高压大截面电缆和金具短路电动力的电磁——结构耦合有限元分析

Electromagnetic-structural Coupling Finite Element Analysis of Short-circuit Electrodynamic Forces for High Voltage Large Cross-sectional Cables and Fittings

高压大截面电缆运行电流大,发生短路故障时产生的短路电动力大大高于普通电缆,更容易造成缆体和固定金具的损伤,威胁输配电安全。为了分析高压大截面电缆短路电动力对缆体和金具的影响,文中建立了330 kV高压大截面品型垂直蛇形敷设电缆的电磁—结构耦合有限元模型,使用Maxwell瞬态电磁场分析法计算出电缆的短路电动力体密度分布;采用顺序耦合法将电动力体密度耦合至结构场计算出电缆金具的应力分布;对缆体磁场分布、受力时变特性及金具的应力分布进行了分析。结果表明,缆体短路电动力的幅值随时间周期性衰减,夹具上表面和螺栓处、电缆支架远端和螺孔等部位在短路电动力下应力最大,具有最大受损风险。

High voltage large cross-sectional cable has a large operating current and the electrodynamic force generated in case of short circuit is much higher than that of ordinary cable,which is more likely to cause damage to cable proper and the fixing fittings and threaten the safety of power transmission and distribution.For analyzing the influence of short-circuit electrodynamic forces of high voltage large cross-sectional cable on cable and fittings,the electromagnetic structural coupling finite element model of 330 kV trefoil formation high voltage large cross-sectional vertical serpentine cable is established in this paper.Maxwell transient electromagnetic field analysis method is used to calculate the density distribution of short-circuit electrodynamic forces of the cable.The stress distribution of cable fittings is calculated by coupling the density of electrodynamic force to the structure field by sequential coupling method.The distribution of magnetic field,the time-varying characteristics of force and the stress distribution of the fittings are analyzed.The results show that the amplitude of short circuit electrodynamic forces of cable proper attenuates periodically with time,and the upper surface of cleats and bolt,the remote end of cable support and screw hole have the greatest stress and the greatest damage risk under short circuit electrodynamic forces.