IEC 61850 - boon or bane?

[Bung]

Does anybody else share my reservations about the effect of IEC61850 on bread-and-butter protection systems? It sounds great for hi-tech transmission grids, but what about the run-of-the-mill distribution systems in small(ish) utilities, industrial plants etc?

Relay manufacturers seem to be so dazzled by the new technology, and their marketing types are hyping it up to make sales, but is it going to spell the end of the bog standard plain vanilla protection relay? The demise of the numeric equivalent of a CDG (or CO) seems almost inevitable. But that will mean that the protection will be just another function in this big multi-function box? If so, how does the average plant maintenance manager cope when the controls fail, but the plant must still run? With discrete protection it could. With fancy boxes, one PSU failure leaves you dead.

Will any manufacturers make a line of protection relays that are aimed at the "low" end of the market, with fewer frills and extras and more simplicity? Who needs the 4 groups of 6 elements each of O/C, E/F, neg seq I, O/V, U/V, over and under freq plus PLC logic capability etc?

I guess that's two issues - 1) bloated "bay controllers" with protection as a sideline, and 2) bloated protection relays.


Bung
Life is non-linear...

 

[buzzp]

We never use all the capabilities but the number of features in these relays adds complexity. Unless your a full blown protection engineer, it is time consuming and difficult to understand if you only have to deal with it once every 3-5 years. On the flip side, these features make it so the manufacturer can make one relay where maybe 2-10 were needed before. It reduces cost (supposed to anyway) since they only have one flavor to cover many, many applications and they will tell you it reduces your inventory cost (dont have to stock so many spares). I can see their reasoning for doing this but it will require full time protection engineers to implement (or at least necessitate the hiring of one as a contractor or employee). There are simpler devices out there but they are becoming harder to find. Chances are they will be in the same size package as the complex unit. Its kind of scary putting all your eggs in one basket. We always require a redundant relay in every application because all of the 'eggs' are in one little relay that could hiccup at anytime.
Things will get worse before they get better since these relays are crossing over into the 'control' area and not just handling protection any more.
I see a market for relay manufacturers between the cheap ice cube relays (not for utilities) and the SELs, GEs, Baslers (basler still makes relays with only one or two functions).

 

[RalphChristie]

Bung, I have not read through the standard yet, but my opinion regarding this new generation relays:

We don't even use 5% of each relay's functions.
Each type of relay have a manual with +200 pages...you have first to learn how to use the manual before even touching the relay...then you have to use a whole day to study the material before going to site...and after 2 months you have already forgot it.
Every different relay manufacturer use different philosophies, logics, programs etc. for their relays, it is a protection tech's nightmare when you are using a lot of different relays.
Faultfinding are much more complex

But, if everything are working correctly, it makes running a plant or whatever much easier


Regards

Ralph

 

[dpc]

One utility I am aware of in the US has been purchasing Schweitzer SEL-321 relays (a multi-function impedance relay) for every feeder relay application, even if all they use is the overcurrent function.

They wanted to stick with one relay that they understood and knew how to configure.

I've worked with a lot of the multi-function relays and it can be time-consuming to learn how the relay should be configured and working through all of the features and functions.

Some of these relays will not provide any protection at all as they come out of the box. Others have a default program with basic protection.

I think they are here to stay but there is much room for improvement in the user interface.

BTW, what is the referenced IEC standard?

 

[Bung]

It has to do with relay-relay, transducer-relay, relay to RTU comms etc, and is based on the USA's UCA2 protocol. It is also a Cigre B5 Preferential subjuect for the Paris 2006 session. It will allow for such things as copper-less tripping of CBs, numeric field-bus for CTs and VTs (eg from Rogowski coils and other NCITs).

Imagine your busbar protection scheme running on an IP network with no copper connections between any of the relays or between the primary plant and the secondary plant. Imagine old Fred who has been testing CDGs (or COs the other side of the water) for 50 years trying to plug an SC-APC connector into the variac. Times, they are a-changin' all right.

I like that idea about just using one "over-size" relay as a one size fits all solution. Might try that - just have to get it round the commercial guys.

Bung
Life is non-linear...

 

[Bung]

See this site for more info:

http://www.nettedautomation.com/index.html

Bung
Life is non-linear...