电气化铁路双边供电及其对电力系统的影响与对策研究

发布时间：2018-04-18 05:02

本文选题：双边供电 + 均衡电流　；参考：《西南交通大学》2017年硕士论文

【摘要】：电气化铁路为单相负荷,对电力系统而言为不对称负荷,为减轻对电力系统的负序影响,无论是普速铁路还是高速铁路,牵引供电系统都采用了分段换相取流的方法,这就导致了牵引变电所出口处和分区所处电分相环节的出现。电分相由于其机械以及电气上的弱点不利于高速和重载运输。于牵引变电所处装设同相供电装置可有效治理负序谐波等电能质量问题以及取消变电所出口处电分相。采取双边供电方式可取消分区所处电分相环节且进一步提升牵引供电系统供电能力及供电可靠性且可配合同相供电技术实现全线贯通供电。但采用双边供电后牵引网将构成电力系统的一个连枝,类似于电力系统的高低压电磁环网,然而二者也有显著的不同,电气化铁路双边供电仅是某一相被连通而不是三相连通。相关研究表明高低压电磁环网会对电力系统的安全稳定运行产生不利影响,因此应结合电力系统与铁路实际进一步研究双边供电对电力系统的影响。首先本文分析影响电力系统侧影响均衡电流的因素,得出均衡电流主要由电力系统等值阻抗与牵引供电系统等值阻抗之比所决定,减小这一比值是控制均衡电流的关键。同时推导了贯通输电线供电方式下稳态均衡电流的表达式并就双边供电是否会对电力系统继电保护构成影响以及系统侧断线引发的潮流转移进行了理论及仿真分析,提出了一种基于分段供电与状态测控技术的双边供电保护方案。其次分析了分区所开关闭合时的暂态过程,建立冲击电流和电压幅值差、相角差的对应关系,通过PSCAD仿真验证了理论计算的正确性,提出根据所允许的稳态电流、冲击电流最大值求解允许双边供电的开关两侧电压幅值差和相角差的限额的方法。从谐波影响方面对双边供电系统谐振机理进行理论分析就谐波向高压三相系统及低压三相系统的渗透特性进行理论推导,提出了基于阻波高通滤波器的谐振及谐波渗透问题解决方案。最后利用PSD电力系统分析软件对双边供电运用于楚雄电网的可行性进行了分析,验证了外部供电方式会对双边供电均衡电流有所影响,正常运行条件下双边供电方式并不会对电力系统稳定性造成影响。
[Abstract]:The electrified railway is a single-phase load and an asymmetrical load to the power system. In order to reduce the negative sequence effect on the power system, the traction power supply system adopts the method of piecewise commutation to take the current, whether on the ordinary speed railway or the high-speed railway.This leads to the emergence of the phase separation link at the outlet of the traction substation and the sub-area.Electrical separation due to its mechanical and electrical weaknesses are not conducive to high-speed and heavy-haul transport.The power quality problems such as negative sequence harmonics can be effectively solved and the phase separation at the outlet of the substation can be eliminated by installing the in-phase power supply device in the traction substation.The two-sided power supply method can cancel the phase separation link and further improve the power supply capacity and reliability of the traction power supply system, and can cooperate with the in-phase power supply technology to realize the power supply through the whole line.However, the traction network with bilateral power supply will form a connecting branch of power system, similar to the high and low voltage electromagnetic loop network of power system. However, there is a significant difference between them. The bilateral power supply of electrified railway is only connected in one phase rather than in three phases.Related studies show that the high and low voltage electromagnetic loop network will have adverse effects on the safe and stable operation of the power system. Therefore, the influence of bilateral power supply on the power system should be further studied in combination with the actual situation of the power system and the railway.Firstly, this paper analyzes the factors that influence the equalization current of power system side, and concludes that the equalization current is mainly determined by the ratio of the equivalent impedance of power system to the equivalent impedance of traction power supply system, and reducing this ratio is the key to control the equalization current.At the same time, the expression of steady-state equalization current under the power supply mode of transmissible transmission line is derived, and the theoretical and simulation analysis on whether the two-sided power supply will affect the power system relay protection and the power flow transfer caused by the system side breakage is carried out.A two-sided power supply protection scheme based on subsection power supply and state measurement and control technology is proposed.Secondly, the transient process when the switch is closed is analyzed, and the corresponding relation between impulse current and voltage amplitude difference and phase angle difference is established. The correctness of the theoretical calculation is verified by PSCAD simulation.The method of calculating the limit of voltage amplitude difference and phase angle difference between the two sides of the switch with the maximum impulse current.From the aspect of harmonic influence, the resonant mechanism of two-sided power supply system is theoretically analyzed. The permeation characteristics of harmonic to high-voltage three-phase system and low-voltage three-phase system are deduced theoretically.A solution to the problem of resonance and harmonic penetration based on high pass filter is proposed.Finally, the feasibility of applying bilateral power supply to Chuxiong power network is analyzed by using PSD power system analysis software, and it is verified that the external power supply mode will have an impact on the bilateral power supply equalization current.Under normal operation condition, the stability of power system is not affected by bilateral power supply mode.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U223;TM732

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