Abstract: There are many connections and potential DC arc fault occurrence points in a large-scale photovoltaic power station.Usually,the arc fault signal needs to pass through photovoltaic module strings and connecting cables to reach the arc fault detection unit.To analyze the possible signal change of the DC arc fault signal from the fault point to the detection point in photovoltaic system,the highfrequency equivalent model of a large-scale photovoltaic array is established in this paper.The transmission behaviors of series and parallel arc signals at different positions in photovoltaic array to the arc detection point on the DC bus are simulated and analyzed.Combined with experimental tests,it is confirmed that the arc signal is mainly affected by the parasitic parameters of the transmission cable,and its frequency characteristics changes in varying degrees.It reminds that the variation should be considered to realize DC arc fault detection using arc signal feature extraction in large photovoltaic power plants.