{"schemaVersion":1,"slug":"single-pole-trip-selection-block","name":"Single-pole trip selection block","kind":"symbol","abbreviation":"STSB","aliases":["Substation protection scheme interfaces","substations Substation protection scheme interfaces","substations","Substations","Phase-selective protection decision","Selected pole trip request"],"category":"measurement-protection","drawingTypes":["Schematic"],"referenceFamilies":["Manufacturer"],"summary":"Routes the assigned fault decision to its identified phase operating output.","description":["Routes the assigned fault decision to its identified phase operating output. A protection scheme combines measurements, decision elements and communication or trip outputs to protect a defined part of the network. A function number names a job; the scheme interface shows how that job connects to other equipment.","In a substation feeder bay, local current and voltage measurements may combine with a remote-end signal before the protection issues the assigned trip request. Backup actions use their own defined initiations and supervision. For this reference, the drawing identifies “Phase-selective protection decision” at the input and “Selected pole trip request” at the output. The breaker must support the operating arrangement.","Keep each protected zone, initiating quantity, blocking signal and trip destination distinct. Settings, communication performance and coordination require the approved protection study and selected relay documentation. 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: Phase-selective protection decision. Identify its source device or document and the state represented on the drawing.","Follow the named output: Selected pole trip request. Cross-reference its destination and separate the command from confirmation that the equipment responded.","The breaker must support the operating arrangement.","Keep each protected zone, initiating quantity, blocking signal and trip destination distinct. Settings, communication performance and coordination require the approved protection study and selected relay documentation."],"drawingChecklist":["Label the source and connection reference for phase-selective protection decision.","Identify the destination and defined state of selected pole trip request.","Record the equipment or control-document revision supporting this functional block.","Check this application limit in the project design: The breaker must support the operating arrangement."],"distinction":"The breaker must support the operating arrangement. 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":"Phase-selective protection decision"},{"label":"Output / connection","value":"Selected pole trip request"},{"label":"Lookup label","value":"STSB is a library lookup label, not a standard device designation."}],"references":[{"sourceId":"pub-function-sel-line","relevance":"Public technical context for substation protection scheme interfaces. Line protection, breaker failure, communications and protection coordination. The application text and educational graphic are independently authored; the publisher does not certify this representation."}],"related":["50bf-circuit-breaker-failure-protection","87b-busbar-differential-protection","three-pole-trip-conversion-block"],"artwork":"pi26-single-pole-trip-selection-block","publishedOn":"2026-11-03","updatedOn":"2026-11-03","provenance":"independent-public-research","representation":{"type":"functional-block","focus":"substations","family":"protection-schemes","input":"Phase-selective protection decision","output":"Selected pole trip request"},"plainEnglish":{"title":"What this block does","introduction":"Routes the assigned fault decision to its identified phase operating output.","example":"In a substation feeder bay, local current and voltage measurements may combine with a remote-end signal before the protection issues the assigned trip request. Backup actions use their own defined initiations and supervision. For this reference, the drawing identifies “Phase-selective protection decision” at the input and “Selected pole trip request” at the output. The breaker must support the operating arrangement.","drawings":"Start at the named input: Phase-selective protection decision. Identify its source device or document and the state represented on the drawing. Follow the named output: Selected pole trip request. Cross-reference its destination and separate the command from confirmation that the equipment responded.","terms":[{"name":"Input","meaning":"Phase-selective protection decision"},{"name":"Output","meaning":"Selected pole trip request"},{"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":["Phase-selective protection decision","STSB","Selected pole trip request"],"caption":"A reading guide. The entry's original illustration and input/output facts describe this application.","sources":[{"label":"SEL-411L line differential protection overview","url":"https://selinc.com/products/411l/"}],"profileId":"power-installation-protection-schemes"},"url":"https://eloragrid.ai/symbols/single-pole-trip-selection-block","illustration":{"url":"https://eloragrid.ai/tools/electrical-library/illustrations/single-pole-trip-selection-block.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"pub-function-sel-line","title":"SEL-411L line differential protection overview","publisher":"Schweitzer Engineering Laboratories","url":"https://selinc.com/products/411l/","type":"manufacturer","scope":"Public explanation of communication-assisted line current differential protection and the associated terminal measurements. Product diagrams and technical papers remain on the publisher site.","checkedOn":"2026-10-13","reuse":"link-only","relevance":"Public technical context for substation protection scheme interfaces. Line protection, breaker failure, communications and protection coordination. The application text and educational graphic are independently authored; the publisher does not certify this representation."}]}