Exploring Temporal and Spatial Evolution of the Patent Collaboration Network: A Case Study of Smart Grid Field in China

Smart grids (SGs) have been widely recognized as an effective way to achieve sustainable energy transformation. SG construction plays an important role in environmental protection and promoting world economic and social development. However, Chinese SG field is still in the technology research and development stage, with immature technology, collaborating with leading partners to achieve effective integration for grid operation control technology, flexible transmission, and other equipment seems to be a major challenge. Therefore, the core content of SG is to form a collaborative innovation network to interactively and instantly connect various partners, which will greatly enhance the interactive operations of power grid and improve the overall efficiency of SG. Under such a background, this article attempts to construct a collaborative innovation network for Chinese SG field and investigate dynamic evolution of this network, in order to form a communicating platform that allows collaboration and operations among different partners. Based on the application data of collaborative patents from National Intellectual Property Administration, PRC, this article employs social network analysis method and visualize the temporal and spatial evolution of collaborative innovation network for Chinese SG field. The results show that there is obvious stage characteristic in the temporal evolution process of the network, there are significant differences in the breadth and depth of interregional collaboration concerned with the spatial evolution, meanwhile, the patent collaboration relationships are diverse, and State Grid Corporation of China is always at the core of the network. Finally, combined with China's actual situation, some policy recommendations are raised.

I. Introduction

With the rapid development of global economy, the pressures on resources and ecological environment are increasing, and sustainable development has been and will be increasingly important to human beings. Nowadays, the demand for electric power has increased sharply in the world, the load of power grid has been increasing continuously, and the traditional power grid has become outdated. Driven by the awareness of green energy-conservation, the smart grid (SG) has emerged and become an important area of competitive development all over the world, the mainstream countries have proposed the construction of economical, efficient, safe, and reliable green power grid [1]–[3]. These countries have their own electricity market and form their own SG development model and practical experience according to their own energy situation [4]. SG construction and technology applications in developed countries such as the United States, the United Kingdom, Canada, South Korea, and the Netherlands are relatively leading [5]–[9]. Developing countries such as China, Brazil, and India have appropriate program and development in the construction and technology application of SGs, and have integrated communication networks into traditional power systems to integrate intelligently distributed energy, which allows the demand side management. Even in the same city in developing countries, there must be huge differences in information and communication technology infrastructure, but in some areas of technology, the level of development of developing countries is considered to be comparable to that of developed countries like the United States [10]–[13]. Therefore, the SG development model of developing countries such as China, India, Brazil can be used as a reference for other developing countries [14], [15]. For example, developing countries such as Pakistan have plenty of opportunities and potentials to use SG technology to cope with resource and environmental issues such as energy crisis [16]. Moreover, some scholars also have studied the island's sustainable and affordable energy needs, and are committed to transforming the isolated island power system into an intelligent system [17].