Application Of Electronic Switch In Ground Automatic Passing Phase Separation

At this stage,the main application in our country is the technology of unilateral power supply.In order to make the load of the entire power supply system reach a balanced state,the locomotives are usually supplied with power by means of phase commutated power supply between each catenary.Since the direct connection between the catenary networks will cause a short circuit,an uncharged neutral zone is established between the various power supply networks.When the train passes through the neutral zone,the train can only pass through the neutral zone at a slow speed due to the lack of power supply in the neutral zone.This thesis studies how to pass the electrical phase split quickly and stably.This thesis mainly adopts the ground automatic over-phase technology.The principle is to switch the voltage on both sides of the neutral zone through a device with a vacuum circuit breaker,that is,a mechanical switch.The disadvantages of traditional mechanical switches are that the response time is too long,the lifespan is short,and the phase when closing is uncontrollable.It will cause the locomotive to lose power for too long when passing through the neutral zone,which is not conducive to the high-speed operation of the locomotive.When the mechanical switch is closed,the phase is uncontrollable,so that the residual voltage on the power supply network is matched with the voltage on the other side,resulting in the generation of overvoltage,causing the trip of the locomotive circuit breaker and even affecting the safety of the entire power supply line.For the new device,a detailed design was made for the train passing through the electrical phase separation zone.In order to eliminate the effects of overvoltage and overcurrent caused by mechanical switches,electronic switches are used instead of mechanical switches.According to the characteristics of the thyristor,its turn-off can be controlled under a reasonable phase angle,and its transient process can be suppressed by adopting the same phase as the residual voltage on the neutral section.The response time of the thyristor to turn off is faster,which can reduce the power-loss time of the train,and the service life of the thyristor is much longer than that of a mechanical switch,and there is no need for frequent maintenance.Use thyristor instead of mechanical switch,design a new ground automatic over-phase device,use thyristor as switch to switch two-phase voltage.In this thesis,firstly,by analyzing the traditional over-phaseseparation device,research its various parts,and design a new type of ground automatic overphase-separation device with electronic switch.Through the calculation of the field data,various parameters of the neutral zone are determined.Mathematical modeling of catenary neutral zone,test train,and over-phase device.Analyze the transient process of the locomotive under the various actions of the switch when passing through the electric phase splitting,and analyze its overvoltage.Study the relationship between the overvoltage and the closing angle of the electronic switch.Aiming at the system problem of overvoltage,a damping system is proposed to suppress it.Design the parameters of the damping system of the new device.Under the condition that the thyristor valve group conforms to the scene,complete the design and selection of the thyristor.Analyze the working conditions of thyristors in electronic switching systems,Whether it meets the design requirements.Under the parameters of the designed devices,the simulation model of the entire new ground automatic phase passing device is built.Verify that the locomotive can work normally through the electrical phase separation zone under the designed parameters.It is verified that the damping device can suppress the overvoltage problem of the system and meet the design requirements.Joint debugging is carried out through on-site devices and field test verification is carried out.The test locomotive completely passed the neutral zone many times under different traction power,without transient process and the locomotive lost power for a short time.The feasibility and reliability of the new ground automatic phase separation device has been verified.When the train passes through the neutral zone,it meets the requirements of heavy load on the middle and high slopes of the railway,which improves the process of passing the phase separation of the train.