How Solar Inverters Synchronize with the Grid

he move towards renewable energy continues, with more and more homes using solar power. Most are still connected to the grid, giving homeowners the option to switch between solar and electricity.

For performance and safety, it is crucial for solar array systems to be synchronized with the grid. This is made possible by the inverter, one of the most important parts of a solar powered home.

Grid based inverters rely on a synchroscope to determine the phase differential between the grid and inverter. The device is equipped with a marker and spinning disc that allows the inverter to modify its parameters and match the grid.

How Does an Inverter Sync with the Grid?

An inverter converts direct current (DC) into AC (alternating current). Solar panels produce DC so an inverter is needed to run most consumer electronics and appliances. Depending on your setup, the inverter may or may not need a battery.

However, solar inverters have another purpose: sync the solar array to the grid. There are three ways this can be accomplished.

Method 1: Synchroscope

A synchroscope is a device that calculates the difference between the grid and your renewable energy system.

By using a reference marker and a spinning disc, the synchroscope can match a fixed marker when the phases are in alignment. This enables the inverter to adjust its settings to sync with the grid.

Method 2: Three Dark Lamps

This approach uses three lamps in a parallel configuration. Once set up, the inverter modifies the lamps’ voltages until all three are off at the same time. When this occurs, the solar system and grid get synced.

Method 3: Two Bright, One Dark

In this method, three lamps are joined in a series. If there is a phase differential between the grid and solar array, the inverter reconfigures the lamps’ voltage until one goes dark and two remain bright. When this is attained, the inverter and grid are synchronized.

For this to work, your solar system needs a high quality inverter. My choice is the SL Euthtion 3000W inverter as it is designed specifically for home use.

Why Grid Inverter Synchronization is Needed

Grid synchronization means matching a renewable energy source (in this case a solar power system) with the grid.

The grid (power grid, utility grid) refers to the power lines and other components that supply electricity to homes, buildings and industries.

There are many reasons why synchronization is needed:

Prevent back feeding. Back feeding happens when electricity generated by solar panels goes into the grid. This carries a risk to power line workers who could get electrocuted.

Improves performance. Synchronization improves the performance of the solar system and energy grid. This reduces the need to use fossil fuels and other energy sources.

Minimizes energy losses. Grid tied solar systems transfer power back and forth. When the system is in synced, the phase, voltage and frequency run more efficiently,

How Grid Synchronization Works

There are two kinds of solar power systems: on and off grid. Off grid solar systems are not connected to any grid power source.

Most American homes are tied to the grid, allowing the homeowner to switch between solar and traditional electricity. Synchronization is needed for this mechanism to work.

Regardless how your home solar panel system is set up, it has to integrate and move in conjunction with the power infrastructure.

This infrastructure, known as the utility grid, power grid or grid, consists of the power transmission lines, cables, substations, transformers and electrical components that supply power to residential homes.

Your home renewable energy system (solar in this case) has to be aligned to this grid to run efficiently. Once the inverter synchronizes your solar system to the grid, power transfer becomes seamless.

Synchronization only takes place when the right conditions are met. The phase angle, sequence, voltage and frequency must all be in alignment.

Benefits of Grid and Solar Inverter Synchronization

All grid tied solar panels are required to be in sync with the system. This is necessary for safety and performance reasons.

Solar inverters are critical because they are the devices that sync the solar system to the utility grid. The phase, voltage, frequency and other properties have to be aligned properly.

When the solar array and utility grid are aligned, the output voltage and frequency always match. The inverter also adjusts its output in line with what the solar panels are producing.

A synchronized energy system is more stable. To match the grid phase for instance, the inverter can check its frequency and make the necessary adjustments.

Aside from safety and optimum performance, synchronized power systems also reduces your monthly utility bill. Solar panels perform better when the system is aligned, and the more you rely on solar, the less you pay to the utility company.

Grid Tied Solar Inverters vs. Standard Off Grid Inverters

Grid tied inverters and regular inverters share functions, but there are also major differences.

Grid Tied Inverters

A grid tied inverter turns solar DC into AC so it can be used by appliances or sent to the power grid. This device can be set between the grid and a power generator.

Because these inverters can transmit electricity into the grid, they have to match its phases, voltage and frequency. Any excess solar power your system generates is sent to the grid, and you can get financial incentives for this.

A grid tied inverter can run your home through solar panels or the grid. It can switch back and forth and make the necessary adjustments.

Standard Inverters

Regular off grid inverters also convert direct current into alternating current. But it cannot synchronize with the grid.

Off grid inverters are so-called because they are not connected to any. While most homes are grid tied, others are 100% reliant on solar power or other renewable energy sources.

In an off grid solar array, there are four main components: solar panels, inverter, batteries and charge controllers.

In a typical off grid solar array, solar panel power is stored in the battery. The inverter converts solar power into AC before transmitting it to appliances. The charge controller is a device that keeps the battery from overloading.

Related Questions

What happens if my inverter does not sync with the grid?

State laws require grid tied solar panels to synchronize with the electric infrastructure it is connected to. Before you can use a solar panel system, its inverter has to be aligned with the grid. Your solar panel installer can do this for you.

If your inverter malfunctions and no longer syncs, it cannot supply electrical power to your home.

Can grid tied solar panels run in case of a power outage?

No. In case of a power outage your solar panels will shut down automatically. Whether it’s day or night, you won’t be able to use it if the grid fails.

All grid tied solar panels work like this to avoid back feeding. It is also necessary to protect utility personnel repairing the grid. If solar panels were turned on, the electricity could hurt the workers.

What happens if my solar panels produce more power than I use?

The extra power goes into the grid and you earn credit for it. This can mean a reduction in your monthly bill or cash. States offer various incentives for homes that run on solar power, so check what is available in your area.

Are grid tied inverters reliable?

Yes. Grid tied inverters have improved over the years and are now built to run for years. If you have a grid tied solar array, it is easy to move back and forth between solar power and the grid.

Solar production fluctuates: on sunny days the panels can reach peak output. On cloudy days it’s going to be lower. At nights you don’t get production at all.

With a grid tied system you can go back to regular electricity when solar is not sufficient. When there’s enough solar power, the inverter can shift into it.