Remote energy metering/PLC
Remote energy metering/PLC
(OP)
This is not about Programmable Logic Controllers - but Power Line Communication. The PLC acronym is used for both so there may be some confusion. But, as said, this is Power Line Communication.
The questions I want some views on are:
A How often are electric power meters read in your area? Other meters (gas, water, heating, cooling etc)?
B What technology is mainly used?
C Are several different technologies used to achieve 100 percent coverage? If so, do you use GSM, internet, fiber, copper, radio link, meter man, other for the "difficult" meters?
D In what stage is your organization? Fully implemented PLC? Partly implemented (how many percent?? Planning stage? Not considering PLC/remote metering at all?
E How well does your implementation work? If there are any problems, please indicate what technology causes the problems and if you think that the situation will improve or if that technology seems to be a blind alley?
F How do you handle the VFDs? What filters have proven effective?
G Any other thoughts?
I am asking this because I have been involved in countless discussions on this subject lately. The reason is that I work with EMI from VFDs and other power electronic devices and that they seem to be a problem for the PLC. (Yes, there are filters, I know. But they seem to short out the PLC carrier as well as the EMI from the VFDs).
There seems to be as many opinions regarding the future of PLC as there are individuals. Please help deblurr the picture by answering this mini-enquête. The more answers we get, the clearer the picture will be.
The questions I want some views on are:
A How often are electric power meters read in your area? Other meters (gas, water, heating, cooling etc)?
B What technology is mainly used?
C Are several different technologies used to achieve 100 percent coverage? If so, do you use GSM, internet, fiber, copper, radio link, meter man, other for the "difficult" meters?
D In what stage is your organization? Fully implemented PLC? Partly implemented (how many percent?? Planning stage? Not considering PLC/remote metering at all?
E How well does your implementation work? If there are any problems, please indicate what technology causes the problems and if you think that the situation will improve or if that technology seems to be a blind alley?
F How do you handle the VFDs? What filters have proven effective?
G Any other thoughts?
I am asking this because I have been involved in countless discussions on this subject lately. The reason is that I work with EMI from VFDs and other power electronic devices and that they seem to be a problem for the PLC. (Yes, there are filters, I know. But they seem to short out the PLC carrier as well as the EMI from the VFDs).
There seems to be as many opinions regarding the future of PLC as there are individuals. Please help deblurr the picture by answering this mini-enquête. The more answers we get, the clearer the picture will be.
Gunnar Englund
www.gke.org






RE: Remote energy metering/PLC
In the US, meters are typically read once a month. For residential, most are still read "manually" the old-fashioned way. Automated Meter Reading (AMR) is a hot topic in the US. Most of the systems around here use a small radio transmitter in the meter or meter base. The meter is then "read" by wireless link to a computer or hand-held device in the meter reader's truck - they just drive a route, collecting meter data as they go. This data can then be downloaded to the billing system.
Power line systems are available in the US, but not much used, at least that I am aware of. The "drive-by" radio systems seem to be much more common. I have one at my house, actually - a Turtle - http://www.hunttechnologies.com/
For larger industrial/commercial metering installations, some local utilities actually use cell phones in the meter and dial in to read the meter.
There is a misguided effort toward "Broadband Over Power Lines" (BPL) in the US that might have similar interactions problems with VFDs, but it has a lot of its own EMC/RFI problems.
You could also check out Itron - they seem to be the major AMR player in the US.
Sorry I can't answer more of your questions.
Dave
RE: Remote energy metering/PLC
I can't answer many questions on this either.
Once a month almost without exception.
Usually walk by.
Eight days ago the city (water) people came by and changed our water meter out for a radio one. (Something to do with our 14 foot high, eight foot wide, hedge that surrounds our house and the attack chickens) I interrogated the ring-leader. He said the meter could now be read by a handheld wand from several feet away or by a more powerful transmitter/receiver from farther away. He indicated the arterial a block away. He said there were two down sides. One the batteries in the water meter would only last 11 years. Eleven years for a receiver is pretty amazing to me!! I have yet to see a transistor radio work for eleven years on a battery. Or one year for that matter!
The other problem he stated was that with no one reading the meter monthly the meters(which include the emergency shut off) get lost. He stated an example where two weeks earlier it was found that six meters had been paved over by a road crew two years earlier and not detected until an emergency arose.
As for VFDs causing a problem how would they affect a large residential area? Carrier current generally has so many little problems with it that I can't imagine it being successful in a broad city application.
I worked on a carrier current data acquisition system for refrigerated containers to allow monitoring of refrigerated containers while en-stacked on ships at sea. This was a specific definable power network. We still had a ton of problems with things blocking and shunting and degrading the signals. It was very difficult! We even blew a 2,500A 480V 3ph breaker feeding 400 refrigerators with one of our interface units.. It was a very difficult project fraught with demons.
I wouldn't go that route I'd go with radio if I was trying to go no-additional-wires in a facility.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Remote energy metering/PLC
Gunnar Englund
www.gke.org
RE: Remote energy metering/PLC
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Remote energy metering/PLC
But I guess lots of people will find this so interesting that they forget about BBQ, fishing rods, baseball and what have you. Just to write down interesting facts about PLC.
Gunnar Englund
www.gke.org
RE: Remote energy metering/PLC
Not much was said about AMR, but it was mentioned that BPL may interfere with some AMR systems. Something to look into.
RE: Remote energy metering/PLC
We have had several AMR sales guys retreat from their sales pitches once they realize that their business cases don't work if 90% of the meters are only being read 6 times per year.
In addition, that once-a-year inspection that utilities may still insist upon reduce the avoided trips from 11/year to only 5 per year!
RE: Remote energy metering/PLC
Legislation is going to once a month, so something has to be changed, though.
Do you have a feeling that the existing AMR installations using BPL are reliable and succesful? Or are they plagued by EMI from drives and other interference?
Gunnar Englund
www.gke.org
RE: Remote energy metering/PLC
Manual reads and Turtle reads are monthly. Most utilities with the higher speed PLC based AMRs read more frequently so that any problems can be detected before month's end.
RE: Remote energy metering/PLC
RE: Remote energy metering/PLC
In Bulgaria the energy meters are read every month. The whole procedure tooks about 3 days mostly, however, instead of every efford, the data is biased by subjective errors.
The reliability of wireless measuring solutions is not proven yet because of the higher price. Implementation of new digital meters with common data transfer protocol is now available.
RE: Remote energy metering/PLC
Is it possible your water meter is a turbine meter which uses the turbine as both the flow transducer and as a source of electrical energy?
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I don't suffer from insanity. I enjoy it...
RE: Remote energy metering/PLC
I would use that technique like mad if I designed it. I failed to ask and would imagine no stated battery life if they did. (SuperCaps)
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Remote energy metering/PLC
Waddayathink? Much better than that exercise cycle idea that has been floating around for some time?
Sorry - didn't mean to steer this highly serious (yes, I mean it) thread off topic.
What about BPL, PLC and other ways of meter reading? Come on.
Gunnar Englund
www.gke.org
RE: Remote energy metering/PLC
ht
My understanding is that BPL has been banned in Japan due to RFI problems/concerns.
None of this directly answers your questions, but might be of interest as background info.
RE: Remote energy metering/PLC
RE: Remote energy metering/PLC
This question has generated a lot of interesting and new information for a lot of us. I think skogsgurra deserves a star for an excellent question.
Respectfully
RE: Remote energy metering/PLC
A. In South Africa, most places I am aware of, read it once a month. In the mine where I am working we use it mainly for electricity, fuel (diesel and petrol) and water.
B. Still a lot of old disc type meters, but electronic meters are winning field.
C. Meterman, Fibers and Radio-link. Internet access in the pipeline.
D. Electricity
66kV from utility: 100%
66kV internally: 80%
11kV internally: 70%
400V internally: 40%
Fuel
100%
Water
10%
E. I would say good. In places like with the fuel system it is excellent, due to the fact that fuel is much more expensive than water or electricity, almost forcing them to monitor it very closely. For the electricity there are a lot of things in place, but it is very poorly utilized, meterman is still used with everything in place. (also on the electronic meters) Maybe not seeing it as that important due to the fact that electricity is fairly cheap or maybe people still used to the old practices?
Can't say we experience really problems with any method, small problems encountered sometimes on all of them, but not something to complain about.
F. -
G. -
Regard
Failure seldom stops us, it is the fear for failure that stops us - Jack Lemmon
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RE: Remote energy metering/PLC
The Hunt T1 system is an ultra-low frequency (5 to 9 hz) PLC that can take anywhere from 12 to 27 hours to transmit a reading (depending on how much info you are trying to get). Very dependable, very little signal attenuation, extremely cheap and easy to install. The meter device pulses a capacitor that puts a signal on the sine wave that a CT picks up in the Substation. One way communication. You must take certain precautions if you tend to switch loads back and forth between substations.
Our Cannon Sytem uses a 12.5 Khz signal that is injected via a coupling capacitor at the substation. Information is real time . Communications work both directions so it can be used for readings, disconnects, controls, etc. Requires blocking devices on capacitor banks to prevent bleeding the signal to ground. Has excellent support. Initial installation is much more expensive than Hunt T1, but has much greater versatility.
TWACs is similar to Cannon, but uses a special transformer to inject the signal. Don't know a whole lot about it, but Pedernales Electric Coop in Johnson city, Texas uses them extensively and can probably give you some good info.
RE: Remote energy metering/PLC
I have also heard about the Hunt T2, but not got any in-depth information. Anyone knows where to search?
Gunnar Englund
www.gke.org
RE: Remote energy metering/PLC
RE: Remote energy metering/PLC
If you would like contact information on the two Texas Coops mentioned plus all utility and non-utility electricity generators in the United States, the Department of Energy's Website has two hand excel spreadsheets with phone numbers for each.
The two coops are listed in the "utility contacts" spreadsheet at this url: (hint: filter by state or search by name)
ht
RE: Remote energy metering/PLC
Quote:
"The reason is that I work with EMI from VFDs and other power electronic devices and that they seem to be a problem for the PLC."
I hate to plead ignorance, but could you explain theses acronyms?
RE: Remote energy metering/PLC
TS2 info can be found at htt
RE: Remote energy metering/PLC
You can find more info on the contact info on www.turtle.nu from the scandinavian distribution company..also have their own technical team.
Best regards
Gestur