PARALLEL (QUASI-PERIODIC) FERRORESONANT OSCILLATIONS IN ELECTRICAL-POWER SYSTEMS

Quasi-periodic oscillations, hitherto unobserved in power systems, was first experienced in the French grid. Besides obtaining numerical sol ution of a set of differential equations or using the method of circle map, there are no known simple analytical tools available to study co nditions for the occurrence of quasi-periodic oscillations. Zn this pa per, quasi-periodic oscillations are analyzed by first neglecting all losses which in effect reduces the dimension of the system, The unpert urbed solution for the reduced system is obtained using the method of harmonic balance. The effect of perturbations (losses) on the unpertur bed solution are then considered one at a time by using Melnikov funct ion. The geometrical interpretation is confirmed by numerical solution on the original set of differential equations.