Fig. 4 shows the configuration of a direct and asymmetrical
PST. The input terminals are L1 to L3. The winding with
variable tap [8] that is connected to the input terminal is
In theory, there is no maximum for P.
Equations 4 and 9 are plotted in Fig. 6 for δ =
π
6
, with |UL1|
and |Ur|
XL+XP ST
equal to 1 pu. The curve of α is relatively linear
up to a value of about 0, 6 rad or 34 ◦
.