To reduce the weight of the string and simplify fittings

how to develop 840 kN large tonnage insulator has become an urgent problem to be solved. The 840 kN large tonnage insulator is a completely new product. In order to determine its long-term mechanical fatigue properties

a set of effective techniques and methods were designed to give the quantitative assessment of 840 kN large tonnage insulator. According to the proposed test methods

the test parameters and the vibration fatigue device was determined. Then

the fatigue tests of 7 different manufacturers

10 types 840 kN large tonnage insulators and 420 kN insulators were carried out

the mechanical properties of 840 kN large tonnage insulators were assessed

and the fatigue weak points were found. It is found that the fatigue property of 840 kN insulator is not worse than that of 420 kN insulators. The research results provide helps for the mechanical properties detection of 840 kN large tonnage insulators

and also provided technical support for the promotion and application of the engineering.