A unified approach to the variable-time-step (VTS) method for transmis
sion-line modelling (TLM) is presented. A generalised VTS TLM algorith
m has been developed for both the short- and open-circuited transmissi
on-line segments. The unified approach simplifies the software impleme
ntation of VTS TLM algorithms and complements the mathematical approac
h previously presented.