Don't the towers have some form of UPS/backup generators? Even in quite extensive power failures I've still always had cell reception.
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Power failures
- Thread starter Syndyre
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Don't the towers have some form of UPS/backup generators? Even in quite extensive power failures I've still always had cell reception.
Generators only last so long before they run out of diesel and have to be topped up...
JimM
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When I worked for Sky TV in the UK, the station would (in the event of a power failure) go onto UPS and after five minutes onto generator which would keep the station on-air for a few days. Fortunately in the UK power outages are still rare and last no longer than an hour at maximum, excluding rural areas with storm damage of course!
A reasonable sized UPS should keep even the busiest of base stations on-air for a day at least.
brad
Well-Known Member
JimM, most of the sites nowdays have battery capacity of over 200Ah. With the bigger sites drawing some 50Amps plus from the 50V battery, you can see that it is not likely that the site will last more than a few hours if the power goes off. The rectifiers in most sites are capable of supplying over 60amps at 50V to run equipment/charge batteries when the power is on.
Then there is the other issue that the equipment can run for short periods without aircon, but after a couple of hours, it generally starts shutting down as the temperature rises to around 50deg C. Most sites are fed with a minimum of a 40A 3phase supply and some of the larger require a 60A supply.
Now what size UPS would one need to run an 18000 btu aircon and supply the power to run the equipment and charge batteries?
If only life was so easy.
JimM, most of the sites nowdays have battery capacity of over 200Ah. With the bigger sites drawing some 50Amps plus from the 50V battery, you can see that it is not likely that the site will last more than a few hours if the power goes off. The rectifiers in most sites are capable of supplying over 60amps at 50V to run equipment/charge batteries when the power is on.
Then there is the other issue that the equipment can run for short periods without aircon, but after a couple of hours, it generally starts shutting down as the temperature rises to around 50deg C. Most sites are fed with a minimum of a 40A 3phase supply and some of the larger require a 60A supply.
Now what size UPS would one need to run an 18000 btu aircon and supply the power to run the equipment and charge batteries?
If only life was so easy.
The numbers - on battery I assume no Aircon - then 2500-3000watt.
Total supply (40A one) includes running equipment, charging batteries and running aircon - appr 22-25kw depending on power factor assumption.
I am sure they can do better - MTN uses 10m litres of diesel in Nigeria a month - most of their base stations run off generators. And they are making money.
Surely they channel money spent on other cr@p to improve this issue.
What topic is this thread again??
Without power - no base station - no throughtput. guess still vaguely related
Where does MTN Nigeria get that diesel from, i.e. do they import it from outside of Nigeria, and how much would that strange 10m litre of diesel cost in SA?The numbers - on battery I assume no Aircon - then 2500-3000watt.
Total supply (40A one) includes running equipment, charging batteries and running aircon - appr 22-25kw depending on power factor assumption.
I am sure they can do better - MTN uses 10m litres of diesel in Nigeria a month - most of their base stations run off generators. And they are making money.
Surely they channel money spent on other cr@p to improve this issue.
What topic is this thread again??
Without power - no base station - no throughtput. guess still vaguely related
My memory did not let me down...
http://mybroadband.co.za/nephp/?m=show&id=5736
Do a google = they are looking at biodiesel et al.
Of course the number may be slightly inflated for marketing/brownies value.
I think over 60% of their 2500 base stations run off diesel generators in Nigeria.
Logic to conquer territory is amazing.
Here they will invest how much for a base station, but rather spend the generator 50-100k on other cr@p.
In another perspective from the GSM Development Fund:
Only 25% of base stations in Nigeria run off the electricity grid - rest on other sources like generators.
African Cellular operations consume 30m litres of diesel per annumn.
They use an average of 18000 litres of diesel per base station. This appears, or may, total diesel / total base stations though.
From between the lines (MTN / GSM Dev Fund) - assume the 18000 is average of diesel only powered and 75% of MTN's 2500 base stations use diesel. We get 2.8m litres. Still a whole lot of it.
MTN may be spinning some bull...t on the 10m possibly. Then maybe they took the 10million (conveniently) from their total African monthly tab. They just need nearly 4 Nigerian scale opps (10m/2.8) = Nigeria is their big one = so maybe 4 or 5.
Jatropha is nothing new - been planted in Africa (west) over 50 years ago... Originates from India - read up quite a lot some time back. Company D1 has/had a deal here as well..
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Hobbit
Active Member
There was a power failure on the west coast yesterday (Monday)at about 10:00 with power only restored this morning (Tuesday) at 08:30. By 18:00 yesterday evening the Vodacom signal from the Yzerfontein Reservior tower had expired. The MTN signal was still available at 20:00 but expired some time during the night. Neither signal was available this morning at 08:00. When power was restored at 08:30 this morning the Vodacom signal was available within 5 minutes but at the time of writing (09:00) the MTN signal has still to be restored.
With the increasing likelihood of power restrictions and failures throughout the country, but in particular the Western Cape, I wonder if the cell companies have any strategy to minimise the impact on their client base.
Perhaps V3g could have a go at answering these question on behalf of his network.
1. What is the standard (if any) backup power time for a tower?
2. Is there a plan in place to replace batteries/refuel generators where the Eskom downtime is extended?
3. In view of the country wide power problem is there any greater plan of action envisaged?
With the increasing likelihood of power restrictions and failures throughout the country, but in particular the Western Cape, I wonder if the cell companies have any strategy to minimise the impact on their client base.
Perhaps V3g could have a go at answering these question on behalf of his network.
1. What is the standard (if any) backup power time for a tower?
2. Is there a plan in place to replace batteries/refuel generators where the Eskom downtime is extended?
3. In view of the country wide power problem is there any greater plan of action envisaged?
vodacom3g
Vodacom Representative
Brad?
Hobbit
Active Member
vodacom3g; said:
Is that a typo?... yes it was bad... had no 'lectric blanket all night..
vodacom3g
Vodacom Representative
Sleeping alone, are we?
No, Brad (one of our top guys in Kzn) hangs around here and have answered power questions before. He'll know much better than me.
@Hobbit, kindly read the following article [link retrieved from one of dionb's recent posts]: http://mybroadband.co.za/nephp/?m=show&id=5736
Hobbit
Active Member
Thanks ic... interesting stuff... in the specific case that I mention it seems that the 8hr backup was about correct. However it was known early on that the outage would be considerably longer (Eskom estimated noon Tuesday)... but neither network seems to have had any plan in place to refuel generators... my guess is that the infrastructure is in place but that the human systems are not.
Moderator note...
Done a Frankenstein reshuffling effort of some power failure related posts from another thread, and moved them into this thread.
Done a Frankenstein reshuffling effort of some power failure related posts from another thread, and moved them into this thread.
Have a look at [post=1084318]what brad posted...[/post]
web
Executive Member
.web
Executive Member
thought i was hallucinating !!!
Csnoopy
Expert Member
Thanks ic for putting posts in the right place. It does happen now and again that we all go off at a tangent.
Hobbit
Active Member
At the risk of boring everyone to tears I'm still not sure that I have an answer... the tower/base station whatever was down for 14.5 hours and came back on line when the Eskom power was restored... in Vodacoms case the tower was down from 18:00 in the evening until 08:30 the next morning
My question is what systems are in place to minimise this sort of downtime? I accept that battery power runs down and that diesel is used up... at what stage does Vodacom dispatch a crew to fill the tank or charge the batteries? do they just wait with fingers crossed until the power comes back up? are there reporting systems in place to alert a person in some control room? in this case the tower was down for 14.5 hours but if the Eskom power had not come back up could it have been down for 24 hours, a week, until the next maintenance is done?
My question is what systems are in place to minimise this sort of downtime? I accept that battery power runs down and that diesel is used up... at what stage does Vodacom dispatch a crew to fill the tank or charge the batteries? do they just wait with fingers crossed until the power comes back up? are there reporting systems in place to alert a person in some control room? in this case the tower was down for 14.5 hours but if the Eskom power had not come back up could it have been down for 24 hours, a week, until the next maintenance is done?
brad
Well-Known Member
Hobbit, I am sure that most of the country operates the same as here in KZN. We have a number of mobile generators which are deployed in the event of power outages. Naturally, this depends on the extent and duration of the outage because there are only a finite number of available generators and if numerous sites are affected by the power outage, there are sometimes not enough to go around. We also use generators hired as and when we need from outside companies to further back up our in house supply of gensets.
The guys from both MTN and Vodacom have been running like mad things for the last day or so trying to get sites back on air after all the power outages with the bad weather. This has been done using gensets from wherever possible. The option of swopping of flat batteries is not really practical due to a few factors:
1. Each battery weighs around 70kg
2. There are between 4 and 16 batteries on each site (depending on size of site)
3. The time required to recharge these 155AH batteries is long (cannot recall the exact charge time) and generally the power is returned within this time
On the question of alarms, each site has numerous alarms which are monitorred 24x7 at the Network Management Centre (NMC) in Cape Town. Some of the alarms they get from each site are:
1. Door and intruder alarms
2. Power failure
3. Equipment failure
4. Aircon failure
5. Over temperature, etc.
Basically everything is done to keep as many sites going as possible cos if the sites are down and you guys cannot use the service, the networks cannot steal your bucks and get rich.