The 21st century has been a time for transition from a more localized approach to life to a global, community oriented experience based not on direct interaction with our peers, but relying on the advancements of computer and communication technologies.

The above applies not only to people, but to all areas of human activity, including electric power systems protection, automation and control.
This does not mean that there were no communications between devices in the electromechanical PAC world of the last century. To understand this we just need to look at the definition of communications – an activity for the exchange of meaningful information.
To achieve this task we need to have:

  • Something that needs to share information
  • Something that needs to receive that information
  • Mechanism for exchanging the information

So if an electromechanical relay needs to know the status of the breaker, we need to make sure that the breaker is able to provide a signal indicating its position. The breaker is the device sharing the information, while the relay needs to receive it to properly perform its functions.
The mechanism for exchange of this information is the hard wiring between the auxiliary contact of the breaker and the binary input of the relay – a very basic communication method.
even in this simple case we face the issue of understanding. Because for communications to be complete, the receiver needs to process the message and extract the correct information.

You may be thinking – "What is here to understand?". 
Well, we should not forget that the breaker may have a Normally Open and a Normally Close auxiliary contact, so we need to have in advance an agreement between the breaker and the relay which one is used.
The development of  the communications between protection devices in many ways resembles the development of communications in human history. Some of the earliest signals used were for protection purposes – to inform a group at a remote location that there is trouble on the way using for example a smoky fire. The same way some of the earliest communications used in the electric power system between devices were for accelerated protection, for example indicating with a binary signal that there is a fault in front of the relay.

Another, quite interesting analogy is the development of languages – very specific within a small geographical area. When people from the different areas started moving outside and contacting their neighbors, the language difference presented a communications problem the same way that the early proprietary vendor protocols did.
The same way the transportation changed dramatically over the last couple of centuries making the world much smaller, the communications technology changed in the last decades, shrinking it even further and allowing instant access to many kinds of information that can help us significantly improve the quality of our life.

Similar events are happening in our industry.  The push for a Smarter Grid is the result of the changing technology, as well as the changing needs of society.  The availability of all the information provided by zillions of Intelligent Electronic Devices can help us optimize the performance of the electric power system under any normal or abnormal condition. But for this to happen, we need to understand the different communication methods and protocols, as well as the needs of the applications, so we can make each device not only to listen, but to also understand the meaning of the received information.
Otherwise no communication will take place.  

“The single biggest problem in communication is the illusion that it has taken place.”

George Bernard Shaw

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