E-Mon E-PS-S-HV-RTU - Manual (Page 77)

Chapter 5 Configuring the PowerSmart Socket PQM General Meter Setup
PowerSmart Socket Power Quality Meter 77
1. When the reactive power calculation mode is selected,
active and reactive powers are directly measured and
apparent power is calculated as:
2. 2 2
Q P S + =
3. 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 following method is preferable.
4. 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:
5. 2 2
P S N − =
Tariff Control
The PowerSmart Socket PQM provides three options for
switching tariff rates:
• automatic via a programmable TOU calendar schedule (see
Configuring the Daily Tariff Schedule for information on
configuring tariff change points)
• external via communications by writing a tariff number to the
meter tariff register (see the PowerSmart Socket PQM Modbus
Reference Guide for information on the active tariff register
location)
• external via digital inputs by providing a tariff code on the
meter tariff inputs
If a digital input option is selected, you can use 1 to 3
consequent digital inputs as tariff inputs. The following table
shows the number of inputs required depending on the
maximum number of used tariff rates.
Number of tariffs Number of tariff inputs
2 1
3 2
4 2
5 3
6 3
7 3
8 3
The following table shows code combinations that should be
provided on the tariff inputs to indicate an active tariff rate.
Tariff code Tariff rate
number
Tariff
input 1
Tariff
input 2
Tariff
input 3
1 Open Open Open
2 Closed Open Open
3 Open Closed Open
4 Closed Closed Open
5 Open Open Closed
6 Closed Open Closed