Risk-Based Security and Control Framework for Power System Operation Under Significant Amounts of HVDC-connected Wind Power Generation

In the context of power system operation, probabilistic techniques can provide a deeper insight into security aspects compared to deterministic approaches, by quantitatively considering power system uncertainties and contingency impact. Moreover, they can be helpful to identify and suggest operators the most adequate control actions to reduce the operational risk. This paper proposes an original framework for risk-based assessment and control of operational security in High-Voltage Alternating Current (HVAC) power systems connected to Multi-Terminal High-Voltage Direct Current (MTDC) networks like those envisaged for the integration of future, large off-shore wind farms. After the presentation of a security assessment methodology based on the concept of risk, the paper investigates three possible preventive control strategies to reduce the risk of high current by exploiting control resources available in the system (specifically, generating units and power injections from MTDC grids). Results of the methodology applied to a test system and to a realistic power system (adapted from the Italian transmission network) are presented and discussed.