Impact of High Proportion of Renewable Energy on Power System Based on Grid Function Layer Analysis

The high-speed promotion of renewable energy bring about problems such as the construction of power grids lags behind that of renewable energy and there are not enough flexibility resources installed near the renewable generation stations. These lead to the inevitable situation that, besides consumed by local load, a proportion of renewable power need to be transmitted to external power systems through the local grid, which would result in the impact of renewable energy on the whole system. To investigate this impact on the system in such a situation, we propose a perspective of grid function for analysis. The functions of local load supply and external power transmission are explained and distinguished based on the power flow tracing method. The indicators of the coupling of the two function layers are proposed, considering both grid structural characteristics and coupling consequences. In addition, an economic dispatch model in AC/DC hybrid system considering system's mitigation effect on volatility is built as an evaluation method. The case study demonstrates the distinction of function layers and the influence factors such as penetration level of renewable generation and structure of the grid are investigated.