The terminology used in this glossary conforms to the International Vocabulary of Basic and General Terms in Metrology and the International Vocabulary of Legal Metrology. In addition, for CLOU documentation purpose, the following definitions shall apply

rate at which energy is transported

*Note: In an electrical system active power is measured as the time mean of the instantaneous power, which is calculated at each instant as the product of voltage and current*

*At sinusoidal conditions active power is the product of the r.m.s. values of current and voltage and the cosine of the phase angle between them, calculated for each phase. It is usually expressed in kW. *

**Formula**

P ≙ active power in W

U ≙ voltage

I ≙ current

cosφ ≙ power factor

elements

Indication minus reference quantity value, divided by the reference quantity value

*Note: The relative error is usually expressed as a percentage of the reference quantity value.*

*In CLOU teminology the short form “error” is used for relative error.*

**Formula**