Research Of Lighting Striking Location On Transmission Line Based On OPGW

Timely and accurately obtaining the point of lighting strike is very important to reduce the losses caused by lightning accidents. Optical fiber composite overhead ground wire(OPGW) is a new kind of overhead ground wire combined with the function of lightning protection and communication. In recent years, with the extensive application of OPGW on the transmission line, lighting location based on OPGW has become a possibility.By describing the Faraday Effect on OPGW, a new method of lightning location on transmission line is researched based on the state of polarization in the OPGW, and locating the strike point based on double-terminal traveling wave method and wavelet transform modulus maxima. Compared with traditional methods, this method has a higher reliability, and doesn't need to separately set up sensors and communication devices, with a strong practical and economical.The equivalent circuit calculation shows that the spiral current on OPGW is defined by the equivalent time constant and the rise time of lightning current. The transmission line model is established by electromagnetic transient analysis software EMTP-ATP to simulate different forms of lightning on transmission lines. The simulation results show that, when lightning tower top and lightning the center of overhead lines, apparent current will be produced on the ground line, and current waveforms in both cases is obviously different. The induced current on the ground line is small when lightning on the wire. Based on this current distribution feature, lightning tower top and lightning overhead lines can be located and identified by the light polarization state change on OPGW.Lightning simulation test showed that the spiral current on OPGW is the main cause of the light polarization state, and straight component is substantially free of light polarization state change; the rise time of light polarization under induced lightning strike is approximately equal to the rise time of lighting current, and much shorter than that of direct lightning strike. Induced lightning strike and direct lightning strike can be distinguished based on this feature. The lighting location error of simulation test based on OPGW is within ±200m, with has a high positioning accuracy, and meeting the actual needs of the project. By applying the present location method for the actual line, and successfully locating the lighting on the transmission line, the feasibility of the method is proved once again.