In order to define a calculation formula go to Administration->Maintenance/Calculation Formula
Find detailed instructions here:
1) Define a formula to calculating Active Energy Net Consumption
2) Define a formula to calculating Reactive Energy Net Consumption
Click button TEST to verify correctness of the definition and existing data for specific device in the system.
* Each relevant device should be configured appropriately to have next electricity consumptions types:
kWh Import, kWh Export, kVarh Import and kVarh Export.
Resulted consumption data will be available in reports.
3) Create new report. Choose "Single period comparison" type.
Choose Groups->Calculations and in Calculation choose a new created formula.