A Novel Control Strategy for Cascading Failures in Coal-fired Units Based on Health Degree of Generators

With the implementation of the power spot market and the requirements for power plant energy conservation and emission reduction, the power plants actively take measures to improve the stability and efficiency of the unit. An improved control strategy based on health degree is established in terms of reducing the risk of cascading failures in coal-fired units (CFICFUs) in this paper. Firstly, health degree of generator (HDOG) is formulated to evaluate whether the load of coal-fired units need to be adjusted. On this basis, a mul-objective optimal model is proposed and the NSGA-II algorithm is used to calculate the Pareto solution set. Trend tracking of critical lines is used to find generators with a large utilization rate of line, whose outputs need to be adjusted to reduce the load rate of key lines which can prevent cascading failures. Therefore, this paper designs an improved control strategy combining prevention control and congestion control to ensure that the generator load in the fault state can be transmitted to other generators in time. Taken IEEE -39 system as an example to conduct simulation, the results show that the control strategy can effectively achieve the safe and reliable grid dispatching and avoid the occurrence of cascading failure in coal-fired units.