Effect of TCPS on oscillations in tie-power and area frequencies in an interconnected hydrothermal power system

The analysis of automatic generation control of a two-area interconnected hydrothermal power system considering a thyristor-controlled phase shifter (TCPS) in series with the tie-line is presented. It is possible to damp the system frequency and tie-power oscillations by controlling the phase angle of TCPS. A control strategy using TCPS is proposed to provide active control of system frequency. Gain settings of the integral controllers with and without considering TCPS are optimised using integral squared error technique following a step load disturbance in each of the areas by minimising a quadratic performance index. Analysis reveals that a TCPS is quite capable of suppressing the frequency and tie-power oscillations effectively under the occurrence of sudden load changes in any of the areas when compared with that obtained without TCPS.