A technique for measuring inter-area damping contributions from power system stabilizers

Some underlying causes of interarea oscillations between power pools consisting of steam and hydro units are outlined, and measurement techniques that facilitate the design of controllers to ameliorate the problem are described. The problem of lightly dampled oscillations on power systems is of interest to utilities in Canada and the US since interarea oscillations in some regions have meant derated power transfer on large interconnecting transmission lines. Simulation studies, eigenvalue analysis and state-space techniques, on-site transfer function measurement and controller design, and other analysis and design approaches have been applied in various approaches to designing power system stabilizers (PSSs) to damp these oscillations. One of the difficulties in designing and testing control strategies for damping interarea oscillations is measuring the relative interarea damping contribution from the control strategy being tested at a particular generator. Factors contributing to negative damping are reviewed, along with power system stabilizer tuning strategies. One approach to assessing damping contributions from PSSs during on-site testing is outlined.<>