Kitz Forum
Chat => Tech Chat => Topic started by: guest on October 01, 2015, 06:37:15 PM
-
I have an APC 1500VA UPS in the garage from the days when you actually needed that much for home servers - it runs at about 13% load now on a 2 year old battery :D
Anyway I (once again - long story) sorted out the UPS alerts so it emails me when there's extended under/overvoltage or mains failure.
Lots of extended overvoltage alerts.
By overvoltage I mean well over 253V, which is the max spec (230V +10%/-6%).
258V is commonplace & we've had 260V in the last day or two. Initially I looked at the overvoltage graph & thought "its at low-demand times", but its not.
The correlation is nearly 100% when the wind speed is over 10mph regardless of time of day - when the wind speed averages 15mph our mains voltage is running at 257.5V and increases to around 260V. The rest of the time then its high (248-250V) but its in spec.
I intend complaining to Western Power Distribution (they deal with mains stuff outside the house here) but I don't really see what they can do about it other than pay daily compensation. Haven't looked into this much but if your mains voltage is out of spec you are entitled to daily compensation rates AFAIK. For anyone wondering "does it make any difference" then yes it does on all your lighting - LED bulbs will blow very early IME.
Was just really surprised that the grid is under that much stress from "renewables".
Edit - we don't have any wind/solar stuff so this is the mains grid voltage varying.
-
Is there a suitable device that could sit at the input to the server and clamp the voltage, preferably without catching fire?
I wonder what the graph of that over voltage looks like? Ripple? Peaks? Or steady and relatively smooth average over-spec.
-
What about a Constant Voltage Transformer ?
Not heard of one for years but AIUI variable input voltage and constant output - NB used to have a reputation for distorting the waveform so may need filtering. Other alternative would be an automatic motorised variac device - probably not economic .
-
Is there a suitable device that could sit at the input to the server and clamp the voltage, preferably without catching fire?
I wonder what the graph of that over voltage looks like? Ripple? Peaks? Or steady and relatively smooth average over-spec.
The UPS will produce its own 240V sine wave when the voltage is over/undervoltage so that's not really an issue for the server - its the rest of the house which bothers me (specifically some LED bulbs which keep popping, now I know why).
The graph of the voltage is mainly spikey when viewed on a 24 hour scale - its only when you reduce the timescale that the correlation with wind speed becomes apparent. Eg we had some overnight wind which peaked at about 15mph about 3am & died away around 5am; I have an email from the UPS about extended overvoltage at 03:43 and the graph shows the voltage back in spec at 5am.
I took a multimeter next door yesterday & checked their supply - its out of spec too (different phase) so presumably anyone using 415V three-phase around here is actually running at 465V....
-
Interesting view of the problem here https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/293405/05-1410-electrical-supply-tolerances-and-appliance-safety.pdf
-
I have the same UPS at home, I'll have to figure how to log/look at the graphs and see what our electric is doing. I also have a ups here at work, but it is more basic, so not sure if it will log voltages although does have overy voltage protection.
-
I have the same UPS at home, I'll have to figure how to log/look at the graphs and see what our electric is doing.
Depends on the version of PowerChute which you use and whether you have a Java runtime environment (JRE) installed.
I have v9.1.1 installed so just hit the "Voltage Analysis" icon and select the time period - this only deals with the last day however. If you require a longer timescale for logging then you need a JRE installed to view the logs within PowerChute - right-click the relevant UPS in PowerChute, select Properties then the Log Files option.
-
I had the same problem here a few years ago, my UPS would go onto battery for no apparent reason from time to time. I didn't have monitoring software at that time, but measurement of the voltage with a meter indicated it was over specification. I contacted my power company and to my amazement they responded and sent an engineer to fix a "device" to my incoming power cables. After a week of monitoring they accepted there was a problem and tweaked something at the substation in the village to reduce the voltage and problem solved.
-
I had the same problem here a few years ago, my UPS would go onto battery for no apparent reason from time to time. I didn't have monitoring software at that time, but measurement of the voltage with a meter indicated it was over specification. I contacted my power company and to my amazement they responded and sent an engineer to fix a "device" to my incoming power cables. After a week of monitoring they accepted there was a problem and tweaked something at the substation in the village to reduce the voltage and problem solved.
I'm trying to find the relevant document again but I think the compo for out-of-spec mains voltage is in the order of £2 or £3/day for a consumer so it'll mean free electricity if they don't fix it :)
You'll find that the distribution companies are very good in terms of responding to consumers - unlike the retail companies which are bloody awful....
-
I intend complaining to Western Power Distribution (they deal with mains stuff outside the house here) but I don't really see what they can do about it
Tell them to look at the 'Tap changer' in the local sub station it's not doing it's job !.
-
Depends on the version of PowerChute which you use and whether you have a Java runtime environment (JRE) installed.
I have v9.1.1 installed so just hit the "Voltage Analysis" icon and select the time period - this only deals with the last day however. If you require a longer timescale for logging then you need a JRE installed to view the logs within PowerChute - right-click the relevant UPS in PowerChute, select Properties then the Log Files option.
Yes I have the same versions, looking through the log via the web interface our voltage tends to rise to 250v in the early hours of the morning. Any idea where the log is stored, can't seem to find the voltage log?
-
I work for a DNO company (Not WPD). As Dray already provided the link for the UK supply tolerances which are generally quoted as 230V +10/-6% [253V/216V]. High and low voltage can be caused by grid wide issues or even a local issue with the LV main, fuse way at the substation, tap changer setting on the local transformer or even the neutral conductor on the service cable itself. Common with a 1970/80's type plastic cable which had aluminium neutral conductors.
All I suggest if you contact your local DNO (http://www.energynetworks.org/info/faqs/who-is-my-network-operator.html) report high voltage they should send someone round to inspect your service cutout, the local substation and if required install a voltage recorder to monitor directly at the cutout.
Out of interest - Do you have a overhead or underground service? A picture of your service cutout (near the electricity meter) might be useful.
-
I've been getting extended over voltage emails from my UPS, every night for the last week, so I've done a little bit of digging around tonight.
There was no option to export the log, but I found the log file C:\Program Files (x86)\APC\PowerChute Business Edition\agent\DataLog and opened it with NotePad++ and found it was a text file with the values seperated by a TAB chr, so I replaced the TAB's with a comma and saved it as a CSV which allowed me to open it with excel.
From that I came up with the attached graph, and you can clearly see the top line where it goes over voltage (blue) and the UPS switches in and the voltage drops as per the brown line.
I'll give the local DNO (UK Power Networks) a ring tomorrow and see what they have to say.
-
Out here, middle of back of beyond, the problem is under voltages.
It happens once a year, regular as clockwork, Christmas Day. There's no automatic alert, just a realisation that the roast potatoes aren't really browning, and turning up the oven doesn't help. A voltage check shows we have dropped to circa 210V. That's only just outside the tolerance of EU-compatible 230V, but even further from the nominal 240V for which our elderly oven was designed. >:(
I assume it is because we are in a rural area and at the very end of a line. Coupled with a usage-peak like Christmas morning, it may be quite hard to bring my voltage up to spec without sending those across the village out of spec with over voltage? Not much point in asking for a voltage monitor though, unless they let me book it just for that one, special day. ::)
-
So they need thicker conductors / better conductivity?
-
So they need thicker conductors / better conductivity?
Depends on the definition of 'need'.
The problem (for me) only happens once a year and that being Christmas Day, evidence is hard to gather. As long as the supply company can say there is no evidence of a problem, their shareholders would be unlikely to support any major spend.
The other solution is, of course, for me to buy a new oven... one that is properly compatible with the modern 230V nominal supply, vs the 240V when my oven was new. :D
-
> The other solution is, of course, for me to buy a new oven... one that is properly compatible with the modern 230V nominal supply, vs the 240V when my oven was new.
Shows you what I know, living in the past. I thought it was 240 V still. But what do I know.
-
In 1995 the UK nominal mains voltage specification was changed from 240V +/- 6% to 230V + 10% / - 6%. Nothing actually changed at the time because the new specification embodied the old one. It was for harmonisation across the EU, and nowadays new electrical equipment can supposedly be used in any EU country.
-
I thought that the new tolerances for the 230v supply were actually staged, becoming more relaxed and reducing the lower limit progressively in several steps, and resulting in a minimum voltage that is now significantly lower than it was in 1995? Or so it said in a forum thread I found recently (Possibly an IEE forum).
I also seem to recall hearing a while ago that, counter-intuitively, the lower voltage actually presented a safety/fire hazard in some circumstances. Not entitely sure, but I think it was along the lines that some appliances (ovens/fridges) that fail to reach target temperature end up running continuously rather than cycling on/off, leading to premature wear.
-
You may be right, I haven't been following the details.
-
You may be right
Don't bank on it, odds (of me being right) seem little better than 50/50 these days. :D
-
I thought that the new tolerances for the 230v supply were actually staged, becoming more relaxed and reducing the lower limit progressively in several steps, and resulting in a minimum voltage that is now significantly lower than it was in 1995? Or so it said in a forum thread I found recently (Possibly an IEE forum).
I also seem to recall hearing a while ago that, counter-intuitively, the lower voltage actually presented a safety/fire hazard in some circumstances. Not entitely sure, but I think it was along the lines that some appliances (ovens/fridges) that fail to reach target temperature end up running continuously rather than cycling on/off, leading to premature wear.
That is correct and reading an article several months back elsewhere this was being discussed that there maybe issues with insulation, high amperages, etc. The original voltages came from the generating stations and single phase from three phase generation that was 440 volt, 415 volt and 380 volt. You used to see 250 volt stamped on items due to the 440 volt. 240 volt due to 415 volt, and 230 volt as 380 volt 3 phase. In the UK I have seen even in recent years domestic voltages from 220 up to 252 volts. When I was responsible for a plant install in Belfast in the 80's the site had all three voltages running as there were supply coming from NI, GB, and Eire. The last information I had was that other counties that had lower voltages were gradually coming up to 230 volts and therefore as stated earlier in thread equipment will be suitable for any EU country.
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/293405/05-1410-electrical-supply-tolerances-and-appliance-safety.pdf
-
I assume it is because we are in a rural area and at the very end of a line.
Are you supplied on 240V? Our first house was supplied on 240 via overhead lines, and you could visibly see the lights dim when switching on the kettle or toaster. I've not seen this in other houses where we've always had our own transformer served off 11kV.
-
Are you supplied on 240V? Our first house was supplied on 240 via overhead lines, and you could visibly see the lights dim when switching on the kettle or toaster. I've not seen this in other houses where we've always had our own transformer served off 11kV.
Being pedantic, it's nominally 230V these days. More to the point, yes, we are fed from, and at the end of, overhead wires. Not entirely sure whether its 3 phase or a single pair but either way these cables have some impedance.
I've just tried an experiment... with just normal stuff (fridge, a few light bulbs, a PC etc) the mains was sitting at 222.5V. Then I switched on both ovens (it's a 'range'), the kettle and the toaster. Voltage dropped to 216.5V. :(
But 216V is actually OK, everything still works. The only time a real problem arises is as I say, on Christmas morning approaching dinner time, when the entire village has their toasters, kettles, and ovens on. Then 210V is not infrequent, at which point the oven's heater element is no longer capable of a decent temperature for roast potatoes. >:(
re 'harmonisation' and 'compatibility'. When I do get around to buying a new oven I'll be able to buy one designed for Europe. Yippee. But it won't stop me being hacked off that I have to buy it in the first place, when the old one still works, if only it could get the mains voltage for which it was designed. :D
-
Have you looked at an autotransformer ? If you use say a 12v 4 amp charger transformer you can get a 12v boost (or buck) and it will handle some 900 kva, 'cos the transformer core only handles the difference in power.
.
-
Have you looked at an autotransformer ? If you use say a 12v 4 amp charger transformer you can get a 12v boost (or buck) and it will handle some 900 kva, 'cos the transformer core only handles the difference in power.
Thanks for the suggestion I think, but it's a bit over my head. Which is depressing and embarrassing as, in a drawer upstairs, I have a nicely rolled up degree certificate from many decades ago, asserting I once knew a thing or two about electronics and electrical engineering. That was before a career misspent as a software 'engineer'. :-[
But even if I could muster the memories of such technology, wouldn't any such activities go awry if the supply company suddenly presented me with the maximum permitted voltage, not minimum?
-
sevenlayermuddle, perhaps you should contact your DNO (http://www2.nationalgrid.com/UK/Our-company/Electricity/Distribution-Network-Operator-Companies/) and state you are experiencing "low volts" and "flickering supply" it could just be a poor connection on the OHL - failing that request a voltage recorder is installed.
Although it maybe the tap changer needs adjusting at the transformer - the voltage recorder should determine that. At the secondary substation level the transformer does have to be isolated as they "offload" taps only. So this would involve a planned shutdown affecting at least that one transformer possibility others depending on the layout of the local HV network e.g remote transformers / switch fuses etc.
-
@starman, I am sure you are right. Indeed it's a bit naughty of me to moan about it without having first asked them to investigate. :-[
TBH the voltages I'm seeing even today surprised me, I hadn't realised it was near-borderline on just a normal Friday evening. I may well make some effort to contact them, thanks for the link.
-
I haven't managed to contact them yet, and am still seeing high voltages every night. Is the voltage recorder a simple plug in device?
-
Being pedantic, it's nominally 230V these days.
I think is was still 240V when we were in that house, that was 1985. However even today I suspect a lot of places still receive 240V, for example see the data plate on our transformerNominal, but what is it really? Our transformer says 250V nominal (see picture) so even using the lower tap that's going to be 239V. Or did they reduce the 11kV distribution voltage? Ours measured 239V just now, but I don't have a true RMS meter so that might not be accurate. I had understood that the issue was fudged by allowing sufficient tolerance so that staying at 240V would still be within tolerance for the EU standard of 230V +??%
(https://forum.kitz.co.uk/proxy.php?request=http%3A%2F%2Fi42.photobucket.com%2Falbums%2Fe320%2FGandyGoose%2FTech%2FDSC_0503-CROP_zps0b786700.jpg&hash=d892acedabd2fe7e9a1a9ba69eee5607cbb50572)
I'll have to have a look and see what taps it actually uses.
-
I haven't managed to contact them yet, and am still seeing high voltages every night. Is the voltage recorder a simple plug in device?
If its fitted by your DNO it will be connected before the meter itself to get a completely clean reading as possible. Normally left installed for 1-2 weeks.
We've had numerous voltages in the UK over the years but the most recent standards were 250V, 240V and the EU harmonized standard 230V. Although I can say I quite regularly see ~246V phase to neutral when testing at the bus-bars at secondary substations.
The tap changers at individual secondary transformers are very rarely adjusted probably because of the time and effort required to alter them. So the grid wide voltage is within tolerance but at a more local level you can see higher voltages.
-
We had a voltage recorder fitted for a different problem at a different house, about 15 years ago. Being a new-build house, it had the meter cupboard on the outside wall. Iirc they placed the recorder inside that external meter cupboard, hard-wired to the incoming supply.
I guess that avoids the results being 'tainted' by dodgy internal wiring, just as happens when we ask BT to investigate a phone fault.
-
I guess that avoids the results being 'tainted' by dodgy internal wiring, just as happens when we ask BT to investigate a phone fault.
Yeah - I'd take an educated guess 65% of the jobs the first line field technicians get are related to internal issues. I personally more often than not have simply reset an RCD on the consumer unit to restore supply.
For the elderly and infirm you do not mind but given I know for a fact that people are asked to reset their trip switches on the phone it can sometimes be annoying :)
-
Every now and then I get a really odd fault.
I think this is one which is a single phase type fault on the HV side of a transformer somewhere remote.
This is a rural area so a TT overhead distribution network fitted with ABC type conductors.
Feed to local substations is 11KV 3phase
Anyway the symptoms are a very low line volts of perhaps 100 volts.
So basically nothing works though you can get an incandescent lamp to sort of glow!
-
How often does that happen? Anything happening at the time? Weather? Specific appliances on?
-
I get quite a few short term faults - those where you can actually count the seconds as the auto-reclosers try to close whatever has tripped against the fault several times and then tripping out again each time after a second. After a few tries that's it until the fault is manually cleared and everything reset.
As to the odd one where I get a left with a 100V supply ......
I suppose I've had it two or three times in the last 5 years - such that I recognize it as being "that fault symptom"
Last time one was during high winds/gales and the other I was out during a normal summerish evening so most things off and came home to find everything a bit 'odd' when I switched a light on - sighed wearily and went to bed - to find things normal in the morning....as you do.
Strangely all these of fault types have been in the evening time.
It's clearly a single phase related type of fault as when I get it, my neighbours on different phases are still on.
The incoming neutral on the TT supply is earthed every now and then round the area at random electric poles.
Those of us on the same phase locally all know each other so when we get an electric cut we ring each other to check that we are all off and that it is a real area phase fault and not just one house as single phase faults seem locally as common as total area-wide failures.
-
Well I finally got around to reporting the over voltage fault as it's still occurring every night, UK Power Networks were very disbelieving, but they are sending someone around to take a look. So we shall wait and see what happens.
-
Let me know what they say I maybe able to offer some guidance.
-
Thanks Starman, the guy I spoke to implied it could be something in the house causing it, which I would think would be very unlikely. If it had been in the middle of a bright sunny day then I may have been looking at the solar panel system, but it's not going to be working by moon light is it :lol:. He also suggested it could be the UPS not reading accurately, which of course is possible, if it was at a more suitable time of day I'd happily get my multimeter out to verify.
I'll keep this thread updated with what happens
-
if it was at a more suitable time of day I'd happily get my multimeter out to verify.
I use a plug-in watt meter, it also reads volts. And a lot safer than fiddling with multimeter leads at mains voltage at the best of times, let alone when I'm half asleep.
If you haven't already got one I recommend them anyway, a very useful toy for investigating power usage.
PS, I haven't yet reported my own under-voltage, I have been away a lot recently. Still intend to do so, though. :)
-
Fortunately I'm very competent with domestic electrical installations, but whether that holds up when I'm tired in the early hours is a different matter. I do have a watt meter so as a quick check I could plug it in and see if it tallys with the UPS., a good idea thanks 7LM.
-
I've just had a quick check and have the following readings:
PV Inverter: 249v
UPS: 249v
Watt Meter: 247v
Multimeter: 246v
Now the PV inverter will kick out slightly more than line voltage, but I'm not sure if the display shows line voltage or what it's giving out, so really need to look when it's dark. Also I've no idea how accurate the multimeter is, it's a UNI-T UT70A but I don't know when it was last calibrated or even if it can be.
Looking at the logs UPS logs it went from 252v to 223v at 23:54, then stay around 223v to 06:50 where it jumped to 250v. The UPS logs the voltage every 20 minutes, is it usual to get such big changes?
-
I'm wondering - are you in an area without mains supply gas? Neighbors on the local LV network may have storage heating operating on economy 7.
That lower voltage is still within spec but given the weather is quite mild I can see why are some points of the year it would decrease so.
You have PV panels? Are you exporting back to the grid?
-
We have mains gas, and being a large estate of the same type of houses I think they all have gas central heating, unless of course people have had it removed, which is very unlikely. We're are very close to a transformer if that makes any difference.
We have a 4kWp array, it was installed back in December and we are exporting back to the grid, so far we've exported 430kWh and generated a total of 790kWh. The export reading is taken from our smart meter which our FITS payment provider refuses to accept, preferring to assume we export 50% of what we generate. We don't have any batteries to store the excess, so it's all exported.
-
Ronski my friend found that. He put in a big array but was getting way less than he generated as the provider paid a fixed 50 PC. So he bought three old immersion heaters which provide his hot water without needing gas. He's using some 75pc of the electric he generates now but gets paid for exporting 50pc
-
I ripped out the hot water tank about 11 years ago and installed a nice big combi, so that idea is a no go. They actually do a kit so that the immersion is only powered when your producing excess electric, which is a great idea for people with hot water tanks. Battery systems are now available which is a better idea but depends on cost, be great if they still paid 50% when it all went into charging batteries, but I bet they have that sown up!
We actually had an engineer arrive yesterday, around 2pm just to check the voltage, he said it was fine but as the problem only shows up at night he'll recommend a monitor is fitted.
-
Yeah a voltage recorder should be fitted - the local voltage complaints engineer should contact you and book an appointment.
-
:cool:
Wonder if our problems here are related. New huge windfarm went up about nine months back and since then we go through lightbulbs at a rate of one or two a week. Halogens are particularly affected. Never connected the two before till I read this post so will check what our voltage is doing.
-
Apparently light bulbs blowing regularly is what most people notice the problem by.
-
i suspect voltage issues myself, i get bulbs blowing early, they also all flicker when first turned on and have not been on for a while
-
Had a phone call from an engineer this morning to arrange for installation of the voltage monitor, he said he had a hunch it might be something to do with our main substation in St Peters. I got a text from him tonight saying he'd made a call after we spoke and his suspicions were confirmed! He'd heard back this afternoon that adjustments had been made at the primary sub and had just checked again and seems to running steady at historic levels. I'm not sure what was adjusted but he's going to ring me next week to see how things are looking.
Whatever they've done I can see the effect already, a distinct decrease in voltage from around 247 to around 240 at 13:30 this afternoon. The attached graph shows the drop off in voltage on the end of the trace, the guide line that's in the top trace being 250v
-
Well if you didn't loose supply then its likely that an on load tap was adjusted.
-
No loss of supply, and no email last night warning of over voltage :fingers: