hager hw+ User Manual

936LE008146B
Measurement functions
6.9 Measuring power factors
The sentinel Energy trip unit calculates every second in real-time the power factor PFtot from
the ratio of total active power to total apparent power. It also calculates the power factors per
phase from the ratios of active power per phase to apparent power per phase.
Example: Formula for the power factor per phase.
The sentinel Energy trip unit also calculates in real-time (every second) the total cos from the
ratio of total active power reduced to the harmonics of rank 1 to total apparent power reduced
to the harmonics of rank 1. In addition, it calculates the cos per phase.
The power factors and the cos are energy distribution quality indicators. Improving these
indicators enables the following:
- Decreasing the reactive energy consumption that may result in penalties related to electrical
consumption costs
- Reducing the cross-section of the cables
- Reducing line losses
- Reducing the voltage drop
- Increasing the power available to the transformer.
The exhaustive list of variables calculated according to the 3-pole or 4-pole version is given in
the following table:
N.B.
The values PFtot and cos tot depend on the arithmetic or vector summation convention for
reactive and apparent power (see § 6.13 - Setting the reactive and apparent power calculation
convention).
PF power factor and cos sign
The Energy trip unit is used to configure the sign convention to be applied to the power factor
and cos values .
Two options are possible:
- IEC Convention: The sign for the power factors and cos follows the active power sign,
- IEEE convention: The sign for the power factors and cos is modified to indicate whether
the electrical system is capacitive (+ sign) or inductive (- sign).
Calculation formula symbol Definition
Phase number.
Electrical variable Symbol 3-pole
version
4-pole
version
Power factor per phase PF1, PF2, PF3
-
■
Total power factor PFtot
■ ■
Cos per phase (fundamental power
factor)
cos 1, cos 2, cos 3
-
■
Total cos (fundamental power factor) cos tot
■ ■

hager hw+ Specifications

General

Brand	hager
Model	hw+
Category	Circuit breakers
Language	English