Hi,
I'm recently added an EM530 with three current transformers. In addition, there is a Huawei Smart meter with current transformers (CT) connected as well. All CTs are mounted directly after the energy meter of the supplier. While the Huawei Energy Meter produces valid measurements, the EM530 does not.
Invalid measurements mean that they are too low, for low consumption even negative. I created a Grafana board to show the difference in measurements. Here are two examples of the same phase, measured with the two devices.
Here is an additional image one showing the total of all phases. Note: the energy total uses a different timeframe that the screenshots above! The graph looks flat because the ESS tries to balance the grid consumption to 100W. Just in cases with high demand, it can't do this. In addition, the Huawei Smart Meter can be asked only every 1-2 seconds, that makes a smooth regulation difficult.
Let's assume that the CTs and the energy meter are wired correctly (installed by an electrician, checked multiple times). The CT ratio is set to 10 because 50A/5A CTs are in use.
- Can there be an issue with two CTs on the same wire next to each other?
- The EM530 is connected to power after an RCD Type B. Could that change measurements?
- What could be the other possible issue I can check?
