At present

the return stroke speed is generally set to some fixed value between 1×10

8

m/s and 2×10

8

m/s when the nationwide lightning location systems are used to invert Cloud to Ground lightning return stroke currents. In this paper

the impact of adopting this method on the accuracy of the return stroke current inversion is discussed. Firstly

the method of using the lightning location system to invert the return stroke current is introduced

and the important influence of the speed of the return stroke on the peak current is analyzed. Secondly

based on

the relationship between the negative return stroke current and the return stroke speed proposed by Lundholm et al.

the analysis on the negative first return stroke reveals that the return stroke current below 25 kA may be underestimated

and the return stroke current above 160 kA may be overestimated. For negative subsequent return strokes

the return stroke current below 5 k A may be underestimated

and the return stroke current above 32 kA may be overestimated. Then

the return stroke speed observation results of negative first return strokes

negative subsequent return strokes

positive first return strokes and positive subsequent return strokes are summarized. It is believed that it is necessary to treat various types of return strokes in the lightning location system differently. Finally

for individual cases

the inversed return stroke currents and those measured from artificially triggered lightning and transmission towers are compared. Based on large samples obtained in Wuhan from 2012 to 2019

the cumulative probability distribution curve of the system inversed return stroke currents and the curve recommended by IEEE are compared. It is considered that the lightning location system of China’s power grid can retrieve reasonable return stroke currents

though the peak current of negative subsequent return strokes may be overestimated to a certain extent

which may be related to the fact that the return stroke speed set by the system is smaller than the actual value.