Is a Three Phase Solar Inverter What You Need?

Recently here at Qld Solar & Lighting we have been informed that inquiries have been made by clients whose properties are fitted with 3 phase power; they have been informed that to suit this they must have a 3 phase solar inverter. This article is to address these inquiries.

Is a Three Phase Solar Inverter Necessary?

This answer can vary from case to case. There are some benefits to having a three phase solar inverter but in comparison with a single phase solar inverter it is much more expensive. Being as the price is higher it is important to ensure that the benefits you will obtain will be worth your expense.

The Benefits of Three Phase Solar Inverters

The primary benefit of a three phase solar inverter is that the solar power they convert into AC power is then equally distributed over all three phases of the property. Let’s say a single phase solar inverter of five kilowatt operating at maximal capacity would distribute five kilowatts of solar energy to one phase, however a three phase five kilowatt solar inverter in the very same situation would equally distribute into all three phases. If you do the math and divide five kilowatts into three phases you will come up with 1.7 kilowatts so each phase will be distributed 1.7 kilowatts of solar energy.

This is crucial to solar inverter systems that are six kilowatts or larger being as if all the energy is being directed to only one phase it may be an overload for the single phase and cause the loading of the phases to be unbalanced. If a solar power system has an inverter of five kilowatts or less this is not usually a concern due to the fact that five kilowatts of power being directed into one phase is not generally an issue. The reason I say not generally is due to the fact that certain smaller power systems of three to five kilowatts can sometimes require a three phase solar inverter.

Three Phase Solar Energy and Self Consumption of Solar Energy

A question that comes up quite often is how does solar self consumption function with single power and three phase power solar inverters, this question in itself can take an entire page to explain. The answer to this question can be found in the next article which is entitled “Three Phase Power: Solar Distribution in Rates — Is a 3 Phase Solar Inverter Needed?

As explained earlier the primary benefit of a 3 phase solar inverter is the power is distributed throughout your property via all three phases. There are however occasions when a single phase three to five kilowatt inverter will not function; better said it will function well with conditions of low light but in perfect conditions will turn out faulty. One of the most frustrating situation is having your solar power system which should be generating at its best generating nothing at all. This situation is brought on because of the resistance of the main power cables located on your property.

How Does a Grid Connect Inverter Feed Energy?

Energex uses on the Gold Coast A grid connected solar energy the Atlas EDMI 3 phase meter which converts the DC solar energy from your roof into AC power in the most efficient way possible this is the distributed to the switchboard on your property. Stated simply put the inverter forces the energy through the properties power cables the more energy that has to be forced through the more strength is needed.

Take the water pipe into consideration, if the amount of water that is needed to flow through the pipe then the amount of pressure required is minimal; if a large amount of water is needed to flow through the same pipe then the amount of pressure needed will be greater.

A solar inverter works the same way; if a lot of energy must be distributed through small cables or said cables cover long distances more pressure is added to distribute the power, this is done so by raising the voltage of the AC.

The AC voltage is under constant monitoring by the grid connectors; if the voltage raises too much then it is automatically shut down if the cables are too small or cover to long of a distance this can occur even when it should be generating at its best.

In a situation such as the one described above by using a 3 phase solar inverter the energy being pushed through each phase will be cut by a third; in other words a 3 phase inverter does not have to work as much as a single phase inverter of the same capacity. If the inverter does not have to push as hard then the voltage will not go up to the extreme that it must be shut down by the inverter.

This is only a problem if the solar power system of three to five kilowatt systems is located far away from the street power lines and or if the power cables of the AC inverter connecting back to the power lines in the street are too small.

If you are located in a rural area where the property is far from the power lines in the street then a site inspection is highly recommended; this way we can make a qualified assessment and decide whether your property would need a 3 phase solar inverter or if a single phase one will suffice. Through an inspection we are able to calculate the amount of voltage which could be expected to rise as well as how efficiently a system would run on your property.

In Conclusion:

On a rural property where the installation of a solar energy system may have to be done at a distance from the street power lines a three to five kilowatt 3 phase solar inverter would be necessary. The reason being is that the inverter may have to increase the voltage over its limits to force the power that is being directed back to the street. Whether or not this is necessary can only be determined by inspecting the site which can be done by one of our qualified experts here at Qld Solar & Lighting.

 

Read more about Single phase inverters on a 3phase property.