I woke around 00:30 this morning from the aircon switching on, then off, then on ....

It is if the power was tripping and coming on the whole time. But, the aircon is on the solar side. So I stood up and solar alarm is going crazy. Solar keeps on resetting as after loadshedding when the power is restored. Switched of solar.

Weird sound in house. Fridge motor is making noise, etc.

After some significant elimination I measured the municipal input voltage. 118V. Then 89V. 

Kill main breaker and switch solar system on. Resets and work. 

Municipal power still around 89V. Tried to switch on main breaker. Solar trips. Kill breaker. Solar works. So I just left the main breaker off. Hopimg the issue will resolve in morning.

Just before trying to get back in bed measured 53V? Is that possible?

I had the exact same issue over the weekend.  Voltage drop to about 150-160v.  Tshwane came out and the main breaker (80A) that connected my house to the grid, located on the top of the pole in the street, was burnt.  They replaced it and all is fine.  It was still one of the old black breakers.

 

Which inverter do you have?

Edited April 14, 20224 yr by FrancoisW

8 hours ago, MorneDJ said:

I woke around 00:30 this morning from the aircon switching on, then off, then on ....

It is if the power was tripping and coming on the whole time. But, the aircon is on the solar side. So I stood up and solar alarm is going crazy. Solar keeps on resetting as after loadshedding when the power is restored. Switched of solar.

Weird sound in house. Fridge motor is making noise, etc.

After some significant elimination I measured the municipal input voltage. 118V. Then 89V. 

Kill main breaker and switch solar system on. Resets and work. 

Municipal power still around 89V. Tried to switch on main breaker. Solar trips. Kill breaker. Solar works. So I just left the main breaker off. Hopimg the issue will resolve in morning.

Just before trying to get back in bed measured 53V? Is that possible?

Those are some very low voltages. Low voltage is a common thing where I live, especially after a load shed, but not as low as you are seeing. We regularly get down to 180.

Now, on my inverter (Goodwe) part of the setup is telling it what grid standard to adhere to. If I set it up for South Africa, it expects 230v at 50Hz, and will disconnect at round about 210 (and reconnect when the grid voltage rises). 

The alternative for me is to run the inverter on 50Hz default. That will accept most anything as long as it is 50Hz A/C.

The Goodwe also matches whatever the input voltage and frequency are. So if the inverter is running in 50Hz default mode, and the grid is sitting at (thumbsuck example) 190V at 50.2 Hz, that is what the inverter will serve up to the backed up circuits.

In my example in the previous sentence, if I were running with the inverter setup for the SA Grid, the Goodwe would disconnect until the the voltage rose again and my a/c (if I had one) would get a nice 230V from the batteries via the inverter. If I had it set for 50Hz default, it would continue to follow the falling voltage, and eventually some device is going to get a voltage it's not happy with.

So I think there are two questions here:
1) Why is the grid voltage dropping so low?
2) How is your inverter configured?

Edited April 14, 20224 yr by Bobster

It sounds as if there is 1 or 2 phases off on the Ht side of the Transf or Minisub.

Nice why of burning all the electrical equipment in your hose.

My one friends on a farm regularly has that issue. As soon I am able I am going to install a Over/Under voltage relay with Contactor to protect the house.