The impact of public lighting on voltage distortion in low voltagedistribution systems

摘要

Harmonic distortion has become a main concern in electricndistribution systems. Several public utilities are experiencing harmonicnproblems on their networks and some of them started to monitor thensituation of the MV and LV distribution networks. The operation of thenMV and LV networks of the AEM-Torino (the city utility) has beenninvestigated with several on-site measurements. The survey led to thenobservation of a step increase in voltage distortion on LV feeder whennthe city street lighting is switched on and, vice versa, a suddenndecrease when it is switched off. This phenomenon can be mainly tracednback to the resonance, under certain conditions, between the capacitancenof the capacitors for the improvement of the lamps power factor and theninductance of the MV/LV transformer. This work investigates thenphenomenon both from a theoretical point and with laboratory and fieldntests. Some possible remedies and their practical implementation tonreduce harmonic distortion are discussed