{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.flexible-ac-transmission-system","code":"thing-q551118","url":"https://ver.cy/models/thing/q551118/","name":"flexible AC transmission system","alternateNames":["Static Synchronous Compensator","Unified Power Flow Controller","static VAR compensator"],"kind":"thing","status":"published","version":"0.1.0-research.1","language":"en","classifiers":{"family":"Thing Registry","category":"Physical world and living systems","entryKind":"thing","plane":"PHY","domain":["PHY.OBJ"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"A flexible AC transmission system (FACTS) is an alternating-current power transmission system incorporating power-electronic and other static controllers to improve controllability and increase usable power-transfer capability.","purpose":"Enable an AI agent to recognise a flexible AC transmission system, assess its available network-control capability, and identify interventions permitted by its operating limits and authority.","scope":{"in":["Classification by shunt, series or combined connection and controlled electrical quantity.","Power-electronic compensation equipment and associated coupling, filtering, cooling and auxiliary systems.","Voltage support, reactive-power exchange, impedance adjustment and power-flow control where supported by the architecture.","Control modes, network interfaces, operating limits and protection states.","Condition evidence, maintenance dependencies and installation-specific acceptance requirements."],"out":["The complete transmission network and its dispatch or expansion planning.","HVDC transmission links as independently modelled transmission systems.","Generator and energy-storage assets beyond their interfaces to the FACTS installation.","Standalone component designs for transformers, capacitors, reactors and semiconductor valves.","Manufacturer product families and individual asset histories as separate registry kinds."],"boundaries":[]},"distinguishingFeatures":["The controlled network connection serves AC transmission; an internal DC link alone does not make the installation an HVDC transmission link.","Its architecture identifies controllable electrical compensation and the quantity it changes, rather than merely using the label 'grid stabilisation'.","A shunt SVC supports dynamic voltage control through reactive compensation; identifying this mechanism distinguishes it from equipment that only measures voltage. See [Hitachi Energy SVC](https://www.hitachienergy.com/us/en/products-and-solutions/facts/static-var-compensation-svc).","Series compensation acts through the transmission path, whereas shunt compensation connects at a bus; topology must establish which capability is actually present.","The adopted FACTS definition must be explicit: commercial portfolios can include synchronous condensers and mechanically switched compensation, so the marketing label alone does not settle membership. See [Siemens Energy FACTS portfolio](https://www.siemens-energy.com/global/en/home/products-services/product-offerings/flexible-ac-transmission-systems.html)."],"structure":{"bundles":[{"id":"identity-and-electrical-boundary","name":"Identity and electrical boundary","description":"Establish what qualifies as this registered kind and where the compensation system connects.","layers":[{"id":"classification-basis","name":"Classification basis","description":"Record the definition and architecture used to establish membership.","findings":[{"id":"facts-membership","name":"FACTS membership","description":"Require a documented membership decision rather than infer it from a product label.","questions":[{"text":"Which technical definition establishes that this equipment belongs to the FACTS kind?","id":"facts-membership-q01","kind":"definition"},{"text":"Does that definition include passive compensation and rotating synchronous condensers, or only specified static controlled architectures?","id":"facts-membership-q02","kind":"boundary"}]}]},{"id":"connection-and-owned-equipment","name":"Connection and owned equipment","description":"Locate the controlled terminals and distinguish integral equipment from neighbouring assets.","findings":[{"id":"electrical-system-boundary","name":"Electrical system boundary","description":"Describe series, shunt or combined interfaces and the components required for their operation.","questions":[{"text":"Which buses or circuit terminals carry the series and shunt connections?","id":"electrical-system-boundary-q01","kind":"boundary"},{"text":"Which coupling transformers, filters, bypass devices and auxiliaries belong to the compensation system?","id":"electrical-system-boundary-q02","kind":"boundary"}]}]}]},{"id":"compensation-mechanism-and-capability","name":"Compensation mechanism and capability","description":"Relate physical implementation to the controllable electrical quantities and their limits.","layers":[{"id":"controlled-electrical-action","name":"Controlled electrical action","description":"Identify how the equipment changes the AC network.","findings":[{"id":"actuation-mechanism","name":"Actuation mechanism","description":"Record the actual compensation mechanism and supported control objectives.","questions":[{"text":"Does the installation vary shunt susceptance, inject converter current, vary series reactance or inject series voltage?","id":"actuation-mechanism-q01","kind":"definition"},{"text":"Which voltage, reactive-power, power-flow or damping objectives can this architecture independently control?","id":"actuation-mechanism-q02","kind":"boundary"}]}]},{"id":"conditional-capability-envelope","name":"Conditional capability envelope","description":"Express capability against terminal conditions, duration and available equipment.","findings":[{"id":"electrical-and-energy-limits","name":"Electrical and energy limits","description":"Require architecture-specific limits and explicit evidence for active-energy capabilities.","questions":[{"text":"What injection, absorption or series-control limits apply at the present voltage, current, temperature and availability?","id":"electrical-and-energy-limits-q01","kind":"measurement"},{"text":"What source or coupling supports any claimed active-power exchange, and for what duration?","id":"electrical-and-energy-limits-q02","kind":"boundary"},{"text":"Which manufacturer curves or acceptance measurements substantiate these limits?","id":"electrical-and-energy-limits-q03","kind":"provenance"}]}]}]},{"id":"regulation-and-network-interaction","name":"Regulation and network interaction","description":"Capture control objectives, dynamic behaviour and dependencies on the surrounding network.","layers":[{"id":"control-objectives-and-authority","name":"Control objectives and authority","description":"Establish active modes, command sources and priority rules.","findings":[{"id":"mode-and-setpoint-governance","name":"Mode and setpoint governance","description":"Link each requested intervention to a supported mode and authorised command path.","questions":[{"text":"Which mode, setpoint, droop, deadband and output limit are currently active?","id":"mode-and-setpoint-governance-q01","kind":"measurement"},{"text":"Who may change them, and how do local, remote and protective commands take priority?","id":"mode-and-setpoint-governance-q02","kind":"action"}]}]},{"id":"dynamic-network-compatibility","name":"Dynamic network compatibility","description":"Record the network conditions under which control performance has been demonstrated.","findings":[{"id":"validated-response-and-interactions","name":"Validated response and interactions","description":"Treat response and stability claims as conditional on studies or measurements.","questions":[{"text":"What response time, settling behaviour and damping performance were demonstrated, and under which disturbances?","id":"validated-response-and-interactions-q01","kind":"measurement"},{"text":"Which studies assess interactions with nearby converters, other voltage controllers and relevant subsynchronous modes?","id":"validated-response-and-interactions-q02","kind":"provenance"},{"text":"Which network changes require revised settings or renewed interaction studies?","id":"validated-response-and-interactions-q03","kind":"action"}]}]}]},{"id":"protection-and-operating-transitions","name":"Protection and operating transitions","description":"Distinguish controllable, limited, blocked, bypassed and isolated conditions.","layers":[{"id":"state-and-transition-permissives","name":"State and transition permissives","description":"Record how operating states are established and which transitions are permitted.","findings":[{"id":"confirmed-operating-state","name":"Confirmed operating state","description":"Use telemetry and interlocks to establish available capability rather than rely on a single status label.","questions":[{"text":"Which valve, breaker, disconnector and bypass indications confirm the current electrical state?","id":"confirmed-operating-state-q01","kind":"measurement"},{"text":"What permissives and approved sequence govern energisation, blocking, bypass and return to regulation?","id":"confirmed-operating-state-q02","kind":"action"}]}]},{"id":"fault-response-and-access","name":"Fault response and access","description":"Connect protective events with equipment exposure and access restrictions.","findings":[{"id":"protective-action-and-residual-energy","name":"Protective action and residual energy","description":"Record architecture-specific protective responses and the evidence needed for safe intervention.","questions":[{"text":"Which overcurrent, overvoltage, thermal or auxiliary failures trigger limiting, blocking, bypass or trip?","id":"protective-action-and-residual-energy-q01","kind":"definition"},{"text":"What verified isolation, discharge and earthing conditions are required before access to capacitor, converter or series-platform equipment?","id":"protective-action-and-residual-energy-q02","kind":"action"}]}]}]},{"id":"condition-and-capability-restoration","name":"Condition and capability restoration","description":"Relate component condition and auxiliary health to derating, maintenance and return to service.","layers":[{"id":"degradation-and-derating","name":"Degradation and derating","description":"Identify failures and trends that reduce available compensation.","findings":[{"id":"capability-affecting-condition","name":"Capability-affecting condition","description":"Track relevant valve, capacitor, reactor, filter, cooling and control-system evidence.","questions":[{"text":"Which alarms, temperature trends, failed modules or unavailable branches presently reduce compensation capability?","id":"capability-affecting-condition-q01","kind":"measurement"},{"text":"How are these conditions translated into revised limits and operator-visible availability?","id":"capability-affecting-condition-q02","kind":"action"}]}]},{"id":"maintenance-and-return-to-service","name":"Maintenance and return to service","description":"Connect maintenance dependencies with demonstrated restoration of function.","findings":[{"id":"restoration-evidence","name":"Restoration evidence","description":"Require applicable procedures, spare compatibility and checks after repair or settings changes.","questions":[{"text":"Which inspections, coolant or filter servicing and component replacements are required by the installed design?","id":"restoration-evidence-q01","kind":"action"},{"text":"Which post-maintenance checks demonstrate restored protection, control response and compensation range?","id":"restoration-evidence-q02","kind":"provenance"}]}]}]},{"id":"requirements-and-performance-evidence","name":"Requirements and performance evidence","description":"Tie installation requirements and claimed network benefits to traceable evidence.","layers":[{"id":"applicable-obligations","name":"Applicable obligations","description":"Determine which technical and connection requirements apply to the architecture and location.","findings":[{"id":"requirement-applicability","name":"Requirement applicability","description":"Record issuers, editions, applicability decisions and unresolved deviations.","questions":[{"text":"Which IEC or IEEE documents, network-operator rules and local requirements apply, with issuing bodies and editions?","id":"requirement-applicability-q01","kind":"provenance"},{"text":"Which requirements cover the complete installation, and which cover only valves, insulation, controls or other components?","id":"requirement-applicability-q02","kind":"boundary"}]}]},{"id":"demonstrated-service","name":"Demonstrated service","description":"Separate rated equipment capability from verified network outcomes.","findings":[{"id":"acceptance-and-benefit-basis","name":"Acceptance and benefit basis","description":"Require stated baselines, operating scenarios and acceptance criteria for performance claims.","questions":[{"text":"Which commissioning tests substantiate the required regulation, harmonics, losses and disturbance response?","id":"acceptance-and-benefit-basis-q01","kind":"provenance"},{"text":"Against which baseline topology and contingency set is any claimed transfer-capacity or stability improvement measured?","id":"acceptance-and-benefit-basis-q02","kind":"measurement"}]}]}]},{"id":"evidence-and-external-alignment","name":"Evidence and external alignment","description":"What the world already says about this thing, gathered so the model can be checked against it.","layers":[{"id":"reported-evidence","name":"Reported evidence","description":"Findings from the breadth pass, kept separate from the structural claims.","findings":[{"id":"evidence-confidence-notes","name":"Check these first","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these check these first hold for the sense of flexible AC transmission system this model covers, and on what evidence?","id":"evidence-confidence-notes-q01","kind":"provenance"}]},{"id":"evidence-kinds","name":"Kinds and varieties","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these kinds and varieties hold for the sense of flexible AC transmission system this model covers, and on what evidence?","id":"evidence-kinds-q01","kind":"provenance"}]},{"id":"evidence-identifiers","name":"Identifiers and schemes","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these identifiers and schemes hold for the sense of flexible AC transmission system this model covers, and on what evidence?","id":"evidence-identifiers-q01","kind":"provenance"}]},{"id":"evidence-standards-and-regulation","name":"Standards and regulation","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these standards and regulation hold for the sense of flexible AC transmission system this model covers, and on what evidence?","id":"evidence-standards-and-regulation-q01","kind":"provenance"}]},{"id":"evidence-real-world-use","name":"Real-world use","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these real-world use hold for the sense of flexible AC transmission system this model covers, and on what evidence?","id":"evidence-real-world-use-q01","kind":"provenance"}]},{"id":"evidence-measurements","name":"Typical measurements","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these typical measurements hold for the sense of flexible AC transmission system this model covers, and on what evidence?","id":"evidence-measurements-q01","kind":"provenance"}]},{"id":"evidence-failure-modes-and-hazards","name":"Failure modes and hazards","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these failure modes and hazards hold for the sense of flexible AC transmission system this model covers, and on what evidence?","id":"evidence-failure-modes-and-hazards-q01","kind":"provenance"}]},{"id":"evidence-regional-variation","name":"Regional variation","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these regional variation hold for the sense of flexible AC transmission system this model covers, and on what evidence?","id":"evidence-regional-variation-q01","kind":"provenance"}]},{"id":"evidence-neighbours","name":"Neighbouring kinds and how to tell them apart","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these neighbouring kinds and how to tell them apart hold for the sense of flexible AC transmission system this model covers, and on what evidence?","id":"evidence-neighbours-q01","kind":"provenance"}]}]}]}]},"agentConduct":{"may":["Explain how flexible AC transmission devices improve control of power flow and stability.","Monitor and report the state of FACTS equipment for the grid operator that authorized it."],"mustNot":["Change set points or switch FACTS controllers without the grid operator's authorization.","Access grid control systems it is not authorized to use.","Disable protection or alarms on high-voltage equipment.","Publish details of grid control systems that could help an attack."],"requiresHuman":["Any control action on transmission equipment during a grid disturbance."]},"ethics":{"considerations":["Power grids keep hospitals, homes and industry running; errors can black out regions.","High-voltage equipment is lethal to people working near it."],"affectedParties":["Electricity consumers","Grid workers","Hospitals and critical services"]},"owners":{"steward":"The transmission system operator that owns and runs the equipment.","roles":[],"masterSystems":[]},"relations":[{"target":"Q12241428","type":"parent","note":"registry parent class"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.flexible-ac-transmission-system","Wikidata: Q551118 (https://www.wikidata.org/wiki/Q551118)"]},"properties":{"applicability":"required","items":["Connection topology: shunt | series | combined | documented hybrid","Compensation architecture: SVC | STATCOM | TCSC | SSSC | UPFC | other documented architecture","Controlled network connection: Referenced AC bus, transmission circuit and connection terminals","Rated connection conditions: kV RMS line-to-line; Hz; kA RMS, with terminal and rating basis","Reactive-power capability: MVAr injection and absorption versus terminal voltage, duration and equipment availability","Series-control capability: Ohm effective reactance, percent compensation or kV injected series voltage, as applicable","Control mode: voltage regulation | reactive-power regulation | power-flow regulation | damping | standby | other supported mode","Dynamic response: ms response and settling time, with stimulus, tolerance band and operating point","Operational availability: available | regulating | limited | blocked | bypassed where applicable | tripped | isolated","Active-energy interface: None declared, internal energy buffer, coupled converter or external storage/source; documented MW and MJ or MWh limits","Auxiliary readiness: Availability of auxiliary supply, cooling, control power and required communications","Applicable requirement set: Issuing body, document identifier, edition, jurisdiction, applicable clause and compliance evidence"]},"recognition":{"applicability":"required","items":["Installations may combine converter or thyristor valve enclosures with substantial cooling equipment beside a transmission substation.","Associated reactors, capacitor banks and coupling transformers can indicate a compensation installation, although these components alone do not establish that it is a flexible AC transmission system.","Equipment labels and single-line diagrams distinguish controlled series or shunt compensation equipment from ordinary transformers and fixed capacitor banks."]},"capabilities":{"applicability":"required","items":["Classify the compensation architecture from connection diagrams and equipment evidence.","Estimate available support from capability curves, current network conditions and equipment availability.","Compare measured response with the active setpoint, control mode and acceptance criteria.","Propose mode or setpoint changes within documented authority and operating limits.","Identify blocking, bypass, isolation or inspection actions required by protection and condition evidence.","Flag missing studies or evidence before attributing transfer-capacity or stability benefits."]},"hazards":{"applicability":"required","items":["High voltage and stored electrical energy can cause fatal electric shock or arc-flash injury.","Cooling failures or electrical faults can overheat equipment and cause fire or damage to nearby assets.","Incorrect control settings or interactions with other network equipment can worsen oscillations, voltage disturbances or transmission outages.","Failure of protection or insulation can expose personnel and connected equipment to dangerous electrical conditions."]},"interfaces":{"applicability":"required","items":["IEC 61954, issued by the International Electrotechnical Commission, specifies testing of thyristor valves used in static VAR compensators.","IEC 62927, issued by the International Electrotechnical Commission, specifies electrical testing of voltage source converter valves used in static synchronous compensators.","IEC 61936-1, issued by the International Electrotechnical Commission, applies to the design and erection of power installations exceeding 1 kV AC that house this equipment."]},"context":{"applicability":"required","items":["Flexible AC transmission systems are installed at transmission substations or along power corridors to regulate electrical network behavior.","Depending on their configuration, they support voltage control, reactive power management, power-flow control and damping of network oscillations.","Utilities use them to improve stability and make greater use of transmission capacity within operating limits."]}},"sources":[{"title":"Wikidata item Q551118: flexible AC transmission system","url":"https://www.wikidata.org/wiki/Q551118","note":"identity and sense of the item"},{"title":"Wikipedia: Flexible AC transmission system","url":"https://en.wikipedia.org/wiki/Flexible_AC_transmission_system","note":"general description of the item"}],"openQuestions":["Which authoritative FACTS definition should this registry adopt, particularly for fixed compensation, mechanically switched devices and synchronous condensers?","Does an existing Vercy world model already own this concept, requiring this registry entry to link to it?","Which architecture-specific IEC and IEEE standards, editions and jurisdictional requirements should be represented after their texts are reviewed?","What sourced ranges of voltage, MVAr, series compensation, footprint and response time are representative of each architecture without implying universal ratings?","Where should the boundary fall for distribution-connected compensators and storage-enhanced systems that share FACTS technology but provide additional services?"],"resources":{"spec":"/models/things/publications/thing-q551118/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q551118/spec.json"],"providers":["Codex"],"researchStatus":"unreviewed","generatedAt":"2026-09-12T09:45:53Z","builder":"tools/build_cards.py@1.0.0"},"completeness":{"sections":{"classifiers":"filled","whatItIs":"filled","purpose":"filled","distinguishingFeatures":"filled","structure":"filled","agentConduct":"filled","ethics":"filled","owners":"filled","relations":"filled","interaction.identity":"filled","interaction.properties":"filled","interaction.recognition":"filled","interaction.capabilities":"filled","interaction.hazards":"filled","interaction.interfaces":"filled","interaction.context":"filled","sources":"filled"},"notes":{"_gate":"Published through the thing publication gate 1.0 on 2026-10-07T10:10:31+00:00: completeness 1.00; sense: Wikidata description; 2 live sources; review by codex: pass"},"score":1.0}}