The interconnection between power grids is the main experience of developing power grids all over the world, and inter regional networking and transnational networking is an important way to optimize the allocation of energy resources and improve the overall economic benefits of power grids in a wider range. As a dynamic balance system of interconnected power grid, fault occurs, the original balance is broken, fault energy moment to the power grid, the system state deteriorated rapidly, defense will lead to improper fault expanded rapidly, even blackout. According to statistics, in twenty-first Century the load loss of more than 3 million kilowatts of large blackouts, and more than 90% after the failure of the dynamic process of transmission section chain breaking and receiving end power grid voltage collapse, the total economic losses caused by more than $100 billion. Compared with foreign countries, China's power transmission scale, transmission distance, voltage level of transmission are ranked first in the world, the safe operation of power grid voltage stability problem of power grid operation face more severe, become the urgent task to establish a reliable interconnection grid dynamic security defense system.

State Grid Electric Power Research Institute of China lasted 14 years, the establishment of a power system forced oscillation theory, overcome the analysis and control technology of dynamic power transmission section, a combined control system is developed to solve the classification, power transmission section and wave oscillation "prediction, identification, location and control" 4 problems; two is a breakthrough in the power grid by the end of the whole process of voltage stability assessment and control technology, developed the first voltage stability evaluation standard of our country, the voltage stability of the entire process control system is developed, and proposes a dynamic voltage support to enhance the capacity of the national grid, greatly enhance the voltage stability level of power grid; three is to develop the world's first "MS - second - level dynamic simulation software of power system" minute class unified time scale simulation of the whole process of implementation of the national grid (about 50000 nodes) tens of minutes Accurate simulation of dynamic process even for several hours.

The project will produce 1 billion 160 million yuan of direct economic benefits, the results are applied to 34 provincial and above power grid planning and scheduling operation, guarantee the large-scale hydropower in Southwest China sent nearly three years to reduce the upper reaches of the Yangtze River abandoned water consumption 53 billion 300 million kwh. The results are applied to 22 power transmission projects and 45 sets of dynamic reactive power compensation equipment, with a total transmission capacity of about 16 million kilowatts. The results are also applied to the security analysis of power grid in Brazil, Portugal and other countries, which greatly enhance China's international influence in related fields.