Locational marginal pricing-oriented transmission network expansion planning with consideration of line capacity sensitivity

Under the market environment, the traditional power grid expansion planning model is difficult to reflect the quantitative impact on the power grid investment income by global supply, demand situation, the willingness of market players and social benefits under the competitive market model in the future. In the high proportion hydropower grid, the mismatch between the capacity of hydropower transmission section and the difference between the high and low power flow leads to network congestion and trade surplus. In this paper, a transmission network expansion planning model based on the market-oriented electricity price is proposed in a high-proportion hydropower scenario. The upper level model maximizes the investment income and forms a planning decision line. The lower layer adopts the improved K-means clustering algorithm to obtain the typical annual operation mode of the high-proportion hydropower grid. Based on the market transaction clearing results and regional load response characteristics, it quantifies the post-load increment and over-network utilization rate of line planning and guides the power grid expansion planning with market price signals to promote the regional hydropower resources consumption. KKT optimal conditions are used to realize the coupling of the upper and lower layers of the model. The bi-level programming problem is transformed into a mixed integer programming problem for stable solution. Finally, a practical power grid with high proportion of hydropower in southwest China is taken as an example. The influence of market signal of high proportion of hydropower connected to the extended planning result is verified by comprehensively comparing the congestion surplus, investment income and proportion of hydropower consumption with different planning methods.