Influence of Bird Droppings Channel on Electric Field Distribution Characteristics for Catenary Positive Feeder Insulator String Under Windy Conditions

Abstract

Under windy conditions, air currents induce changes in the shape and trajectory of birddropping channels. Therefore, it is crucial to examine the impact of the bird droppings channel on the electric field distribution under such conditions. This study established a simulation experiment system to model the bird droppings channel's morphology under windy conditions. The experiments have identified three typical morphologies of the bird droppings channel under windy conditions: quasi-linear, wavy, and fan-shaped. A simulation model of the bird droppings channel around the insulator string of the catenary feeder was also established, analyzing the influence law of three typical bird-dropping channel forms on the local electric field intensity distribution characteristics of catenary feeder insulator strings under windy conditions. The simulation results reveal that the quasi-linear bird droppings channel causes a distorted area of the electric field on the insulator surface concentrated at the head of the channel. The electric field intensity increases with the angle of the channel offset, and the closer the channel is to the insulator edge, the stronger the electric field intensity at the head. The wavy bird droppings channel directly short-circuits the 1# insulator, resulting in the most severe distortion of the 1# insulator's surface electric field. The influence of the fan-shaped bird droppings channel on the surface electric field is mainly concentrated at the joints between the insulator cap, shed, and air. The study results indicate that, under windy conditions, the wavy-shaped channel has the most severe impact on the voltage distribution of the insulator string, whereas the quasi-linear and fan-shaped bird droppings channels exhibit nearly the same impact as under ideal working conditions. The results of this paper can provide a reference for the analysis of the causes of the bird dropping channel flashover fault of catenary feeder under windy conditions. INDEX TERMSWindy conditions; Bird droppings channel morphology; Catenary positive feeder; Insulator string; Electric field distribution