Modern protective relays 2

This is a general discussion for the fraternity to ponder and put their views.

In the era of digital technology, the development of relays have gone far beyond what is really required. As many features are being added to the relays they are getting too complicated. Some of the relay manuals are now reaching to more than one thousand (1,000) pages! In the internet age where the attention span of the people is getting reduced, it is serving the purpose by publishing such a huge instruction manuals?

The protection relay itself is loosing its focus from the basic functionality. In my opinion the time has come for the relay manufacturers to adapt different strategy. Make the protection relay simple and easy to understand the set. The relays can be handled by an average qualified technician. This would benefit all in the industry.

As the technology is getting cheaper by the day, it has become a trend for the relay manufacturers to make it more fancy and sell with these features.

Any thought on this view or anyone who share these views?

 

[Mbrooke]

@David Beach, do you use acselerator quickset? No excel and its easier in general IMHO.

 

[cranky108]

We had a different story, in that for one project the 421 relays were used, not just for protection, but also for automation. In mid stream, the protection engineer quit, and a consultant was brought in, who then hired SEL to help with the automation. So now we have a unique system for both protection and automation, that none of the tech's understand.

My position for this, is that we take a step back, and try to simplify. The relay does protection, and the RTU does control. And with help of a RTAC, the relay now also does metering.

The point is if you attempt to cram too many functions into one box, you have problems. So the relay does protection, and the RTU does control. We may revisit the one box approach one day, but not to day.
The other thing is introducing too many new things too fast will cause problems.

You need to determine how much complexity your company can stand, and don't exceed those limits. And those limits will change with time, and you should change at that time.
Most of the complexity limits, and change limits will happen at some retirement party, so you should go to those.

 

[davidbeach]

The protection scheme should be exactly as complex as necessary. Any less complex and it won't accomplish all of what is required of it; any more and it is needlessly difficult to work on.

The excel spreadsheet I mentioned is the setting calc spreadsheet. There's a bunch of questions about the application that determine the logic that will be needed; lots of fault cases get entered, specific fault cases get selected to drive certain settings, the usual stuff for a setting calc sheet. The spreadsheet addresses the whole gamut of the settings from actual protection settings to display points to SER points to ...; pretty much the whole works. When that's all taken care of and reviewed, the engineer clicks a button and a text file is produced. That text file then gets used twice. One use is that it is imported into AcSELerator, every setting in all settings groups, the whole works. The other use is that it is read by a different VBA script which parses it out and writes a OneLiner RAT file that gets imported into our OneLiner model. This leaves the engineers working on engineering and the computer gets to play the clerk/typist role in getting the settings from the calc sheet and into the relay. The vast majority of the individual relay settings are never touched by the Protection Engineer doing the settings.

 

[Mbrooke]

@cranky- what are you automating and how with the line protection relays?

@David Beach- ok, that makes sense now- and I like your approach btw.

 

[cranky108]

The automation is placing the SCADA functions into the 421 relays, which our testing group then needs to test as the 25 relay functions are mixed with control functions.

And two of four the 421 relays are only being used as over-current relays to backup the 387 relays, as well as the automation.

 

[Mbrooke]

I might be way off, but the desire is have the SCADA automation through an SEL-2032 or RTAC? In that case I would prefer that over cramming it all in the line protection relay.

 

[cranky108]

The SEL-2032, or RTAC can't do the 25 function, or I would agree. I favor an output hard wired to a 25 relay (a 351, 311, or 421), that way it can be tested outside the SCADA functions.

 

[Mbrooke]

Cranky108- we see eye to eye then- same preference