SATEC SA300 ezPAC Operation Manual - Manual (Page 66)

Chapter 7 Programming the SA300 Local Settings
66 SA300 Substation Automation Unit
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:
1. 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 following method is preferable.
2. 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 − =
Local Settings
This setup allows you to select the external time synchronization source and daylight
savings time options.
To configure the local time options in your device, select the device site from the list
box on the PAS toolbar, select General Setup from the Meter Setup menu, and then
click on the Local Settings tab.
The available options are described in the following table: