Secondary Development And Application Of Power Transformer Main Insulation Electric Field Simulation Software

Transformer insulation reliability not only depends on the electric field intensity but also relates to other factors.At present,the insulation margin is widely used as criterion in insulation design of transformer.However,more popular general electric field simulation software on the market can calculate electric field distribution and the maximum electric field intensity,but can not calculate the insulation margin.So,for power transformers,the secondary development about insulation margin based on the general software has an important practical significance and application value.In this background,firstly,the general electric field simulation software Elecnet has been developed by Visual Basic.Field value information,such as the electric field intensity of element and the potential value of node obtained by FEM,are extracted through VB program and library function of ElecNet.On this basis,the method of drawing power line is founded by electric flux.Then,the electric field intensity value and the minimum insulation margin on each power line or interface of oil and paper related to oil gap length are calculated.The secondary software is verified by comparison of analytic values,measured values with calculated values,which provides a reliable analysis method for the transformer insulation design.Then,using secondary development software,the 2D and 3D main insulation electric field and insulation margin of typical transformer are calculated and analyzed,and the conclusion that insulation weak positions are consistent with experimental breakdown phenomenon is obtained.The factors affecting the reliability of the insulation are studied,and insulation structure is improved,making the product pass the insulation test.Finally,the electric field and insulation margin of HV bushing are calculated and analyzed.The conclusion about distribution of electric field and insulation margin are gained,which can guide product design.Therefore,the engineering application value of secondary development software is proved.