Researches On Analysis Method Of Power System Voltage Stability And Static Angle Stability

Power system voltage stability and angle stability is one hotspot of powersystem research. Since the nineteen ninties, many scholors in power system syabilityhave a literature study of voltage stability and angle stability relationship. From thevoltage and angle instability phenomena they analized the coupling relationshipbetween them, they also seek to seek to propose a criterion to differentiate theinstability model is vltage stability or angle stability. In recent years, with theevolution of research people imminently want to study the relationship between them,so that the nature of stability can be revealed and the explanation of voltageinstability mechanism can be well made. To date, has not yet formed a systematicanalysis method for there is no practical comprehensive evaluation of voltagestability and angle stability index.This paper summarizes the current methods of the relationship between voltagestability and angle stability, indicates the benefit and disadvantage of the methods,The unified analysis method of dynamic voltage stability and power-angle stabilitywas established by using the the decentralized dynamic equivalent method.Theselected topics not only bear academic significance and theoretical methodinnovation but also of practical applied values.Voltage stability and power-angle stability are only two extreme cases of powersystem stability analysis. When Jacobian matrix is singular, it’s not only criticalpoint of voltage stability, but static critical point of power-angle stability. Accordingto the general principle of extreme value analysis of nonlinear equations, theequivalence relation of static power-angle stability and voltage stability was proved.The decentralized dynamic equivalent method was proposed, by introducing currentauxiliary variable and flow equations. The unified analysis method of dynamicvoltage stability and power-angle stability was established by using the dynamicparameters in Jacobian matrix and the nonlinear dynamic analysis principle. Throughthe application of direction differential of complex current (voltage), the relation-ship between integrated dynamic equivalent impedance and load static equivalentimpedance were studied and the comprehensive evaluation of voltage stability andstatic power-angle stability margin index were proposed. Impedance margin meansthe unitization of limit load power and the transformation of power-angle curve into power-impedance curve. The impedance margin is not only a sensitivity index, buthas good nonlinear properties. Take the dynamic characteristics of injection powerinto account further; we will promote the online application value of resistancemargin in the static stability, transient stability and dynamic stability analysis.By establishing the power system dynamic equivalent model, put forward awide range limit load power and voltage stability limit threshold voltage analyticcalculation. The decentralized dynamic equivalent method principle is able toquickly and accurately predict power system limit load power and voltage stabilitylimit threshold voltage, which can solve the trend of convergence and accuracy lossof of the saddle-node bifurcation point calculation.IEEE14node system simulation results verify the correctness of the proposedmethod. By calculate the impedance modulus margin index, the margin of resistancethe voltage stability critical voltage and the power limit of the power system inIEEE14node system, simulation results verify the correctness of the proposedmethod.