基于数据物理融合驱动配电网三相线性化潮流及线损分析应用

分布式电源规模化并网引入了下垂控制等非光滑本地控制约束,易导致传统基于前推回代法的潮流计算方法收敛失败,且由于分布式电源并网改变系统潮流方向,导致传统等值电阻法、压降法等理论线损计算方法不再适用。为解决上述问题,提出计及有载调压变压器调压、分布式光伏下垂控制的光滑化模型,构建了基于数据物理融合驱动的三相配电网线性化理论线损快速计算模型。在传统基于稳态运行特性线性化、一阶泰勒展开线性化的基础上,利用偏最小二乘法补偿线性化误差。相比纯物理驱动线性化,在负荷重载条件下仍具有较高精度;相比于纯数据驱动线性化,能够保留支路拓扑信息,适用于开关状态变化场景。所提模型仅对线性化误差进行拟合补偿,在保证线性化精度的前提下,极大地提高了潮流模型的收敛性与计算效率,且能够适应不同负荷水平实现精确误差补偿。基于实际42节点三相配电网系统仿真,验证了所提模型具有较高精度,且能够实现配电网理论线损鲁棒、快速计算。

Improving the surface insulation of epoxy resin by plasma etching

Epoxy resin(EP)tends to accumulate a large amount of charge on its surface when exposed to a high-voltage DC electric field,which leads to a reduction in its insulative performance and an increase in potential safety risks in power systems.To suppress charge accumulation,improve the flashover voltage of the EP,and reduce the risk of gas insulated switchgear(GIS)/gas insulated transmission line(GIL)failure,we used two plasma-etching methods,i.e.,atmospheric-pressure dielectric barrier discharge(DBD)and the atmospheric-pressure plasma jet(APPJ),to modify the surface of the EP.The surface morphology and electrical properties of the modified materials were explored as a function of time.The results show that after DBD treatment,the roughness of the sample increases by 103.9 nm,the conductivity increases by3.9×10^(-18)S,and the flashover voltage increases by 14.4%;after APPJ treatment,the roughness of the sample increases by 223.5 nm,the conductivity increases by 3.4×10^(-17)S,and the flashover voltage increases by 18%.This shows that both plasma-etching methods can improve the insulation properties of materials by improving the surface-charge characteristics.The two methods are compared with each other:the APPJ treatment method is better at improving the surface roughness and electrical properties of materials,and this flexible treatment method has greater potential in industrial applications.

Effect of plasma step gradient modification on surface electrical properties of epoxy resin

In this paper,plasma fluorination is combined with plasma silicon deposition to achieve step gradient modification on an epoxy resin surface.The physicochemical characteristics of samples are investigated and the electrical performances measured.The obtained results show that compared with untreated and single treated samples,the samples treated by step gradient modification significantly improve the flashover performance.According to experiment and simulation,the mechanism explanations are summarized as follows.First,it is found that the step gradient conductivity can effectively optimize the electric field distribution of a needle-needle electrode.Then,step gradient modification suppresses the accumulation of surface charge at the triple junction and makes the charge distribution more uniform.Furthermore,it can accelerate the surface dissipation on a high electrical field region and control the dissipation rate on a low electrical field region.All these results can restrain surface discharge and increase the flashover voltage.The step gradient modification method proposed in this paper provides a new idea for improving the surface insulation performance.

Improving the surface flashover performance of epoxy resin by plasma treatment:a comparison of fluorination and silicon deposition under different modes

This work treats the Al_(2)O_(3)-ER sample surface using dielectric barrier discharge fluorination(DBDF),DBD silicon deposition(DBD-Si),atmospheric-pressure plasma jet fluorination(APPJ-F)and APPJ silicon deposition(APPJ-Si).By comparing the surface morphology,chemical components and electrical parameters,the diverse mechanisms of different plasma modification methods used to improve flashover performance are revealed.The results show that the flashover voltage of the DBDF samples is the largest(increased by 21.2%at most),while the APPJ-F method has the worst promotion effect.The flashover voltage of the APPJ-Si samples decreases sharply when treatment time exceeds 180 s,but the promotion effect outperforms the DBD-Si method during a short modified time.For the mechanism explanation,firstly,plasma fluorination improves the surface roughness and introduces shallow traps by etching the surface and grafting fluorine-containing groups,while plasma silicon deposition reduces the surface roughness and introduces a large number of shallow traps by coating Si Oxfilm.Furthermore,the reaction of the DBD method is more violent,while the homogeneity of the APPJ modification is better.These characteristics influence the effects of fluorination and silicon deposition.Finally,increasing the surface roughness and introducing shallow traps accelerates surface charge dissipation and inhibits flashover,but too many shallow traps greatly increase the dissipated rate and facilitate surface flashover instead.