复合绝缘子暴露在自然环境中的可靠性评估

Reliability evaluation of composite insulators exposed to natural environment

复合绝缘子在电力传输系统中,主要功能是实现电气绝缘和机械固定,即在输电线路中防止电流回地和支撑导线.复合绝缘子在规定的机、电负荷和各种环境条件下长期运行会产生劣化,也会遭受过电压、机械应力等外部冲击.复合绝缘子长期暴露在自然环境下的可靠性,对其生产商和线路传输具有重要作用.首先,针对复合绝缘子的老化失效问题,考虑疏水性的自康复过程,对复合绝缘子建立一个自然退化与多种外部冲击共同作用的相依竞争失效模型;然后,对复合绝缘子的可靠度和平均使用寿命进行研究,用极大似然估计的方法对模型中的参数进行估计;最后,利用数值模拟验证模型的有效性.

In the power transmission system,the main function of composite insulators is to achieve electrical insulation and mechanical fixation,that is,to prevent electric current from returning to the ground and support wires in the transmission line.It will be degraded in long-term operation under specified mechanical and electrical loads and various environmental conditions,and will also be subject to external shocks such as overvoltage and mechanical stress.The reliability of composite insulators exposed to the natural environment for a long time plays an important role in composite insulator manufacturers and line transmission.Aiming at the problem of aging and failure of composite insulators and considering the self-healing process of hydrophobicity,a dependent competitive failure model of natural degradation and multiple external shocks is established for composite insulators.The reliability and mean time to failure of composite insulators are studied,and the parameters in the model are estimated using the method of maximum likelihood estimation.Finally,numerical simulation is carried out to verify the effectiveness of the proposed model.