kWh
Active-energy meter
An active-energy meter accumulates active power over time.
SLD / Schematic
Symbols · kVAh
Apparent-energy meter
Integrating meter that totalises apparent energy in kVAh, used where tariffs charge on kVA rather than kW.
In plain English
What does Apparent-energy meter mean?
An apparent-energy meter totalises volt-amperes over time. Some network tariffs and demand charges are based on kVA, so this register appears on supply-point single-line diagrams beside the kWh and kvarh registers of the revenue meter.
A simple example
Apparent energy can be calculated in more than one way when harmonics or unbalance are present, for example arithmetically from each phase or vectorially from total watts and vars. The symbol does not say which method is used, and two meters with different methods can disagree.
What the drawings help you do
Check which calculation method the meter uses. Read with the kWh and kvarh registers at the same point. A kVAh meter totalises apparent energy; a kWh meter totalises only the active part.
This particular reference
Integrating meter that totalises apparent energy in kVAh, used where tariffs charge on kVA rather than kW. A kVAh meter totalises apparent energy; a kWh meter totalises only the active part.
- Phase
- One of the related AC waveforms in a power system.
- Schematic
- A drawing showing function and connections rather than physical appearance.
Read the source: Power and energy measurement quantities · IEC graphical symbols for diagrams
SLD / Schematic · kVAh
What it represents
An apparent-energy meter totalises volt-amperes over time. Some network tariffs and demand charges are based on kVA, so this register appears on supply-point single-line diagrams beside the kWh and kvarh registers of the revenue meter.
Apparent energy can be calculated in more than one way when harmonics or unbalance are present, for example arithmetically from each phase or vectorially from total watts and vars. The symbol does not say which method is used, and two meters with different methods can disagree.
How to read it
- Check which calculation method the meter uses.
- Read with the kWh and kvarh registers at the same point.
Information to show or reference
- State calculation method
- Show CT and VT ratios
- Give accuracy class
A distinction that matters
A kVAh meter totalises apparent energy; a kWh meter totalises only the active part.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
Power and energy measurement quantities
Public explanation of energy and power measurement quantities used by meters.
IEC graphical symbols for diagrams
IEC context for graphical symbols used in diagrams; no IEC graphic is reproduced.
About this graphic
This illustration was authored independently by Elora Grid to explain the concept. It is not reproduced from a customer drawing, an official standard graphic or a manufacturer CAD file. Its correspondence to an exact IEC or IEEE symbol identifier has not been certified.
SVG and DXF downloads contain this original artwork. DXF uses unscaled drawing units; a GA envelope supplies no product dimensions, clearances or fabrication information. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.
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