STABILITY ANALYSIS OF A H.V.D.C. TRANSMISSION LINK
This thesis presents a brief description of the steady state and dynamic operation of a high voltage d.c. transmission link. A block diagram model and the state space equations are developed from the small signal equations. The system stability regions and the current controller, parameters for near-critical damping of the integral controller with and without phase lead, compensation are determined from root locus plots. The time domain response of the system using these controllers was calculated by digital computer solution of the state pace, equations. These studies were repeated on a small scale model and the digital solutions were found to be similar to the simulator performance. The state regulator technique was applied for optimal and suboptimal control of a h. v .d . c. link. The dynamic performance of the optimally and suboptimally controlled system were digitally calculated. The suboptimal controller was also designed and used for constant current control of the simulator. The calculated 'system performance compares favourably with the simulator response. The tracking technique is also used for constant current controller optimization and is found to increase the system response speed considerably. This research was supported by the National Research Council under Grant Nos. A-2765 and, A-7249.