ABSTRACT
There are various kinds of transients in a power system. In general, the overvoltages caused by the transients are important in the power system because of its insulation against the overvoltages. Table 2.1 summarizes the overvoltages in the power system [1,2]. The temporary overvoltage is an overvoltage caused by an abnormal system condition such as a line fault and is evaluated by a steady-state solution of the abnormal system condition. Thus, the temporary overvoltage is not considered as a transient overvoltage. A typical example of a temporary overvoltage is shown in Figure 2.1 caused by a line-to-ground fault. Right after the initiation of the line-to-ground fault, a transient called “fault surge” occurs but is died out by few milliseconds. Then, a sustained dynamic overvoltage is observed, and this is called “temporary voltage.”
