Research On Transmission Expansion Planning Method Of Power Grid With Wind Farms

As an emerging renewable energy, wind power attracts attention for the advantage of huge reserves and wide spread, and develops rapidly in recent years. With the large-scale wind farms accessing the power system, the volatility and random of wind power bring extra difficulties to the planning and operation of the grid. Therefore, it is necessary to study the transmission expansion planning considering wind farms so that the security and reliability of power grid with the wind farms accessed can be ensured.In this paper, the probabilistic load flow and dependent chance programming method are used as a tool to study the access of wind farms and the method of transmission network expansion planning. First, considering the frequency constraints and peak-load regulation capacity constraints of the grid, the capacity of the power grid to accept wind power is calculated. The best access-point of wind farms is also discussed to provide the basis for the transmission network expansion planning with the wind farms accessed the grid. Second, the characteristics of wind speed and wind power output is analyzed, then the model of wind power output and the AC probabilistic load flow model are established. The expansion planning model of power grid with the wind farms is established using dependent chance programming method, and the model can be solved by using the hybrid intelligent algorithm to form a set of initial feasible planning schemes. To determine the optimal scheme, the Probabilistic Risk Assessment method is used to assess the initial schemes. In this paper the Probabilistic Reliability Indices are modified, and a probabilistic index which can describe the overall reliability of the system can be weighted calculated. On this basis, a concept of Probabilistic Incremental Reliability Value (PIRV) is proposed and applied to transmission planning to ensure the greatest economic and social benefits be brought about by the planning result. Finally, planning studies of Garver-6bus system are performed by using MATLAB to compile programs, so that the reasonable and effective of the method proposed in the paper is verified.