Simulation Study on Zero Value Characteristics of 110 kV Cathead Straight-Line Tower Suspension Double-String Insulators

Porcelain insulators are widely used in high-voltage transmission lines. Over prolonged periods of operation, their insulation and mechanical performance inevitably deteriorate, which can lead to flashovers in the external insulation of transmission lines and even the explosion of porcelain insulators, causing power outages. In this study, a simulation was conducted using relevant finite element analysis software on a model of the 110 kV straight-line cathead tower suspension double-string insulators. The simulation considered the comprehensive effects of the tower structure, tower head shape, fittings, and conductors. Changes in the position and quantity of zero-value insulators were made to measure variations in the surrounding electric field strength and compared with the field strength distribution under normal operating conditions. The results indicate that the quantity and location of deteriorated insulators have a significant impact on the distribution of the surrounding electric field strength. When insulators near the high-voltage end reach zero value, there is a noticeable increase in the overall electric field strength of the insulator string. Deterior ation of insulators on the opposite side has limited impact on the field strength measured on this side. The research findings provide a theoretical basis for the diagnosis and detection of deteriorated insulators, offering valuable insights for the operation and optimization of insulators.