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Is the ESKOM grid busy crashing? Or is it just my suburb? Have electricity but no frequency!?!

Some energy save lights come on, led on the kettle comes on but not enough power to get it boiling.

 

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54 minutes ago, WannabeSolarSparky said:

no frequency!?!

How did you measure?

If there was no frequency (ie the power is DC), the transformers would not work, so I doubt that is the case. I'd have to assume the frequency is outside the correct range, and the voltage too. Maybe your neighbourhood lost a phase or something like that.

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Posted (edited)
6 minutes ago, plonkster said:

How did you measure?

If there was no frequency (ie the power is DC), the transformers would not work, so I doubt that is the case. I'd have to assume the frequency is outside the correct range, and the voltage too. Maybe your neighbourhood lost a phase or something like that.

Hi there
I have a power meter monitoring my eskom grid side and my solar side which measures amps frequency volts

The power meter is showing 0 hz and the volts are the usual 230v
EDIT: my bad, its the voltage thats down, measuring now with multimeter showing 130v

energy save lights are working.
low amp loads all seem to be working fine e.g. internet modem
kettles led come on but takes more than an hour to get up to boiling temp.
Microwave comes on, but not enough power to cook.
Neighbours all having the exact same issue.

Edited by WannabeSolarSparky

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Posted (edited)
21 hours ago, WannabeSolarSparky said:

Is the ESKOM grid busy crashing? Or is it just my suburb? Have electricity but no frequency!?!

Some energy save lights come on, led on the kettle comes on but not enough power to get it boiling.

 

A friend of mine had similar "symptoms" when they substation blew up. Had very low voltage. Kettle would take 30 mins to boil 'n cup of water, only some lights in sockets came on, but no ceiling lights, etc.

It sounds similar. Maybe test the voltage between live and ground?

Edit: Nvm, see later on you identified the low voltage.

Edited by jykenmynie

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Update: It was road works people damaged an underground feeder cable.

Was just weird that there was still voltage (130v) thats why I though something weird was going on.

So does this mean that they maybe just broke a single phase of the feeder cable link?

Just trying to understand how it works :)

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14 minutes ago, Jaws said:

what energy meter is that ?

Hi there @Jaws
its a custom raspberry pi zero setup with some custom voltage and current sensors feeding data into an influx database and then displayed using grafana

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10 minutes ago, WannabeSolarSparky said:

Update: It was road works people damaged an underground feeder cable.

Was just weird that there was still voltage (130v) thats why I though something weird was going on.

So does this mean that they maybe just broke a single phase of the feeder cable link?

Just trying to understand how it works :)

So here goes my guess at this: I don't think that is how it works. Three-phase power has to do with the frequency, not the voltage (infinite phases would give you DC, I guess). A damaged cable would leak to earth, not sure why your kiosk didn't trip its E/L.

Let's see when one of the guys that knows these things come along, give me marks, and then give the correct explanation. :)

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Posted (edited)
21 minutes ago, WannabeSolarSparky said:

So does this mean that they maybe just broke a single phase of the feeder cable link?

Losing a neutral can cause such weirdness. As one example.

Let's start with this almost counter-intuitive statement: In a three-phase star aka wye setup that is perfectly balanced, there is no current on the neutral cable. The neutral cable only carries the difference in current between the phases.

wye.png.303af1dac4f7137fbaeee8e645227b9e.png

If you loaded up the three phases equally, you could literally disconnect the neutral and nothing would happen to the other voltages.

Now imagine you lost the neutral, and lets just consider two of the phases, eg:

lost-neutral-wye.png.78acae443feb1fee831a3f9973bb374c.png

Your house is connected where I put the question marks, across one half of a long transformer winding that forms a voltage divider. Now, again, if the loads on phases A and B are exactly equal, the impedances are the same, and as a voltage divider the voltages are the same. But if one phase is loaded higher than the other (has a lower impedance) it gets a lower voltage.

The other phase gets the remainder of the 400V (ish), so in this scenario, you have 130V while the other guys had 270V.

Roughly every third house in the street is on the same phase, so one way this would play out is that every third house has 130V, every neighbour to that house has 270V, and the remaining guys have no power...

🙂

Low voltages like this are the ones that damage induction motors (such as the compressor in your refrigerator). That's because current still flows through the windings, making it hot, but there is not enough torque to actually get it going...

Edited by plonkster

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8 minutes ago, plonkster said:

The other phase gets the remainder of the 400V (ish), so in this scenario, you have 130V while the other guys had 270V.

🙂

Low voltages like this are the ones that damage induction motors (such as the compressor in your refrigerator). That's because current still flows through the windings, making it hot, but there is not enough torque to actually get it going...

Thanks :)
I thought it might be something like that, will have to go learn a bit more about how this stuff on the grid side works :)

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On 2020/07/31 at 9:30 AM, WannabeSolarSparky said:

Update: It was road works people damaged an underground feeder cable.

Was just weird that there was still voltage (130v) thats why I though something weird was going on.

So does this mean that they maybe just broke a single phase of the feeder cable link?

Just trying to understand how it works :)

It must of been the common wire

I had the same issue ,stolen street wire

 

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On 2020/07/31 at 9:35 AM, WannabeSolarSparky said:

Hi there @Jaws
its a custom raspberry pi zero setup with some custom voltage and current sensors feeding data into an influx database and then displayed using grafana

Can you share what custom sensors you are using. I got a few 30A CT clamps i have been playing with along with converting a 9VDC adapter to AC and reading that into a ardiuno

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8 hours ago, PhatWheZ said:

Can you share what custom sensors you are using. I got a few 30A CT clamps i have been playing with along with converting a 9VDC adapter to AC and reading that into a ardiuno

For the AC side (Eskom)

sensor I currently use (they not in stock at the moment)
https://www.pishop.co.za/store/rpiz_ct3v1-3-current-and-1-volt-30a-ac-adapter-for-raspberry-pi-zero?keyword=current&category_id=0

This sensor is more suited as you can measure up to 7 circuits with it - https://www.pishop.co.za/store/rpict7v1-30a-version2---7-ct---1voltage---master?keyword=current&category_id=0

You can use that with raspberry pi3/4 or pizero w ( I use a pi zero w for the eskom side)
I tried a self made 9v ac but had no luck so just bought one to save/prevent all the smoke I was creating
https://www.pishop.co.za/store/power-other/acac-power-supply-230-vac-to-9-vac

For the DC side

I am still busy making sensors to measure battery current in and out as well as solar amps and voltage in.

The voltage sensor for the battery bank was quite simple. I just made a simple voltage divider to bring the readings down to a voltage acceptable for the sensor and read it into a
ESP8266 NodeMCU CP2102 ESP-12E Internet WiFi Development Board which sends the data to influx for use in grafana

You can use that same esp8266 to read all the different amps and voltages if you add a ADS1115 16 Bit 16 Byte 4 Channel I2C IIC Analog-to-Digital ADC PGA Converter, that will save some costs :)

DATA Recording and Viewing

All the data from the different sensors all get sent wireless to my pi4 into an influx database, and then graphed using grafana also on the same pi4
You can then view the graphs via your browser on the same network.
I can provide the grafana json template if anyone wants it.

Mobile App

Busy designing that at the moment so that I can view all the data from anywhere in the world.

All the software including the mobile app are all opensource and free to use/modify as required

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On 2020/08/05 at 7:28 AM, WannabeSolarSparky said:

Mobile App

Busy designing that at the moment so that I can view all the data from anywhere in the world.

All the software including the mobile app are all opensource and free to use/modify as required

This will be amazing!

 

Ive looked at those boards before but never pulled the trigger on getting one of them. Really like your dashboard, so might end up biting the bullet once and for all

 

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