Study On Load-shedding Model In Power System Risk Assessment Based On Improved Power Flow Tracing Method

At present, power system of the world is in the trend toward large-scale internet and the increasingly complex network structure, which brings potential problems of security and stability. How to increase grid reliability and improve the ability to withstand the grid risk is a topic worthy of further study. This paper is studying on the load shedding model which is used in the failure state analysis in the power system risk assessment. The main work of this paper is as follows:Firstly, the Power flow regulating method based on the power flow tracing is studied in this paper. Based on the proportional sharing principle to allocate the power to load and generator buses, we can determine the location and quantity of load shedding and generation tripping. By regulating the flow of this nodes, it can change the over load flow, and achieve the purpose of adjusting the power flow.Secondly, the improved method of load-shedding model based on power flow tracing is proposed in this paper. Contribution factors and distribution factors between loads and generators are introduced in this paper. Those nodes with larger contribution factors and distribution factors will be selected to be adjusted. By this means it ensures that the adjustment on the overload lines is the most effective, while having little impact on the non-overload lines. The IEEE24-bus system is used to verify the algorithm proposed in this paper, and the result shows its validity and efficiency.Finally, the comprehensive application of power flow risk assessment and power flow tracing method is achieved in this paper. By calculating the system risk indicators, we can find the weakness of the system, such as the serious contingencies and weak components, which can provide a reference and suggestion to the power improvement method. The IEEE118-bus system is used to demonstrate its application, which verifies the algorithm's efficiency.