104 results about "Traction substation" patented technology

The invention discloses a distributed cooperative voltage control method for a hybrid flexible traction substation group, and aims at solving the problems of output voltage cooperation, no-load circulating current suppression and multi-substation load distribution during networking operation of a plurality of hybrid flexible traction substations (HFTSS). Rapid synchronization of output voltage phases of the substations is achieved by introducing an average consistency algorithm, and nearby distribution of train loads among the traction substations is achieved by combining self-adaptive virtual impedance. According to the method, the capacity of the hybrid flexible traction substation for coping with the dynamic change of the external power grid voltage phase can be effectively enhanced, the loss of a contact network is reduced, the regenerative braking energy utilization efficiency is improved, and a feasible path is provided for large-scale application of a low-cost hybrid flexible traction power supply system and improvement of a cooperative control technology system.

The method is applied to the fields of train regenerative braking energy utilization, stray current and rail potential treatment and the like in electrified rail transit, especially urban rail transit. The invention provides a direct-current traction power supply system capable of reducing the energy storage capacity of a super capacitor of urban rail transit, which is combined with a super capacitor energy storage device of the urban rail transit and supplies power to a power electronic device for treating stray current and rail potential by utilizing regenerative braking energy of a train. The super-capacitor energy storage device has the following advantages that on one hand, the energy storage capacity of the super-capacitor bank in the super-capacitor energy storage device between train braking and traction can be reduced, and the utilization efficiency of regenerative braking energy stored by the super-capacitor bank is improved; on the other hand, the problems of stray current, rail potential and the like in the system can be solved from the source, and the power supply distance of a traction substation is remarkably increased. Therefore, the direct-current traction power supply system is of great significance to green and safe operation of urban rail transit.

The invention discloses an electrified railway hybrid electric energy quality treatment device which comprises a balancing transformer, a TCLC branch and an active electric energy quality regulator. The balancing transformer comprises a primary side end and a secondary side end, the primary side end is connected with a three-phase public power grid in the traction substation, the secondary side end is provided with a series winding used for being connected with an alpha-phase traction network and a closed-loop triangular winding used for being connected with a beta-phase traction network, and the closed-loop triangular winding is provided with a first self-coupling tap and a second self-coupling tap; the first self-coupling tap, the second self-coupling tap and the remaining vertexes are connected into the TCLC branch in parallel; and the other end of the TCLC branch is connected with an IGBT switch bridge arm of the active power quality regulator. The invention further provides an electrified railway hybrid power quality management control method. According to the device cooperation control method provided by the invention, the overall cost and the installation space of the device are effectively reduced on the premise that the problems of negative sequence, low power factor and harmonic waves existing in the traction substation are comprehensively treated.

The application discloses a high-speed railway pantograph-catenary arc electromagnetic radiation interference modeling analysis method, constructs a pantograph-catenary arc-pantograph power supply system integrated model containing a traction substation model, a traction network model, a train traction transmission system model, a train-track return current grounding system model and a pantograph-catenary arc model; under a pantograph-off arc transient condition, arc current is obtained through simulation calculation; and based on the arc current, a relationship between arc radiation power and spatial equivalent electric field intensity is established to represent the influence of time-varying characteristics of traction network electrical parameters on pantograph-catenary arc electromagnetic radiation interference. Under the pantograph-off arc transient condition, the real-time changes of impedance and capacitive reactance parameters of the traction network are involved in the unified solution of arc current formation, radiation power evolution and spatial electric field intensity calculation, and meanwhile, key coupling factors of the train high-voltage system and the train-track grounding system are mainly considered, so that the accuracy and engineering applicability of pantograph-catenary arc electromagnetic radiation interference analysis are improved.

The invention belongs to the technical field of electrical monitoring, and particularly relates to a railway traction substation three-dimensional visual monitoring system, which comprises a data acquisition unit, a data processing unit and a data feedback interaction unit, and is characterized in that the data acquisition unit is used for acquiring working condition data of electrical equipment in a railway traction substation; comprising a fixed acquisition module and a mobile acquisition module; according to the invention, image information acquisition is carried out on dead corners which are difficult to cover by the fixed acquisition module through the mobile trolley, comprehensive coverage and full monitoring of the railway traction substation are realized under dynamic and static cooperation mutual verification, and the safety and reliability degree of information acquisition is improved; moreover, when the information acquisition devices corresponding to the fixed acquisition modules in part of the areas break down, the mobile trolley can be controlled to go to the fault area as a supplement, so that the blank of a monitoring network is filled, and the anti-risk capability of the whole railway traction substation monitoring system is improved.

The invention discloses a graphical fault distance measurement method and system, relates to the field of traction substation tripping fault mark distance measurement in the railway industry, and can read a fault report of a fault distance measurement device and constant value parameter configuration of the fault distance measurement device off line, and calculate and analyze a fault type, whether line current is balanced or not and a fault distance according to the data and parameters. And a result is graphically displayed, so that the distance measurement error range can be narrowed by modifying and verifying the constant value parameters, and the corrected constant value parameters are exported and stored, thereby achieving the purposes of facilitating fault analysis, improving the working efficiency and shortening the maintenance time. Maintenance personnel are helped to quickly find out fault points, timely process faults and recover normal operation of lines, and the method is very important for safe, reliable and efficient transportation of a railway system.

The utility model discloses a digital twin operation and maintenance data holographic sensing system for supporting a high-speed railway traction substation, which comprises a substation intelligent monitoring control system. A substation on-line monitoring subsystem, a substation dynamic ring measurement and control subsystem, a substation security monitoring subsystem, a substation unmanned aerial vehicle inspection system, a substation integrated automation system and a substation intelligent monitoring control workstation are respectively connected through a substation intelligent monitoring control switch. A one-way isolation device is arranged between the substation integrated automation system and the substation intelligent monitoring control switch and used for achieving one-way isolation when data of the substation integrated automation system is transmitted to the substation intelligent monitoring control system. The substation unmanned aerial vehicle inspection subsystem is connected with the substation intelligent monitoring switch through the substation wireless access security gateway; and the substation intelligent monitoring control system processes the accessed system data and transmits the processed data to the substation intelligent monitoring control workstation and the railway integrated data network.

The present application relates to the technical field of electrified railway control, and discloses a phase control closing method and a heavy haul locomotive circuit breaker, the method comprising: step one, establishing equivalent mathematical models for the heavy haul locomotive, traction substation, AT substation and traction network; step two, establishing a vehicle-network-station simulation model based on a MATALB / Simulink simulation platform; step three, obtaining the influence of different line loads on phase selection closing according to the vehicle-network-station simulation model; and step four, determining a phase control closing scheme and conducting test verification. The phase control closing and opening method of the heavy haul locomotive circuit breaker with the above structure can establish equivalent mathematical models for the heavy haul locomotive, traction substation, AT substation and traction network, and then establish a vehicle-network-station simulation model, analyze the influence of different line loads on phase selection closing, and determine a phase selection closing scheme according to the breakdown characteristics of the circuit breaker and the analysis results. The phase selection closing scheme determined through test verification can achieve the purpose of reducing the overvoltage of the closing system.

The invention provides an urban rail transit traction power supply flywheel energy storage and medium-voltage energy feedback collaborative optimization configuration method, and the method comprises the steps: introducing a flywheel energy storage unit FESE and an inversion energy feedback unit IEFE into an urban rail transit power supply system at the same time, and constructing an urban rail transit AC-DC hybrid power flow analysis model; taking the daily total cost and the static recovery period as targets to construct a comprehensive cost index; the number of FESEs and the number of IEFEs are used as discrete variables, a charging voltage threshold value and a discharging voltage threshold value of the FESEs and an action voltage threshold value of an inversion energy feedback unit are used as continuous variables, a hierarchical swarm intelligent optimization method is adopted, the purpose of minimizing a comprehensive cost index is taken as a target, and on the premise that the operation constraint of a power supply system is met, the power supply system is optimized. And outputting a collaborative optimization configuration scheme including the FESE number, the IEFE number and the sum of the FESE number and the IEFE number of the traction substations.

The invention discloses an intelligent traction power supply system power adjusting method and system. Comprising the following steps: calculating real-time transfer power, and calculating compensation current in real time by combining a power transfer error and negative sequence current; calculating a current tracking value based on the current inner loop instruction value and the voltage synchronization signal; designing a feedforward-feedback composite controller, and respectively calculating a feedforward compensation quantity and a feedback control quantity; based on the feedback control quantity and the feedforward compensation quantity, the total duty ratio of the PWM modulation signal is calculated, and a railway power regulator is driven to output an actual current value; the control method and system provided by the invention are low in engineering implementation cost, adaptive to the RPC application scene of the traction substation, and easy to popularize.

The application discloses a fault ranging method in a 1-2 mode of a traction power supply system feeder breaker, relates to the technical field of electrified railway traction power supply, and converts the uplink and downlink feeder currents of a traction substation by means of the cross-link current of an AT substation and a partition substation, so that the first fault interval from the traction substation to the AT substation can also be subjected to fault ranging by the fault ranging principle of the cross-link current ratio method. The method simultaneously considers the difference between type I and type II substation, and the fault ranging precision of the first fault interval can be improved by using the method, the ranging error is controlled within a range of 250 meters, the fault point can be quickly positioned by operation and maintenance personnel when a fault occurs, the fault is timely disposed and the line is recovered to normal operation, and the method has important significance for guaranteeing the safe, stable and efficient operation of a railway transportation system.

A kind of multi-bus traction substation self-healing reconfiguration failure recovery power supply method and system, including: in situ self-healing reconfiguration action, bus fault power supply low voltage side breaker refuses to divide, corresponding switch is locked by GOOSE signal, preset switch number constant value, breaker time delay is gradually opened in the criterion of switch number satisfaction, spare power supply high voltage side breaker time delay is closed, spare power supply low voltage side breaker has no blocking signal, then time delay is gradually closed in the criterion of switch number satisfaction, in situ self-healing reconfiguration action, bus spare power supply low voltage side breaker refuses to close, breaker time delay is gradually closed in the criterion of switch number satisfaction.The present application has the advantages that: when the self-healing action fails due to the failure of self-healing reconfiguration process, the bus will not stop power recovery, and the power supply range can be maximized, avoiding the power failure of non-fault phase bus, the present application does not need to add new equipment, and can be realized by upgrading the existing protection device.

The application discloses a kind of traction network impedance simulation system and control method based on voltage source converter, and main substation is simulated by three-phase transformer, and traction substation is simulated by single-phase transformer.Three-phase transformer steps down power supply voltage, and the voltage on the high-voltage side of the single-phase transformer of the traction substation group comes from the same two-phase voltage of the three-phase transformer, which supplies the traction network after stepping down the voltage. Among them, for the impedance simulation of the traction network, the movement of the train is equivalent to the change of the line impedance, and the VSC is used to simulate the impedance of the traction network. The VSC is used to realize the change of the impedance of the traction network on both sides of the train during the train operation. The VSC device is used to simulate the impedance of the traction network on both sides of the train during the train operation, and relevant researchers can use the invention to carry out experimental verification of the related theory of the new type of substation group bilateral traction power supply system, and promote the development of the new type of substation group bilateral traction power supply technology.

This utility model discloses a DC traction substation distribution cabinet device, including a cabinet body. A closed door is movably connected to one side surface of the cabinet body, and heat dissipation holes are provided on both sides of the cabinet body. A positioning top plate is fixedly connected to one side surface of the cabinet body, and a lifting adjustment component is provided at the lower end of the positioning top plate. This utility model changes the position of the connecting rod by moving the toggle block and squeezing the limit spring, thereby changing the engagement relationship between the cross-shaped locking block and the cross-shaped slot. This allows the connecting rod and related components to rotate independently without being rotated by the circular tube, enabling the protective plate to be opened and closed independently. Only the parts that need to be inspected or maintained are exposed, which can significantly reduce the opportunity for operators to come into contact with other unrelated parts inside the cabinet, simplify the operating environment, and thus reduce the risk of equipment failure or safety accidents caused by accidental contact.

The invention belongs to the technical field of electrified railway traction power supply, and particularly relates to a traction network multi-terminal longitudinal differential protection system and method in a bilateral through AT power supply mode. The system is provided with multi-terminal longitudinal differential protection elements according to uplink and downlink feeder lines, multi-terminal branches formed by traction substations, AT stations and partition stations are covered, and each branch is provided with a current transformer. The protection element comprises a power frequency variable quantity current differential element, a T line / F line current differential element and a low-voltage differential current starting element which are respectively adaptive to fault transient state and steady state characteristics, and rapid fault identification and accurate fault removal are realized through cooperative action. The method combines a current threshold criterion, a voltage criterion and an opposite-side permission signal, ensures the action quickness, selectivity, sensitivity and reliability, realizes quick removal of power supplies at two ends of a fault, reduces the fault isolation range, and ensures safe and stable operation of a traction network.

The application is applied to the fields of train regenerative braking energy utilization, stray current and track potential treatment in electrified rail transit, especially urban rail transit. The application provides a DC traction power supply system for reducing the super capacitor energy storage capacity of urban rail transit, which is combined with the super capacitor energy storage device of urban rail transit, and uses the train regenerative braking energy to supply power to the power electronic device for treating stray current and track potential. The application has the following advantages: on the one hand, the super capacitor group in the super capacitor energy storage device can reduce the energy storage capacity between train braking and traction, and improve the regenerative braking energy utilization efficiency of the super capacitor group; on the other hand, the problem of stray current and track potential in the system can be solved from the source, and the power supply distance of the traction substation can be significantly improved. Therefore, the DC traction power supply system has important significance for green and safe operation of urban rail transit.

The invention discloses an intelligent voltage monitoring and switching device and method for a traction substation, and relates to the technical field of railway traction power supply. Each section of bus of the traction substation is provided with a main voltage transformer and a standby voltage transformer, and each voltage transformer is provided with a voltage transformer fault monitoring module; each voltage transformer fault monitoring module comprises a voltage discrimination circuit, a voltage normal discrimination circuit, a non-voltage discrimination circuit, a low voltage value discrimination circuit, a high voltage difference discrimination circuit, a voltage transformer abnormity discrimination circuit and a voltage transformer normal discrimination circuit. And the voltage automatic switching device judges whether to switch the currently running voltage transformer according to the voltage transformer abnormal signal or the voltage transformer normal signal output by each voltage transformer fault monitoring module. Whether the voltage transformer is abnormal or not is comprehensively judged according to the normal mark of the voltage transformer, so that the fault of the used voltage transformer is determined, and the standby voltage transformer is automatically put into use.

The application discloses a hybrid regenerative braking energy absorption system and a control method thereof. The system has three different branches, namely a branch one feeding back to a 400V power distribution system, a branch two feeding back to a secondary side 1180V loop of a rectifier transformer and a branch three storing regenerative braking energy by using an energy storage unit. The regenerative braking energy is firstly supplied to a low-voltage power and lighting system through the branch one. If the braking energy is greater than the rated capacity of the branch one, the excess energy is fed back to a high-voltage AC power grid through the branch two and the rectifier transformer for a traction substation high-voltage. If the regenerative braking energy is greater than the capacity of the entire feedback part, resulting in continuous increase of the traction grid voltage, the excess energy is stored by the energy storage unit. Any branch in the system can be operated independently, and the required floor area is small, so that the system is convenient to access the already operated urban rail transit traction substation.

This invention discloses a fault location method for a traction power supply system feeder circuit breaker in a 1-to-2 mode, relating to the field of electrified railway traction power supply technology. By converting the cross-connecting current between the AT substation and the section substation into the up and down feeder currents of the traction substation, the first fault interval from the traction substation to the AT substation can also be located using the cross-connecting current ratio method. This method also considers the differences between Type I and Type II substations. Using this method can improve the fault location accuracy of the first fault interval, controlling the location error within 250 meters. This ensures that maintenance personnel can quickly locate the fault point, promptly handle the fault, and restore normal line operation when a fault occurs, which is of great significance for ensuring the safe, stable, and efficient operation of the railway transportation system.

The application discloses a site selection and capacity determination method and device for a traction substation of a flexible direct current power supply system based on a double-layer planning, and the method comprises the following steps: a double-layer optimization model of the traction substation of the traction power supply system is established, and decision variables of the double-layer optimization model are determined, objective functions of a planning layer optimization model and a running layer optimization model are established; a planning layer constraint, a planning layer additional constraint and a running layer constraint are established; an updated double-layer optimization model is obtained; an iterative solution algorithm is used to solve the updated double-layer optimization model, optimal configuration parameters are obtained, and the site selection and capacity determination of the traction substation of the traction power supply system are performed based on the optimal configuration parameters. The application considers the investment cost change caused by the system structure parameter change, considers the influence of the system running parameter change on the system running cost, proposes an iterative algorithm of the double-layer optimization model, realizes efficient and accurate solution of the double-layer optimization model, and makes the final optimization scheme more in line with engineering requirements.

A traction power supply system fault calibration method applied to an electrified railway bilateral power supply mode relates to the technical field of electrified railway traction power supply systems, and mainly comprises the following steps: dividing short-circuit current distribution of different traction substations into a plurality of short-circuit current distribution modules according to short-circuit fault point positions; superposing the plurality of short-circuit current distribution modules to obtain a power supply system fault mathematical model; the method comprises the following steps: taking a traction substation feeder line, a parallel station and a partition station incoming line circuit breaker as monitoring key nodes, and performing image drawing on each current and impedance function; judging that the fault point is located on the first side or the second side of the traction substation, the upper line or the lower line of the traction network and the left side or the right side of a parallel substation; and calculating a fault position by adopting a cross-linked current ratio curve method. According to the method, the characteristic that the power flow meets mutual superposition of power flow distribution under the action of an independent power supply when the bilateral power supply double power supplies act is utilized, and fault calibration of the bilateral power supply system traction network with a more complex topological structure can be achieved.

The application discloses a single-double edge power supply junction traction substation incoming line protection method, corresponding criteria are set according to different incoming line fault types, when any criterion is met, the protection is started and an outlet action is performed, the traction substation incoming line circuit breaker is tripped, and fault isolation is completed. Compared with the prior art, the application can realize reliable action and effective isolation under any fault type of the single-double edge power supply junction traction substation incoming line side, guaranteeing the safe and stable operation of the traction power supply system; based on part of the criteria, the corresponding fault phase can be further determined. In addition, the application can effectively avoid the adverse effects of weakly fed short-circuit current, and does not need to consider communication synchronization cooperation, avoiding the influence of time scale information error and the risk of channel interruption, and solving the technical limitations of the prior art, such as single adaptation scene and insufficient applicability of cross power supply mode.

The present application relates to the technical field of intelligent operation and maintenance of traction power supply system, in particular to a traction substation equipment detection and state consistency analysis method and system, comprising: acquiring an inspection image of the equipment to be detected, calculating a dense displacement field through a reference base map to perform non-rigid resampling on the inspection image to obtain a registration image; constructing a multi-scale image pyramid and mapping the registration image into a normalized feature tensor; for each spatial position in the normalized feature tensor, retrieving and aggregating the nearest neighbor sample features in a dynamic feature retrieval library to calculate a generated feature distance tensor graph; combining the global mean value and local connected domain characteristics of the feature distance tensor graph to determine the macroscopic switch state and microscopic defect position of the equipment to be detected, and complete the state consistency analysis of the equipment to be detected. Based on the present application, the intelligent level, stability and practical value of the traction substation auxiliary monitoring system can be greatly improved.

The application discloses a traction substation voltage intelligent monitoring switching device and method, relates to the technical field of railway traction power supply, and is characterized in that a main voltage transformer and a standby voltage transformer are arranged on each bus of a traction substation, a voltage transformer fault monitoring module is arranged for each voltage transformer, each voltage transformer fault monitoring module comprises a voltage discrimination circuit, a voltage once normal discrimination circuit, a no-voltage discrimination circuit, a voltage value low discrimination circuit, a voltage difference high discrimination circuit, a voltage transformer abnormality discrimination circuit and a voltage transformer normal discrimination circuit, and a voltage automatic switching device judges whether to switch the currently operated voltage transformer according to the voltage transformer abnormality signal or the voltage transformer normal signal output by each voltage transformer fault monitoring module. Whether the voltage transformer is abnormal is comprehensively judged according to the voltage transformer once normal sign, so that the voltage transformer fault used is determined, and the standby voltage transformer is automatically put into.

This invention discloses a power regulation method and system for an intelligent traction power supply system; including: calculating real-time transfer power, and calculating compensation current in real time by combining power transfer error and negative sequence current; calculating current tracking value based on current inner loop command value and voltage synchronization signal; designing a feedforward-feedback composite controller to calculate feedforward compensation amount and feedback control amount respectively; calculating the total duty cycle of PWM modulation signal based on feedback control amount and feedforward compensation amount, and driving the railway power regulator to output the actual current value; the control method and system provided by this invention have low engineering implementation cost, are suitable for traction substation RPC application scenarios, and are easy to promote.

This invention relates to high-voltage measurement or relay protection equipment for power supply systems, specifically a current transformer for electrified railways. It includes a casting body and a coil body encapsulated within the casting body. The coil body includes a secondary winding, a primary winding wound around the outside of the secondary winding, and a secondary winding support for supporting the secondary winding. The secondary winding comprises multiple secondary winding units arranged side-by-side, forming an integral structure by wrapping the secondary winding with an outer shielding layer. The secondary terminals of the secondary winding are located at the bottom side of the casting body, and the primary terminals of the primary winding are located at the top of the casting body. Multiple mounting inserts are provided at the bottom of the casting body. This invention is manufactured using epoxy resin vacuum casting, resulting in a product with small size, flexible installation, reliable insulation, high pollution resistance, high dynamic and thermal stability current, and low temperature rise. It is suitable for use in railway traction substation environments, thus improving the overall manufacturing level of railway substation equipment.

This invention provides a configuration method for urban rail transit ground energy storage systems based on energy coupling and co-evolution. The method includes: establishing an equivalent circuit for the system based on the load and line information of the DC traction power supply system, using the location and installed power of the traction substation where energy storage is installed as decision variables; dividing the daily train operation scenario into peak and off-peak periods based on passenger flow; determining the expression for the system energy saving amount under the daily typical scenario where energy storage is installed relative to the system without energy storage; simultaneously, using the installed energy storage capacity as a decision variable, establishing an optimal configuration model for the urban rail transit ground energy storage system considering energy storage charging and discharging losses; and solving the model using a genetic algorithm combined with a co-evolution strategy to obtain the optimal configuration results for energy storage installation location, installed power, and capacity. This invention considers the energy coupling between traction substations, trains, and energy storage, enabling precise matching of the dynamic energy demand of trains and achieving efficient utilization of overall system resources.

The utility model relates to the technical field of rail transit power supply systems, and discloses a main wiring circuit for enhancing the reliability of an urban rail transit direct current power supply system, which comprises a main / standby medium-voltage alternating current bus, a main / standby direct current bus, a transformer unit, a medium-voltage power supply unit, a direct current power supply unit and a rectifying unit. Through the designed main wiring diagram of the traction substation of the power supply system, the reliability of power supply of the traction substation can be enhanced from the perspective of uninterrupted overhaul and maintenance, main and standby redundancy support and power supply system investment saving; the problems that the site selection of a traction substation is difficult, the investment is increased and the like due to the fact that an urban rail transit power supply system excessively depends on a large bilateral power supply mode to support power supply are solved, and the method has high application and popularization value in the field of urban rail transit power supply systems in China.

The utility model discloses a lightning arrester counter mounting device for a round steel column of a high-speed rail traction substation, which comprises a fixed hoop piece and a mounting hoop piece which are combined, connecting holes are symmetrically arranged on two sides of the fixed hoop piece and the mounting hoop piece, and the fixed hoop piece and the mounting hoop piece are connected and fixed on the round steel column through bolts. The center of the outer side of the installation hoop piece is fixedly connected with an installation bottom plate, the installation bottom plate is provided with two angle steel installation holes and fixed to the vertical face of the angle steel through bolts, and the plane of the angle steel is provided with counter installation holes with the same specification as a lightning arrester counter base correspondingly and fixedly connected with a lightning arrester counter through bolts. The installation structure has the advantages that installation is convenient, meanwhile, falling and damage caused by collision in the later transportation process after welding in advance are avoided, compared with an existing installation structure, the installation structure can better adapt to construction conditions of different environment sites, and transportation is convenient.

The utility model provides a subway power supply system, and belongs to the technical field of power supply. According to the subway power supply system, the input end of a first voltage regulation and control module is connected with a first power supply, the output end of the first voltage regulation and control module is connected with the first power supply ends of a relay K1 and a relay K3, and the second power supply ends of the relay K1 and the relay K3 are grounded; the input end of the second voltage regulation and control module is connected with a second power supply, the output end of the second voltage regulation and control module is connected with the first power supply end of a relay K2, the second power supply end of the relay K2 is connected with the first end of a relay K3, and the second end of the relay K3 is grounded; the first end of the relay K1 is connected with a first power supply, the first end of the relay K2 is connected with a second power supply, and the second end of the relay K1 and the second end of the relay K2 are used for being connected into a traction substation. Normal running of the train can be guaranteed.