典型植被灰烬颗粒对导线-板间隙放电特性的影响

摘要

In order to analyze the influence of the typical vegetation ashes/particles on the discharge characteristics of conductor-plane air gap,in this paper experimental studies were conducted on the AC breakdown characteristics of gap under typical vegetation ashes/particles of thatch,straw and fir branch condition by using forest fire simulation test platform.In order to analyze the influence mechanism of multiple particles on the breakdown characteristics,the simulation model was built.The results show that the existence of the ashes and particles lead to a great decline of the dielectric strength of the air gap under AC voltage,which is reduced to about 54％ of the pure air gap under standard atmosphere,the impact of ashes/particles of thatch on the AC breakdown characteristics of gap is greater than other vegetation;the existence of particles make the electric field distribution between conductor and plane become uneven,the maximum electric field strength near the elongated particle is about 10.2 times larger than that of the backgroundelectric field,and the maximum electric field strength of the gap increases by about 55.7％ when the length of the elongated particle is changed from 15 mm to 25 mm;the closer the particle is from the simulation conductor and the larger the relative dielectric constant of particles,the greater degree of electric field distortion.%为分析典型植被灰烬颗粒对导线-板间隙放电特性的影响,利用模拟山火试验平台研究茅草、秸秆、杉树枝叶三种典型植被灰烬颗粒下间隙的交流击穿特性;同时建立仿真模型,系统分析颗粒对间隙击穿特性的影响机制.结果表明:在交流电压下,灰烬颗粒的存在使间隙的绝缘强度大幅度下降,平均击穿电压梯度约降至纯空气间隙的54％,茅草的灰烬颗粒对间隙交流击穿特性的影响大于其他植被;颗粒的存在会使间隙背景电场发生明显的畸变,长条形颗粒附近的最大电场强度约增大为背景电场强度的10.2倍,当长条形颗粒的长度由15 mm增至25 mm时,间隙的最大电场强度增大约55.7％;颗粒离模拟导线越近,相对介电常数越大,其对间隙电场的畸变程度越大.