Probabilistic Stability Analysis of Low Frequency Oscillation of Large- Scale Interconnected Power Grid Based on the Theory of Point Estimation Method and Risk Assessment

Original scientific paper The indicators and methods of the probabilistic stability analysis of interconnected power grid’s low frequency oscillation are put forward in this paper, and the case study based on the real interconnected power grid is investigated. As the probabilistic distribution of various uncertain factors of power grid is known, the method of two-point-estimation is adopted to calculate the probabilities of low-frequency oscillation caused by these uncertain factors based on small perturbation calculation method. The theory of risk assessment is used to analyse the instability condition of power system’s low frequency oscillation caused by multiple disturbances, and then the control cost and the risk of low frequency oscillation of power grid are given. The expenses between the risks the power grid companies have taken and the costs the transmission capacity has increased are obtained through comprehensive probability analysis of small disturbance and large disturbance, which can give insights for grid operators to address the economy and security issues.