Effect of renewable and load uncertainties on the assessment of power system operational risk

Probabilistic techniques can provide a deeper insight into security analysis within operational planning and operation contexts, by quantitatively considering power system uncertainties and contingency impact. This paper proposes a methodology aimed to evaluate how uncertainties on a future power system operating condition affect operational risk indices. Major uncertainties in operational planning are due to errors in the forecasts of renewable generation and load demand, performed some hours ahead of actual PS operation. A probabilistic power flow technique based on Point Estimate Method is used to account for the uncertainties in the initial power system conditions, moreover a third-order polynomial normal transformation is used to account for dependence among random inputs. This technique is integrated inside a risk assessment method and tool to quantify the effect of uncertainties on the operational risk. An application example on the Sicilian power system is described and discussed.