Probabilistic risk and severity analysis of power systems with high penetration of photovoltaics

Abstract The main challenge of integrating high photovoltaic (PV) systems in power grids is managing their associated uncertainty which poses significant risks on the system stability and reliability. A probabilistic approach is well-suited to explore and analyse the impact of these intermittencies and uncertainties on power system operation. This paper proposes a probabilistic risk-based assessment (PRBA) framework which is suitable for power systems with high penetration of renewables such as PVs. Conventional analytical security assessment approaches typically examine the behaviour of electromechanical modes under varying operation scenarios in the power grid and often focus only on a few specific modes of interest. However, this may impose a small-disturbance stability risk of missing out critical information from other unobserved modes. The methodology proposed in this paper aims to capture the behaviours of all critical modes through modal analysis and risk matrices in order to quantify the stability risks associated with high PV-integrated power networks. Feasibility of the proposed framework is tested on a modified version of the 39-bus New England test network. Probabilistic risk-based assessment is performed and the severities measured are assessed using a sensitivity matrix to evaluate the overall small-signal instability risks associated with various PV penetration levels.