An assessment method for the reliability of on-load tap-changer of power transformer

Based on the thorough analysis of typical failure modes and influences of on-load tap-changers in power transformer, the fault-tree of tap-changers is set up using fault-tree analysis techniques and the assessment method for the reliability of tap-changers, combined with the index of the importance and the weight integration method based on the multi-objective decision-making theory and subjective and objective integrated weights, is put forward. The assessment examples show that the method can deduct and ratiocinate the failure modes of tap-changers clearly, find out the weaknesses in time during the operation, reflect the influence degree of each fault modes, obtain the reliability level of tap-changers in the operation and get better assessment results.     

Effects of the Adaptable Distribution for Lateral Forces Considering modes Coupling on Structural Pushover Analysis

Two high and flexible RC frame structures are analyzed;the paper explains the rise in the structural damping ratio and the base mode's drifting,and the modes coupling is caused by the greatly rising damping ratio.The paper also proposes that the modes coupling need be considered in the pushover analysis of the high and flexible RC frame structures.A CQC adaptive distribution for lateral forces in considering the modes coupling at every load step is given,and is compared with the traditional SRSS one.Meanwhile,some practical engineering suggestions are given.     

A Stolving method for a group of differential equations and the solution of circular plate thermo-bending

A theorem solving a group of non-homogeneous linear differential equations tlirough integrating its basic solutions is putforward and proved,the mothematical play and physical natrue of the theorem is expouded, As an example,the theorem is applied to solving the question of thermo-bending of circular plate irradiated by laser.