Comparing Wave Propagation Characteristics of Various Smart Electricity Distribution Networks

In Nordic countries, electricity distribution networks are consisted of underground cables or overhead insulated conductors or mix of both. However, each alternative has its own pros and cons. This chapter concentrates on determining the wave propagation characteristics of single-phase medium voltage (MV) cross-linked polyethylene (XLPE) cable and covered-conductor (CC) overhead electricity distribution networks. For this purpose, time domain reflectometry (TDR) measurement technique is applied. TDR delivers the complex propagation constant (attenuation and phase constants) of lossy transmission lines as a function of frequency. The frequency-dependent propagation velocity is also determined from the TDR measurements through the parameters extraction procedure. The calibration of the measuring systems is carried out to avoid the effect of multiple reflections on the accuracy of measurements. The wave propagation characteristics of XLPE cable and CC line are compared and it is proved that CC line has lower attenuation and higher propagation velocity than power cables. The measured wave propagation characteristics can be used as a design aid to develop an intelligent fault diagnosis and management system for distribution networks that may improve the safety and result in reduced maintenance costs and visual inspection work. In addition, the reliability of the distribution system will improve which is considered one of the significant characteristics of the future smart distribution networks.