Analysis And Countermeasure Research On Influence To Electrical Power When The Large Capacity Synchronous Motor Starting

Synchronous motor has become widely used in key water control project,because of the advantages of adjustable power factor and speed can not change with the load, but it is difficulty to start. Synchronous motor starting process have a huge impact on the current, can reach 4-7 times the rated current of the motor, which would produce a voltage drop in the transmission and distribution lines and other electrical components,resulting in bus voltage drop of at all levels of power distribution system. If the voltage drop is large and longer duration, it will affect the normal operation of other electrical equipment distribution system, even the stable operation of the power system.In this paper, taking synchronous motors of shaanxi pumping irrigation project —Donglei pumping station(2×8 MW 10.5 k V) and Huang Jinxia pumping stations(7×18.5MW 13.8 k V) as the research object, studies the starting methods, starting characteristics of large capacity synchronous motor and its influence to the power distribution system.Firstly, the article introduces the working principle and the starting methods commonly used of synchronous motor, and using the power system simulation software to simulate different starting methods comparison to illustrate the characteristics of different starting methods. Secondly, the article taking synchronous motor of Donglei pumping station as a case, which has run more than twenty years, in accordance with the calculation principles of synchronous motor starting, calculates the bus voltage drop at all levels of power supply system, which using full-voltage starting method. Besides, this paper gives dynamic simulation results of the full-voltage starting process of synchronous motor with ETAP.Then, analyses the influence of bus voltage drop to the unit operation stability and the useful measures than can be used to improve the impact of starting pressure drop in accordance with the requirements of synchronous motor starting.Thus making the 8MW high-capacity synchronous motor of the full-voltage starting in a reliable theory of the foundation. Thirdly, taking the building project—Huang Jinxia pumping station as a case,calculates the bus voltage drop of power distribution system when the synchronous motor with full-voltage starting. Then according to the Huang Jinxia pumping station motors,power generators, wiring form and system parameters, analyzing and evaluating the influence of the terminal voltage to motor starting when every bus is running or not based on optimization theory. Besides, selecting a reasonable tap for main transformer. Proposing the feasible advice for the synchronous motor starting method, according to the results and actual project requirements and modeling and simulation of starting process usingMATALB. Finally, the article carries on the summary and the forecast to the research content, which providing the reference for the research on large capacity synchronous motor starting process and the effects on distribution system using different starting methods.