IEEE C62.92.5-2020 pdf free.IEEE Guide for Surge Protection of DC Power Feeds to Remote Radio Heads.
Type (b) flashes have negative charge polarity, but an upward leader Isee Figure I(b)J. This type of lightning occurs only to relatively tall towers. It is infrequent and the database for it is small, most of it going back to Berger. Anderson. and Krominger. 1975 (ill]. For tall towers, protection design should be based on the data (however limited) for this type of lightning.
Type (d) flashes have positive charge polarity and an upward leader [see Figure Hd)J. This type of lightning occurs only to relatively tall owers. ii rarely occurs, but the efiects can be large when it does. Because there is so little data on Type (b) and Type (d) lighning. data for both are combined in one table in Table 7.3 of CIGRE TB 549(2013).
For example, for a tower 100 m tall on a mournain rising 3(X) in above its surroundings. the eflective height of the lower is 397 m. Zhou ci al. 1B31 state that the maximum Uncertainty of the values where X ? 5 in Fable 2 is 105% to 322%. Where X 4 in Table 2, ills 20% to 65%. In either case, the values in Table 2 can be much larger or smaller than those shown.
Table 2 can be used in conjunction with Figure 2 to predict the percentage of upward flashes expected to hit the tower. In the absence of better information, it is reasonable to assume that tall towers will be struck mainly by flashes with upward leaders; which in turn suggests that values from Table 7.3 ofCIGRETB 549(20 13) be used to estimate the flash waveform.
Towers, regardless of height, are likely to be struck by lightning, which will cause a surge on the RRH power feed. Because of that. surge protection is needed. What will this protection have to deal with? Two use cases illustrate the issue. The details of these cases can be found in Zatiris [B30] and Xiong [B28j. In both cases, a simulated tower and metal-oxide varistor (MOV) protection were set up in a lab, for example as in I Igme 3. For Figure 3, the simulated tower consisted of square steel tubes bent in a U shape to reduce the length of the generator leads, and the feed wire was protected with MOVs at each end.IEEE C62.92.5 pdf download.