JHB voltage drop

[Jladan]

Anyone else notice JHB voltage is currently dropping especially during peaks to around 190 - 200?

If it is being widely observed what could be the cause ? Us just not getting enough juice from Eskom ?

 

[Willie Trombone]

Anyone else notice JHB voltage is currently dropping especially during peaks to around 190 - 200?

If it is being widely observed what could be the cause ? Us just not getting enough juice from Eskom ?

Overloading likely. Substations haven't been upgraded while consumption has gone up. Illegal connections. Business expansion, more domestic use...
We saw this years ago in some suburbs in East London where hospitals (heavier users) had been built in residential suburbs and the infrastructure couldn't keep up. It wasn't unusual for the voltage to read 170-190 some days.

 

[Lupus]

Anyone else notice JHB voltage is currently dropping especially during peaks to around 190 - 200?

If it is being widely observed what could be the cause ? Us just not getting enough juice from Eskom ?

Nope most places are between 217 to 240 that I know of, sounds like your area is overloaded.

 

[Mike Angelo]

Your local sub is overloaded. I've been getting between 209 and 213 volts the last couple of weeks. Normally pick it up in the morning when I have to put the toast back in for a second time.

 

[Lupus]

Your local sub is overloaded. I've been getting between 209 and 213 volts the last couple of weeks. Normally pick it up in the morning when I have to put the toast back in for a second time.

Shoo I've only seen mine drop to 219, on average it's around 230

 

[ArmatageShanks]

Massive issue in our buidling, but its local to the buidling

Dropping to 170 last I checked, lights sometimes pretty much go off its so bad, you cant cook or use the microwave when this happens, the microwave just tunes you hommmmmmmmmmmnnnnnnnope.

 

[Willie Trombone]

Shoo I've only seen mine drop to 219, on average it's around 230

It's likely suburb specific or even block specific in some cases.

 

[Lupus]

It's likely suburb specific or even block specific in some cases.

Normally is, voltage drops are indicative of load, voltage increases are oversupply... We know that last option won't really happen in SA

 

[Willie Trombone]

There are many transformers between the point of supply and the generation source.

We have 400 kV transmission lines which gets stepped down to 132 kV and then 66 kV. The last bit is typically 33 kV and 11k V but I see newer suburban distribution is at 22kV before the minisubstation in your suburb or complex steps down to 3Phase 420V / 1P 230V

Now every transformer in the long chain has a tap changer that is used to regulate the voltage as the loads changes except for the Minisubstation that will have a manual tap changer with 5 taps.
-5% -2.5% 0 +2.5 +5%

National Energy regulations allows a 10% deviantion from the decalared voltage

View attachment 1315040

Good point. Reporting this to Eskom might result in a fix.

 

[Jladan]

Well I’ve got nice graphs showing the dip so will send onto councillor and see if anything happens

 

[thehuman]

Well I’ve got nice graphs showing the dip so will send onto councillor and see if anything happens

Do share that graph here too ,
And also what your min and max values

 

[Geoff.D]

Well I’ve got nice graphs showing the dip so will send onto councillor and see if anything happens

And do your graphs show how the frequency varies as well?

 

[gbyleveldt]

And do your graphs show how the frequency varies as well?

Frequency is a function of the source (ie grid), not the load or any peripherals in between. It hovers around 50Hz and does deviate a little though, as the grid compensates for demand

 

[Progenix Oj101]

And do your graphs show how the frequency varies as well?

Back in Feb ours was jumping between 49.8 Hz on the low side and 51.2 Hz on the high side, fluctuating multiple times per second. At the same time, voltage down at around 187v. Two days ago, stable but down at 180v / 49.7 Hz. At the moment, stable 226v / 49.9 Hz.

 

[Jladan]

Last

 

[Geoff.D]

Frequency is a function of the source (ie grid), not the load or any peripherals in between. It hovers around 50Hz and does deviate a little though, as the grid compensates for demand

Not really the case, as it is a function of generation, distribution and load.

The limits used to be 50 +/- 0.5 Hz. Currently, the upper limit has been changed to +1.5 Hz according to some sources.

 

[Geoff.D]

Back in Feb ours was jumping between 49.8 Hz on the low side and 51.2 Hz on the high side, fluctuating multiple times per second. At the same time, voltage down at around 187v. Two days ago, stable but down at 180v / 49.7 Hz. At the moment, stable 226v / 49.9 Hz.

touche! Enough said

 

[Progenix Oj101]

Not really the case, as it is a function of generation, distribution and load.

The limits used to be 50 +/- 0.5 Hz. Currently, the upper limit has been changed to +1.5 Hz according to some sources.

That makes sense. I read at the time (can't find the source now) that a power station should auto shut-off at 49.4 or 50.6 Hz and wondered how we were still on.

 

[thehuman]

Please change scale between 240 and 160 , this should eliminate loadsheding drops .
Don't think they will be able to bump up the voltage at the transformer.
Would be nice to compare neighbors too.

These low voltages will destroy your fridge motor, suggest you buy a fridge safe from ellies

 

[ChuckNorris]

Easy solution is for them to approve grid tie inverters with export and the volts will pickup when the sun shines.