Battery knowledge · Applications and market
Reactive power support
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.
- Also called
- reactive power, volt-var control, var support
- Unit
- var
- Relationship
- S² = P² + Q²
Example
Read an apparent-power limit
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.
Explore the graph
The apparent-power circle bounds combinations of active and reactive power.
At P = 0.8 MW, the ideal rating permits up to ±0.6 Mvar.
S² = P² + Q²; |Q| ≤ √(S² − P²)
Illustrative model. Ideal fixed apparent-power limit. Actual converter capability also depends on current, voltage, temperature, DC-link and control limits.
Use in Lemonergy
Start with mission energy, peak power and operating conditions.
This is a reference concept. No executable Lemonergy block has been verified for this term.
References & further reading
Further reading on this topic
These sources provide broader context; they are not presented as citations for every statement in this entry.
- DOE/EPRI 2013 Electricity Storage Handbook in Collaboration with NRECA
Sandia National Laboratories · 2013
Topic background · Storage technologies and grid services. The publisher notes that its historical cost and deployment figures are outdated.