The Development of a New Two-Input PSS to Control Low-Freqency Oscillation in Interconnecting Power Systems and the Study of a Low-Frequency Oscillation Model

Abstract

In Japan, large and small power systems were interconnected over time and thus ultimately grew into large-scale national power system. A highly important stability problems arising from large-scale power system. interconnections is low-frequency oscillation (about 0.3Hz to 0.5Hz) of interconnected systems. The ΔP-type PSS has been applied to all generators in trunk power systems as a measure to improve the damping of local mode oscillation (about 1Hz) . However, it is difficult for this PSS to improve the damping of low-frequency oscillation because of the hardware and the design of PSS control constants. It has therefore become necessary to develop a new two-input PSS. This paper explains the development of this two-input PSS and the study of a low-frequency oscillation model. The abstract of the paper can be summerised as followes:
(1) The effect of control over low-freqency oscillation is affected by the kinds of PSS detecting signals. The Δω-type or Δf-type detecting signals used for lead phase compensation are suitable for this purpose.
(2) It is possible to cause low-frequency oscillation studies in a one-machine infinte-bus power system model with medium loads.
(3) According to the simulation of a three-machine and an actual large power system models, dynamic stability was largely increased by this two-input PSS used for generators.