​What Is a Grid-Tied Inverter? Explained

A grid-tied inverter, also known as a grid-connected or on-grid inverter, is a critical device that connects solar panels to the utility grid. Its primary function is to convert the direct current (DC) generated by solar panels into alternating current (AC) for home or business power supply.

 

A solar panels, also known as a grid-connected or on-grid inverter, is a critical device that connects solar panels to the utility grid. Its primary function is to convert the direct current (DC) generated by solar panels into alternating current (AC) for home or business power supply. But how is a grid-tied inverter different from other types of inverters?

A key feature of a grid-tied inverter is its seamless integration into the utility grid. Unlike off-grid inverters, grid-tied inverters do not require energy storage solutions such as batteries. Instead, they are synchronized with the grid, allowing excess power generated by solar panels to flow back into the grid. This excess energy will be credited to your account, effectively "reversing the meter" on a sunny day, ultimately lowering your electricity bill.

 

How long does a grid tie inverter last?

 

The lifespan of a grid-tied inverter largely depends on its quality, installation, usage, and maintenance. Nonetheless, on average, a well-maintained grid-tied inverter can last for around 10 to 15 years, or even longer with excellent care.

 

Operation

A grid-tied inverter converts direct current into alternating current suitable for input into the utility's grid. The grid-tied inverter (GTI) must be phase-matched to the grid and keep the output voltage slightly above the grid voltage at all times. High-quality modern grid-tied inverters have a fixed unit power factor, which means that their output voltage and current are perfectly matched, and their phase angle is within 1° of the AC grid. The inverter has a built-in computer that senses the current AC grid waveform and outputs a voltage consistent with the grid voltage. However, it may be necessary to supply reactive power to the grid to keep the local grid voltage within the allowable range.

 

The design of the grid-tied inverter allows it to be quickly disconnected from the grid in the event of a failure of the utility grid. The National Electrical Code (NEC) states that in the event of a power outage, grid-tied inverters must be shut down to prevent the electricity they generate from causing harm to those who are repairing the grid.

Properly configured, grid-tied inverters allow buildings to use alternative power generation systems such as solar or wind without extensive rewiring and without the need for batteries. If the system does not generate enough electricity, the utility grid will make up for the shortfall.

 

 

8kw-12kw Grid-tied inverter

 

Types of Grid-tied inverters

 

Grid-tied inverters include traditional low-frequency (with transformer-coupled) inverters, new high-frequency (also with transformer-coupled) inverters, and transformerless inverters. Instead of directly converting direct current to alternating current suitable for the grid, high-frequency transformer inverters use computer programs to convert electrical energy into high-frequency electricity, which is then converted to direct current, and finally to an AC output voltage suitable for the grid.

 

Transformerless inverters are popular in Europe and are lighter, smaller, and more efficient than inverters with transformers. However, the entry of transformerless inverters into the U.S. market has been slow due to concerns that there is no electrical isolation between the DC side of the transformerless inverter and the grid, which could inject dangerous DC voltages and currents into the grid in the event of a fault.

 

However, since 2005, NFPA's NEC standard has removed the requirement that all solar power systems must have a negative electrode grounded and has imposed new safety requirements, allowing the use of transformerless (or non-galvanically isolated) inverters. The revisions of VDE 0126-1-1 and IEC 6210 define the design and procedures required for such systems: mainly earth current measurement and DC grid isolation tests.

 

Advantages of grid-tied inverters

 

Grid-tied inverters have a number of advantages that make them a popular choice for many solar enthusiasts:

 

Cost-effective: Grid-tied systems are often more cost-effective to install than off-grid or hybrid systems because they do not require expensive battery packs.
Reduce your electricity bills: By generating electricity and selling excess energy back to the grid, a grid-connected system can significantly reduce your monthly electricity bill.

Low maintenance: Grid-tied inverters require minimal maintenance compared to off-grid systems with batteries, which makes them an effective option for homeowners.
Sustainability: By using renewable solar energy, grid-connected systems can reduce their carbon footprint and contribute to building a greener planet.

 

If you're looking to maximize cost savings and reduce upfront costs while maintaining grid connectivity, a grid-tied inverter is the way to go. As with any big decision, consulting with a solar professional can help you find the ideal system that best meets your unique needs.

 

At Zhong Yu, we are committed to helping you make informed decisions about your solar journey. Get in touch with our design team and let's explore the possibilities of clean, renewable energy. The potential of solar energy is limitless, and with a grid-tied inverter, you can make the most of its unlimited energy and contribute to a better future.