Figure 8: Allocation Of Active And Reactive Energy In The 4 Quadrants; 3-Phase Power Measurement Module - WAGO 750-494 Series Manual

34 Function Description
Calculating Power
Individual, synchronous sampling values for current and voltage are used for
calculating active power (P). Phase shifts between the currents and voltages are
taken into account for power calculation. Positive values occur when the power is
"consumed" by a load, i.e., current has a phase shift of -90° ... +90° compared to
voltage (operation under load, Quadrant I and IV). Negative values are yielded
when the power is "fed in" by a generator, i.e., the current has phase shifting of
90° ... 270° relative to voltage (generator operation, Quadrant II and III).
Negative active power!
Negative active power occurs when the connections of up-circuit current
transformers are reversed!
Active power minimum and maximum values are determined over a configurable
time period (WAGO-I/O-CHECK or parameters 37, 38, 39).
In real supply networks, not all electrical loads are purely ohmic. Phase shifting
occurs between current and voltage. However, this does not affect the method for
determining the RMS values for current voltage previously described. The I/O
module calculates both the reactive power (Q) and the apparent power (S) for
each phase.
Calculating Energy
Time-based integration of power yields the level of energy for each phase. The
I/O module provides the values for active, reactive and apparent energy. Values
for the individual phases and an overall value are provided both for active and
reactive energy. A distinction can also be drawn between acquisition/delivery of
active energy and inductive/capacitive reactive energy (see figure below).

Figure 8: Allocation of Active and Reactive Energy in the 4 Quadrants

WAGO-I/O-SYSTEM 750

750-494 3-Phase Power Measurement Module

Manual
Version 1.2.0