Time Delay Compensator Design for Wide-Area Power System Stabilizer to Damp Out the Inter-Area Oscillations

Power system networks are continues subjected to faults and disturbances. These disturbances could be small or severe in nature and trigger electro-mechanical oscillations due to relative motion between the rotors of synchronous machines. These oscillations can be classified as intra-plant, local plant, inter-area and torsional oscillations. Although adequate damping for all these oscillations is important, but inter-area modes are of major concern as they are difficult to control and may affect group of generators or generating plants and may result in sub-optimal power flows and inefficient operation of the grids. The low frequency oscillations in the power system network especially the inter-area oscillations (0.1 to 1 Hz) is the key factor that influence the stable operation of interconnected grids and limits the transmission capacity of large-scale power system. This dissertation deals with the stability problems of a power system with signal time delay. The usage of remote signals obtained from a wide-area measurement system (WAMS) introduces time delays to a wide-area Power System Stabilizer (PSS), which would degrade system damping and even cause instability. In this dissertation, design a delay-dependent Wide-area Power System Stabilizer (WPSS) to damp-out the inter-area oscillations in a large scale power system. The controlled signal obtained by geometric approach is used as a control input for the proposed damping controller to damp out the inter-area oscillations. Some simulations results on Kundur Two-Area Four Machine system show that the proposed controller effectively damp-out the inter-area oscillations.