摘要
近年来随着城市建设的不断发展,地下多回路敷设电缆线路越来越多,金属护套环流的损耗问题日趋严重。为此基于电磁感应原理计算三、四回路单芯电缆线路不同敷设方式下护套感应电压,通过建立电缆线路阻抗模型推导环流矩阵方程,获得金属护套环流变化规律。结果表明,多回路系统下,靠近中间的回路环流相对两边要小,回路数增多,环流最大值也增加;随着相间距及接地电阻的增加可以降低环流;分段越不均匀,对环流最大值影响较大且三相环流差别越大;三回路中,并列平行敷设方式下,环流最小的相序组合为ABC-CAB-ABC和ABC-CBA-ACB,品形敷设方式下,环流最小相序为ACB-BAC-ACB、CAB-CBA-CAB;四回路中,并列平行敷设方式下,环流最小的相序组合为ABC-CAB-ABC-CAB,环流最大值约为2 A,其他相序组合下环流最大达到5.5A,品形敷设方式下,不论何种相序组合方式的环流均≤2 A,环流最小相序为CAB-CBA-CAB-CBA。以上分析结果对电缆线路规划、设计及运维具有较好借鉴意义。
In recent years, with the continuous development of urban construction, more and more multi-loop cable lines are laid under ground, so the problem of the loss of circulating current on metal sheath is becoming serious. On the basis of the principle of electromagnetic induction, we calculated the induced voltage of multi-loop single core cables, figured out the circulating current matrix equation by the impedance model, got the change law of circulating current on the men- tal sheath, and finally got the results of circulating current on the metal sheath of different voltage cable lines and the interdependent of each other. The results show that, under the multiple loop system, the circulating current is relatively smaller near the middle of the circulation loop compared with the both sides, and the circuit current increases with the numbers increasing. The growth of phase spacing and grounding resistance can reduce the circulation. While the cable section is more uneven, the influence on the maximum circulating current and difference between three-phase circulating current will be greater. The phase sequence combination of the smallest circulating current is ABC-CAB-ABC, ABC-CBA-ACB under the tri-loop of flat formation and ACB-BAC-ACB, CAB-CBA-CAB under the tri-loop of trefoil laid formation. Under the four-loop of flat formation, the phase sequence combination of the smallest circulating current is ABC-CAB-ABC-CAB and the maximum circulating current is about 2 A under the best phase sequence combination but more than 5.5 A under other combinations. Under the four-loop of trefoil laid formation, the phase sequence combination of the smallest circulating current is CAB-CBA-CAB-CBA and the maximum circulating current is no more than 2 A under any phase sequence combinations. The results above will have good reference for cable route planning, design, operation, and maintenance.
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2016年第8期2426-2433,共8页
High Voltage Engineering
基金
国家电网公司科技项目(5111ZJ320TB)~~
关键词
电力电缆
敷设方式
环流
多回路
金属护套
感应电压
power cable
way of laying
circulating current
multi-loop
mental sheath
induced voltage
