The Effect of 330 kV Porcelain Insulators Deterioration on Distributed Voltage

Abstract

As a commonly used insulator type for 330 kV transmission lines, porcelain insulators are susceptible to damage by external forces during operation, resulting in deterioration. The study on the change of the distributed voltage of porcelain insulators in different deterioration states is important for the timely and accurate detection of deteriorated insulators and the maintenance of safe operation of the power grid. This paper establishes a finite element model of a 330 kV AC transmission line. By changing the resistance values of single insulators at different positions in the insulator strings, the distributed voltage variation law of insulators under different deterioration states is simulated. Analysis of the results shows that the voltage drop is higher in the presence of two consecutive degraded insulators than in the case of a single degraded insulator with the same degree of deterioration. The existing criterion of “less than 50% of the standard value of the distributed voltage” for determining insulator degradation is likely to cause misjudgment in the case of high insulation resistance of low-value insulators and needs to be improved.