Automatic Topology Mapping with PLC
For utilities, automatic topology information is becoming more important, and power line communications technology inherently supplies it.
After ENEL, Italy's largest utility, confirmed the viability of our PLC technology for smart metering (2000 to 2004), virtually all smart metering systems in the world (with some exceptions in the United States and Australia) have used PLC.
This is because it has become very important to know which transformer is supplying which customers, information that is inherently available when data flows over a physical wire, but very difficult to obtain when it is transmitted via radio frequency. It is also important to know which of three phases a single phase residential customer is on so that the system can be balanced.
Of course all utilities have wiring drawings and records, but in the course of service expansion and change, these drawings may not be accurately updated. Today, a typical utility’s power line topology documentation can often be 15 or 20% inaccurate.
Duke Energy’s Findings
The images show before and after maps of transformer-to-customer connections in a neighborhood in Duke Energy’s North Carolina service territory. The top image is the previously assumed connections, the bottom image the actual connections discovered after deploying our Networked Energy Services (NES) smart metering system.
Consequences of Inaccurate Topologies
Imagine a situation in which you believe the top image is correct, and you need to reduce demand on an overloaded transformer. You send out “reduce load” messages. If most customers who reduce load are on the same phase, and the other two phases remain heavily loaded, the transformer is still in jeopardy.
Assumed grid topology before power line communications
Corrected topology using power line communications
