Schneider Electric HRB1684301-01 Manual De Usuario

HRB1684301-01

135

This section describes how the meter interprets and calculates power and power factor.

A typical AC electrical system load has both resistive and reactive (inductive or 
capacitive) components. Resistive loads consume real power (P) and reactive loads 
consume reactive power (Q).

Apparent power (S) is the vector sum of real power (P) and reactive power (Q):

Real power is measured in watts (W or kW), reactive power is measured in vars (VAR 
or kVAR) and apparent power is measured in volt-amps (VA or kVA).

The meter uses the values of real power (P) and reactive power (Q) on the 
PQ coordinate system to calculate apparent power.

Positive power flow P(+) and Q(+) means power is flowing from the power source 
towards the load. Negative power flow P(-) and Q(-) means power is flowing from the 
load towards the power source.

S

P

2

Q

2

+

=

+Q

(+kVAR)

-P

(-kW)

-Q

(-kVAR)

+P

(+kW)

P (+)

S

P (-)

S

P (+)

S

P (-)

S

Q (-)

Q (-)

Q (+)

Q (+)