Mathematical Modeling And Application Research Of Flexible Wire In 1000kV Transformer Substations

1000kV transformer substation is a brand new field,and it's the world's highest voltage level currently.Compared with traditional substation,1000kV transformer substation has larger transmission power,less wear and tear,and also has more complex spatial structure,but mathematical models of its flexible wire have been rarely studied.The flexible wires in the substation are short-distance overhead lines,and the fittings,including insulators and clamp,have a great impact on the length and force of soft-bus conductor in substation.Currently,to flexible wire,the computational theory,which has been often used in long-distance lines,usually gets large errors.Moreover,this theory does not consider the impact of bending stiffness,so it will reduce the calculation accuracy of short-distance flexible wires.In addition,there are many empirical formulas used in the computational theory,as a result,tedious manual adjustments through climbing poles is required after construction.This paper made researches on mathematical modeling and application of flexible wire in 1000kV transformer substations,including general analytical model and numerical calculation model of flexible wire in 1000kV transformer substations,and software based on VC ++ for numerical calculation of flexible wire,with four points of details and innovations as follows:(1)In view of the assembly structure of flexible wires in the substation,based on catenary theory and the theory of oblique parabola,the general analytical model of flexible wire in 1000kV transformer substations is established to obtain the relationship about wire sag,wire length and design stress,and to get accurate sag and length by using design stress directly.(2)Against the deficiency of the general analytical model,numerical method is used to solve practical problems.Under the assumption of that the horizontal stress is known,the numerical calculation model of flexible wire in 1000kV transformer substations is established,and it consists of five modules,namely the dichotomy adjustment of sag step,the horizontal stress calculation and adjustment,the projection length calculation,the adjustment for calculation error of total sag,and the calculation of soft-bus conductor length.Then,the Matlab simulation is carried out with specific parameters.(3)Considering the impact of bending stiffness,general analytical model and numerical calculation model of flexible wire with stiffness in 1000kV transformer substations are established,by reanalyzing the shape,sag and stress of space suspension curve.What's more,the calculation of bending stiffness is discussed,and through the simulation of the specific parameters,the influence of stiffness on the length of the material is remarkable.Finally,the numerical model is applied to substation jumper.(4)Implement the software for numerical calculation of flexible wire in 1000kV transformer substations.With numerical calculation model as core,the software for numerical calculation of flexible wire in substation is designed,which is based on VC++.The software has the function of managing data,setting parameters and storing records.In addition,the software can input material parameters directly through the database,complete calculation of flexible wire length automatically and display results.Above all,it can store data for the user to record.