 # Calculation methods for energy

Last Updated by LaoRen

We got several questions related to the different recording methods for electrical energy meters. Here is the behaviour with different settings:

Vector registration method (L)
By vector method the vectors of each phase L1, L2 and L3 are summed:
- When the vector sum of energies is positive, the meter registers A+ energy.
- When the vector sum of energies is negative, the meter registers A- energy.

Example (same load in each phase)

 phase L1 L2 L3 load A+ A- A+

Total registration: OBIS 1.0.1.8.0 = (A+) + (A-) + (A+) = A+

Arithmetic registration method
The meter can register A+ and A- energy at the same time with the arithmetic registration method.
Example (same load in each phase)

 phase L1 L2 L3 load A+ A- A+

Total registration, import (forward) direction: OBIS 1.0.1.8.0 = (A+) + (A+)
Total registration, export (reverse) direction: OBIS 1.0.2.8.0 = (A-)

Absolute registration |A |

The registration of absolute active energy |A| is as follows:

Example (same load in each phase)

 phase L1 L2 L3 load A+ A- A+

Total registration, import direction: OBIS 1.0.1.8.0 = |A+| + |A-| + |A+|
With this settings the meter registers only forward energy.