Load Modeling And Application Research Of Power System In Petrochemical Enterprises

The object of traditional load modeling is generally large load nodes of the grid.It’s rarcly to see the load modeling for a specific enterprise.The closer to the user side, the more obvious performance of the load characteristics. Petrochemical enterprise, as the concentrated area of large electricity load, the proportion of induction motor load is extremely high. The dynamic performance of induction motor is the most active factor in load characteristics, so it’s of great significance to establish its precision load models.This thesis describes two basic methods of the power system load modeling at first,introduces several power system load models.Then we use the component-based load modeling approach to achieve our goal according to the load characteristics of petrochemical enterprises.The composite load model is adopted which takes the power source,the impedance of distribution networks and reactive power compensation into consideration.we did a detailed survey of Tianjin Petrochemical Co.,obtained the statistics of the reactive power compensation capacity,the configuration of power sources, equivalent impedance of the lines and the detailed parameters of the induction motor load. Proposed a classification method of load buses, presents a classification principles and calculation methods. The completely load model of the enterprise is established then. Finally, we tested and verified the load model established above by simulating with PSCAD.The characteristics of large induction motors in the enterprise power system is analysed with the use of electromagnetic transient simulation software PSCAD.Specifically,we studied the starting process of the induction motors,the steady features under different terminal voltage,the transient characteristics under faults of external network.Then analysed the influence to transformer output voltage and bus voltage druing the starting process of the induction motors.Established the computational model in power system analysis software BPA based on the lood model presented above. Calculated the power flow of the enterprise power network in different conditions based on the load model. optimum distribution of reactive power compensation is discussed in order to meet the voltage requirements of the bus. Analysed the transient stability of the power system of the enterprise in the condition of different short-circuit faults.