Analysis And Control Of Voltage Stability Based On Higher Order Taylor Series

In recent years, the scale of power grid expands unceasingly, and the multinational and cross regional interconnection is gradually implemented. The power system has entered the transmission era of large units, ultra-high pressure and long distance. Coupled with the increasing proportion of new energy in the power grid and the deepening of the power market reform, the structure and operation mode of power system is becoming more and more complex, and the problem of voltage stability becomes more and more prominent. Therefore, a rapid analysis of the voltage stability of power system under current operation mode and giving the corresponding stable control strategy under the condition of voltage instability is one of the important tasks to ensure the safe and stable operation of power system.Analysis of the voltage stability under current operation mode determines whether the current operating point is in the range of voltage stability region. According to the characteristics of PV curve, the high order Taylor series method is used to fit the load growth step accurately, which approaches the point of voltage collapse quickly, based on the analysis of the advantages and disadvantages of the continuous power flow method and the direct method. In the process of increasing the load step, it is easy to identify whether the system could induce the limited bifurcation based on the judgment of the power output of generator nodes. when the operating point approaches the point of voltage collapse, the voltage stability load margin index value could be obtained quickly by curve fitting method. The accuracy and rapidity of the method are verified with the IEEE-118 bus system and a practical system.The preventive control of voltage stability is an effective method to prevent voltage instability of power system. In this paper, the corresponding strategy for voltage stability preventive control is proposed through the voltage instability determined by the expected fault set in the system. Based on Taylor series expansion method, the derivative of the load margin index to the control parameters is calculated, the correlation between them is found out and the validity of the derivative prediction is verified. The effectiveness of the voltage stability preventive control is ensured and the disadvantages of the calculation speed and the calculation error caused by the the linearization of the nonlinear model is overcomed through controlling the parameters of the set and the effective range of sensitivity; Finally, with the minimum cost control as the objective function, considering the power balance and operation constraints of power system, a linear programming model for the control of voltage stability is established. Tests with a network system indicate that the proposed method is correct and effective.