Abstract
A method using steady-state solution is proposed for theoretical calculation of lightning overvoltages at a substation. The system condition which has maximum overvoltages at a substation is estimated from the frequency responses of lightning surges entering a substation and substation impedance applying this method.
This paper describes the investigation of phenomenon of the resonant, oscillating overvoltage in a transformer winding which is occurred in recent years using steady-state calculation. From tie results, it is found that this phenomenon occurred when the component of overvoltages at transformer terminal, which is coincident of tap winding frequency, is high. And the system condition which has large overvoltages depends on the length of each element of power system equipment which has periodical function. The calculated results by this method agree reasonably with the transient solutions calculated by the EMTP. The method is quite useful for lightning surge analysis which needs many calculations such as the study of relation between the length of power system equipment and an overvoltage generated.
