Modeling Of Power System Shock Load And Analysis Of Its Effect On Voltage Stability

With the increasing proportion of industrial load in power grid,as a special type of load,industrial electrolytic aluminum load also brings new challenges to the safe and stable operation of regional power grid.In order to make the planning and dispatching of the power grid more reasonable and ensure the safe and stable operation of the power grid,it is of great significance to establish a load model consistent with the power grid for the area with industrial electrolytic aluminum load.Because of the special production characteristics of electrolytic aluminum load,its “anode effect” often produces power impact on the power grid,so it can be classified as impact load for research.In this thesis,the typical impact load of industrial electrolytic aluminum is studied as follows.This thesis introduces the production principle and characteristics of electrolytic aluminum load,and analyzes the causes of power impact in the production process.The electrolytic aluminum load is divided into two parts: power supply system and electrolytic cell.The internal components and transient model are studied in detail.In Matlab / Simulink,the physical model of electrolytic aluminum load including high-voltage power grid,on load voltage regulation,rectifier system and electrolytic cell is built,and the variation curves of voltage,current and power in the production process are simulated.In order to build the mathematical model of impact load,three modeling methods of topdown,collaboration and bus splitting are studied.This thesis analyzes the traditional mathematical models of static load and dynamic load,and builds a shock load model which can reflect the power impact characteristics.In order to identify the parameters of the model,a new optimization algorithm Gray Wolf algorithm is adopted in this thesis.Based on the gray wolf algorithm,the identification method of typical impulse load parameters is proposed by using the load bus voltage and power variables.According to this,the identification program of impulse load parameters is compiled.Finally,through the parameter identification of the simple system model established in Matlab / Simulink and the measured load data in Yunnan power grid,the rationality of the proposed model and the effectiveness of the algorithm are verified.Finally,the bifurcation theory of power system stability analysis is applied to analyze the common bifurcation types of power system and the tracing method of predictive modified equilibrium solution manifold.On this basis,the voltage bifurcation curves of conventional static load and dynamic load are calculated.Finally,the parameters of Yunnan power grid impulse load identified in this thesis are used.The bifurcation points of single machine impulse load system dominated by impulse characteristics and load characteristics are searched respectively in Matlab / Matcont,and the influence of active and reactive power impulse of impulse load on system voltage stability is obtained.