Flexible self-adjustment method's application in mid- and long-term dynamic simulation of power systems

There exists large difference among the response time constants of mid- and long-term dynamic process, and models used for the mid- and long-term dynamic simulation are relatively complex, so strong stiffness appears in the dynamic simulation process, which leads to difficulty in numerical stability and computational efficiency. This paper proposes a kind of flexible self- adjustment method for the mid- and long-term dynamic simulation of power systems. This method can dynamically and adaptively control variable grouping, relative step factor and minimal integral step size adjustments. These strategies can magnify the step sizes of some slower variables under the allowable precision, which avoids low efficiency of the conventional methods or programs with the same step size for all variables. This method overcomes the defect of the present grouping methods that is difficult to adaptively adjust multi control parameters at the same time. Simulation results are given to show the effectiveness and precision of the method, so it can adapt to the variety of mid- and long-term dynamic process.