Led Lighting Spd Design Installation Guide Page 6 LED Lighting SPD Design & Installation Guide

LED Lighting Surge Protection Modules Design and Installation Guide 2015 Littelfuse LED Lighting SPD Module Design and Installation Guide www.littelfuse.com The DOE test waveform used to evaluate surge immunity of luminaires used in outdoor lighting ( Figure 4 ) is a combination 1.2x50 s open circuit voltage and 8x20 s short circuit current waveform. To perform this test, the specified peak current is calibrated on the surge generator by shorting the output to ground prior to connection to the luminaire. Figure 4. Open-circuit voltage and short-circuit current waveforms to represent transient surges on an AC power line. Vp and Ip represent the peak voltage and current, respectively. Regional Differences in Lightning Frequency Lightning frequency may refer to the number of lightning strikes in a region during a particular period or to the probability quotient of lightning strike frequency. Satellite-based Lightning Imaging Sensor (LIS) observations are used to study lightning activity in different regions of the world. This research has shown clear differences in both flash frequency and optical radiance in different regions. The flash activity in different regions shows a clear difference, corresponding to the local climate, topography, and environment conditions. IEEE studied the effect of indirect lightning on outdoor lighting and recommended transient surge testing levels (3kA and 10kA) for the United States. For other regions for which lighting survey data and regional regulations aren't available, NASA's research on worldwide lightning strike frequency ( Figure 5 ) may be useful as a reference for comparison. Central and South America, Africa, Southern and Southeastern Asia have lightning strike frequencies similar to Florida in the United States, so an equivalent surge immunity level (10kA) is suggested. For regions with fewer lightning strikes, such as Europe, Eastern Asia, and Australia, a lower surge immunity level could be considered at 3kA. 1.0 0.8 0.6 0.4 0.2 0 20 40 60 Time (s) V(t)/Vp 80 100 Duration - 50 s Front Time - 1.2 s 1.0 0.8 0.6 0.4 0.2 0 10 20 30 Time (s) I(t)/Ip 40 50 Duration - 20 s Front Time - 8 s Regional Differences in Lightning Frequency 6

Previous Page
Next Page