Research On Early Warning Method And Visualization Technology Of Cascading Failures In Large Power Grid

With the rapid economic and social development, the reliability of power supply demands more requirements. However, modern power grid is large-scale interconnected. At the same time of improving the reliability and economy of power system, the dynamic behavior of power system is made more complex, in which some failures in local power grid may spread to neighboring regional power grid, triggering cascading failures, finally resulting in outage accidents or even the collapse of the power grid. Therefore, the early warning and prevention of cascading failures are important research value and the key to avoid power outages due to cascading failures.Firstly, the analysis of the reliability in power grid planning and the research on modeling cascading failures are combed. And the law of the development and dissemination of cascading failures is summarized. In the end, the explanation of the mechanism of cascading failures is illustrated.Cascading failures early warning method of large power grid is proposed based on the contents above in this article, mainly consisting of the prediction of spread chain of cascading failures. It is based on the DC sensitivity method to identity the critical lines of cascading failures, which is also the first failure. Taking into consideration overload, hidden failure and the association between components in the grid, the possible failure spread sequence is formed. In addition, the early warning information, spread sequence of cascading failures and voltage distribution included, is demonstrated with the visualization technology.As a matter of practice, the study on cascading failures is still far from the prevention and control over the cascading failures. Therefore, the prevention and control strategy of cascading failures is proposed for those situations in which there is cascading overload because device quit, unbalanced power flow and other adverse conditions. This strategy formulates the adjustment project of generators’active power according to the sensitivity analysis and the reverse same-amount pairing principle, in order to improve the power flow distribution of the system and delay the system to self-organized critical state transition process and ultimately reduce the possibility of cascading failures in power grid.In the last, IEEE-30system is used as an example of calculation and analysis, which verifies the correctness and effectiveness of the early warning method and prevention and control strategy proposed in this article.