{"schemaVersion":1,"slug":"protection-electronics-supply-branch","name":"Protection-electronics supply branch","kind":"symbol","abbreviation":"PSB","aliases":["Switchgear control-power supervision","switchgear Switchgear control-power supervision","switchgear","Switchgear","Protected auxiliary supply","Protection-device power"],"category":"control-circuits","drawingTypes":["Schematic"],"referenceFamilies":["Manufacturer"],"summary":"Identifies the supply dedicated to the assigned protective relays and their electronics.","description":["Identifies the supply dedicated to the assigned protective relays and their electronics. Control power supplies the command, protection and indication equipment associated with a switchgear assembly. The drawing must distinguish the source, each distribution branch and the functions lost if that branch fails.","In a switchgear lineup, separate protected branches may feed trip coils, closing coils and protection electronics. Their alarm contacts help the station controller identify which operating capability is unavailable. For this reference, the drawing identifies “Protected auxiliary supply” at the input and “Protection-device power” at the output. Relay power is distinct from trip-coil power.","Follow the actual positive, negative or neutral returns and the protective device on each branch. A healthy voltage indication does not establish that every downstream path can deliver its required operating current. 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: Protected auxiliary supply. Identify its source device or document and the state represented on the drawing.","Follow the named output: Protection-device power. Cross-reference its destination and separate the command from confirmation that the equipment responded.","Relay power is distinct from trip-coil power.","Follow the actual positive, negative or neutral returns and the protective device on each branch. A healthy voltage indication does not establish that every downstream path can deliver its required operating current."],"drawingChecklist":["Label the source and connection reference for protected auxiliary supply.","Identify the destination and defined state of protection-device power.","Record the equipment or control-document revision supporting this functional block.","Check this application limit in the project design: Relay power is distinct from trip-coil power."],"distinction":"Relay power is distinct from trip-coil power. 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":"Switchgear"},{"label":"Input / boundary","value":"Protected auxiliary supply"},{"label":"Output / connection","value":"Protection-device power"},{"label":"Lookup label","value":"PSB is a library lookup label, not a standard device designation."}],"references":[{"sourceId":"pi26-station-power","relevance":"Public technical context for switchgear control-power supervision. Independent AC and DC sources for station auxiliary power. The application text and educational graphic are independently authored; the publisher does not certify this representation."}],"related":["relay-coil","ac-to-dc-power-supply","indication-lamp-supply-branch"],"artwork":"pi26-protection-electronics-supply-branch","publishedOn":"2026-11-03","updatedOn":"2026-11-03","provenance":"independent-public-research","representation":{"type":"functional-block","focus":"switchgear","family":"control-power","input":"Protected auxiliary supply","output":"Protection-device power"},"plainEnglish":{"title":"What this block does","introduction":"Identifies the supply dedicated to the assigned protective relays and their electronics.","example":"In a switchgear lineup, separate protected branches may feed trip coils, closing coils and protection electronics. Their alarm contacts help the station controller identify which operating capability is unavailable. For this reference, the drawing identifies “Protected auxiliary supply” at the input and “Protection-device power” at the output. Relay power is distinct from trip-coil power.","drawings":"Start at the named input: Protected auxiliary supply. Identify its source device or document and the state represented on the drawing. Follow the named output: Protection-device power. Cross-reference its destination and separate the command from confirmation that the equipment responded.","terms":[{"name":"Input","meaning":"Protected auxiliary supply"},{"name":"Output","meaning":"Protection-device power"},{"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":["Protected auxiliary supply","PSB","Protection-device power"],"caption":"A reading guide. The entry's original illustration and input/output facts describe this application.","sources":[{"label":"SEL-RPM redundant power module","url":"https://selinc.com/products/RPM/"}],"profileId":"power-installation-control-power"},"url":"https://eloragrid.ai/symbols/protection-electronics-supply-branch","illustration":{"url":"https://eloragrid.ai/tools/electrical-library/illustrations/protection-electronics-supply-branch.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"pi26-station-power","publisher":"SEL","title":"SEL-RPM redundant power module","url":"https://selinc.com/products/RPM/","scope":"Independent AC and DC sources for station auxiliary power.","type":"manufacturer","checkedOn":"2026-11-03","reuse":"link-only","relevance":"Public technical context for switchgear control-power supervision. Independent AC and DC sources for station auxiliary power. The application text and educational graphic are independently authored; the publisher does not certify this representation."}]}