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