Power systems depend on discrete devices, such as shunt capacitors/reactors and on-load tap changers, for their long-term reliability. In transmission systems that contain large wind farms, we must take into account the uncertainties in wind power generation when deciding when to operate these devices. In this paper, we describe a method to schedule the operation of these devices over the course of the following day. These schedules are designed to minimize wind-power generation curtailment, bus voltage violations, and dynamic reactive-power deviations, even under the worst possible conditions. Daily voltagecontrol decisions are initiated every 15 min using a dynamic optimization algorithm that predicts the state of the system over the next 4-hour period. For this, forecasts updated in real-time are employed, because they are more precise than forecasts for the day ahead. Day-ahead schedules are calculated using a two-stage robust mixedinteger optimization algorithm. The proposed control strategies were tested on a Chinese power network with wind power sources; the control performance was also validated numerically.
Connecting high penetration of wind power into power grid usually makes voltage fluctuate, due to the volatile nature of wind power injection. This paper therefore proposes a quadratic robust optimization model to guarantee the voltage of each wind unit within the security region, no matter how the wind power varies. Based on the wind power prediction, the prediction error is regarded as uncertainties, and the robust solution can be found by regulating the reactive power equipment and each wind unit using the duality filter method. In the proposed model, linearized derivation instead of original non-linear expressions in the objective function and constraints has been utilized. Furthermore, inner loop iterative method is introduced to reduce the linearized error, which divides the optimal voltage control into multiple steps with piecewise values and updates the sensitivity at each step, according to different wind farm size and condition. A test system with 36 wind units has been simulated, and the result using Monte Carlo simulation. Comparison with traditional method shows the effectiveness of proposed method. Index Terms--robust optimization, automatic voltage control, duality filter, inner loop iteration, wind power I.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.