Probabilistic Frequency Stability Assessment as Affected by System Load and Renewable Generation Uncertainties

The growing integration of intermittent renewable energy sources (RESs) in conjunction with fluctuations in system loads is causing an escalation in operational uncertainties within the power network. This phenomenon has the potential to impact the frequency stability of future power grids. This paper employs a probabilistic approach to introduce a comprehensive frequency stability analysis under various network scenarios, including (i) different levels of system load uncertainty, (ii) different levels of system loading, (iii) different levels of wind speed uncertainties, (iv) different levels of wind power penetration, (v) different levels of PV generation. The DIgSILENT PowerFactory is used to simulate the IEEE 39 bus network for probabilistic frequency stability analysis, employing 2000 Monte Carlo (MC) simulations. The simulation findings reveal the influence of distinct power network uncertainties on frequency stability, specifically the frequency Nadir. Increasing the uncertainty level of the system parameters (i.e., system load, wind speed, and PV generation) leads to an increase in the range of the frequency Nadir responds, which can violate its acceptable range. Also, raising the wind power penetration level and the proportion of the system loading increases the frequency response variation, resulting in a delay in system frequency recovery to a steady state.