Modernizing the XY Controller with a 3rd Turtle

Last week I discussed the application specific space saving application of the XY controller.  When having to modernize these, not only do we have to work with the specific constraints of the hardware - [see last weeks post] - but also the fact that at the same time, we might have to jump 40 years in technology.

In this post I extend the conjectured modernization by considering the modernization of an 20th century item of plant control to the 21st century use of lets say semantic technology.  For this example being substation oriented, we should consider going from the Master Slave relay logic direct to it's representation as an IEC 61850 object publication and control. This is not a post about IEC 61850 specifically, but uses that new technology to illustrate the point relating to modernization and re-integration of older technology into the new semantic type technology.

If you have read this far, you might want to know why does that matter ?  I will try to keep to the point in less than 600 words, and the graphic may help, but please read to the end, think for a few minutes and make any comment about modernization you feel relevant.

Let's start where we left off last week.  The XY controller being the ancient item, which no one wants to touch but which needs to be modernized and at the same time brought up to the 21st century style of representation in it's own environment.  So imagine that last week all we talked about was the creation of the 4th Turtle in the above diagram.  We have a modern controller managing the encoding of the XY control arrangement, and the existing wiring/diodes/relays acting as the decoder.  So far so good.

The issue becomes then, what happens when we want to bring other modern equipment into that same substation.  The other modern equipment may be new protection relays, or newer packaged controllers of some kind.  Vendors these days would be creating devices based on IEC 61850 .SCL language wouldn't they ?  Yes, in short, the 3rd Turtle is where the modernization happens.  The 3rd Turtle creates an IEC 61850 namespace and logical node which correctly represent the circuit breakers, yes, all 800 of them that could be controlled by the XY controller, and presents them to an IEC 61850 station bus in .SCL language format.  This allows other peer 3rd Turtles which also communicate in .SCL semantics to interact with any one of the 800 circuit breakers.  The 3rd Turtle then becomes a special XY controller service and marries the XY hard wired function to the IEC61850 high speed network [Station Bus].

From then on a 2nd Turtle layer is added to make the necessary conversion to a communications system using the standard DNP3 protocol.  This unfortunately loses some of the semantics, but since they are now understood, these can be remapped at the 1st Turtle into Elephant Speak.

Why Elephant Speak, I am sure you ask ?  This is going to be related to the operational language of the Elephant, which may or may not be something like IEC 61850, probably not, since in most cases the Elephant could be quite old and sagacious as well.

Go ahead and let your inner 3rd Turtle a comment on modernisation . The concepts involved etc.  Comments will be open for a month and moderated for content, excessive positivity or negativity, and relevance to the topic.

Chris J Smith

FOXBORO, MA

just past the Ides of March 2012

PS: Invensys offers the FOXBORO SCD5200 Remote Terminal Unit Station Computing Device which can take on aspects of the 2nd, 3rd, and 4th Turtles all in one controller.  It is this ability which makes it an ideal component in the modernization of older equipment such as the XY controller.