载波信号在中压地埋电缆中的耦合原理及信道模型

载波信号在中压地埋电缆中的耦合特性及信道模型是分析其传输特性的基础。在电磁感应原理基础上,结合卡接式电感耦合器耦合方式及中压地埋电缆的结构形式,推导卡接式电感耦合器的耦合模型。然后依据实际中压配网拓扑结构及电缆接地方式,利用多导体传输线理论及支路追加法搭建载波信号在中压地埋电缆中的信道模型。最后在信道模型基础上,分析载波信号在中压地埋电缆各导电层中的传输特性及不同位置的总传输特性,并对其进行了仿真及实验室测试。结果显示:载波信号在三相缆芯中传输特性完全一致;载波信号强度在铠装层最大,屏蔽层次之,三相缆芯最小;每流经一次环网柜,载波信号强度均会出现-15 dB左右的衰减。

Coupling principle and channel model of carrier signal in medium voltage buried cable

The coupling characteristics and channel model of the carrier signal in the medium voltage buried cable are the basis for analyzing the transmission characteristics. Based on the principle of electromagnetic induction, combined with the coupling mode of the snap-in inductive coupler and the structure of the medium-voltage buried cable, the coupling model of the snap-in inductive coupler is derived. Then, according to the actual medium voltage distribution network topology and cable grounding method, the multi-conductor transmission line theory and the branch addition method are used to construct the channel model of the carrier signal in the medium voltage buried cable. Finally, based on the channel model, the transmission characteristics of the carrier signal in the conductive layers of the medium voltage buried cable and the total transmission characteristics of the different locations are analyzed, and the simulation and laboratory tests are carried out. The results show that the carrier signal has the same transmission characteristics in the three-phase cable core; the carrier signal strength is the largest in the armor layer, the shielding level is the smallest, and the three-phase cable core is the smallest; the carrier signal strength will have an attenuation of about -15dB for each time through the ring network cabinet. This work is supported by National Natural Science Foundation of China (No. 51807063) and Fundamental Research Funds for the Central Universities (No. 2019MS081).