Goodwe inverter ~ Incorrect CT meter readings / CT meter connection reversed ~ solved (kinda)

[A3jan]

Before having a PV system installed I was surprised how little community-based information there was online. This forum is one of the few that is available and it helped me substantially in my decision making. So, given that I have benefitted, and am still benefitting, I would like to share a problem that I had and how it was (kinda) solved. Maybe someone else can benefit. 

Here is my setup: Goodwe GW5048D-ES Inverter; 12x375W (4500W total) PV; Pylontech US5000 (5 kWh) battery

My inverter, which is set up not to export the grid, tripped at about 20 minutes into a power failure (load-shedding). At the time, the usage data were not correctly uploaded to the SEMS, so I could not see that it was caused by spike (10kW) in load (yellow peak at around 14:20. I still do not know what could have used so much energy (everyone in the house was chilling at the time), but the tripping occurred twice thereafter (coinciding with the two orange peaks at around 15:00) during the same outage. See graph below.  

I thought there was a problem with the inverter so I went into PV Master app and checked out the error (alarm) messages. There was nothing unusual (apart from the outage notification at 14:00). But then I made the mistake to run a CT meter test at about 14:45. Apparently, based on a post on this forum, this is not a good idea because there was no load from the grid, but I was ignorant to this at the time. As you can see from the graph above, this caused the metering system to go haywire, because suddenly it showed that the inverter is exporting a ridiculous amount (>6000W) of power to the grid, which is not possible given that my generating capacity is only 4500W. The PV Master app also showed that the direction of current in the PV Master app was consistently in the home > grid direction at this point (despite having the export limitation set to 0). This weirdness continued for several days. For instance, I was exporting power to the grid later that day even in complete darkness. Also note that the Load (yellow) is zero from about 14:45 onwards, so it looks like Meter (orange) and Load were being confused by the metering system.

The graph below shows the situation the next day. Almost no solar energy was generated and the battery was only used during outages (i.e. looks similar to backup mode). The installer came the next day (and several days thereafter) to try and fix the problem, but he was unable to do so. We tried many things, including resetting the inverter and smart meter and rerunning the CT meter test, to no avail. 

 

At some point, we were getting data loading errors from the PV Master app, after which the installer sent a support call to Goodwe. After many days of waiting for Goodwe to provide support, I decided to do some online reading (mostly from this forum) and experiments of my own. Many failed, but this one solved the issue. 

1. Disconnect (switch off) the PV strings from the inverter 
2. Wait until the battery was at 100% charge
3. Start a device with high wattage (I started a tumble dryer) to increase load from the grid to > 1500W
4. Go to basic settings in PV Master app
   1. Under Select Safety, set the region to the correct country (i.e. no change)
   2. Under modes, set Inverter to backup mode. 
   3. Run the CT test (in my case this failed with error "CT meter connection reversed") The idea with these steps is to only have current in the home < grid direction. Despite the fact that the CT test failed, the arrows were now in the right direction (i.e. home < grid). 
5. Run Basic Settings again
   1. Under Select Safety, set the region to the correct country (i.e. no change)
   2. Under modes, set Inverter to normal mode.
   3. Run the CT test (in my case this failed again with error "CT meter connection reversed") Strangely, after doing this the arrow was back to pointing towards the grid
6. Restart the PV Master app Now the the arrow was pointing towards the house (as it should be)
7. Reconnect (switch on) the PV strings. After this things were back to "normal"

I say "normal" because the CT meter test still shows a "CT meter connection reversed" message. The installer assures me that it is connected in the right direction, so I it is not clear what is causing this. Nevertheless, at least my system is up and running again.

I hope this helps someone.  

 

Edited June 8, 2023 by A3jan
Typo

[ckies]

Thanks for this post! I've had exactly the same issue and wrecked my brain a few days until this came through! 

[John Does]

Im glad this sorted it out for you, however im sitting with exactly the same issue, and it is frustrating as hell to try and solve this. I followed the above instructions without success. I really dont know what to do. Currently getting fed up as im struggling to find a Installer that is a) Answering his phone. b) sticking around long enough to actually help.

So, bit of back ground. Running the ES 4.6 Goodwe Inverter. Installed an additional Battery recently (past two weeks) Currently running 2 X US3000B's and one US3000C (The Master). Had the existing system running like this (without the 3rd battery that i bought recently) for about 3-4 years. Installed the Battery and let it run for a while as I wanted to see how things are going and now i want to start optimising the system, now i wanted to tweak the system to offload some of the Battery more etc etc. Once Applying the Basic Settings it did another CT check. and the dreaded CT Reversed error message pop up. All of a sudden it showed that its starting to Export power to the grid, even though the settings are set to 0. and you know the rest. I tried the above resolution without success. Im at the point where I want to get a Electrician to swap the CT Clamps in an attempt to get this resolved (If it even resolves it).

Any advice or assistance would be appreciated.

 

 

[Cef]

10 hours ago, John Does said:

Any advice or assistance would be appreciated.

What firmware number do you have installed?
You may have a faulty CT unit.

Try raising a service ticket on the Goodwe website and try to fix the problem directly with them by jumping to your installer/dealer.
If they do not provide a solution in a reasonable amount of time, ask that the problem be escalated to the second level engineer. The 1st level will rarely offer you a solution to problems that are not simple. If your equipment is still under warranty, you must be forceful in that request.

[John Does]

Hi Cef

Thank you in that regards, I appreciate it.

I have been able to resolve the issue by contacting Goodwe and im so happy about that! I provided them with the information, and they indicated that I was running an older firmware version. She also explained to me that I must not run a CT check everytime I apply settings (Something I didnt know). She the also indicate to me that she will apply a Configuration post Firmware update and that it would resolve the Issue with the Reversed CT check.

 

Im happy this was as simple as that. I also have another Issue that I would like to discuss that on a new Topic.

 

Thanx a bunch again!

[A3jan]

Excellent, happy to hear it. Can you share what the issue was? 

[John Does]

Hi A3jan

Im just glad its sorted man, I unfortunately cannot pin point and say with 100% confidence what the exact resolution she applied was. But I can 100% confirm it's not something I did that resolved. It. I believe that they remotely reconfigured the Inverter to "Swap" the settings from input and output. But Im electrically illiterate  

[FrancoisV]

I noticed when doing the CT test on my Goodwe you have to pull load on the non-essential side (Between CT meter and Inverter) whilst doing the test, or else I also get the "CT Reversed" error. I usually switch a couple of stove plates on before starting.

 

[A3jan]

OK @John Does, did not realize they can do that. Good to know.

[A3jan]

@FrancoisV, interesting. I don't think I did that as my tumble dryer is on essentials. Nevertheless, I think it is worth trying.  

[A3jan]

As an update to my original post, the "CT meter connection reversed" message disappeared after a while. Not sure when or why.

[Neil H]

On 2023/05/04 at 3:08 PM, FrancoisV said:

I noticed when doing the CT test on my Goodwe you have to pull load on the non-essential side (Between CT meter and Inverter) whilst doing the test, or else I also get the "CT Reversed" error. I usually switch a couple of stove plates on before starting.

 

Been having this problem for nearly a week and inverter discharging to grid with export turned off 

I have had to turn them off so will try this asap to see if it works 

 

[Neil H]

tried the fix last nigh dint work