Signal Injection Strategies for Smart Metering Network Deployment in Multitransformer Secondary Substations

This paper analyzes the strategies for injecting power-line communications (PLC) metering signals in secondary substations with multiple distribution transformers. The study is based on real measurements of PLC connectivity across the low-voltage sections of transformers in a representative set of secondary substations. The results show that there is not a general rule indicating the quality of the PLC channel among secondary windings of distribution transformers in a secondary substation and, consequently, there is no general solution based in pre-existing information. Following this conclusion, a strategy is defined to maximize the performance of the PLC system, based on the PRIME PLC specification. This strategy is based in the use of a base node connected to one of the low-voltage panels, together with auxiliary nodes connected to the remaining low-voltage panels, and interconnecting all of the elements (base node and auxiliary devices) by means of non-PLC technologies.