10kV中压电力线信道传输特性测量与研究(一)——信道传输的一般特性

Measurement and research of channel transmission properties on 10 kV medium voltage power lines Part 1:General properties

在2座典型变电站10kV电力网络中,采用环网线路测量信道的频率响应,采用信号发送/接收的方式测量信道的路径损失。根据测量结果,结合传输线的基本模型,对信道的传输特性作了初步研究,频率范围40kHz￣1.5MHz。研究表明,在无分支线的情况下,信道的功率衰减为10￣20dB/km。信道是时间色散的:在频域,幅频响应呈频率选择性衰落,相频响应基本上为线性相位;在时域,信道的冲激响应表现出时延扩展。rms时延扩展和相干带宽均与具体的信道结构有关,大致在数十微秒和数十千赫兹数量级。信道的窄带衰落服从Nakagami-m分布,在信息传输速率达到Kbit/s及以上时,信道可以视为时不变信道。

In two typical 10 kV power networks,the frequency response is measured on loop wires and the path loss is obtained by employing the transmitting/receiving mode. Based on the empirical data,transmission properties of the channel are investigated using the transmission line model. The frequency range is over 40 kHz- 1.5 MHz. Results show that the power attenuation through the channel is about 10-20 dB/km when the channel does not have a branch. The channel is time dispersed. In the frequency domain,the amplitude response is frequency selective while the phase response is linear. In the time domain,the impulse response shows a delay spread. The rms delay spread and the coherence bandwidth are in correlation with the network structure,and corresponding values are on the order of ten μs and ten kilohertz. The narrow fading of the channel follows Nakagami-m distribution. The channel is varying weakly with respect to time. When the data rate is up to Kbit/s,the channel can be regarded as time invariant.