Design and optimization of load shedding scheme in power systems

Load shedding is an emergency control action in power systems to protect power systems from blackouts. Under frequency load shedding schemes have been widely used to restore the stability of power system post disturbances and to avoid frequency instability. Rate of change of frequency is a suitable parameter to enhance the adaptability of under frequency load shedding scheme. A detailed step-wise description of load shedding algorithm is presented in this thesis. The test systems used for load shedding scheme is designed, modeled and simulated in Power System Simulator for Engineers (PSS/E).;The actions taken in under frequency load shedding scheme assure stability of the system but the post disturbance state may not be an optimal operating point. Hence, a problem has been formulated which gives optimal solution for post contingency state by re-dispatching generators along with minimizing the load curtailment and frequency deviation from the nominal value.;An optimal load shedding scheme based on phase angle and voltage sensitivity factors has been proposed. The optimal load shedding scheme designed helps in planning proper allocation of load shedding and minimizes the cost of shedding load during the power imbalance in the system and reduce the customer impact.