Prevention and control method for cascading failures of coal-fired unit

The invention discloses a prevention and control method for cascading failures of a coal-fired unit. The method comprises the steps of acquiring a health degree, failure maintenance cost and failure load transferring cost of each coal-fired unit; computing the failure rate of the coal-fired unit via the health degree, and computing the risk factor of the same through combining with the failure maintenance cost; building a multi-target function by using minimization of the risk factor and failure load transferring cost as targets; solving a health degree threshold by using Pareto of a multi-target particle swarm optimization algorithm via the multi-target function; and when the health degree is more than the health degree threshold, keeping the running state of the coal-fired unit, and otherwise, transferring load. According to the method provided by the invention, the health degree threshold is analyzed according to the running state of the coal-fired unit, the health degree of the unit is compared with the h