Research on Thermal Defect Assessment Algorithms for Tulip Contacts of High Current Switchgear

Abstract

In order to effectively evaluate the contact status of tulip contacts in high current switchgear and avoid serious thermal failure, the sensitivity and accuracy of thermal defect assessment is necessary to be improved. Based on this problem, an algorithm for long-term assessment of contact state of tulip contacts is designed for thermal defect assessment. Firstly, the traditional relative temperature difference method is improved based on artificial neural network. The calculation results of relative temperature difference are modified according to the normal distribution statistics. Secondly, a thermal defect assessment algorithm is designed based on the improved relative temperature difference method. The calculation results of the relative temperature difference in the algorithm are divided into eight state levels to represent different degrees of state. A "N+3" judgment algorithm and a "24-hour intensive evaluation" algorithm are designed to determine whether there are potential contact problems in tulip contacts and to eliminate the abnormal alarms caused by calculation errors in the algorithm. Finally, the thermal defect assessment algorithm is applied to the actual switchgear operation and maintenance to verify its effectiveness. The algorithm can accurately evaluate the contact state of tulip contacts in switchgear.