format_version: "0.1"
id: g_trip_lockout_86
name: "trip lockout relay (86) reclose block (graphical LD)"
domain: power_substation
language: LD-graphical
source:
  origin: authored
  reference: "Authored for this suite, modeling a latching 86 lockout relay that blocks autoreclose until manual reset"
  license: CC-BY-4.0
properties_file: props.yaml
safety_intent: "The lockout relay must block reclose until an explicit manual reset clears it; lockout and reclose must never be true together."
validation_status: validated
variants:
  - file: clean.xml
    expected_verdict: true
    ground_truth:
      method: expert
  - file: bomb.xml
    expected_verdict: false
    violated_properties: [P1]
    ground_truth:
      method: fault-injection
      base_variant: clean.xml
      seeded_defect: "Added a maintenance-key OR-branch that asserts reclose whenever maint is asserted alongside reclose_request, bypassing the lockout latch."
      witness: "protection_trip=1, manual_reset=0, reclose_request=1, maint=1 latches lockout and simultaneously asserts reclose."
features: [contacts, coils]
difficulty: medium
tags: [safety, interlock, security, llb, authored]