高压电缆金属护套交叉点行波折反射的规律  

Study of Traveling Wave at the Sheath-crossing Point of High Voltage Power Cable

作　　者：陈玉林[1] 陈允平[1] 孙金莉[1] 

机构地区：[1]武汉大学电气工程学院,武汉430072

出　　处：《高电压技术》2006年第10期11-14,24,共5页High Voltage Engineering

摘　　要：高压电缆的金属护套交叉互联导致行波在多个波阻抗不连续点产生了复杂的折反射行为,这对高压电缆线路的行波故障测距产生很大的影响。为研究高压电缆中行波的折反射规律,在波动方程的基础上,从独立的模量域推导出多导体系统在相量域的波阻抗矩阵,并利用相量域的波阻抗矩阵求解出折反射系数矩阵。此折反射系数矩阵表征了行波在护套交叉点的折反射规律。EMTDC仿真结果验证了所求取的折反射规律的正确性。进一步的理论计算和仿真试验表明,经多次折反射,行波线模总量保持不变,且三相线模含量存在着趋于一致的规律。The reflection and refraction of traveling wave are quite complicated at the sheath-crossing point of high voltage power cable, due to its remarkably noncontinuous surge impedance. The complicated reflection and refraction will induce great difficulty to fault location of high voltage power cable. Thus it is necessary to study the multiconductor system＇s peculiar action of traveling wave at the sheath-crossing point. This paper presents a method to describe the traveling wave＇s complicated action with a reflection and refraction coefficient matrix. First, the basic traveling wave equation is established and transformed to uncoupled module equation. Secondly, a module surge impedance matrix is introduced to describe the relationship between the module voltage and module current. Thirdly, the phase surge impedance matrix, which describes the relationship of voltage and current in the phase domain, is obtained through inverse transformation. At the last step, the phase surge impedance matrix is used to calculate the reflection and refraction coefficient matrix of traveling wave at the cable sheath-crossing point. EMTDC simulation shows that the proposed method is reasonable to research traveling wave＇s complicated reflection and refraction action at the power cable sheath-crossing point. Further study shows that the aerial mode of the traveling wave has the trend to disperse averagely among the three phases, while the total aerial mode component will keep its level unchanged.

关 键 词：高压电缆 金属护套 行波 折反射 护套交叉点 

分 类 号：TM247[一般工业技术—材料科学与工程] TM861[电气工程—电工理论与新技术]