| With the rapid development of Urban Rail Transit system, there is higher andhigher requirement on the security and reliability of DC traction power supply system.As an important component of the system, DC traction reflux system is becomingmore of a concern. The DC traction reflux system is composed of rail and itsattachment, backflow cables, Rail Over-Voltage Protection Device, Unilateralconnecting device, Drainage Cabinet, track bed steel bars, and so on. All this partscomplement each other and constitute together to provide a path which traction returncurrent can backflow to traction substation negative in both normal state and faultstate. It has a very important significance to study the DC traction reflux system types,rail insulation analysis of rail potential, stray current protection, restriction and otherissues related to the them.This paper briefly introduces the principle and structure of DC traction powersupply system, and the function of each part, based on the direct grounding,floatingground and diode grounding,the three different connection ways between the tractionnegative and the ground, compares the effect of return system of rail potential, straycurrent and leakage current, thinking diode grounding system with the contact voltageis small, which can reduce the stray current advantages effectively and improves thesystem short circuit protection sensitivity.According to the dynamic characteristics of DC traction reflux system, designthe drainage automatic drainage cabinet baseding on the polarity, and put forward themulti-point monitoring data and comprehensive evaluation of automatic drainagecabinet whetherput into use. According to the distribution regularities of stray currentin identified monitoring point setting principles and different regional standardscomparison threshold. Based on the GOWA operator fuzzy control algorithm set thethreshold of the fuzzy processing and multiple attribute decision making with aplurality of monitoring points of the polarization potential positive offset averagevalue judging the need for drainage or adjustment of current drainage cabinet, througha comparison the result.Based on multi point monitoring data of dynamic drainage method, equivalentingthe exhaust flow control to the duty cycle adjustment, structure the automatic drainagecabinet duty-cycle adjusted prediction model based on the BP neural network, throughcarrying the measured data out on the model training, combining with the actualproject for the drainage flow control, then the results show that the prediction model can realize the drainage optimal control effectively.Reflux system parameters testing is currently the most difficult work generally.In view of the existing test methods about rail insulation parameter, this paperpresents a simple and feasible track-to-bed resistance online test method. According tothe date characteristics in rail insulation damage case, put forward the monitoringparameter feature extraction method based on the theory of information entropy, andthe experimental results show that the algorithm can do the insulation damage regionpositioned in between a monitoring point quickly and accurately. The rail damagelocation based on traveling wave method is applied to the rail insulation damagelocalization feasibility analysis and simulation experimentThe abnormal high rail potential lead to the Thereis of frequent action of ovpo,which greatly increased the stray current corrosion. The paper proposed a activemethods of limit rail potential: reducing the start coincidence degree by adjust thelocomotive's time in platform. The simulation results show that the two measures canreduce the rail potential effectively. |
