Seeking Solutions for Solar Energy Monitoring in My 10kW System

[arthur_morgan]

Hello DIY Solar Forum members!

I recently embarked on a fascinating journey with solar energy, installing a 10kW grid-tied solar system at my home. It's a big step forward, especially since in my country, any residential grid-tied system over 7kW necessitates a three-phase connection.

My main goal is to get a clearer understanding of the energy flow in my system. I want to monitor:

1. The total solar energy produced.
2. The amount of solar energy I am using.
3. The solar energy being exported to the grid.

For this purpose, there are two meters installed:

• Solar Generation Meter: Connected to solar inverter through a three-phase wire, this meter tracks the solar units generated.
• Net Meter: It's linked to:
  • The grid's three-phase line.
  • A looped cable from the Solar Generation Meter.
  • My household load.

Here's the challenge: Although these meters serve their purpose, they feel quite generic. More importantly, to gather data, I have to manually check these meters, which is cumbersome and time-consuming. In my city, we don't have smart meters yet, so a technician visits once a month to manually record/capture images of the readings to generate electricity bills. Unfortunately, there have been several instances of technicians recording incorrect readings, leading to inflated electricity bills. This adds another layer of urgency to find a more reliable and personal monitoring solution.

This is why I'm thinking of a DIY project, perhaps using an Arduino, to bring together these three key metrics in a user-friendly interface. I'm open to any suggestions if you think there's a better way other than Arduino to approach this.

Given that both meters installed by the government are bi-directional (logging power flow both from and to the grid), I'm curious about the best way to integrate and record/log this information in a clear, concise manner.

I'm looking to this community for ideas, advice, and any guidance you can offer on creating a more efficient and accurate system for monitoring my solar energy usage and production.

I have conducted extensive research on the components/sensors needed to achieve my goal. I discovered that non-invasive current sensors (reference image attached below) can be used to log/record electricity transfer or usage. These sensors are placed on the wire to measure the total energy being transmitted through it. The three-phase wire providing grid electricity from the pole is connected to a bidirectional meter (net meter), indicating potential bidirectional electricity flow (from grid to home and solar to grid). My concern is whether these sensors might get confused with the bidirectional flow. What are the optimal locations for placing these sensors?

Thank you for your insights and suggestions!

 

[12VoltInstalls]

My concern is whether these sensors might get confused with the bidirectional flow. What are the optimal locations for placing these sensors?

Aren’t most ‘dumb’ CT’s going to add up regardless of the direction of current flow?
That is my understanding and I could be wrong.

 

[OzSolar]

Have you bumped into the Emporia VUE energy meter? I think it does everything you want.

As 12Volt mentioned CT's (when used in an AC applications) can't tell the direction so they will count both directions as a total.

The Emporia handles this nicely with a CT dedicated to the solar inverter and software.

 

[12VoltInstalls]

can't tell the direction so they will count both directions as a total

That’s good. I have a couple cheapo inductive meters that have an arrow and instructions mentioned it which at the time made me think I must not know everything. ?‍ imagine that… I did know just about everything when I was 16…

 

[arthur_morgan]

Aren’t most ‘dumb’ CT’s going to add up regardless of the direction of current flow?
That is my understanding and I could be wrong.

Im not aware of how they will work in my scenario. I have one Ct which has a arrow mark but it is for case where the flow is unidirectional.

 

[arthur_morgan]

Have you bumped into the Emporia VUE energy meter? I think it does everything you want.

As 12Volt mentioned CT's (when used in an AC applications) can't tell the direction so they will count both directions as a total.

The Emporia handles this nicely with a CT dedicated to the solar inverter and software.

I have seen a few videos of Emporia VUE energy Meter on youtube and from what I can understand they are an excellent piece of tech but my situation is a bit different. The difficult task is to differentiate and log the inward and outward flow of electricity separately flowing through the wire going to grid.

 

[Crowz]

I have seen a few videos of Emporia VUE energy Meter on youtube and from what I can understand they are an excellent piece of tech but my situation is a bit different. The difficult task is to differentiate and log the inward and outward flow of electricity separately flowing through the wire going to grid.

It does that on my Emporia at least on the part coming in. I don't feed to the grid so I can only go by what they claim it will do on that.

You can see how much is coming in from the grid or going out to the grid.

According to their website :

Generating Energy?​

The Emporia Gen 2 Vue monitors renewable energy net metering out of the box, giving you clear measurements of how much energy is being returned to the grid (and saving you money).

 

[Texican]

I have 3 emporia vue systems. 2 are in panels with grid tie inverters.
the large 200a ct monitor total usage FROM the grid, and you put a smaller ct in reverse direction on the wire from the inverter into the breaker where it feeds the panel
tells you second by second what if anything you are buying from the grid and also exactly how much the PV is creating
as well as the net difference