The application of flexible AC transmission system (FACTS) is quite promising in power systems. The thyristor controlled series compensation (TCSC) is an important member of FACTS family. With TCSC established as a studying object, this paper mainly aims at noncommittal actuality of base-wave impedance and prosecutes a detailed analysis in time domain. With series-current-source model selected, a unique definition is provided through strict, mathematic deduction, rectifying some expressions in nowadays rese...