Study On The Influence Of The Changes Of The Load Dynamic Character On Power System Static Voltage Stability

The modern power system is developing into a high parameters, the large units, bigpower plant, power grid, high voltage, high automation and long-distance transmissionsystem. These changes not only promote the social development but also bring newproblems, namely, voltage stability problems. Load character is one of the most active,direct factor effecting voltage stability, which largely determines the voltage stabilityand the process of voltage collapse. Therefore, it is necessary to study the dynamic loadcharacter. This paper analysis the equivalent impedance load model which inject slip,the changes reflect the changes of the dynamic load character, discusses the changes ofthe node load voltage and power when the dynamic load character changes, obtainingP-φ curve, V-φ curve. And using three element analysis method which deduces thevoltage stability of the transmission network, this paper analysis the influence of thechanges of load character and load proportion on the power system static voltagestability. At last, this paper analyses voltage instability mechanism caused by load dynamiccharacter based on three element analysis method in P-φ space and V-φ space.