Study on Inter-area Oscillation Frequency of Power Systems

Inter-area oscillation analysis is very important in power system stability research. There are many factors influencing inter-area oscillation. The relationships between various factors and inter-area oscillation are very complex. Most current studies on the relationships are quite limited, without enough theoretical analysis. Using theoretical deduction, this paper focuses on the frequency of inter-area oscillation from two aspects: power network structure and network operating conditions. Based on the concept and the deduction of eigenvalue sensitivity with respect to inter-area transfer admittance and inter-area relative angle, the influences of power grid interconnection tightness and inter-area transfer power on the frequency of inter-area oscillation are analyzed. Two illustrative examples, i.e. four-generator two-area system and the interconnected system of Northeast China and North China Power Grid are presented. They verify the validity of the theoretical analysis.