Can I use two grid tie Inverters?


Back in 2020, I came across a huge difficulty with my GTI. I installed grid-tie inverters three years ago and was pretty much happy with their performance. However, the problem started to sprawl up due to poor sunlight.

Then, I consulted an engineer to integrate an additional inverter. To my surprise, he recommended to install a smaller one and to connect the grid. He also added, having two grid-tie inverters is actually a smart choice.

Here, in this article, I will share my experience. Moreover, I would like to help you guys to clear your doubts related to a grid-tie inverter.

How to integrate two grid-tie inverters?

Functionally, grid-tie suggests you need some additional resources of backup power.

Grid-tie inverters are truly energy efficient. Their peak efficiency ranges from around 94% to 96%, which is great. 

Hence, its additional perks triggered my decision when I switched grid-tie inverter. The two inverters need to be synced to supply the power and feed the load. It is as simple as multiplication.

Generally, you won’t have any technical problems to integrate. However, the building codes of these two systems might have an issue. It concerns how much you feed into the breaker panel. That’s the reason you should always consult a professional to set up the entire system.

Understanding grid-tie inverter and its integration

If you want to sync two grid-tie inverters, it’s a smart decision. However, you need to put in enough power to keep up the voltage. Solar panels are typically aimed at different directions, isn’t it? It helps them to acquire more light and generate more power. Now, these panels should be on their own MPPT input.

Complete-Diagram-of-Grid-Tied-Solar-Inverter.png

Now the trick is to place your panels in a multi-faced direction. Hence, the east-facing panel would generate power in the morning. Similarly, the south-facing panel would start the add-in. Therefore, all the mechanism ensures to increase the power peak. A separate MPPT on each string would generate a bit more power for sure.

This way, you can save your money from installing an additional inverter. On top of that, the engineer’s charges would also help you have a pretty much penny. However, from my experience, I found the grid-tie system is extremely efficient and reliable. Of course, if you are more concerned about the quality power!

While solar inputs are a more economical option, they can’t compete with the unmatchable performance of the grid-tie inverter. Interestingly, I had one set to charge the battery from the grid. And the second is a generator backup. 

I use the second set if the first one runs off battery. Hence, I use both grid-tie and battery storage capabilities.

How is the system of grid-tied inverter wired?

The integration of the system entirely depends on the types of the inverter. The configuration process uses three-layered wireframe. In addition, it also parallels connected with the three-phase system. The system deals with four significant mechanisms:

  • Parallel
  • Grid-tie series
  • Series/parallel
  • Three-phase

The master inverter is set to 3ph. When I installed the system, the engineer suggested me a smart technique. While processing the configuration, he had used two hot legs and a neutral port to attach the three-layered wireframe.

 If the power load is moderate or light, the power save level allows the inverters to go off sleep. A manual master button is integrated to monitor the automated system.

Once the load goes high, the master inverter will enable the power level at 12aac. Furthermore, the power level would go up from 12aac to 24aac. When the power level is around 4aac, the inverter goes off through an automated technology.

Facts to know before installing the second grid inverter

  • If the grid is down and connected, it is unlikely to generate the required power. On the other hand, if the grid is connected, it should go down and act accordingly.
  • If they don’t have enough load and the grid is disconnected it would be reluctant to accept the current.
  • It is ideal to discuss the intended design with a system engineer to avoid any difficulties. Also, it might require some additional equipment and interface.
  • Off-grid is a separate mechanism with multiple functions. At the same time, grid access enables a reliable source of power generation that is an economically viable choice.

I have used this integrated system uninterruptedly. Moreover, the system gracefully maintained a surplus maintenance process (periodic refresh, pole transformer, power outages, etc.).

To Wrap Up

Finally, I can definitely suggest you guys to use two grid-tie inverters. Moreover, you are concerned about the high-efficiency power and voltage; it’s a smart and reliable choice. Theoretically, they try to assist each other within the stipulated limit of available power.

In addition, if the system is unable to find the right balance of power, they both (or anyone) would shut down. In that case, they would use their ‘fail safe’ technology.

People also asked:

Is it possible to use the same inverter for grid-connected and standalone operation?

YES, YOU CAN DO IT. HOWEVER, IT IS RECOMMENDED TO USE A REAL-TIME PV VOLTAGE CHECKER. IN ORDER TO INITIATE THE PROCESS, FIRST, YOU NEED TO DISCONNECT THE INVERTER FROM THE GRID. Once the PV can generate enough voltage, you can turn it back to the grid power system.

Can grid-tie inverter be used off-grid?

YES, IT IS POSSIBLE. Typically, grid-tie inverter works based on the grid-feeding strategy. Moreover, it supplies a synchronized current to the grid. In that case, output voltage and frequency need to be monitored.

What does a grid inverter do?

A grid inverter is capable of converting Direct Current into an Alternating Current. Hence, it is suitable for injecting electrical power grid. Ideally, grid-tie inverters are used in local power generators like solar panels, hydro-electric, and grids.

Matt

I’m Matt, a computer and electronic embedded system developer. Currently, working as an electronic engineer. In my leisure time, I do love to blog about technology stuff. Specially, new advance high tech devices. Portable solar systems are one of topic that I love to investigate. They are becoming more powerful day by day which keep me alert.

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