Harmonic detection and filtering - Schneider Electric

Solutions to attenuate harmonics6.1.6 Selection of a suitable system earthingarrangementb TNC systemIn TNC systems, a single conductor, the PEN, ensures protection in the event of anearth fault and carries imbalance currents.Under steady-state conditions, the harmonic currents flow through the PEN.However, the PEN has a certain impedance, resulting in slight voltage differences (afew volts) between devices which may lead to malfunctions of electronic equipment.The TNC system must therefore be used only for the supply of power circuits on theupstream end of installations and must never be used for the supply of sensitiveloadsb TNS systemThis system is recommended when harmonics are present.The neutral conductor and the protection conductor PE are completely separate,thus ensuring a much more stable voltage on the distribution system.32