Research On Comprehensive Reliability Assessment Model For Transmission Grid Under Lightning Disasters Based On Complex Network Theory

The security and stability of electric power production, is the foundation of the national economy and society. The transmission grid’s stable operation is the priority among priorities as an important part of power system. In recent years, lightning fault has become the first factor to affect safety operation of transmission grid. In order to draw up more economical and rational lightning protection measures, it is the extremely important content of research on reliability of power transmission grid to further study the lightning properties and accurate assessment of the reliability index of existing transmission network. This article researched on the transmission grid reliability taking lightning disaster factors into account. The results are valuable for the application of reliability model for transmission grid. The main work is organized as follows:Firstly, analyzing the lightning parameters、corresponding indicator of lightning protection performance and calculation method of lightning outage rate, the failure rate、repair rate and state model of the transmission line are established. For each transmission grid component under lightning disaster, a transmission reliability model is established according to climate model and line segments simulation, proposing the concept of lightning disaster level.Secondly, for the substation’s direct lightning protection, into line protection and valve lightning arrester protection effect, summarizing the advantages and disadvantages of calculation of the insulation fault rate of the traditional substation equipment using density function method and the interval combination method. Substation equipment reliability model is established based on probability theory and mathematical statistics theory and high-voltage power transmission equipment used in conjunction with guidelines insulated.Thirdly, for different calculation methods of weight, a new method of the weight calculation based on the degree of nodes and edges in complex network theory is proposed. Reliability index weight set of each transmission grid component is established based on the complex network theory, analyzing the statistical characteristics of complex network theory and different complex network model.Finally, a grid reliability comprehensive assessment model under the lightning disaster is established. The comprehensive assessment model is verified to be scientific and reasonable by a local high-voltage transmission network example. The influence of the weight coefficient to improve the transmission grid reliability under lightning disaster is analyzed comparatively with sensitivity and some recommendations for power system against lightning design is proposed according to study results.