{"schemaVersion":1,"slug":"station-bus-supervisory-interface","name":"Station-bus supervisory interface","kind":"symbol","abbreviation":"SSI","aliases":["Digital substation process interfaces","substations Digital substation process interfaces","substations","Substations","Station IED data","Station supervisory communications"],"category":"measurement-protection","drawingTypes":["Schematic"],"referenceFamilies":["Manufacturer"],"summary":"Carries the documented station-level monitoring and control data distinct from the process measurement stream.","description":["Carries the documented station-level monitoring and control data distinct from the process measurement stream. Digital substation interfaces carry measurements, status and control information between primary equipment and protective devices. Measurement streams, event messages and time synchronization are separate dependencies even when they share an Ethernet network.","In a digital substation bay, a merging unit digitizes local measurements and a protective relay subscribes to the assigned data stream. The command return path and communication-health indications are drawn separately. For this reference, the drawing identifies “Station IED data” at the input and “Station supervisory communications” at the output. Process bus and station bus have different functions.","Identify publisher, subscriber, data meaning and quality handling. Protocol labels alone do not establish protection performance, compatibility or network redundancy; these need the selected system configuration and validation. The functional block is an independent explanation of this named application. Equipment-specific ratings, terminal connections and operating conditions must be established in the project documentation."],"readingNotes":["Start at the named input: Station IED data. Identify its source device or document and the state represented on the drawing.","Follow the named output: Station supervisory communications. Cross-reference its destination and separate the command from confirmation that the equipment responded.","Process bus and station bus have different functions.","Identify publisher, subscriber, data meaning and quality handling. Protocol labels alone do not establish protection performance, compatibility or network redundancy; these need the selected system configuration and validation."],"drawingChecklist":["Label the source and connection reference for station ied data.","Identify the destination and defined state of station supervisory communications.","Record the equipment or control-document revision supporting this functional block.","Check this application limit in the project design: Process bus and station bus have different functions."],"distinction":"Process bus and station bus have different functions. This reference describes the named application; it does not establish a new IEC graphical symbol, an ANSI device-function number or an exact manufacturer connection diagram.","facts":[{"label":"Representation","value":"Functional block"},{"label":"Installation focus","value":"Substations"},{"label":"Input / boundary","value":"Station IED data"},{"label":"Output / connection","value":"Station supervisory communications"},{"label":"Lookup label","value":"SSI is a library lookup label, not a standard device designation."}],"references":[{"sourceId":"pi26-sampled-values","relevance":"Public technical context for digital substation process interfaces. Merging units, sampled measurements, GOOSE, process bus and network redundancy. The application text and educational graphic are independently authored; the publisher does not certify this representation."}],"related":["numerical-protection-relay","optical-fibre-cable","process-network-link-health-input"],"artwork":"pi26-station-bus-supervisory-interface","publishedOn":"2026-11-03","updatedOn":"2026-11-03","provenance":"independent-public-research","representation":{"type":"functional-block","focus":"substations","family":"digital-substation","input":"Station IED data","output":"Station supervisory communications"},"plainEnglish":{"title":"What this block does","introduction":"Carries the documented station-level monitoring and control data distinct from the process measurement stream.","example":"In a digital substation bay, a merging unit digitizes local measurements and a protective relay subscribes to the assigned data stream. The command return path and communication-health indications are drawn separately. For this reference, the drawing identifies “Station IED data” at the input and “Station supervisory communications” at the output. Process bus and station bus have different functions.","drawings":"Start at the named input: Station IED data. Identify its source device or document and the state represented on the drawing. Follow the named output: Station supervisory communications. Cross-reference its destination and separate the command from confirmation that the equipment responded.","terms":[{"name":"Input","meaning":"Station IED data"},{"name":"Output","meaning":"Station supervisory communications"},{"name":"Application reference","meaning":"An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections."}],"diagram":"flow","steps":["Station IED data","SSI","Station supervisory communications"],"caption":"A reading guide. The entry's original illustration and input/output facts describe this application.","sources":[{"label":"Digital secondary systems: Sampled Values","url":"https://selinc.com/solutions/digital-secondary-systems/sampled-values/"}],"profileId":"power-installation-digital-substation"},"url":"https://eloragrid.ai/symbols/station-bus-supervisory-interface","illustration":{"url":"https://eloragrid.ai/tools/electrical-library/illustrations/station-bus-supervisory-interface.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"pi26-sampled-values","publisher":"SEL","title":"Digital secondary systems: Sampled Values","url":"https://selinc.com/solutions/digital-secondary-systems/sampled-values/","scope":"Merging units, sampled measurements, GOOSE, process bus and network redundancy.","type":"manufacturer","checkedOn":"2026-11-03","reuse":"link-only","relevance":"Public technical context for digital substation process interfaces. Merging units, sampled measurements, GOOSE, process bus and network redundancy. The application text and educational graphic are independently authored; the publisher does not certify this representation."}]}