E-Mon E-PS-E-RTU-N - Manual (Page 80)

Chapter 5 Configuring the PowerSmart+ PQM General Meter Setup
80 PowerSmart+ Power Quality Meter
Power Calculation Modes
The power calculation mode option allows you to change the method for
calculating reactive and apparent powers in presence of high harmonics.
The options work as follows:
• When the reactive power calculation mode is selected, active and
reactive powers are measured directly and apparent power is
calculated as:
2 2
Q P S + =
This mode is recommended for electrical networks with low harmonic
distortion, commonly with THD < 5% for volts, and THD < 10% for
currents. In networks with high harmonics, the second method is
preferable.
• When the non-active power calculation mode is selected, active
power is measured directly, apparent power is taken as product S
= V x I, where V and I are the RMS volts and amps, and reactive
power (called non-active power) is calculated as:
2 2 P S N − =
Configuring Digital Inputs
The PowerSmart+ PQM can be provided with four to twelve (depend on
DI/O module type) digital inputs that can be linked to control setpoints to
give an indication on input status change (see
Configuring Alarm/Control
Setpoints ), or can be linked to general pulse counters to count incoming
pulses (see Configuring Counters ). They can also be linked to the
Billing/TOU registers to count pulses from external wattmeters or gas and
water meters.
Using Power Software
Select General Setup from the Meter Setup menu, and then click on the
Digital Inputs tab.
Figure 5-8: General Setup Dialog Box – Digital Inputs Dialog Box