Calculation of DC component of short-circuit current based on PSS/E and its effect on the breaking ability of circuit breaker

With the development of the power system, the system short circuit capacity exceeding problem has been more and more prominent, therefore accurate calculation of DC component of short-circuit current is necessary for the stable operation of the power grid. Conventional electromechanical transient simulation software of power system such as BPA, PSASP cannot calculate the DC component of short-circuit current, but PSS/E BKDY module can estimate DC component of short circuit current. In this paper the estimated DC component attenuation by PSS/E BKDY module is compared with the results of ATP-EMTP electromagnetic transient simulation and is proved to be quite accurate. Thus the influences on the breaking capacity of circuit breaker can be evaluated rather accurately to safeguard the power system operation.