Preliminary
6 Power factor / ta
n δ measurements
6.1 Definitions
IEC defines the power factor cos φ as the ratio between the absorbed active power to the absolute
value of the reactive power. This corresponds to tan δ.
The picture below shows the definition of dielectric variables tan δ (dissipation factor) and cos φ
(insulation power factor) in an equivalent parallel circuit.
Example: Equivalent parallel circuit
1
According to IEEE Std C57.152-2013
90315-1.2 Instruction Manual CAPO
Page 23 of 117