On-line measurement of metal oxide arrester is superior in many respects to conventional off-line DC test.However

on-line measurement faces the interference from the electriferous equipments around MOA and the interphase interference from MOA itself.For the MOAs that are generally arranged in line

this paper analyzes the leakage current characteristic of the MOAs under the interfering environment.The result shows that the resistive component of leakage current of MOA is difficult to be accurately measured under the interfering environment.While measuring the increment of the resistive current is the key to on-line measurement of MOA.