{"schemaVersion":1,"slug":"grid-following-inverter","name":"Grid-following inverter","kind":"symbol","abbreviation":"GFL","aliases":["GFL inverter","current-source mode inverter","grid-tied inverter"],"category":"microgrid-systems","drawingTypes":["SLD"],"referenceFamilies":["IEC","IEEE / ANSI"],"summary":"An inverter that tracks an existing network voltage with a phase-locked loop and injects controlled current into it.","description":["A grid-following inverter measures the network voltage, locks to it with a phase-locked loop and injects a controlled current. Most rooftop and utility-scale solar inverters work this way. They need a stable voltage from the grid, a synchronous machine or a grid-forming inverter to operate, and they disconnect when that reference is lost.","Drawings use the standard inverter symbol with a GFL note or a current-source annotation. Anti-islanding protection, often shown as a protection relay or a function list, is associated with this type so that it does not energise a dead network.","In weak networks with high converter penetration, grid-following control can become unstable, so system strength studies are needed. The symbol does not show the phase-locked loop settings or the reactive power mode."],"readingNotes":["Check that a forming source exists if the inverter is expected to run in an island.","Anti-islanding settings are often listed as protection functions next to the inverter."],"drawingChecklist":["State reactive power mode and ride-through settings.","Show anti-islanding protection.","Reference system strength assessment."],"distinction":"A grid-following inverter needs an external voltage reference; a grid-forming inverter provides that reference.","facts":[{"label":"Control behaviour","value":"Current source synchronised by PLL"},{"label":"Islanding","value":"Disconnects without external reference"},{"label":"Typical use","value":"Solar and wind plant inverters"},{"label":"Preview","value":"Independent educational illustration; consult the applicable standard and project legend for the exact graphic"}],"references":[{"sourceId":"pub-symbol-pv-inverter","relevance":"Public photovoltaic inverter function context."},{"sourceId":"expansion-20261027-pv","relevance":"Public solar electrical system architecture context."}],"related":["grid-forming-inverter","photovoltaic-inverter","pv-string-inverter","27t-low-voltage-ride-through-supervision"],"artwork":"s28-grid-following-inverter","publishedOn":"2026-10-28","updatedOn":"2026-10-28","provenance":"independent-public-research","plainEnglish":{"title":"What does Grid-following inverter mean?","introduction":"A grid-following inverter measures the network voltage, locks to it with a phase-locked loop and injects a controlled current. Most rooftop and utility-scale solar inverters work this way. They need a stable voltage from the grid, a synchronous machine or a grid-forming inverter to operate, and they disconnect when that reference is lost.","example":"Drawings use the standard inverter symbol with a GFL note or a current-source annotation. Anti-islanding protection, often shown as a protection relay or a function list, is associated with this type so that it does not energise a dead network.","drawings":"In weak networks with high converter penetration, grid-following control can become unstable, so system strength studies are needed. The symbol does not show the phase-locked loop settings or the reactive power mode.","terms":[{"name":"Coil","meaning":"A wound conductor that can produce a magnetic field when energised."},{"name":"Phase","meaning":"One of the related AC waveforms in a power system."},{"name":"Rating","meaning":"A value stating the conditions for which equipment is specified."}],"diagram":"flow","steps":["Identify the device and form","Read the connections and state","Check the equipment reference"],"caption":"A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.","sources":[{"label":"Photovoltaic technology and inverter functions","url":"https://www.electrical-installation.org/enwiki/Photovoltaic_background%2C_technology"},{"label":"Solar electrical system architecture","url":"https://www.ti.com/applications/industrial/energy-infrastructure/solar-energy/overview.html"}],"detail":"An inverter that tracks an existing network voltage with a phase-locked loop and injects controlled current into it. A grid-following inverter needs an external voltage reference; a grid-forming inverter provides that reference.","profileId":"reviewed-symbol-20261028"},"url":"https://eloragrid.ai/symbols/grid-following-inverter","illustration":{"url":"https://eloragrid.ai/tools/electrical-library/illustrations/grid-following-inverter.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"pub-symbol-pv-inverter","title":"Photovoltaic technology and inverter functions","publisher":"Schneider Electric","url":"https://www.electrical-installation.org/enwiki/Photovoltaic_background%2C_technology","type":"manufacturer","scope":"Public manufacturer explanation of the equipment function and selection context.","checkedOn":"2026-10-13","reuse":"link-only","relevance":"Public photovoltaic inverter function context."},{"id":"expansion-20261027-pv","title":"Solar electrical system architecture","publisher":"Texas Instruments","url":"https://www.ti.com/applications/industrial/energy-infrastructure/solar-energy/overview.html","type":"manufacturer","scope":"Public functional documentation. Original explanatory text and educational block artwork; no publisher graphics or files reproduced.","checkedOn":"2026-10-27","reuse":"link-only","relevance":"Public solar electrical system architecture context."}]}