Time-varying Outage Models Of Overhead Transmission Line Based On Adverse Disaster

The power system is a combination of a lot of electrical equipment, so the increasing demands of the safe and stable operation means that, the electrical equipment need to be paid more attentions. The research on electrical equipment reliability, which is one of the key factors to ensure the safe and stable operation, laid the foundation of risk management of the whole power system. As a result, the level of asset management can also be improved effectively.Overhead transmission line, connecting the power grid, is a huge component in the power system, with a large geographical span exposure under various external natural environments. These characteristics make it one of the most important roles that cannot be ignored in the research of power system reliability. Overhead transmission line is easily influenced by extreme climate and harsh environment, like strong winds, fires, lightning, ice and some other disasters. Therefore, there is an urgent need to quantify the impact of bad disaster on the overhead transmission line outage probability, and to develop the appropriate grid security technology. In this thesis, considering two factor—fire and strong wind, which are very common and have greater impact on the overhead transmission line outage, the probabilistic models are separately established.Some overhead transmission corridors pass through fire-prone regions such as mountain and rural areas, and forest fire greatly effects on transmission line reliability. At present, in the research on reliability model of overhead transmission line, the condition of forest fire is seldom taken into account. In this article, the forest fire conditions obtained from mathematical model of surface fire behavior are taken as input variables and led into the computation of reliability of overhead transmission line. Based on the reasons causing breakdown of air gap of overhead transmission line, corresponding probabilistic model of overhead transmission line outage is built, in which the air gap breakdown mechanism under forest fire is considered, to predict the outage probability due to phase-to-ground discharge and phase-to-phase discharge.A real-time probabilistic model of overhead transmission line outage due to strong wind is also be researched. According to the changing of wind parameters, how heavy the wind load the transmission line is bearing can be obtained. Combined the design wind load, the dynamic of transmission line outage probability can be analyzed. Besides considering the influence of strong wind in short time, the fatigue breakage factor is introduced to reflect the bad impact of exposure to the harsh environment on long-serving transmission lines.On the basis of theoretical studies, the Power Grid Risk Dispatch System is built. In this system, the disaster risk identification module of transmission line is developed.