Electric Power Quality Control Study Based On The Measured Data

With the development of the power system, high quality of power is increasingly required. Great attention are attracted by problems caused by electrified railway due to its particularity and inportance. There are 32,000 kilometers electrified railway in China, in which external power supply are used in complex condition.。At present, the overwhelming majority of universal electrified railway's load is direct current locomotive, which is a kind of rectifier load and results in problems including:harmonics, voltage fluctuation and flicker, power factor, three-phase power system load unbalanced. Compared with other loads in power system,it possesses characteristics of stochastic volatility and single-phase asymmetry. Besides, as one of the few customs which connect high voltage power system directly, electrified railway produces harmonics and has great influences on the other customers of the whole power system.In this paper, present situation of the power quality problems caused by traction load are introduced based on mass measured data analysis. Based on measured data of Zhejiang power system, including substation in Jiangshan, Yiwu, Shaoxingdong, Xinwenzhou,Taizhou, voltage unbalance degrees and the harmonic content in those traction substations are analyzed. Moreover, different traction transformer article's affect on the primary side of power system is analyzed.In terms of SVG, modeling and simulation of the SVG compensation plan is made by MATLAB/SIMULINK power system simulation component library based on the compensation principle of SVG. Afterwards, based on measured data of substation in Nanxiang, the compensation effect on degree of voltage unbalance and current distortion rate is evaluated.Moreover, on the basis of the proposed theory of co-phase power supply systems, co-phase power supply plan is simulated by MATLAB/SIMULINK. After that, based on the measured data in Meishan traction substation, the control effect on the degree of voltage and current unbalance,power factor is analyzed.The rusults has verified that the co-phase power supply device can compensate reactive power and suppress negative phase sequence well, and achieve management requirements of power energy quality.