PROJECT TITLE :

Statistical analysis on measured lightning overvoltage surges in a 110 kV air-insulated substation

ABSTRACT:

The wide selection of lightning stroke characteristics and therefore the modifying effects of power system elements lead to a diversity of intrusive lightning voltage waveshapes that stress transformers. These are not the traditional normal lightning impulses with a waveshape of 1.two/50 μs. Therefore the applicability of the standard lightning impulse voltage to power transformer testing has been questioned, and the overvoltage employed in the take a look at on transformers ought to be in accordance with the lightning overvoltage measured in the sector. During this study, a lightning overvoltage monitoring system was installed in a very one hundred ten kV air-insulated substation, and the lightning overvoltages from 2007 to 2012 are measured. Analysis was conducted on the measured information, which indicated that bidirectional oscillatory lightning waveforms rose up in the measured overvoltages. Using the energy method, the bidirectional oscillatory lightning waveform was reformulated into double exponential waveform, and therefore the characteristic parameters, like peak amplitude, front time and tail time, of the measured knowledge were statistically analysed.