Effect of source inductance on controlled var operation of 12- pulse converter

This paper presents a detailed investigation of controlled Var operation of 12-pulse thyristor converter operating under asymmetrical firing angle mode. The converter is analyzed for constant active power operation and constant reactive power operation. The effect of source inductance on the operation for controlled p-q is analysezed. The different combinations of firing angles for converter 1 and converter 2 can be found to do such operation. The study shows that the best 12-pulse converter operation condition will be at Var level of 0.5 p.u., without source inductance which provides the widest range of active power control. With source inductance the best operating condition is above 0.5 p.u. The presence of 6p plusmn 1 harmonics in the input current, THD_i in the input current is more severe in asymmetrical mode as compared to the equal firing angle mode.