When we talk about power we always need to indicate the direction and which sort of power.

We can have:

**Active power, P**

Active power is expressed in watt (W). Sometimes this power is also called “real power”

This is the power you are actually consuming.**Reactive power, Q**

Reactive power is expressed in volt-ampere reactive (var)

This power is stored in components, then released again back to the source through the AC cycle. Capacitors and inductors do this.**Apparent power, S**

Apparent power is expressed in volt-ampere (VA)

(RMS voltage times the RMS current). A power supply must be capable to output the full apparent power delivered to a circuit, not just the active power.

**Quadrant I**

Quadrant I is defined as an area where both powers flow positively. Both are delivered to the consumer load. In many cases the CLOU terminology is *forward*. The power factor is lagging, we have inductive influence.

The IEC literature is using the term ** import**.

In this quadrant we have Import of active power and Import of reactive power.

**Quadrant II**

In quadrant II, reactive power is positive and active power flows negatively. In many cases the CLOU terminology is *reversed*. The IEC literature is using the term ** export**.

**Quadrant III**

In quadrant III, reactive and active power flow negatively (both powers are received from the customer). This is also a *export* condition.

**Quadrant IV**

In quadrant IV, reactive power flows negatively, and active power flows positively. This is a *import* condition.

The interactive diagram below shows the relationship between the phase angle φ, apparent-, active- and reactive power respective energy. The diagram is in accordance with clauses 12 and 14 of IEC 60375. Reference is the current vector (fixed on right-hand line, 0°). The phase angle φ between voltage V and current I is taken to be positive in the mathematical sense (counter clockwise).

**Four Quadrant Simulation (IEC62053-23)**

Geometric representation of active and reactive power

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The information on the internet is often ambiguous.

It should always be specified who is used as a reference of 0 degrees: voltage or current.

For example, on this site where the reference voltage is used, the diagram is completely reversed:

https://ez.analog.com/energy-metering/f/q-a/31692/four-quadrant-energy-metering

Thank you for valuable input, Nick. Actually our diagram follows the IEC62053-23 definition, which is valid since the year 2003. The older engineers are still familiar with the representation shown in your link.