There is huge spatial disparity between Chinese electricity production and consumption. Most of coal, hydropower, wind and solar power resource are distributed in western provinces while population and industrial activities are agglomerated in eastern provinces, which lead to a huge amount of inter-provincial electricity flow and trade to realize supply-demand balance. Based on the annual reports of the State Power Market Trading and the China Energy Statistical Yearbook, etc., this paper established the inter-provincial electricity O-D flow matrix for 2006 and 2015 with a degree of interpretation over 95%. Then, taking the influence, extroversion, acceptability and dependence degree as main indicators, this paper analyzed the scale and strength of output and input points of 25 provincial administrative units and 2 regional units in China. The source and sink points of the inter-provincial electricity flow were determined, their field characteristics were studied, and the differences between the two years of 2006 and 2015 were compared. Further, the characteristics and changes of the spatial structure of inter-provincial electricity network were analyzed with the method of network analysis. At last, some conclusion can be drawn as follows.
Firstly, with the development of coal-fired and wind-based clean energy bases in the northwest region and the vigorous development of hydropower resources in the southwest region, the surplus of electricity in the western region has grown rapidly. China's electricity source points gradually shifted from the central to the western region and more concentrated in southwest region. Inner Mongolia, Sichuan and Yunnan became the top three source points of Chinese electricity flow with the proportions of outward electricity to total being more than 10%. Also, their proportions of outward electricity to production were all more than 30%, which means that nearly one-third of electricity was produced for other users. On the other hand, three most prosperous metropolitan regions in China, namely Beijing-Tianjin-Hebei, Shanghai-Jiangsu-Zhejiang and Guangdong, were still the main sink points with their proportions of inward electricity to total being more than 20%. Secondly, the spatial disparities of the electricity production and consumption increased, leading to the increase of sizes of the source output and the sink input. Also, the scale of inter-provincial electricity flow and network contact density showed an increasing trend. During this period, the size of interprovincial electricity flow increased 3.1 times and the inward electricity flow of Jiangsu-Shanghai-Zhejiang, Guangdong and Beijing-Tianjin-Hebei increased 5.0, 3.4 and 2.3 times, respectively. Thirdly, the inter-provincial power flow field presented a significant three-channel pattern of "West-to-East Power Transmission" from north to south, which was affected by geographical location and subordinate regional power grids. From 2006 to 2015, this pattern of three major channels remained unchanged. Further, with the development and application of UHV technology in China, long-distance power transmission became possible so that some large electricity input points can rely on multiple sources of power instead of a single source. Therefore, the inter-provincial electricity network tends to be perfect and balanced in the future.