Research On Unit Commitment Considering Clean Energy

As an important part of power system, energy-saving scheduling has been paid to much attention. This paper discusses both hydro power and wind power clean energy, and focus on the analysis of cascade hydropower station, vibration problems of hydro units, pumped storage and unit commitment considering wind power uncertainty.Due to the close contact characteristics among cascade reservoirs, this paper proposes an immune algorithm in which set theory is used to deal with cascade reservoirs. In use of memory adjustment mechanism and the advantage of dealing with discrete variables of immune algorithm, hydro-units of cascade reservoirs are encoded according to hydraulic connections. Through overall coding the hydropower units of cascade reservoirs, the optimization region of hydro-thermal coordination scheduling with cascade reservoirs is reduced to enhance the efficiency of solution. Additionally, in order to enhance the efficiency of solution, the mutation rates are set according to generator types. Experiment demonstrates the effectiveness of the proposed approach.Considering the vibration problems of hydro units, the immune algorithm is improved as follows. Firstly, pseudo integer variables are used to describe the hydro units’discontinuous dispatch-able ranges. The stable intervals are memorized by units re-encoding. Antibody coding is not lengthened while algorithm efficiency is improved. Secondly, a self-adaptive mutation method considering both antibody affinity and unit characteristics is adopted to reduce the blindness of algorithm and improve the optimization efficiency. Experiment demonstrates the practicality of the proposed approach.Considering the characteristic of the pumped storage station (PSS) and the economic influence of thermal units’pollutant emission, a hydrothermal scheduling model with PSS is proposed based on economic-environmental comprehensive benefit. The algorithm uses two segments to encode PSS units for pumping and generating states while the state coupling constraints are introduced to effectively deal with the coupling problems of pumping and generating states. Then the equivalent environment value is introduced to convent emissions to pollutant value in order to estimate total affinity with coal consumption costs. Numerical examples show that this algorithm has good convergence and stronger practicability.Considering the uncertainty of wind power, this paper uses wind curtailment and reserve to deal with wind deviation. The compensation costs of wind curtailment and reserve costs are added to the objective function while wind curtailment and reserve shortage are limited by chance constraints. Then, a point estimate method is proposed to solve this uncertain model. The algorithm constructs a few specific estimate points and the estimate value of objective function is determined by a few deterministic computations. An example is used to analyze the effectiveness of the proposed method and the optimal allocation of reserve capacity can be ensured by the algorithm. At the same time, the conclusion which power structure may be adjusted in the wind power system with high permeability is obtained.