How to choose a solar inverter for a three-phase electric home?

08/26/2022

For a three-phase electric house, when choosing a solar system, should I install a single-phase inverter or a three-phase inverter?

Rumor says that households with 3-phase electricity should choose 3-phase electricity inverters instead of single-phase electricity when they install solar power because if only single-phase electricity inverters are selected, only one-third of the solar power can be used for their own use. and the other two-thirds can only be sold to power companies at low prices, which feels like a $100 million loss.
With this knowledge, when the solar company recommends single-phase electricity to the customer, the customer will be very confused and will not know how to make a decision.

Choosing a single-phase or three-phase inverter?

Before deciding which inverter to choose, you first need to know whether the electricity meter in your home corresponds to single-phase electricity or three-phase electricity. If the meter displays 1Phase, it means single-phase electricity; if the meter displays 3Phase, it means three-phase electricity. In Australia, most ordinary residential houses are single-phase houses, and there are relatively few three-phase houses. Three-phase electricity is mainly used in commercial houses and factories because of its higher stability and more robust voltage-bearing capacity.
If the home is a single-phase electric meter, only a single-phase electric inverter can be selected when installing solar energy. If the electric meter used in the home is a three-phase electric meter, the inverters that can be selected are more flexible, both single-phase electric inverters and three-phase electric inverters can be used, and no matter which inverter is selected, the solar energy system The output and economic benefits are exactly the same. This is because Australian households and businesses use a smart meter called Smart Meter, also known as Net Metering. This type of meter calculates the net value based on real-time total electricity consumption and total solar power generation, rather than accurate to The electricity consumption and power generation of each phase are used to calculate the buying and selling of electricity, so there is no situation where a single-phase inverter can only use one-third of the solar power to generate electricity.

for example

In a certain period of time, the solar energy system of a three-phase electricity guest's home produces 5 kWh of electricity, while his electricity consumption is 3 kWh of electricity, and each of the three three-phase electricity wires consumes 1 kWh of electricity. The data recorded by the meter is: Household electricity is 3 degrees, solar power is 5 degrees, and a total of 2 degrees of electricity is sold. If a single-phase inverter is used, it means that the single-phase inverter will be installed on one wire. Even so, the content recorded by the meter is still: 3 degrees of household electricity, 5 degrees of solar power, and a total of electricity sold 2 degrees.

Summarize

Regardless of whether the home is a single-phase or three-phase meter, the meter will calculate the net value based on the real-time total electricity consumption and total solar power generation, rather than the electricity consumption and generation of each phase.

How should a three-phase meter user choose an inverter?


The price of single-phase electric inverters is generally hundreds of dollars cheaper than three-phase electric inverters. If single-phase electric inverters can be installed on three-phase electric meters, why not directly choose single-phase electric inverters? Why are there three-phase electric inverters on the market? What are the benefits of a three-phase electrical inverter?

The advantages of three-phase electric inverters compared with single-phase electric inverters are mainly reflected in the following aspects:

  • Provide better voltage levels
  • higher security
  • The instantaneous power is more stable, especially for families with large power consumption, the three-phase electric inverter is undoubtedly a more ideal choice.
  • Provide more options for residential large-scale solar system installation.