In this paper, a configuration of a single-stage AC-DC converter and a high voltage resonant controller
IC L6598 for LED street light driver is discussed. The converter is obtained by integrating two boost
circuits and a half-bridge LLC resonant circuit. A voltage double rectifier circuit is adopted as output
to lower the voltage stress on transformer and the associated core. The two boost circuits work in
boundary conduction mode (BCM) to achieve the power factor correction (PFC). The converter works
in soft-switching mode allowing the power switches to operate in zero-voltage-switching (ZVS) and
the output diodes to operate in zero-current-switching (ZCS). This reduces the switching losses and
enhances the efficiency. The converter features lower voltage stress on the power switches and the bus
voltage is reduced to slightly higher than the peak input voltage. Therefore, the converter can perform
well under high-input-voltage. Here, the DC bus and the output filter capacitances are greatly reduced.
So, electrolytic capacitor-less converter can be realized for a long lifetime LED driver. Simulation results
from PSpice are presented for a 100-W prototype.
Flashover on transmission line insulators is one of the major causes of line outages due to contamination from the environment or ageing. Power utility companies practicing predictive maintenance are currently exploring novel non-contact methods to monitor insulator surface discharge activities to prevent flashover. This paper presents an investigation on the UV pulse signals detected using UV pulse sensor due to the discharges on the insulator surfaces under varying contamination levels and insulator ages. Unaged and naturally aged insulators (0 to >20 years) were artificially contaminated (none, light to heavy contamination). The electrical stresses on the insulator surfaces were varied to generate varying discharge intensity levels on the surfaces of the insulator. The DC and harmonic components of UV pulse signals detected during surface discharges were recorded and analysed. Results show a positive correlation between the discharge intensity level of contaminated and aged transmission insulators with the DC and harmonic components of the UV pulse signals. Furthermore, the study revealed that under dry insulator surface conditions, insulator ageing has a more profound effect during discharges than contamination level. The findings from this study suggest that the use of UV pulse sensors to monitor UV pulse signals emitted during insulator surface discharges can be another novel non-contact method of monitoring transmission line insulator surface conditions.