The Scheduling Approaches Of Steelmaking Industry Equipped With Self-generation Power Equipment Under Time-of-use Electricity Tariffs

In the face of the current global energy shortage and the increasing awareness of environmental protection,energy conservation and emission reduction have become a strong demand for social development.As a resource,energy consumption,and emission-intensive industry,the steel and iron manufacturing industry has great potential for energy conservation and emission reduction.The scheduling approach of iron-steel plant equipped with self-generation equipment under time-of-use electricity tariffs is different from the traditional pattern,and has some new features,such as three kinds of electricity prices: the time-of-use electricity tariffs,the self-generation cost and the on-grid electrovalence;the relationship between multiple electricity prices,power generation,and consumption as well as load demand and time are more complex.Aiming at the challenges of operational efficiency,cost control,energy efficiency,and environmental protection brought about by a series of new problems in scheduling problem of iron-steel plant equipped with self-generation equipment under time-of-use electricity tariffs,the scheduling approach and the power load disaggregation of the steelmaking-refining-continuous casting stage for iron-steel plant equipped with selfgeneration equipment under time-of-use electricity tariffs are studied in this paper.(1)Aiming at the traditional scheduling method under time-of-use electricity tariffs,only the time-of-use electricity tariffs is considered and the self-generation cost,and on-grid electrovalence are not considered,we study the scheduling problem of the steelmaking-refining-continuous casting stage for iron-steel plant equipped with selfgeneration equipment under time-of-use electricity tariffs with considering three types of electricity prices.A two-stage programming model,including the single cast stage and multiple casts stage,is proposed.In the single cast stage,we minimize the makespan based on the process constraints with a relaxing electrical factor to ensure continuity of production of the charges in the same cast;in the multiple casts stage,we minimize the total electricity costs based on the first stage scheduling solution and the constraints of the generator while considering three types of electricity prices involving time-of-use electricity tariffs,self-generation cost,and on-grid electrovalence.Second,two improved genetic algorithms that are based on the hybrid adjustment strategy and relationship propagation chain are developed.A real-life case study from a Chinese iron-steel plant equipped with self-generation equipment compared with the traditional solution method to verify the effectiveness of the proposed method.(2)For traditional power load decomposition,only the startup and shutdown states of the device are taken into account,and various operating states,durations of states,and the impact of time-of-use price on the device state are not taken into account at the same time.With considering the time-of-use price factor,the various operating states of the equipment and the duration of the state,we research the power load decomposition for iron-steel plant equipped with self-generation equipment under timeof-use electricity tariffs,taking into account the time-of-use price a factor semi-Markov is proposed.The model transforms the problem of power load decomposition into equipment state prediction and state duration prediction.First,the EM algorithm is used to estimate the model parameters of a single device,and then the total model parameters are calculated.Based on the total model parameters and the total load observed,the optimal state sequence of each device is obtained using the improved Viterbi algorithm,and the load of each device at each predicted time point is obtained accordingly.A reallife case study from a Chinese iron-steel plant which contains multiple equipments to verify the effectiveness of the proposed method.The approaches established in this paper for the scheduling problem of the steelmaking-refining-continuous casting stage and the power load decomposition problem can provide an effective production scheduling scheme for the steel manufacturing industry and the power consumption of production equipment,thus reducing the cost of electricity as well as achieving energy conservation and emission reduction.