Research On Preventive Control Strategy Of Cascading Failures In Power Grid Based On Power Flow Tracing

With the rapid development of the global economy, the large-scale interconnection of power grid has become an inevitable trend for the development of power system, the complexity of the power grid also increases. The improving economy of power system operation proposes an even more stringent requirement for the reliability of power supply. The fault in some part of the grid might spread to the nearby power grid, and induce a chain reaction. The fault in some part of power grid might spread to the neighboring regional power grid, and induce a chain reaction, finally resulting in widespread power outages and even the collapse of the entire power grid. Therefore, finding the weak link in power grid and puting forward effective preventive control strategy of cascading failure is the key to avoid widespread power outages due to cascading failures.Firstly, the paper systematically summarizes the research status of analysis and preventive control of power grid cascading failure. The law of the development and dissemination of the cascading failure is summarized, and the explanation of the mechanism of cascading failures is illustrated which based on the theory of self-organized criticality. Analysing the shortage of analysis models for cascading failure, proposing the practical analysis method for cascading failure is necessary to further research, and given the power grid real-time cascading failure model based on the DC power flow model in order to identify the current weaknesses in power grid, so we can predict the spread sequence of cascading failures may occur in power grid.Based on the thought of power flow tracing, the concept of using share, supply rate and absorption rate is proposed, and the analytical model of the distribution relationship between generator, load and power transmission lines is established. In addition, put forward the preventive control strategy of cascading failure. First, The strategy get the using share of each generator and each lode to the each line, then adjust the line power flow by controlling the generator’s active power output, in order to achieve the purposes of improving flow distribution in power system and delaying the power system transit to a self-organized critical state, and eventually reduce the possibility of cascading failure occurred.Finally, the paper validate and analyze the correctness and validity of the preventive control strategy of cascading failure by the typical winter heavy load data of2012Gansu power grid. The example of calculation can achieve the desired result, provided a effective method for prevent the occurrence of widespread power outages.