Characterization of a thyristor controlled reactor

This paper characterizes the operation of a thyristor controlled reactor (TCR) which consists of an inductance and a bi-directional thyristor switch connected in parallel. Firing angle control of the thyristor switches regulates the time for which the inductance is included in the circuit. This controls the average value of the inductance. The continuously regulated inductance can be used for line flow regulation and short circuit current reduction. It can also be used for series compensation when the TCR is connected in series with a fixed capacitor and when the combination is inserted in series with transmission lines. This paper analysis the operation of the TCR using equations and EMTP simulations. The analysis shows that a series compensator using TCR regulates the level of compensation from inductive to capacitive and the system response is faster than the recently commercialized 'Advanced Series Compensation' (ASC) scheme. Also, the problems of resonance and harmonic instability associated with the ASC are eliminated. The TCR can control short circuit current within half cycle.