Wind power and solar energy are representatives of renewable resources, and their volatility and randomization make power grid regard wind power and solar energy as negative load in daily dispatch. The increase of wind power and solar energy in the system may lead to the increase of uncontrollable factors, so the abilities for power grid to receive wind power and solar energy might be limited. Limiting factors including power grid's peak-load regulation capacity, frequency regulation capacity, wind power and solar energy output characteristics, load characteristics, external transmission channel of power network and so forth, setting up renewable resources index that the power grid can shoulder can reflect the "saturation level" of power grid, providing reference and evaluation basis for the operation and management of electric system. According to various kinds of factors that may affect power grid's acceptance ability, the index system which can reflect multi-time scale power grid's acceptance ability about renewable resources put forward. The power grid's acceptance ability is evaluated by power grid's short term, mid-term and long term these three time dimensions, and the operation security of the system and the restriction of the economy can also be took into consideration. Through index quantization value the power grid's acceptance ability towards different proportion's renewable resources can be reflected.
