the electric field characteristics. The results show that, when the short circuit distance is increased, the maximum values of electric field of ball end and snap ring body are obviously increased; the opening angle of snap ring is larger and the maximum value of electric field of ball end is higher; when the pipe diameter is increased, the maximum value of electric field of snap ring body is reduced considerably; the ball end is bigger and the maximum value of electric field of ball end is less; the ring pipe diameter is the structure parameter having the largest influence on the surface electric field; for the ball end at the end of ring electrode, the structure parameter having the largest influence on the electric field is the diameter of ball end. Reducing the distance that the ball end stands out of the ring plane can decrease the maximum value of electric field of ball end.