Current harmonic losses resulting from first and second generation LED lights replacement with sodium vapor lights in a LV feeder

Abstract

The LED lamps require a DC current for proper functioning, thus, in order to supply this current, the diode bridge rectifiers in the internal circuit of these lamps are used. One of the problems in the old generation LEDs was the low power factor in these lamps. After development of electronic devices with soft switching, a new generation of LED lamps with high power factor has come into the commercial market. For power factor correction of LED lamps, the single-stage power factor correction circuits (PFC) are often used including a DC-DC boost converter with pulse width modulation and transformer. Despite the recent developments, the low power quality and harmonic current distortion of LED lamps is one of the basic challenges. Although a low power LED lamp doesn't have significant harmonic effects in distribution networks, however, the integration of LED lamps, especially in the lighting feeders, would increase the harmonic current distortion and reduce the power quality. Increase in the current harmonics will increase the ohmic losses along the Feeder conductors of the distribution network. In this article, there has been an attempt to examine the decreased harmonic power losses resulting from replacement of older generation (150Watt) 38 LED lights (without power factor correction circuit) and modern LED lights (with single-stage power factor correction circuit) with (160Watt) sodium vapor lamps in a lighting feeder on a street. The low voltage feeder and LED lights information has been taken from a real network. Results show that by installing LED street lights with power factor correction circuit (PFC), the harmonic losses along the network conductors are decreased by 11% compared to the sodium vapor lights. In contrast, the harmonic losses are increased by 57% with LED lights replacement without power factor correction (PFC).