Question:
We would like to know what P1, P2, Q1, Q2, Q3, Q4 are. Also can you tell us which ones we would need to be using for our system to calculate KWH.

Answer:
his call works for meter with half hour profiles. Each profile period is identified by the time when it ends.
The values that are brought back per half hour is the kW and kvar, in other words, to get the kWh and kvarh, you have to multiply it with 0.5 (half an hour).
P1 is active energy in kW. This is the one that relates to KWH.
P2 is also in kW units: it is when the electricity flows in the opposite direction.
Q1-Q4 are reactive energies (kvar): Quadrant 1 to Quadrant 4. For Eskom tariffs, you would typically only use Q1 in conjunction with P1 to work out your kVA for a specific half hour (apply the theorem of Pythagoras: P1 and Q1 are perpendicular to each other, and the kVA is the length of the diagonal line inbetween)
For Cape Town, you must subtract Q4 from Q1 first before working out the kVA (up to a minimum per half hour of 0); since Cape Town credits people for a positive power factor (for a part of any particular half hour); whereas Eskom does not. This becomes apparent from the respective Tariff booklets and bills by the different billing authorities when compared with the measured values.