CPF Prediction On The Node Type Conversion And Voltage Control Research

Voltage stability becomes one of hot spots with the constant expansion of the power system and the increment of customers' demand.Voltage stability becomes a prominent problem of the analysis on stability of the power system.The research of static voltage stability has got widespread used as most voltage instability is monotone in the power system.The thesis starts on voltage stability research.Additionally,this thesis states the CPF research history,analyzes the basic principles and advantages of node type conversion and introduces the influences on the power system accurate analysis.The thesis analyses the essence of the node type conversion from the angle of the reactive power balance,points out that the node type conversion is due to node constraint condition conversion,introduces the basic procedure of node type conversion.On the basis of the existing Taylor principle,this paper constructs the high order Taylor series of node voltage,line current and reactive power on power variable,constructs the mathematical model of node type conversion,deduces the prediction method of node type conversion.As in the CPF,the sudden conversion of node type leads to the burst of PV curve,the thesis ensures the CPF accuracy concerning the PV curve burst.By calculating every node type conversion point accurately,the PV curve can be deduced by adjusting calculate step length timely.Being simple and intuitive,the method can calculate the critical power variable beyond allowable error range.By constructing the high-order Taylor series of node voltage amplitude,the thesis establishes the low-voltage load-cut startup equation during the peak time and proposes a low-voltage load-cut method based on the node voltage amplitude prediction.The thesis firstly displays the operability of this method with the simple 3-node power system simulation results,the IEEE bus system simulation results verify the correctness of the proposed method.In the following chapter,the thesis carries on the IEEE bus system simulation analysis for the low-voltage load-cut project based on voltage amplitude prediction,creates one centralized load-cut control method which applies to the peak time power generation.