Have you noticed that your inverter seems to trip frequently, or that it’s reducing power on over-voltage. While it may seem like your inverter has a mind of its own, there’s actually a simple explanation.
According to Australian Standards, an inverter must immediately disconnect from the grid, or ‘trip’, if the AC voltage over any 10-minute period exceeds 255V, or the voltage at any time exceeds 258V. If you see an over-voltage error when your inverter trips, then your inverter has not complied with one or both of these standards.
Another common problem isn’t that the inverter disconnects, but that it goes into a power reduction mode. This happens when the voltage isn’t quite high enough to trip the inverter, i.e. you haven’t broken one of the rules outlined above, but the voltage is still at a concerning level. To cope, your inverter might reduce its power output, something that’s called ‘volt-watt response mode’.
It’s important to realise that your system isn’t doing this randomly, or just to annoy you. These are safety features that have been designed to maintain your grid and avoid any potentially dangerous situations that can result from excessive voltage.
If you’re seeing tripping or power reduction frequently, then it may be that your grid is not complying with Australian Standards. 230V should be the standard voltage with a +10%, -6% range, meaning it should not go above 253V. If it is tripping, then you’re seeing voltages of over 258V. Contact your local distribution network service provider, who should immediately come and fix the issue.
There is also another culprit, and that’s if your local grid sits just under the limit, and your system pushes it over. A voltage rise can occur at the point of common coupling, due to the electrically resistant nature of the cable. The maximum voltage rise allowed in Australia is 2%. This could be all it takes to push you over the edge and trip the inverter. The larger the cable running from your meter box to the connection of your inverter the lower risk you have of encountering this issue. The most common place for this to occur is typically when a customer request we install a solar system on their existing shed. More often than not, there is only a very small power feed supplying the shed with power for very small loads. A solar system can send back quite an amount of power at times and small power feeds really struggle with sustaining this and then that leads to Voltage Rise.
To diagnose your particular issue, ask an electrician to test your local grid voltage while the solar system is off. If the voltage is still high, when the system is off, on a sunny day mid-afternoon, then you might have an issue. You may need to get your electrician to record both the instantaneous reading, as well as the 10-minute average, and then take these findings to your local distribution network service provider for further support.
If you would like to learn more about this our team of trained professionals are always more than happy to assist. You can call our office on (08) 7127 0752 or email our team anytime at firstname.lastname@example.org