HVDC “Superline” for improved angular stabilityof AC-DC system
High Voltage DC Transmission (HVDC) is used for bulk power transfer over long distances. Manitoba Hydro system involves collection of AC power in the north where it is converted to DC and then transferred to southern Manitoba (approx 900km) where it is converted back to AC to feed consumers. Recently the problems of inter area oscillations have been reported in the system. Manitoba Hydro uses feedback signals such as frequency from the converter stations as control input to modulate power through HVDC links to damp these oscillations. However, sometimes these feedback signals may lack the observability of critical modes which may result in sustained oscillations and eventually in system collapse. In this research, we will investigate the local and remote signals rich in modal information to design the control system. Furthermore, we will develop a control strategy which is robust towards the loss or delay in these remote signals.