How does grid islanding work? - Page 1
Forum section: electronics / beginners

author: rthorntn
author_rank: Frequent Contributor
timestamp: January 06, 2020, 09:50:43 am
content: Hi,How does grid islanding work and why do so few inverters support it, complexity, compliance?Is it possible to put a gizmo between the grid and your old "anti-islanding" inverter to replicate what the new hybrid inverters are doing to save you replacing a perfectly fine inverter just to get grid islanding?I get the feeling that the grid will get more unstable as time goes on, it's batteries and islanding for me but I still want the grid for power hungry devices.Thanks.Richard

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 07, 2020, 06:21:54 pm
content: There are many ways to do this and there are several different set's of regulations around the world such that most devices have to have either different firmware or a switch selection (hidden from the user) to achieve compliance in different places. I refer you tohttps://en.wikipedia.org/wiki/Islandingfor some methods.

author: CRCLARKE
author_rank: Contributor
timestamp: January 07, 2020, 10:01:24 pm
content: Islanding occurs when your power source stays online after the grid goes off line. when this happens you are feeding a voltage back that gets equally stepped up to a line that is supposed to be dead, this can be very dangerous for repair men and equipment. luckily this is pretty difficult do because there are 2 main types of inverters/gen-sets. there are grid tie and stand alone setups. grid tie units require the presence of grid power to align the sine wave to. with out it the inverter or gen-set will not function. and thus avoids islanding. stand alone units cannot be directly connected to the grid because they have no way to align sine waves and would liked be damaged right away. instead they require a disconnect relay that switches when the grid goes down. but of coarse if you were to directly connect a stand alone unit to the grid while the power is out you could achieve that dangerous islanding situation.

author: rthorntn
author_rank: Frequent Contributor
timestamp: January 07, 2020, 10:22:00 pm
content: Thanks, the wikipedia explains anti-islanding, in the case of "microgrid" or "level 3 hybrid" inverters, they allow you to island so that if the grid goes down your panels can continue to power your home, why do so few inverters support this, complexity, compliance?Is it possible to put a gizmo between the grid and your old "anti-islanding" inverter to replicate what the new hybrid inverters are doing to save you replacing a perfectly fine inverter just to get microgrid?Could the gizmo "pass through" voltage, frequency and phase to the old inverter when the grid was up, if the grid goes down the gizmo detects this and disconnects from the grid and "spoofs" a voltage, frequency and phase to the old inverter, or you could just defeat or disable the anti-islanding on the old inverter?

author: CRCLARKE
author_rank: Contributor
timestamp: January 07, 2020, 11:02:55 pm
content: https://www.magnum-dimensions.com/renewable-energy-products.https://gpelectric.com/products/50-amp-transfer-switch/check these out, though they are pretty small for hi demandmaybe it will help you......the only other way i can think to emulate a sine wave is with a small stand alone pure sine inv. that comes on and off with the auto disconnect.