Identification of Lightning Disturbance in UHVDC Transmission Lines Using Correlation Degree Based on Short Time Window Data

In this paper, the simulation of ±800kV UHVDC transmission line in which fault lightning stroke and non-fault lightning stroke, line short circuit occur shows: because there is fault current lumped parameter access to earth during the fault lightning stroke or ground fault, the voltage waveform decrease suddenly and cross repeatedly the zero line in 5ms time window；There is no fault current accessing to earth during non-fault lighting stroke, the disturbance caused by lightning is too less than value of the pole voltage. The voltage waveform comes from the protect position change up and down around the direct voltage line and decays to the pole voltage line in the 5ms time window at last. In the case of the fault lightning or ground fault non-lightning, the correlation degree of transient component and pole voltage line in the time window is little. On the contrary, it is large during the non-fault lighting. Above this, the correlation degree is calculated using 5ms samples. This kind of algorithm can resist random noise effectively,calculating speed is very fast. Many PSCAD simulations show that the algorithm can identify lighting disturbance correctly.