Analysis and Suggestions on MOA Protection Failure of Overhead Transmission Lines

As one of the main technical means of lightning protection, MOA has been widely used in overhead lines in southern China. However, in recent years, line arrester failures have occurred in many places. In this paper, the appearance inspection, insulation resistance, DC leakage current, 8/20 $\mu\mathbf{s}$ impulse current and dissection test were carried out on the arrester in a power grid company. The results showed that the appearance inspection and electrical test of the same manufacturer and the same batch of products all met the standard requirements. It was found that there was no non air insulation filler between the valve piece a of the test object and the outer epoxy cylinder. Based on the analysis of the test and field inspection, it was considered that one of the reasons for the failure of the arrester protection was the design defect, one was the production quality control was not in place, and the other was the defect in the installation mode. In view of three different types of faults, suggestions are put forward from design selection, production process control, installation, operation and maintenance.