Research on Diagnostic Methods for Zero-Value Insulators in 110 kV Transmission Lines Based on Spatial Distribution Characteristics of Electric Fields

Porcelain insulators in power systems are subject to prolonged mechanical and electrical loads, as well as environmental factors such as climate variations. These conditions often lead to degradation of insulation performance and structural damage, resulting in a decrease in insulation resistance and the formation of cracks, which in turn produce “zero-value” insulators. The presence of zero-value insulators significantly increases the risk of pollution flashovers and electrical arcing, with flashover occurrences possible even under normal operating voltages. This poses a severe threat to the safe and stable operation of the power grid. This study develops a high-fidelity simulation model of insulator strings containing zero-value defects for a 110 kV transmission line. The impact of variations in the position and quantity of zero-value insulators on the spatial electric field distribution is analyzed in detail. Based on the electric field changes, a detection method for zero-value insulators is proposed. Additionally, a prediction model for the electric field strength of insulators with zero-value defects is developed using a Multilayer Perceptron (MLP) neural network. A spatial electric field distribution database for insulator strings containing zero-value defects is also established. The accuracy of the model is validated through laboratory testing.