Investigation methods for power quality problems in large scale LV network

Abstract

Nowadays  the  number  of  nonlinear  loads  and dispersed  generators  connected  to  the  LV  network  increases.  The influence  of  nonlinear  devices,  like  energy  saving  lamps,  com-puters or photovoltaic inverters on power quality in the grid has to be investigated. Analysis of a large number of nonlinear devices in complex network is difficult since every device has to be simulated with  the  complete  model.  For  this  reason  a  new  method  is  devel-oped. In this method the complete model of a device is replaced by an  equivalent  reduced  model.  Since  the  model  is  simple,  a  large number of the devices can be simulated. In  this  paper  an  improved  equivalent  reduced  model  is  pre-sented. The improved model allows simulations of the behavior of the devices when a dip or swell occurs. Three nonlinear devices are measured  and  modeled.  Experimental  and  simulation  results  are presented.