2.Problem Formulation
In order to diversify the generation requirements, four types of generators with different parameters are considered in this study. These four types of generators feature different generation cost and operation characteristics. Particularly, each type of generator features maximum output power constraints. When being connected into the grid, their output power features various minimum power level. Meanwhile, each generator features a starting cost, which is used to limit the on/off times. When each generator is operated with minimum output power, each of them features a fixed hourly rate. When the output power is higher than the minimum output power, the marginal cost should be considered, as introduced above.
In order to simplify the proposed problem to some extent, it is assumed that the start point appears at the beginning of each time interval. Meanwhile, compared to the generation cost of each generator, the shut-down cost is much lower. Hence, the shutting down cost is eliminated here. In order to ensure the reliable operation of generators, sufficient generation margin should be guaranteed with respect to the maximum allowable generation power. Here, it is set that the surplus generation cost is set to 30% of the maximum demand requirements. This is involved to avoid the reliability and stability issues induced by sudden load change.
It is assumed that the load demand follows the chart in Fig. 1. The detailed load data is shown in Table 1. Meanwhile, the generation parameters of each generator are summarized in Table 2. The data shown in Table 1 and Table 2 will be used in the following analysis. Meanwhile, system parameters are listed in Table 3.