Conducted mains test method in 2-150 kHz band

The frequency band from 2 to 150 kHz is used for most mains related power conversion applications, like uninterruptable power supplies (UPS), pulse width modulation (PWM) drives, active in-feed converters (AIC), switched mode power supplies (SMPS), solid state ballasts, LED drivers which are all polluting the domestic and industrial mains distribution networks. On the other hand, the same frequency band is used for power line communication (PLC) and distribution line carrier (DLC) communication systems as well as for most active capacitive, inductive and even resistive sensors. Most of these sensors have their carrier frequency within this band. As such, conducted emission as well as conducted immunity requirements need to be established for single phase, symmetrical and three phase applications and for grounding structures by using coupling and decoupling networks with a defined source/load impedance. The coupling and decoupling network shall be mains distribution network type independent: TN-S, TN-C, TT, IT. Disturbances within this band can occur either in unsymmetric, asymmetric or differential mode and may affect systems like power meters, residual current detection devices (RCD), active sensors and many other telemetry systems. Several International Standards (IS) have been published [3 15] but none of them offers (yet) an unambiguous solution for the coupling and decoupling network(s) required. In this paper, a coupling and decoupling network is presented which can be used in this frequency range for measuring the RF emission from as well as enable the injection of disturbance onto a dedicated mains port. A network has been implemented for 3-phase power applications, is transparent at the mains frequencies: 50/60 Hz, and capable to handle up to 150 Amp/phase.