Frequency control strategies in a renewable energy intensive power system: options for South Africa

Abstract Inertia reduction due to high-level penetration of converter interfaced components may result in frequency stability issues. The paper analyses different frequency strategies for both solar photovoltaic (PV) and wind generators to support inertia, and also evaluates the contribution of synchronous condensers (SCs) to the system inertia of the power grid. Decommissioned power plants can potentially be retrofitted to SC mode in order to provide inertia support after they are retired. This paper investigates the various frequency control strategies available to the South Africa power grid in the face of increasing renewable energy integration, and makes a case for the modification of the many mothballed coal-fired power plants to SC mode.