阅读说明：本技术 一种适用于高速列车的第三轨独立接地系统 (Third rail independent grounding system suitable for high-speed train ) 是由 肖嵩 张灿 孟举 赖新安 叶智宗 童梦园 李玉航 吴京驰 罗远培 饶阳 高国强 于 2019-11-07 设计创作，主要内容包括：本发明公开一种适用于高速列车的第三轨独立接地系统,包括工作接地系统和保护接地系统；工作接地系统包括接地第三轨,接地第三轨平行于两钢轨并设置在两钢轨外侧,列车受电弓依次经过真空断路器、车载变压器一次侧,主变压器一次侧后,通过第一滚筒接地碳刷与接地第三轨滚动连接,使工作电流经接地第三轨回流至牵引变电所；保护接地系统包第二滚筒接地碳刷,列车转向架与车体通过第二滚筒接地碳刷及车轮与钢轨滚动连接,使漏电流经钢轨回流至牵引变电所。本发明能有效的改善动车组车轨环流现象,防止车载弱电设备因车轨环流抬升车体电压受到损害,以及防止雷击冲击和升弓浪涌产生的过电压对弱电设备的反击,提高动车组运行的安全可靠性。(The invention discloses a third rail independent grounding system suitable for a high-speed train, which comprises a working grounding system and a protection grounding system, wherein the working grounding system is connected with the protection grounding system; the working grounding system comprises a grounding third rail, the grounding third rail is parallel to the two steel rails and is arranged on the outer sides of the two steel rails, a train pantograph sequentially passes through the vacuum circuit breaker and the primary side of the vehicle-mounted transformer, and the main transformer is in rolling connection with the grounding third rail through a first roller grounding carbon brush after the primary side of the main transformer, so that working current flows back to the traction substation through the grounding third rail; the protective grounding system comprises a second roller grounding carbon brush, and the train bogie and the train body are in rolling connection with the steel rail through the second roller grounding carbon brush and the wheels, so that leakage current flows through the steel rail and flows back to the traction substation. The invention can effectively improve the rail circulation phenomenon of the motor train unit, prevent the vehicle-mounted weak current equipment from being damaged by the voltage of a vehicle body raised by the rail circulation, prevent the lightning stroke impact and the back attack of overvoltage generated by the bow-raising surge on the weak current equipment, and improve the safety and reliability of the operation of the motor train unit.)

1. A third rail independent grounding system suitable for a high-speed train is characterized by comprising a working grounding system and a protection grounding system; the working grounding system comprises a grounding third rail (3), the grounding third rail (3) is parallel to the two steel rails (1 and 2) and is arranged on the outer sides of the two steel rails (1 and 2), a train pantograph (13) sequentially passes through a vacuum circuit breaker (24) and a primary side of a vehicle-mounted transformer (12), and after the primary side of the main transformer, the main transformer is in rolling connection with the grounding third rail (3) through a first roller grounding carbon brush (4), so that working current flows back to a traction substation through the grounding third rail (3); the protective grounding system comprises a second roller grounding carbon brush, and the train bogies (10, 14) and the train body (6) are in rolling connection with the steel rail (1) through the second roller grounding carbon brush and the wheels (8, 9), so that leakage current flows back to the traction substation through the steel rail (1).

2. The third rail independent grounding system for high-speed trains according to claim 1, characterized in that a grounded third rail protection cover (5) is arranged outside the grounded third rail (3).

Technical Field

The invention relates to the technical field of high-speed train power utilization safety, in particular to a third rail independent grounding system suitable for a high-speed train.

Background

The high-speed motor train unit is used as a key part of a high-speed railway running system, and the safety and stability of the high-speed motor train unit are important. With the continuous improvement of the running speed of high-speed trains in China, the requirement on traction power is continuously increased, the requirement on a grounding system of a motor train unit is higher and higher, the unreasonable design of the grounding mode and parameters of the motor train unit can cause serious influence on the safe running of the motor train unit, such as the phenomena of abnormal abrasion of a grounding carbon brush, lifting of the electric potential of a train body, error reporting and even burning of a vehicle-mounted sensor and the like.

According to the grounding mode and the functional characteristics, the grounding of the motor train unit is divided into two modes, namely a mode of grounding vehicle-mounted traction electrical equipment (working grounding), namely refluxing the working current of the whole vehicle to a traction substation, mainly providing a grounding channel for a traction transformer and a traction motor, and simultaneously providing a discharge channel for overvoltage such as lightning impulse, lifting bow surge and the like; the other mode is that weak current equipment is grounded (protection grounding), namely, the mode that the induced current of the electric equipment of the whole vehicle or the leakage current of the electric equipment flows back to the traction substation provides a grounding channel for the weak current control equipment and the vehicle body. The two grounding modes are generally composed of a specific cable and a carbon brush arranged at the shaft end of a bogie, the working grounding cable is connected with the primary side of a main transformer of the whole vehicle, and the protective grounding cable is connected with a bogie frame and a vehicle body.

On one hand, the working grounding system of the high-speed motor train unit is an important channel for ensuring that the traction current of the motor train unit flows back to the traction substation; on the other hand, the protective grounding system of the high-speed motor train unit can connect the train body with the steel rail, the vehicle-mounted weak current equipment of the motor train unit takes the train body potential as the common reference ground potential, and the unreasonable grounding mode can lead the train body potential of the motor train unit to be unstable, the phenomenon of vehicle body potential lifting occurs, the normal work of the vehicle-mounted weak current equipment is influenced, and the safe operation of the motor train unit is influenced.

The train body of the motor train unit is generally used as a common reference ground of an on-board strong electric system and a reference ground of a communication, control and other weak electric systems. When lightning stroke occurs or overvoltage is operated, a lightning arrester or a grounding protection switch on the roof is closed, so that huge lightning stroke and surge current are diffused to the ground through the vehicle body, the grounding carbon brush, the wheel pair and the steel rail. In addition, the steel rail is polluted, so that the loop resistance of the steel rail is larger than that of the vehicle body, part of traction backflow flows to the vehicle body through the protective grounding system, rail circulation is formed, and weak current equipment such as vehicle-mounted control and communication can be damaged. At present, in order to solve the problem of rail backflow, a ground resistor is generally added between a vehicle body and a ground carbon brush, and generally, the sliding contact resistance between the ground carbon brush and an axle is in the milliohm magnitude, so that the traction current mainly enters the ground through the ground carbon brush, the traction current component entering the vehicle body through an isolation resistor is small, and the induced current generated by the traction current in a vehicle body loop is further inhibited due to the connection of the ground resistor. Therefore, the current entering the vehicle body can be reduced, and the current passing through the bearing can be effectively reduced, so that the aim of protecting the axle bearing is fulfilled. However, when overvoltage impact such as lightning trip occurs, the lightning arrester or the grounding switch is closed, transient impact current is directly added to the grounding resistor, and the potential of the vehicle body is sharply increased. It follows that the selection and arrangement of the grounding point of the train, as well as the grounding parameters (resistance, capacitance and inductance in the grounding loop) are directly related to the grounding effect. If the grounding point and the grounding parameter are not properly selected, the overvoltage cannot be effectively released; and the improper selection of the position of protection ground connection and work ground connection will probably lead to the traction current of work ground connection release to pass through the protection ground connection to the automobile body for automobile body potential lifting causes the threat to personnel and on-vehicle weak current controlgear.

At present, the grounding mode and the grounding parameter are not set uniformly, and even vehicles of the same model do not have the uniform grounding mode and the uniform grounding parameter, so that an optimal grounding mode of a high-speed train is urgently required to be sought.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide a third rail independent grounding system suitable for a high-speed train, which can effectively improve rail circulation of a motor train unit, prevent vehicle-mounted weak current equipment from being damaged by vehicle body voltage raised by rail circulation, prevent overvoltage generated by lightning strike impact and pantograph-raising surge from counterattacking the weak current equipment, and improve the safety and reliability of operation of the motor train unit. The technical scheme is as follows:

a third rail independent grounding system suitable for a high-speed train comprises a working grounding system and a protection grounding system; the working grounding system comprises a grounding third rail, the grounding third rail is parallel to the two steel rails and is arranged on the outer sides of the two steel rails, a train pantograph sequentially passes through the vacuum circuit breaker and the primary side of the vehicle-mounted transformer, and the main transformer is in rolling connection with the grounding third rail through a first roller grounding carbon brush after the primary side of the main transformer, so that working current flows back to the traction substation through the grounding third rail; the protective grounding system comprises a second roller grounding carbon brush, and the train bogie and the train body are in rolling connection with the steel rail through the second roller grounding carbon brush and the wheels, so that leakage current flows through the steel rail and flows back to the traction substation.

Furthermore, a grounded third rail protective cover is arranged outside the grounded third rail.

The invention has the beneficial effects that:

according to the invention, the special grounding third rail is arranged, so that the working grounding system and the protective grounding system of the existing high-speed train are effectively isolated, and the current situation that the rail circulation is easily caused because the grounding return ends of the working grounding system and the protective grounding system of the existing high-speed train are on the same side of the steel rail is avoided; because the working grounding system and the protective grounding system are isolated, the traction current does not enter the vehicle body through the protective grounding system, the damage of the grounding carbon brush caused by abnormal heating of the grounding carbon brush is avoided, the lifting of the vehicle body potential caused by the vehicle rail circulation is avoided, and abnormal error reporting and damage of the vehicle-mounted sensor are reduced.

Compared with the technical scheme that the grounding resistance is added between the grounding carbon brush and the train body of the existing high-speed train for solving the technical problem of rail backflow, the grounding resistance is omitted, the phenomenon that the train body voltage is rapidly raised due to lightning stroke and lifting bow surge is effectively restrained, counterattack caused by the impact voltage of vehicle-mounted weak current equipment is avoided, and the safe and reliable operation of the motor train unit is ensured.

Drawings

Fig. 1 is a schematic view of the contact between the train and the grounded third rail.

Fig. 2 is a cross-sectional view of the train contacting the grounded third rail.

Fig. 3 is a top view of the transformer car ground.

Fig. 4 is a main circuit diagram of the working grounding system.

In the figure: 1-steel rail; 2, steel rails; 3-grounding the third rail; 4, roller grounding carbon brush; 5-grounding the third rail protective cover; 6, a vehicle body; 7-a carriage junction; 8, a wheel; 9-a wheel; 10-a bogie; 11-wheel axle; 12-vehicle mounted transformer; 13-pantograph; 14-a bogie; 15-a wheel; 16-a wheel; 17-protection grounding; 18-working ground; 19-vacuum circuit breaker control loop; 20-an electric energy monitoring device; 21-traction converter (2 car); 22-a voltage transformer; 23-a lightning arrester; 24-vacuum circuit breaker; 25-a ground protection switch; 26-primary side current transformer of transformer; 27-high voltage reactive power compensation device; 28-traction converter (4 cars); 29-transformer ground side current transformer; 30-a current transformer on the whole vehicle network side; 31-grounded carbon brush.

Detailed Description

The invention is described in further detail below with reference to the figures and specific embodiments. A novel third rail independent grounding mode suitable for a high-speed train is characterized in that a schematic contact diagram and a sectional view of the train and a grounded third rail are shown in figures 1 and 2. The grounding system of the motor train unit comprises working grounding and protective grounding. The backflow mode of the working grounding system is shown in fig. 3, a grounding plan view of a carriage of the transformer, and fig. 4, a main circuit diagram of the working grounding system, wherein the working grounding system comprises a grounding third rail 3, the grounding third rail 3 is parallel to the two steel rails 1 and 2 and is arranged on the outer sides of the two steel rails 1 and 2, the motor train unit is contacted with a contact net through a pantograph 13 to obtain traction current, the traction current sequentially passes through a vacuum circuit breaker 24 and a primary side of a vehicle-mounted transformer 12, and the first roller grounding carbon brush 4 is in rolling connection with the grounding third rail 3 after the primary side of the main transformer, so that the working current flows back to a traction substation through the grounding third; the protective grounding system is that the train bogies 10 and 14 and the train body 6 are in rolling contact with the steel rail 1 through grounding carbon brushes and wheels 8 and 9, and then flow back to the traction substation. The working grounding system is effectively isolated from the protection grounding system by the newly arranged special grounding third rail 3. And a grounding third rail protective cover 5 is arranged outside the grounding third rail 3 and covers the first roller grounding carbon brush 4 to play a role of safety protection.

In the grounding mode adopted by the existing high-speed motor train unit, the current of a working grounding system and a protective grounding system is released to a steel rail on the same side, the loop impedance of a train body is smaller than that of the steel rail due to the pollution of the steel rail and the like, so that the traction current flowing into the steel rail by the working grounding system enters the train body through the protective grounding system to cause the circulation of the train rail, and in order to reduce the damage of the circulation of the train rail, a resistor is usually connected between the train body and a grounding carbon brush to increase the loop impedance of the train body. Compared with the existing grounding mode of the high-speed motor train unit, the grounding method disclosed by the invention has the advantages that the working grounding system and the protection grounding system are isolated, and the damage caused by rail circulation can be effectively reduced. The traction current of the motor train unit is released to the special grounding third rail 3 through the working grounding system and flows back to the traction substation, and the traction current enters the train body without passing through the protection grounding system because the working grounding system is isolated from the protection grounding system, so that the damage of the grounding carbon brush caused by abnormal heating of the grounding carbon brush is avoided, the lifting of the potential of the train body caused by the circulation of the train rail is avoided, and the abnormal error reporting and damage of the vehicle-mounted sensor are reduced.

In order to reduce the damage of rail circulation of the existing motor train unit, a resistor is connected between a train body and a grounding carbon brush, and the impedance of a train body loop is increased so as to inhibit the rail circulation. When overvoltage such as lightning stroke impact and pantograph rising surge occurs, transient impact current can be loaded on the grounding resistor, so that the voltage of a train body is instantly increased, and counterattack caused by the impact voltage can damage weak-current equipment such as vehicle-mounted control and communication and influence the safe operation of the motor train unit. In the invention patent, the rail circulation is restrained by adopting a mode of isolating a working grounding system and a protection grounding system. The distribution mode of the grounding system designed by the invention has the advantages that under special working conditions such as lightning stroke impact, pantograph lifting and the like, the generated transient impact current can be directly discharged through the roller grounding carbon brush through the steel rail, the resistance value of the roller grounding carbon brush is small (set to be tens of milliohms), and the large influence on the voltage of a vehicle body can not be generated. Particularly, when the vehicle-mounted transformer is subjected to lightning overvoltage in a traditional grounding mode, under the condition that a grounding resistor is connected with a main transformer in parallel, high-voltage lightning waves are applied to two sides of the vehicle-mounted transformer and are further coupled to the secondary side of the transformer, and damage to equipment connected with the secondary side is caused.