【作者】 周娟；

【导师】 陈小川；

【作者基本信息】 西南交通大学 ， 电力系统及其自动化， 2008， 硕士

【摘要】 同相供电系统由于采用平衡变换装置,可以消除系统不平衡,滤除谐波并补偿无功,使变化剧烈、含有大量谐波、低功率因数的不对称单相牵引负荷,对电力系统而言仅相当于一个纯阻性的三相对称负荷。其一次侧不再换相连接,牵引侧各供电臂电压相同,从而可以取消电分相,从根本上解决因电分相的存在而带来的一系列问题。作为同相供电的重要组成部分,保护的配置至关重要。同相供电后,牵引网的电流、电压分布发生变化,原有的保护配置对同相供电系统不再完全适用。因此研究同相供电的特点,利用各种现代技术,配置适用的同相供电保护方案对于高速、重载的铁路运输的高效、安全、可靠运行具有非常重要的作用。本文首先通过对同相AT牵引供电系统负荷电流和故障电流特点的分析,提出了一种采用全并联AT的双边供电(或多电源供电)的牵引网供电方式,并对所提出的牵引网供电方式的电能损失及故障越区时的电压降与现有的AT分区所并联的单边供电系统进行了比较。对全并联AT双边供电(或多电源供电)的供电臂保护控制方案逻辑、流程进行了分析,对其与常规供电方式的相互转换进行了研究。其次,本文分析了大负荷突增、馈线短路对平衡变换装置的影响,对平衡变换装置本身的预防保护进行了研究并进行Matlab/Simulink仿真验证。之后分析了平衡变换装置撤出运行对系统电能质量的影响,提出了平衡变换装置的平衡变换性能检测保护。最后,本文详细分析了全并联AT双边同相供电系统牵引网各种短路故障情况,通过数学方法,得出了各种故障情况下的牵引网阻抗及短路电流分布规律,并与单边全并联AT供电进行了比较。以此为基础,综合各个方面的因素,提出了全并联双边供电(或多电源供电)的牵引网保护配置方案。更多还原

【Abstract】 Thanks to the use of balance convert devices, cophase power supply system can eliminate system imbalance, filter harmonic current and compensate reactive current, so the unsymmetrical single-phase load which usually have a sharp change, abundant harmonic and low power factor may be regarded as a pure resistance symmetrical three-phase load to the power system. There is no necessary for its primary phase-changing and the feeder voltage from substations is the same value. The electric neutral section can be removed and problems which arise from it can be solved fundamentally. As one part of cophase power supply system, protection scheme is always important. In the cophase system, current and voltage in traction power supply changed and the regular protection scheme is not adaptive to the system any longer. So configuring a good protection scheme using all kinds of modern science technology considering cophase system’s characteristics plays a very important role in the high-speed and overloading railway transport’s high efficiency and safe operation.In this thesis, firstly, through the analysis of the load current and fault current characteristics of cophase AT traction power supply system, a double-end (or multi power supply) feeding system with all-parallel AT is proposed. Its electrical energy loss and the voltage drop of power supply across regions under fault is compared in theory with the existing single-end feeding system with AT-parallel only in the section posts. Furthermore, the feeder protection and control scheme logic and flow of double-end (or multi power supply) feeding is discussed. The mutual transition between it and regular feeding system is studied.Secondly, the effect of heavy load input and feeder short circuit on balance convert device is analysised and preventive protection sheme of balance convert device is studied. They are simulated by the tools Matlab/Simulink. Later the effect of balance convert device which came out of action on the system power quality is presented and the balance convert performance detective protection scheme of balance convert device is proposed.Thirdly, the various feeder short circuit faults of double-end cophase feeding system with all-parallel AT are discussed in detail. Through the mathematical analysis, the impedance and current distribution of traction power supply network under various faults is founded. Then it is compared with all-parallel AT with single-end power supply and On the basis of this, considering other factors, a set of traction power supply network protection scheme is brought forward.更多还原