What is anti-islanding protection?

Anti-islanding protection is a way for the grid-connected solar inverter to sense when there is a problem with the utility grid, such as a power outage, and shut itself down to stop feeding solar power to the grid. Anti-islanding systems protect mainly people on the network side, such as engineers fixing the network issues. Without islanding protection, the solar system feeds the electricity to the grid.

Anti-islanding protection is a mandatory safety feature that is built into all grid-tied and hybrid inverters that operate in India and various other countries across the globe including US, Germany, etc. This protection feature is required because in case of power failure or outage the utility needs the power lines to be completely safe for maintenance.

Some of the regulatory requirements in India for anti-islanding are as follows:

  • according to IEEE 1547 and  Central Electricity Authority of India (technical standards for connectivity of the distributed generation resources) Regulation 2013 – for an unintentional island the grid-tied inverter shall detect the island and cease to energise within two seconds of the formation of an island.
  • according to IEEE 1547 the grid-connected rooftop solar system shall include an adjustable delay (or a fixed delay of five minutes) that may delay re-connection for up to five minutes after the grid voltage and frequency is restored. As per Central Electricity Authority of India Regulation, 2013 the delay shall be for at least 60 seconds.


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