3D Electric Field Analysis And Insulation Design Of The ODFPS-1000000/1000Transformer Medium Voltage Outlet Ends

Power transformer plays a key role in power system，its safe and reliableoperation concerns the people’s livelihood. Because the power transformer faults aremostly due to the insulation breakdown, so in the course of transformer development,the determination of insulation structure is the priority and difficult point of researchwork. To ensure low-loss and economic operation of transformers, there must beproper insulation margin. Therefore, a reasonable arrangement of power transformerinsulation structure and the correct selection of insulation material have importantsignificance in technology and economy.In this paper, according to the insulation structural characteristic of southernZhejiang station ODFPS-1000000/1000transformer,3D design software Pro/E isused to establish3D models of the medium voltage winding end, medium voltagewinding cable and medium voltage winding lead the three regions, and the finiteelement3D electric field analysis software ELECNET is used to analyze andcalculate and achieves the purpose to update insulation structure.For medium voltage winding end regions, it respectively uses parameter-drivenelectrostatic ring radius of curvature and the insulation thickness, the number ofparameter-driven angle ring of winding end, the number of parameter-driven windinginsulation tube to analyze and calculate. Analysis shows that the above parametershave certain effects on electric field strength, through reasonable comparison, it cansum optimum insulation structure scheme, give a correct safety margin and providethe basis for future design of similar products.For medium voltage winding cable area, it uses the cable to analyze the3Delectric field of limb plate and drawstring, gives the maximum field strength of a keypart and insulation improvement program, and provides the design basis forinsulation design. Analysis shows that the value of the electric field strength near thedrawstring is higher, which requires special attention in insulation design. At the sametime as the parallel connection exists, leading to the potential line almost orthogonalto peripheral screen of coil wire, so special attentions should be paid to the problemof surface creepage along screen here.For medium voltage winding lead, it uses the lead to analyze the3D electricfield of drawstring and oil tank, gives the maximum field strength of the key parts.The calculation results show that equipotential lines and external screens betweenlead and high voltage windings intersect a lot, and special attentions should be paid to the problem of surface creepage along screen here.