Probability Simulation And Inhibition Studies Of Over-voltage When Locomotive Passing Through Electrical Sectioning Device

The main use of voltage level in Chinese electrified railway is25kV, which is asingle-phase power frequency (50Hz) in AC as traction power supply. Segmented flow withphase method in electrified railway is mainly to make three-phase AC power system can keepthe symmetry, which can be achieved through recycled commutation method.In this paper, an analysis method of probability is proposed for circuit hidden in thetransition process. This paper is mainly proposed to the potential voltage circuits hidden in theworking state system, potential circuit under specific conditions once fired will cause thesystem to produce over-voltage, which even make power equipment insulation breakdown,causing the problem of power system fault. Some protective measures were put forward andtransition process of the electromagnetic produced over-voltage is studied by constructing thepotential chain circuit model and using the method of analysis time. At the same time analysisover-voltage on each case of Monte Carlo simulation, and find out the rules of them.The distributed capacitance and induction residual pressure theory calculation wereanalyzed through studying theoretical model of electromagnetic transient and according to thespecific structure of the traction and the joint type electric phase. A chain network modelestablished according to movement of the locomotive in traction network and electric phaseand circuit form in transient transition, which is controlled and coordinated by the timingswitch. The changes in transition state of locomotive circuit were studied. The combinedsimulation model of electric locomotive-traction network-electric phase is established byusing the PSCAD/EMTDC transient simulation software, which pave the way for studyover-voltage phenomenon when locomotive passes neutral section and put forward inhibitingmethod. In order to determine oscillating voltage in the neutral section effect on the transitionprocess of closing transient and tripping induced transient, the inhibition voltage methodswere proposed in the seven cross section articulated neutral fracture isolation and doubleneutral section of bilateral with capacitance protective, which got after comparing combinedsimulation of electrical locomotive-electric phase-traction network and analysis ofexperimental data. The results show that the weaken oscillation voltage in neutral sectionhelps to reduce impact of over-voltage on the locomotive roof insulation and traction powersupply network. Finally, Monte Carlo analysis is used to analysis over-voltage to predictover-voltage under various conditions of locomotive in random process.Research results verify that: neutral line segment method will inhibit transient overvoltage; the maximum over-voltage is reduced from108.0kV to72.3kV by installing ofsuppression circuit in electrical sectioning neutral wires, which reduced the over-voltage insulation impact for traction net and locomotives. The maximum overvoltage decreases from95.57kV in the single neutral section of the seven-span overlapping electrical sectioningdevice to59.28kV in the bilateral neutral passive RC circuit of the eight-span overlappingelectrical sectioning device, which suppressive effect is obvious. The probability of maximumovervoltage on the bilateral passive RC circuit of the eight-span electrical sectioning device ismore than60kV by Monte Carlo simulation, of which suppressive effect is obvious.