A review of the functional and analytical characteristics of thyristor controlled series capacitor (TCSC) in electric power system

Abstract

In this work, consideration is solely laid on functional characteristic of Thyristor Controlled Series Capacitor (TCSC) in electric power system. Several operational characteristics of TCSC in electric power system are revealed. The thyristor based controller is modeled to show the various variables that constitute its adjustable reactance, XTCSC and their manner of functional dependency upon one another. With a properly presented graph, the relationship between the thyristor firing angle and the TCSC equivalent reactance are illustrated, thus, showing the two important regions- capacitive and inductive regions, and their extent of restriction with respect to the existing resonance angle, αr. From the graph, several operational modes of the device are explained as it affects the variability of the TCSC reactance in relation to the thyristor firing angle. TCSC control scheme as well as the mutual interactive response of Flexible Alternating Current Transmission System (FACTS) equipments, in general, is looked into; pointing at four effective FACTS localization Techniques that give room for cordial functional combination of FACTS implements on a system .The characteristics impact of the TCR segment of TCSC is shown, taking a look on the deformed current - voltage waveform outputs of the thyristor controlled series capacitor as generated by its TCR and capacitor branches into electric power system .This is considered under a steady state condition and within capacitive and inductive mode. With Laplace transform, the deformed current and voltage waveforms are derived, analyzed and represented in a skeletal form. Compensating voltage versus current characteristics is examined and explained with well defined diagrams. Lastly, the effect, merit and demerit of the TCR branch of a TCSC circuit are highlighted as relates to the size of the branch (TCR). This branch (TCR) is the major power controlling center of the TCSC device. It is constituted of the Thyristor component which is the switching organ of the compensator for swift response to system frequent phenomenal load changing behavior: a common factor for which the commonly used static Var compensators such as capacitors, reactors etc will soon be relegated .The paper deeply recommends the need for application of the FACTS implement in the modern power technology. This as an emphasis finds roots on the ease for system parameter controllability (using the device )with effect to proffering flexibility in the face of managing system load flow dynamism in modern electricity industry