In this paper, a low-voltage power line carrier channel impedance testing terminal is designed according to impedance measure principle of free-axis, which realizes real-time measurement for impedance and phases of carrier channel, data remote transmission and remote monitoring for the impedance characteristics of carrier channel by the master monitor computer. According to the commands from the master monitor computer, at the frequency of 100~500kHz, the impedance testing terminal can realize cycle testing for the impedance phase A, B, C at the same time or one of the three phases at any five carrier frequencies or single carrier frequency, and the minimum interval between carrier frequencies is 0.1kHz. The range and accuracy of the impedance testing can reach (5~10Ω) ± 10% and (10~500Ω ) ± 5%. In this paper, the impedance measurement results of power line channel are discussed, which were measured in public building in different seasons and in residential district under the low-voltage power line carrier communication with poor performance in winter, and provide powerful means for power line impedance monitoring and communication performance of power line carrier system improving.%依据自由坐标轴阻抗测试原理,设计了低压电力线载波信道阻抗测试终端,实现了载波信道阻抗模值和阻抗相位的实时测量、数据远程传输以及主站监控计算机对信道阻抗特性的远程监控.阻抗测试终端依据主站监控计算机的控制命令,能够实现在100～500kHz频率范围内的任意5个载波频率点或单一载波频率点处,同时对A、B、C三相或某一相的循环阻抗测试,且载波频率点间的最小间隔为0.lkHz.阻抗测试范围与精度可达到(5～10Ω)±10％、(10～5002)±5％.本文分析了公用建筑不同季节和住宅小区冬季载波通信性能较差情况下的电力线信道阻抗测量结果,为电力线阻抗监测及改善电力线载波系统通信性能提供有力手段.
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