The Study of Fast Optimal Emergency Control Based on Time-Domain Simulation

The optimal emergency control is the best economical measure which can ensure power system keep stability when a catastrophic fault which may cause system instability happens. There are always two methods to simulate the transient stability, which are the time-domain method and the direct method. As the latter has poor adaptability of the model, this paper uses the former. The system instability mode usually is the first swing instability, and then the role of regulators is not clear, so the generators could be simulated by using the classical second-order model, and the loads with the constant impedance model. In order to improve computing speed, this paper uses predictor-corrector method with large integral step. This paper uses generator shedding as the emergency control measures. As the optimal generator shedding control is essentially the optimal control problem, and the generator shedding variables are always constant, thus it\´s convenient to use the control parameter algorithm for solving. This paper takes full advantage of the physical meaning of the gradient and the discrete characteristics of generation shedding, proposes the "micro-step discrete method", and improves it from the stability criterion, integral step and micro-step factor. It confirms that the method is rapid, accurate, and practical and so on through the analysis of the New England 39-bus test example.