{ "node": { "id": "term:reactive-power-support", "type": "Term", "label": "Reactive power support", "properties": { "id": "reactive-power-support", "name": "Reactive power support", "aka": [ "reactive power", "volt-var control", "var support" ], "section": "topic-applications", "definition": "Supplying or absorbing reactive power to hold local grid voltage within limits. A battery’s inverter can do it at any state of charge, since reactive power circulates rather than draining stored energy, but it shares the inverter’s apparent-power rating with real power: a 1 MVA inverter exporting 0.8 MW has 0.6 Mvar left.", "formula": "S² = P² + Q²", "unit": "var", "related": [ "inverter", "stationary-storage", "frequency-regulation", "power" ], "example": { "title": "Read an apparent-power limit", "text": "For an ideal converter limited to 10 kVA and operating at 8 kW active power, the circular capability relation allows up to 6 kvar magnitude. Real equipment capability can impose tighter limits." }, "url": "https://lemonergy.com/learn/glossary/reactive-power-support/", "mentions": [ "state-of-charge" ] } }, "edges": [ { "id": "edge:6842", "source": "term:reactive-power-support", "target": "topic:topic-applications", "type": "belongsTo", "properties": { "sourceFile": "terms.json" } }, { "id": "edge:6843", "source": "term:reactive-power-support", "target": "term:inverter", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:6844", "source": "term:reactive-power-support", "target": "term:stationary-storage", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:6845", "source": "term:reactive-power-support", "target": "term:frequency-regulation", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:6846", "source": "term:reactive-power-support", "target": "term:power", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:mentions/reactive-power-support/state-of-charge", "source": "term:reactive-power-support", "target": "term:state-of-charge", "type": "mentions", "properties": { "sourceFile": "terms.json", "method": "build_glossary.mention_index + mentions", "field": "definition", "meaning": "Text mention; not a causal claim" } }, { "id": "edge:6848", "source": "term:reactive-power-support", "target": "visual:apparent-power", "type": "illustratedBy", "properties": { "sourceFile": "visual-pages.json" } } ], "neighbors": [ { "id": "topic:topic-applications", "type": "Topic", "label": "Applications and market", "properties": { "id": "topic-applications", "name": "Applications and market", "lede": "Where batteries are used, and the terms used to buy, size and compare them.", "context": "Start with mission energy, peak power and operating conditions.", "example": "20 kWh total energy and a ten-second 100 kW peak constrain different design aspects.", "lesson_url": "https://lemonergy.com/learn/fundamentals/capacity-and-c-rate/", "lesson_label": "Open energy and power" } }, { "id": "term:inverter", "type": "Term", "label": "Inverter", "properties": { "id": "inverter", "name": "Inverter", "aka": [ "power conversion system", "PCS" ], "section": "topic-pack", "definition": "The power electronics that turn the battery’s DC into AC for a motor or the grid, and back again for charging. In stationary storage it is called the power conversion system and its rating in kW or MW sets the system’s power independently of the battery’s energy.", "related": [ "pre-charge", "dc-dc-converter", "stationary-storage", "energy-management-system", "direct-current", "iec-62477-1" ], "url": "https://lemonergy.com/learn/glossary/inverter/", "mentions": [] } }, { "id": "term:stationary-storage", "type": "Term", "label": "Stationary storage", "properties": { "id": "stationary-storage", "name": "Stationary storage", "abbr": "BESS", "aka": [ "battery energy storage system", "ESS" ], "section": "topic-applications", "definition": "Batteries installed in a fixed place — a container at a solar farm, a cabinet in a home — to shift energy in time or support the grid. LFP cells dominate because cost per cycle and safety matter more than mass.", "related": [ "lfp", "energy-management-system", "inverter", "energy-arbitrage", "long-duration-storage", "ul-9540a" ], "url": "https://lemonergy.com/learn/glossary/stationary-storage/", "mentions": [] } }, { "id": "term:frequency-regulation", "type": "Term", "label": "Frequency regulation", "properties": { "id": "frequency-regulation", "name": "Frequency regulation", "aka": [ "ancillary services", "frequency response" ], "section": "topic-applications", "definition": "Rapidly injecting or absorbing power to hold the grid frequency at 50 or 60 Hz, a service batteries do better than any generator because they respond in milliseconds. It cycles the battery shallowly but very often.", "related": [ "stationary-storage", "energy-arbitrage", "specific-power", "equivalent-full-cycle", "rate-of-change-of-frequency" ], "url": "https://lemonergy.com/learn/glossary/frequency-regulation/", "mentions": [] } }, { "id": "term:power", "type": "Term", "label": "Power", "properties": { "id": "power", "name": "Power", "section": "topic-units", "definition": "The rate at which a cell delivers or absorbs energy: voltage times current, in watts. Power is limited by internal resistance and temperature long before capacity runs out.", "formula": "P = V × I", "unit": "W", "related": [ "watt", "specific-power", "state-of-power", "internal-resistance" ], "example": { "title": "Separate power from energy", "text": "A 100 W load running for 30 min uses 50 Wh. Power tells you how fast energy is transferred; the duration determines how much energy is transferred." }, "url": "https://lemonergy.com/learn/glossary/power/", "mentions": [] } }, { "id": "term:state-of-charge", "type": "Term", "label": "State of charge", "properties": { "id": "state-of-charge", "name": "State of charge", "abbr": "SOC", "section": "topic-state", "definition": "How full a cell is, as a fraction of its available capacity. State of charge, like temperature, affects how fast a stored cell ages.", "unit": "%", "related": [ "depth-of-discharge", "ocv-soc-curve", "coulomb-counting", "state-of-health", "bms" ], "lesson": "fundamentals/battery-aging/#storage-soc", "example": { "title": "Interpret a charge inventory", "text": "If available capacity is 5 Ah and 3 Ah remains by the chosen estimator, SOC is 60%. A different estimate of available capacity changes this percentage, so compare SOC values only with the capacity convention recorded." }, "url": "https://lemonergy.com/learn/glossary/state-of-charge/", "mentions": [ "usable-capacity" ] } }, { "id": "visual:apparent-power", "type": "Visual", "label": "Active and reactive power share an inverter rating", "properties": { "title": "Active and reactive power share an inverter rating", "summary": "The apparent-power circle bounds combinations of active and reactive power.", "readout": "At P = 0.8 MW, the ideal rating permits up to ±0.6 Mvar.", "formula": "S² = P² + Q²; |Q| ≤ √(S² − P²)", "note": "Ideal fixed apparent-power limit. Actual converter capability also depends on current, voltage, temperature, DC-link and control limits.", "software": { "status": "reference", "label": "Reference concept", "body": "This reference power triangle does not model AC grid control. The native Studio bidirectional converter is an average active-power boundary.", "href": "../chapter-1/" }, "html": "
Ideal apparent-power envelope
Ideal apparent-power envelopeActive power P (MW) versus Reactive power Q (Mvar). Positive Q bound; Negative Q bound. Interpretation follows the graphs.-1-1-0.5-0.5000.50.511Active power P (MW)Reactive power Q (Mvar)
Positive Q boundNegative Q bound (dashed)
" } } ] }