Quantitative Analysis of Power System Flexibility Based on K-Means Method and Copula Function

Power system flexibility analysis is important for grid development. For solving this problem, this paper constructs a flexible resource model of the power system to analyze the flexibility. The k-means method is adopted to classify the data. The probability models of wind power, PV output and load fluctuation in each scenario are constructed based on the Copula function, and the conditional probability of adjacent moments is solved by the Bayesian formula. Random sampling is performed based on the probability to generate the time series. The system flexibility margin expectation, shortage expectation and shortage probability are considered, and the operational economy is taken into account to establish quantitative assessment indices. The probabilistic optimal power flow (P-OPF) model with flexibility resources is constructed, and Monte Carlo simulation method is used to calculate the values of the assessment indexes. The IEEE RTS-24 system is used as an example to analyze the system flexibility.