Last Word Opinions

Last Word – Issue 051 March 2020

No more wires!

Since the beginning of the electric power industry the protection, automation and control systems have been wired. We go to a substation control house and this is what we see – relay panels and wires. So, when I think about the developments in power system protection, to me one of the most important ones is the disappearance of the wires.

There are many reasons that the wires are disappearing, as can be seen in the picture from an energized substation in France and here I will talk about just one.

It costs a lot of time and money to build a substation protection and control system using copper wires for the analog and binary signals. One of the reasons is that for each hardwired signal we need to:

  • Measure the length of the individual wire between the terminal of the relay and the terminal block of the protection panel
  • Cut the wire and strip its ends
  • Prepare and put the labels at each end of the wire
  • Connect the ends of the wire to the terminals
  • Test the connection

Once we complete the wiring between the relays and the terminal blocks of the panel, we need to do the same for all the signals between the panels. And then we need to wire all the interfaces between the breakers, disconnectors, current and voltage transformers and the panels in the control house.

Considering that we need to do this for thousands of signals in the substation, we need to ask ourselves “Do we need to keep doing what we have always done?”

And the answer is “It depends!” If we want to waste our time doing protection and control systems using wires as we always have, we can do it, but this is not an efficient way of doing it. It is much better to shift from hardwired based systems to IEC 61850 communications-based solutions. This will eliminate the wires and terminals blocks and replace them with a limited number of fiberoptic cables and Ethernet devices. No more wires!