Probabilistic security constrained optimal power flow for a mixed HVAC and HVDC grid with stochastic infeed

This paper formulates a probabilistic security-constraint optimal power flow considering a combination of an AC system and a multi-terminal HVDC grid that can depict the future power systems. The probabilistic formulation is discussed considering uncertainty in the generation infeed (e.g. wind power). To achieve a tractable problem we use a linearized version of the power flow equations of the combined grid where the voltage angles (of the HVAC grid) and the voltage magnitudes (of the HVDC grid) are eliminated. The flexibility introduced by the HVDC terminals is exploited for control of the power flows in a corrective way, i.e adjust their setpoints after the occurrence of a contingency. The method is applied at the three area IEEE RTS96 test system and the costs, power flows and security levels are investigated. A comparison between a deterministic and the proposed probabilistic method is done.