Will Solar work in a power cut?

The sun is shining and your solar cells are supplying all the power you need, and then your grid connection suffers a power cut. You are laughing right? Wrong! In most cases your solar will switch off automatically when the power cut happens.

But there is a way...

Young businessman tearing electricity cable with hands
 

Why does my Solar switch off?

Some of the primary applications for energy storage were explained in an earlier blog. When a generator is cut off from the grid, but still supplying a local network, it is called an Island. Most domestic Solar PV systems are installed with anti-Islanding equipment designed to detect when grid power is lost and then immediately disconnect the local generator.

This is for a few reasons:

  • Safety. If there was a power cut and someone is looking to fix the problem, it is dangerous if a local network is still supplying mains power (although in reality, this is not considered much of an issue as electrical workers are used to coping with unexpectedly energised lines).
  • Reconnect problems. There are concerns that automated grid systems for reconnecting lines after an outage may be confused or cycle on and off due to anomalous power readings.
  • Frequency/voltage problems. If a generator is Islanded and then wants to reconnect to the grid, it must be able to synchronise frequency and voltage with the grid.

 

Is there a way to keep my Solar on?

Yes there is, but perhaps not surprisingly it is a little more complex and costs a bit more. The key problem is the frequency/voltage one.

The Inverter in island mode must maintain the 240v/50Hz of the grid so that household goods can run efficiently. However, it is inevitable that it will diverge from the grid system, so it needs a way to sense the grid frequency and align itself on reconnection.

 

Practical Home Systems

At Fuel Included we use Victron Inverters when someone has a need for full Islanding. For example the Victron Quattro. A useful overview of Victron Energy Storage Systems (Solar + Battery) can be found here

20180914_Viktron_Quattro_JTisdallVictron Quattro Inverter

As mentioned in this blog, we recently added the BYD B-Box battery to our supported supplier list, and this is a great fit for the Quattro for a high performance Island-capable system.

20180807_BYD_B-Box-Pro_JTisdall

BYD B-Box Pro 10 kWh Battery

 

Can Generators Help?

If off-grid power is an important consideration, then your energy storage system can be augmented with a generator. This can be configured to auto start in certain conditions so giving you a balanced off-grid alternative with automatic fail-over.

 

If you are interested in Islanding or our new battery range, please follow this link and write your particular interest in the notes field.

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