The Impact of the Use of Large Non-Linear Lighting Loads in Low-Voltage Networks

Abstract

The principal numerical and experimental results obtained by the authors on the harmonic power losses in low-voltage networks in the lighting area have been summarized in this review. Light-emitting diodes (LEDs) and compact fluorescent lamp (CFL) loads were considered. Four-core cables and four single-core cable arrangements were examined. The cables were modeled by using electromagnetic finite element analysis software. It was found that the cross section of the neutral conductor plays an important role in the derating of the cable ampacity due to the presence of a high level of triplen harmonics in the distorted current. In order to reduce the third-order harmonic currents in the neutral conductor, an experimental investigation of diversity factors for LED in combination with CFL and LED lamps was also performed. Attention was paid to the reduction of the thirdorder harmonic current, which is mainly responsible for the strong increase in power losses in the neutral conductor of low-voltage installations. The convenience of having LED lamps designed to operate as two-phase loads is suggested for certain applications.

Impact of Nonlinear Lighting Loads on the Neutral Conductor Current of Low Voltage Residential Grids

“…According to Reference [3], the research regarding harmonics caused due to the lamps can be divided into two major topics: (1) the accurate modeling in the frequency domain of CFL and LED lamps [4][5][6][7], and (2) studies on the influence of nonlinear lighting loads on harmonics distortion [2,4,5,[8][9][10][11][12][13][14][15][16][17]. Most works covering the former rely on the use of models based on Frequency Coupling Matrices (FCM) [5][6][7], where the accuracy of a determined model is usually assessed by comparison with laboratory measurements.…”

“…Aggregation of CFL and its relationship with excessive neutral conductor currents in 3P4W networks, which predominant component is the third harmonic, have been studied through measurements at two installations [8], laboratory tests [15], and determining analytical expressions to estimate the value of the neutral current [9]. The replacement of certain luminaires by LED lamps and their impact on voltage and current distortion levels in LV grids [13,14], as well as on the reduction of the neutral conductor current [14,16,17], has been analyzed performing laboratory or on-site measurements. Further research has focused on the harmonic aggregation of commercially available LED lamps by experimental measurements [10,11,16].…”

“…The replacement of certain luminaires by LED lamps and their impact on voltage and current distortion levels in LV grids [13,14], as well as on the reduction of the neutral conductor current [14,16,17], has been analyzed performing laboratory or on-site measurements. Further research has focused on the harmonic aggregation of commercially available LED lamps by experimental measurements [10,11,16]. For instance, Reference [11] demonstrates the cancellation and summation of harmonics by the combined use of different LED lamps.…”