Life expectancy of microprocessor-based protective relays (IED)
Life expectancy of microprocessor-based protective relays (IED)
(OP)
The question has arisen at my workplace as to what we expect out of these things. I have devices installed in excess of twenty years ago.
What do I tell our managers about their life expectancy? We're starting to see sporadic failures on devices.
That is not to mention that software, firmware and hardware revisions have passed up my installed devices long ago. My employer replaces laptop computers at five years. What am I supposed to believe about IED's that protect the plant power system that have been in service twenty years?
What's the industry consensus?
What do I tell our managers about their life expectancy? We're starting to see sporadic failures on devices.
That is not to mention that software, firmware and hardware revisions have passed up my installed devices long ago. My employer replaces laptop computers at five years. What am I supposed to believe about IED's that protect the plant power system that have been in service twenty years?
What's the industry consensus?
old field guy






RE: Life expectancy of microprocessor-based protective relays (IED)
RE: Life expectancy of microprocessor-based protective relays (IED)
The software is a very good point: at my previous employer I was running MS-DOS as one boot option on my laptop so I could talk to the ABB REG216 relays in our HV substation. The REOR100 event recorder software ran under Win 3.11. That was at 17 years or so into their life, and in software and operating system terms that is forever.
RE: Life expectancy of microprocessor-based protective relays (IED)
Microcontrollers that are not re-programmable will probably run happily for about 20~25 years.
Microcontrollers that are programmable.. Twenty years is pushing it especially if it is a safety device and not, say, a pinball machine where one might lose a game and 25⊄ in a failure. You can expect about 8~10 years before soft errors can start coming out of the firmware due to the re-programmable memory starting to 'forget' due to multiple physical mechanisms.
This can be mitigated by reprogramming the processors via reading them out while they're still viable and simply reprogramming them. Some companies bright enough to understand this offer re-programming service where they'll send out a new set of chips and you return yours so they can reprogram them and send them to the next guy. That has your 'machine' down only long enough to swap the firmware chips. Other companies have to keep updating their firmware and this gets done automatically with no one catching on until they stop updating the firmware because they finally (think) they've reached nirvana.
The above usually works well only for systems with plug-in EPROMs and in some cases plug-in EPROM based microcontrollers. For other systems the only alternative would be a new set of control boards with 'freshly programmed firmware'.
OTPROMs or One-Time-Programmable-Read-Only-Memory can last indefinitely if it is the type that blows fuses during programming as then there are no memory cells to forget with. However other companies have OTPROMs that are merely windowless and therefore un-eraseable but still have memory cells that will forget. Often they can still be re-programmed to freshen them up but, of course, you can only exactly reprogram them as no values can actually be changed.
Keith Cress
kcress - http://www.flaminsystems.com
RE: Life expectancy of microprocessor-based protective relays (IED)
RE: Life expectancy of microprocessor-based protective relays (IED)
RE: Life expectancy of microprocessor-based protective relays (IED)
RE: Life expectancy of microprocessor-based protective relays (IED)
But I agree that 20 to 25 is looking like the end of the bathtub.
The microprocessors are not like the EMs we took out of service at 75 years.
RE: Life expectancy of microprocessor-based protective relays (IED)
RE: Life expectancy of microprocessor-based protective relays (IED)
RE: Life expectancy of microprocessor-based protective relays (IED)
FWIW, can you still buy new EM relays like distance and time over current?
RE: Life expectancy of microprocessor-based protective relays (IED)
Last I heard you could still buy new EM replacements for IAC, CO, and KD relays, if not others. A brand new KD might well cost as much as a brand new SEL-411L, but as far as I know they can be had. Other than having to remove the mothballs from the factory, a new KD is nearly 100% profit at what ever cost; anybody that actually wants one really, really, really wants one and will pay any price so why not the top price? The ones we have are sunk costs, fully amortized. Can't possibly imagine going there again; they don't do so well with two breaker (ring, BAAH, DBDB, etc.) applications when compared with the modern relays. That's why the two breaker configurations didn't really take off until newer relays could provide two electrically independent trip contacts.
oh, but the EM relays don't give a sh!t about EMP and other esoteric threats to the power system. My gut feeling is that if an EMP event takes out our relays there probably is a whole heck of a lot of load left serve in the immediate aftermath either.
RE: Life expectancy of microprocessor-based protective relays (IED)
https://cdn.selinc.com/assets/Literature/Publicati...
It is being entertained and there are POCOs that are more even more optimistic then the writers.
In terms of single breaker designs, I think PGE got it right initially- they are still being built all over the world. BAAH is over-rated in my book :P
EMPs- not sure how credible the concern is- but I would imagine you would have mach larger issues if that truly was to happen. FWIW, there is a rumor that the 1965 blackout was cuased by EMPs from UFOs.
RE: Life expectancy of microprocessor-based protective relays (IED)
It is like the human beings of new generation with fast food culture and the older generation of traditional (ethnic food) food culture. even though the life expectancy has improved now, the modern generation is much more sick as compared to the older generation.
I find some similarities between the relays and the humans beings!
RE: Life expectancy of microprocessor-based protective relays (IED)
RE: Life expectancy of microprocessor-based protective relays (IED)
RE: Life expectancy of microprocessor-based protective relays (IED)
I think this discussion naturally leads into discussions regarding maintenance cycles for IEDs as well. I think the industry will start moving towards ditching maintenance on IEDs and just swapping them out for fresh models at some regular interval.
RE: Life expectancy of microprocessor-based protective relays (IED)
Age on these range from late 1990's to 2005.
The present software offered by GE for current relays does not communicate with 1990'vintage SR series installed in a facility I 'inherited'. I had to get an older DOS-based program and run it under an emulator to deal with these.
Some UR series installed in the early 2000's are a different hardware and firmware revision than the newer versions we installed in 2005. The UR platform is modular but modules do not interchange from the older to the newer versions, or vice versa.
Since I'm now dealing with a large company with a wide installed base of devices, we're looking at codifying a maintenance and replacement policy.
old field guy
RE: Life expectancy of microprocessor-based protective relays (IED)
So we use test switches.
As far as problems with GE software, and other also, That's exactly one of the reasons we don't use GE relays.
I can still plug a dumb terminal into any of my standard microprocessor relays from the 80's through a new one.
That's not to say the versions, or microprocessor are the same, but I can still communicate with all of them.
And here is where I say, price is not everything. And you need to make your management understand that.
Besides, old dos requirements are a new securty feature from young hackers.
RE: Life expectancy of microprocessor-based protective relays (IED)
Thank you all.
Muthu
www.edison.co.in
RE: Life expectancy of microprocessor-based protective relays (IED)
Quote "The IEC describes useful life as “the time interval beginning at a given moment in time, and ending when the failure intensity becomes unacceptable or when the item is considered to be unrepairable as a result of a fault (IEV 191‐19‐06) [1].” Therefore, according to this definition the end‐of‐life is when the failure intensity becomes unacceptable or when the [recovery/repair] time is considered to be unacceptable as a result of a fault. Some examples for end of life include the loss of life of capacitors (loss of capacitance because of electrolyte drying and leakage), and loss of semiconductors (mainly ICs) that degrade because of thermal, vibration and humidity. The ability to determine the end‐of‐life will better prepare the utility for a successful asset management strategy as well as bolstering their rate case application." Unquote.
It seems not easy to give a figure like 20-years with the dynamics of technology and various factors involved in assessing the end of useful life for numerical relays.
Most of the vendors offer 10-years warranty and hence, what we can definitely say is 10-years as a minimum. Beyond that, every utility needs to evolve their own strategy it seems.
The above technical paper can be downloaded from
http://www.pes-psrc.org/Reports/I22-UsefulLife-Fin...
Rompicherla Raghunath
RE: Life expectancy of microprocessor-based protective relays (IED)
RE: Life expectancy of microprocessor-based protective relays (IED)
Once the relays get that old, you probably want to change them out to match the system and stock in the warehouse.
RE: Life expectancy of microprocessor-based protective relays (IED)
Sometimes, the offered generation of relays series may be at its final stages of obsoleting by the manufacturer. But, there may be some inventory left with them and they need to clear it out. So the relay vendor may give discount to the main equipment manufacturer. But the end user suffers due to this. If it is a long gestation project, before you commission, the relay vendor may tell you that now these relay series is obsolete even during the commissioning. Thus everything they supply (spares, service etc.) on that relay will be at premium for that relay.
It is like writing the obituary before the child is even born!
So to avoid this, the buyer should always ask the vendor to submit the obsolescence strategy showing in the bar chart, where the subject relays are located.
Normally, these are in four stages, like,
a) development & trial run stage (this is where lot of troubles coming in the product)
b) People should buy when the product is in the initial stage of stabilization of the product.
c) Matured stage (stabilized stage, where the relay is well established)
d) Phase out stage (where the manufacturer will be planning to develop a new series of product and planning to obsolete this series. One should not buy the product at this stage)
e) Obsolete, but manufacturer has not declared, and waiting to clear out his inventory (this is a very problematic area, where the un-suspecting customers fall to the trap!
RE: Life expectancy of microprocessor-based protective relays (IED)
RE: Life expectancy of microprocessor-based protective relays (IED)
If you have had poor results from buying from a company, and you keep buying from them because they are cheaper, or the salesperson takes you out for lunch, then you are foolish.
On the other hand, you should look at buying from two or more manufactures just so you know you have a backup source if your chosen company fails.
I sort of do this.
No we do not replace capacitors. We replace the whole device. The cost of having someone sit down and un-solder, and re-solder another one is more than a replacement or the failed devices.
RE: Life expectancy of microprocessor-based protective relays (IED)
This approach will protect you (sort of an assurance) to some extent. You must request this from the vendor during the bidding stage itself.
I am not talking here only for the protection relays. This is also applicable for few other systems, like PLC systems, PMS/ECMS, switchgears etc.
May be not that relevant when it comes to totally custom deigned equipments, such as transformers, distribution boards etc.