Embedded Runge Kutta method for Power System Transient Stability Analysis

The importance of the dynamic stability analysis has been increased in the complicated power systems. Since power system operators have to confirm the status whether it is stable or not for various contingencies, faster and more accurate dynamic analysis becomes indispensable. This paper proposes an application of the explicit embedded Runge-Kuttamethod (ERK) with error assessment to the power system transient stability studies. Historically, the Tokyo Electric Power Co. (TEPCO) has been used “classical” 4 th order Runge-Kutta method (RK 4) with fixed integration step size since 1960 s. Extensive efforts have been devoted to improve the program, together with TEPCO and Mitsubishi Electric Co. (MELCO). Most of apparatus/controllers used in practical and future systems have been implemented. But we do not have variable step-size simulation nor any assessment for accuracy of dynamic studies, so far. Concerning to accuracy issue, we applied one of ERK (Dormant & Prince 41H and 51H order Pair). The proposed method will be implemented to the practical program which has been used in TEPCO. Tests are carried out with models based on existing system.