A three-phase busbar auxiliary grid-connected power supply system for rail vehicles

Abstract

The utility model discloses a three-phase busbar auxiliary grid-connected power supply system for a rail vehicle, which comprises: a first busbar AC BUS SE1, a second busbar AC BUS SE2, a third busbar AC BUS SE3, a fourth busbar AC BUS SE4, a fifth busbar AC BUS SE5, a first medium-voltage busbar contactor Q23, a second medium-voltage busbar contactor Q24, a third medium-voltage busbar contactor Q13, and a fourth medium-voltage busbar contactor Q28. The utility model provides a three-phase busbar auxiliary grid-connected power supply system for a rail vehicle, which solves the problem that when a busbar with a short-circuit fault is cut off, the faulty vehicle loses all air-conditioning loads, resulting in a loss of 1 / 2 of the air-conditioning load of the entire train.

Description

Technical Field

[0001] The utility model relates to a three-phase busbar auxiliary grid-connected power supply system for a rail vehicle, and belongs to the technical field of rail transit vehicle design. Background Art

[0002] At present, rail transit vehicles are usually composed of multiple carriages, including Tc cars, MP cars and M cars. The auxiliary grid-connected power supply of rail transit vehicles adopts a three-phase busbar design. Generally, a contactor is set for the three-phase busbar of the auxiliary grid-connected power supply. When a single-point short-circuit fault occurs in the three-phase busbar of the auxiliary grid-connected power supply, it is used to cut off the busbar with the short-circuit fault. When it is cut off, the faulty car will lose all the air-conditioning loads, resulting in the loss of 1 / 2 of the air-conditioning load of the entire train, which has a great impact on passengers. In addition, the loss of 1 / 2 of the key auxiliary loads of the entire train will cause the train to be delayed and offline due to failure. Summary of the invention

[0003] The technical problem to be solved by the utility model is to overcome the deficiencies of the prior art and provide a three-phase busbar auxiliary grid-connected power supply system for rail vehicles, which solves the problem that when the busbar with a short-circuit fault is cut off, the faulty vehicle will lose all air-conditioning loads, resulting in the entire train losing 1 / 2 of the air-conditioning load.

[0004] In order to solve the above technical problems, the technical solution of the utility model is:

[0005] A three-phase busbar auxiliary grid-connected power supply system for a rail vehicle, comprising: a first busbar AC BUS SE1, a second busbar AC BUS SE2, a third busbar AC BUS SE3, a fourth busbar AC BUS SE4, a fifth busbar AC BUS SE5, a first medium-voltage busbar contactor Q23, a second medium-voltage busbar contactor Q24, a third medium-voltage busbar contactor Q13, and a fourth medium-voltage busbar contactor Q28;

[0006] The first busbar AC BUS SE1 is used to supply power to the first air conditioner HVAC1 of the Tc1 car, the Mp1 car and the M1 car, and the first busbar AC BUS SE1 is connected to the inlet terminal of the first medium-voltage busbar contactor Q23;

[0007] The second busbar AC BUS SE2 is used to supply power to the second air conditioner HVAC2 of the Tc1 car, the Mp1 car and the M1 car, and the second busbar AC BUS SE2 is connected to the inlet terminal of the second medium-voltage bus contactor Q24;

[0008] The third busbar AC BUS SE3 is used to supply power to the first air conditioner HVAC1 of the Tc2 car, the Mp2 car, and the M1 car, and the second air conditioner HVAC2 of the Mp3 car. The third busbar AC BUS SE3 is connected to the outlet terminal of the third medium-voltage bus contactor Q13;

[0009] The fourth busbar AC BUS SE4 is used to supply power to the second air conditioner HVAC2 of the Tc2 car, the Mp2 car, the M2 car and the M3 car, and the fourth busbar AC BUS SE4 is connected to the outlet terminal of the fourth medium-voltage busbar contactor Q28;

[0010] The fifth busbar AC BUS SE5 is used to supply power to the first air conditioner HVAC1 of the Mp3 car and the first air conditioner HVAC1 of the M3 car. The fifth busbar AC BUS SE5 is respectively connected to the outlet terminal of the first medium-voltage bus contactor Q23, the outlet terminal of the second medium-voltage bus contactor Q24, the inlet terminal of the third medium-voltage bus contactor Q13 and the inlet terminal of the fourth medium-voltage bus contactor Q28.

[0011] Furthermore, it also includes a Tc1 car auxiliary converter box, a Tc1 car air compressor and a Tc1 car load contactor Q1, wherein the output end of the Tc1 car auxiliary converter box is connected to the first bus AC BUS SE1, and the Tc1 car air compressor is connected to the first bus AC BUS SE1 and the second bus AC BUS SE2 respectively through the Tc1 car load contactor Q1.

[0012] Furthermore, it also includes an Mp1 vehicle traction converter box, an Mp1 vehicle brake resistor box and an Mp1 vehicle load contactor Q2, wherein the Mp1 vehicle brake resistor box is connected to the Mp1 vehicle traction converter box, and the Mp1 vehicle traction converter box is respectively connected to the first busbar AC BUS SE1 and the second busbar AC BUS SE2 through the Mp1 vehicle load contactor Q2.

[0013] Furthermore, it also includes an M1 vehicle traction auxiliary converter box, an M1 vehicle brake resistor box, an M1 vehicle reactor box and an M1 vehicle load contactor Q3. The M1 vehicle brake resistor box is connected to the M1 vehicle traction auxiliary converter box, the output end of the M1 vehicle traction auxiliary converter is connected to the second bus AC BUS SE2, the incoming end of the M1 vehicle load contactor Q3 is respectively connected to the first bus AC BUS SE1 and the second bus AC BUS SE2, and the outgoing end of the M1 vehicle load contactor Q3 is respectively connected to the M1 vehicle traction auxiliary converter box and the M1 vehicle reactor box.

[0014] Furthermore, it also includes an Mp3 vehicle charger auxiliary electrical box, an Mp3 vehicle traction inverter box, an Mp3 vehicle brake resistor box and an Mp3 vehicle load contactor Q4. The Mp3 vehicle brake resistor box is connected to the Mp3 vehicle traction inverter box, the incoming line end of the Mp3 vehicle load contactor Q4 is respectively connected to the third bus AC BUS SE3 and the fifth bus AC BUS SE5, and the outgoing line end of the Mp3 vehicle load contactor Q4 is respectively connected to the Mp3 vehicle charger auxiliary electrical box and the Mp3 vehicle traction inverter box.

[0015] Furthermore, the first medium-voltage bus contactor Q23, the second medium-voltage bus contactor Q24, the third medium-voltage bus contactor Q13 and the fourth medium-voltage bus contactor Q28 are all arranged in the auxiliary electrical box of the Mp3 vehicle charger.

[0016] Furthermore, it also includes a Tc2 car auxiliary converter box, a Tc2 car air compressor and a Tc2 car load contactor Q5. The output end of the Tc2 car auxiliary converter box is connected to the third bus AC BUS SE3, and the Tc2 car air compressor is connected to the third bus AC BUS SE3 and the fourth bus AC BUS SE4 respectively through the Tc2 car load contactor Q5.

[0017] Furthermore, it also includes an Mp2 vehicle traction inverter box, an Mp2 vehicle brake resistor box and an Mp2 vehicle load contactor Q6. The Mp2 vehicle brake resistor box is connected to the Mp2 vehicle traction inverter box, and the Mp2 vehicle traction inverter box is respectively connected to the third bus AC BUS SE3 and the fourth bus AC BUS SE4 through the Mp2 vehicle load contactor Q6.

[0018] Furthermore, it also includes an M2 vehicle traction auxiliary converter box, an M2 vehicle brake resistor box, an M2 vehicle reactor box and an M2 vehicle load contactor Q7. The M2 vehicle brake resistor box is connected to the M2 vehicle traction auxiliary converter box, the output end of the M2 vehicle traction auxiliary converter box is connected to the fourth bus AC BUS SE4, the incoming line end of the M2 vehicle load contactor Q7 is respectively connected to the third bus AC BUS SE3 and the fourth bus AC BUS SE4, and the outgoing line end of the M2 vehicle load contactor Q7 is respectively connected to the M2 vehicle traction auxiliary converter box and the M2 vehicle reactor box.

[0019] Furthermore, it also includes an M3 car traction auxiliary inverter box, an M3 car brake resistor box, an M3 car reactor box and an M3 car load contactor Q8. The M3 car brake resistor box is connected to the M3 car traction auxiliary inverter box, the output end of the M3 car traction auxiliary inverter box is connected to the fifth bus AC BUS SE5, the incoming end of the M3 car load contactor Q8 is respectively connected to the fourth bus AC BUS SE4 and the fifth bus AC BUS SE5, and the outgoing end of the M3 car load contactor Q8 is respectively connected to the M3 car traction auxiliary inverter box and the M3 car reactor box.

[0020] By adopting the above technical scheme, the utility model proposes a design of a three-phase busbar for auxiliary grid-connected power supply for rail vehicles, which realizes that when a single-point short-circuit fault occurs in the three-phase busbar for auxiliary grid-connected power supply, a single faulty vehicle only loses one air-conditioning load, and the entire train loses at least 1 / 8 of the air-conditioning load and at most 1 / 4 of the air-conditioning load, with little impact on passengers and no loss of key auxiliary loads in the entire train, thereby ensuring that the train runs on time and does not go offline. The utility model can be widely used in high-speed railways, subways, urban buses and other vehicles in the rail transit industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The utility model is a principle block diagram of a three-phase busbar auxiliary grid-connected power supply system for rail vehicles. DETAILED DESCRIPTION

[0022] In order to make the content of the utility model more clearly understood, the utility model is further described in detail below based on specific embodiments and in conjunction with the accompanying drawings.

[0023] like Figure 1 As shown, this embodiment provides a three-phase busbar auxiliary grid-connected power supply system for rail vehicles, which is applied to rail trains. The rail trains in this embodiment include Tc1 car, Mp1 car, M1 car, Mp3 car, M3 car, M2 car, Mp2 car and Tc2 car. Each car is equipped with two air conditioners HVAC1 and HVAC2, and the whole train has a total of 16 air conditioners, which are respectively hung under different buses.

[0024] like Figure 1As shown, this embodiment provides a three-phase bus auxiliary grid-connected power supply system for rail vehicles, including: a first bus AC BUS SE1, a second bus AC BUS SE2, a third bus AC BUS SE3, a fourth bus AC BUS SE4, a fifth bus AC BUS SE5, a Tc1 car auxiliary converter box, a Tc1 car air compressor and a Tc1 car load contactor Q1, an Mp1 car traction converter box, an Mp1 car brake resistor box and an Mp1 car load contactor Q2, an M1 car traction auxiliary converter box, an M1 car brake resistor box, an M1 car reactor box and an M1 car load contactor Q3, an Mp3 car charger auxiliary electrical box, an Mp3 car traction converter box, an Mp3 car brake resistor box and an Mp3 car load contactor Q4, an M3 car traction auxiliary converter box, an M3 car brake resistor box, an M3 car reactor box and The M3 car load contactor Q8, the M2 car traction auxiliary inverter box, the M2 car brake resistor box, the M2 car reactor box and the M2 car load contactor Q7, the Mp2 car traction inverter box, the Mp2 car brake resistor box and the Mp2 car load contactor Q6, the Tc2 car auxiliary inverter box, the Tc2 car air compressor and the Tc2 car load contactor Q5, the Mp3 car charger auxiliary electrical box is equipped with the first medium-voltage bus contactor Q23, the second medium-voltage bus contactor Q24, the third medium-voltage bus contactor Q13 and the fourth medium-voltage bus contactor Q28.

[0025] like Figure 1 As shown, the auxiliary converter box of the Tc1 car of this embodiment outputs the first busbar AC BUS SE1, and the first busbar AC BUS SE1 is used to supply power to the first air conditioner HVAC1 of the Tc1 car, the Mp1 car and the M1 car. The first busbar AC BUS SE1 is connected to the inlet end of the first medium-voltage bus contactor Q23, and the outlet end of the first medium-voltage bus contactor Q23 is connected to the fifth busbar AC BUSSE5. The output end of the auxiliary converter box of the Tc1 car is connected to the first busbar AC BUS SE1, and the air compressor of the Tc1 car is respectively connected to the first busbar AC BUS SE1 and the second busbar AC BUS SE2 through the Tc1 car load contactor Q1.

[0026] like Figure 1As shown, the traction auxiliary converter of the M1 car in this embodiment outputs the second busbar AC BUS SE2, and the second busbar AC BUS SE2 is used to supply power to the second air conditioner HVAC2 of the Tc1 car, the Mp1 car and the M1 car. The second busbar AC BUS SE2 is connected to the inlet end of the second medium-voltage bus contactor Q24, and the outlet end of the second medium-voltage bus contactor Q24 is connected to the fifth busbar AC BUSSE5. The brake resistor box of the M1 car is connected to the traction auxiliary converter box of the M1 car, and the output end of the traction auxiliary converter of the M1 car is connected to the second busbar AC BUS SE2. The inlet end of the load contactor Q3 of the M1 car is respectively connected to the first busbar AC BUS SE1 and the second busbar AC BUS SE2, and the outlet end of the load contactor Q3 of the M1 car is respectively connected to the traction auxiliary converter box of the M1 car and the reactor box of the M1 car.

[0027] like Figure 1 As shown, the Mp1 vehicle brake resistor box of this embodiment is connected to the Mp1 vehicle traction converter box, and the Mp1 vehicle traction converter box is respectively connected to the first busbar AC BUS SE1 and the second busbar AC BUS SE2 through the Mp1 vehicle load contactor Q2.

[0028] Normally, depending on the odd or even date, the air compressor of Tc1 vehicle selects the first bus AC BUS SE1 or the second bus AC BUS SE2 for power supply through the load contactor Q1 of Tc1 vehicle. When a power supply bus failure occurs, the load contactor Q1 of Tc1 vehicle can switch the bus for power supply. The fan in the brake resistor box of Mp1 vehicle and the fan in the traction converter box of Mp1 vehicle, the fan in the traction auxiliary converter box of M1 vehicle, the fan in the brake resistor box of M1 vehicle and the fan in the reactor box of M1 vehicle are all powered by the bus selected by the load contactor of this vehicle according to the same logic.

[0029] like Figure 1 As shown, the auxiliary converter box of the Tc2 vehicle in this embodiment outputs the third busbar AC BUS SE3, and the third busbar AC BUS SE3 is used to supply power to the first air conditioner HVAC1 of the Tc2 vehicle, the Mp2 vehicle, and the M1 vehicle, and the second air conditioner HVAC2 of the Mp3 vehicle. The third busbar AC BUS SE3 is connected to the outlet end of the third medium-voltage bus contactor Q13, and the inlet end of the third medium-voltage bus contactor Q13 is connected to the fifth busbar AC BUS SE5. The output end of the auxiliary converter box of the Tc2 vehicle is connected to the third busbar AC BUS SE3, and the air compressor of the Tc2 vehicle is respectively connected to the third busbar AC BUS SE3 and the fourth busbar AC BUS SE4 through the Tc2 vehicle load contactor Q5.

[0030] like Figure 1As shown, the traction auxiliary converter box of the M2 car in this embodiment outputs the fourth busbar AC BUS SE4, and the fourth busbar AC BUS SE4 is used to supply power to the second air conditioner HVAC2 of the Tc2 car, the Mp2 car, the M2 car and the M3 car. The fourth busbar AC BUSSE4 is connected to the outgoing terminal of the fourth medium-voltage bus contactor Q28, and the incoming terminal of the fourth medium-voltage bus contactor Q28 is connected to the fifth busbar AC BUS SE5. The brake resistor box of the M2 car is connected to the traction auxiliary converter box of the M2 car, and the output terminal of the traction auxiliary converter box of the M2 car is connected to the fourth busbar AC BUS SE4. The incoming terminal of the load contactor Q7 of the M2 car is respectively connected to the third busbar ACBUS SE3 and the fourth busbar AC BUS SE4, and the outgoing terminal of the load contactor Q7 of the M2 car is respectively connected to the traction auxiliary converter box of the M2 car and the reactor box of the M2 car.

[0031] like Figure 1 As shown, the brake resistor box of the Mp2 vehicle in this embodiment is connected to the traction converter box of the Mp2 vehicle, and the traction converter box of the Mp2 vehicle is respectively connected to the third busbar AC BUS SE3 and the fourth busbar AC BUS SE4 through the load contactor Q6 of the Mp2 vehicle.

[0032] Normally, depending on whether the date is odd or even, the air compressor of the Tc2 vehicle selects the third bus AC BUS SE3 or the fourth bus AC BUS SE4 for power supply through the Tc2 vehicle load contactor Q5. When a power supply bus failure occurs, the bus can be switched for power supply through the Tc2 vehicle load contactor Q5. The fan in the traction converter box of the Mp2 vehicle and the fan in the brake resistor box of the Mp2 vehicle, the fan in the traction auxiliary converter box of the M2 vehicle, the fan in the brake resistor box of the M2 vehicle, and the fan in the reactor box of the M2 vehicle are powered by the bus selected by the load contactor of this vehicle according to the same logic.

[0033] like Figure 1As shown, the traction auxiliary converter box of the M3 car in this embodiment outputs the fifth busbar AC BUS SE5, and the fifth busbar AC BUS SE5 is used to supply power to the first air conditioner HVAC1 of the Mp3 car and the first air conditioner HVAC1 of the M3 car. The fifth busbar AC BUS SE5 is respectively connected to the outlet terminal of the first medium-voltage bus contactor Q23, the outlet terminal of the second medium-voltage bus contactor Q24, the inlet terminal of the third medium-voltage bus contactor Q13, and the inlet terminal of the fourth medium-voltage bus contactor Q28. The brake resistor box of the M3 car is connected to the traction auxiliary converter box of the M3 car, the output terminal of the traction auxiliary converter box of the M3 car is connected to the fifth busbar AC BUS SE5, the inlet terminal of the load contactor Q8 of the M3 car is respectively connected to the fourth busbar AC BUS SE4 and the fifth busbar AC BUS SE5, and the outlet terminal of the load contactor Q8 of the M3 car is respectively connected to the traction auxiliary converter box of the M3 car and the reactor box of the M3 car.

[0034] like Figure 1 As shown, the brake resistor box of the Mp3 vehicle in this embodiment is connected to the traction converter box of the Mp3 vehicle, the incoming line end of the load contactor Q4 of the Mp3 vehicle is respectively connected to the third busbar AC BUS SE3 and the fifth busbar AC BUS SE5, and the outgoing line end of the load contactor Q4 of the Mp3 vehicle is respectively connected to the auxiliary electrical box of the charger of the Mp3 vehicle and the traction converter box of the Mp3 vehicle.

[0035] Normally, depending on whether the date is odd or even, the fan in the traction converter box of the Mp3 car, the fan in the brake resistor box of the Mp3 car, and the fan in the auxiliary electrical box of the charger of the Mp3 car select the third bus AC BUSSE3 or the fifth bus AC BUS SE5 for power supply through the load contactor Q4 of the Mp3 car. When a power supply bus failure occurs, the bus can be switched for power supply through the load contactor Q4 of the Mp3 car. The fan in the auxiliary traction converter box of the M3 car, the fan in the brake resistor box of the M3 car, and the fan in the reactor box of the M3 car are powered by the fourth bus AC BUS SE4 or the fifth bus AC BUS SE5 selected by the load contactor of this car according to the same logic.

[0036] like Figure 1As shown, the first busbar AC BUS SE1 of this embodiment is mounted with the air conditioner HVAC1 in the Tc1 car, the Mp1 car and the M1 car, for a total of three air conditioners. The second busbar AC BUS SE2 is mounted with the air conditioner HVAC2 in the Tc1 car, the Mp1 car and the M1 car, for a total of three air conditioners. The third busbar AC BUS SE3 is mounted with the air conditioner HVAC1 in the Tc2 car, the Mp2 car and the M2 car, and the air conditioner HVAC2 in the Mp3 car, for a total of four air conditioners. The fourth busbar AC BUS SE4 is mounted with the air conditioner HVAC2 in the Tc2 car, the Mp2 car, the M2 car and the Mp3 car, for a total of four air conditioners. The fifth busbar AC BUS SE5 is mounted with the air conditioner HVAC1 in the Mp3 car and the M3 car, for a total of two air conditioners. When a single-point short-circuit fault occurs in the three-phase busbar of the auxiliary grid-connected power supply, the faulty car only loses one air conditioner load, and the entire train loses at least 1 / 8 of the air conditioner load and at most 1 / 4 of the air conditioner load.

[0037] like Figure 1 As shown, the four medium-voltage bus contactors Q23, Q13, Q24, and Q28 in the auxiliary electrical box of the charger of the Mp3 car of this embodiment are closed in normal mode. The first bus AC BUS SE1, the second bus AC BUS SE2, the third bus AC BUS SE3, the fourth bus AC BUS SE4, and the fifth bus AC BUS SE5 are connected to the grid and output to supply power to the auxiliary loads of the rail train. When a short circuit fault occurs in any bus, the medium-voltage bus contactor corresponding to the bus will be disconnected. If the third bus AC BUSSE3 fails, the corresponding third medium-voltage bus contactor Q13 will be disconnected, and the air conditioner HVAC1 in the Tc2 car, Mp2 car, and M2 car will be powered off, and the air conditioner HVAC2 in the Tc2 car, Mp2 car, and M2 car will be powered off, and the air conditioner HVAC1 in the Mp3 car will still be powered on. At the same time, the Tc2 car load contactor Q5 control can keep the Tc2 car air compressor, the Mp2 car traction converter box fan, the Mp2 car brake resistor box fan, the M2 car traction auxiliary converter box fan, the M2 car brake resistor box fan, the M2 car reactor box fan, the Mp3 car traction converter box fan, the Mp3 car brake resistor box fan, the Mp3 car charger auxiliary electrical box fan power supply. This is the worst working condition, the whole train loses 1 / 4 of the air conditioning load, but the whole train does not lose the key load.

[0038] If the fifth busbar AC BUS SE5 fails, the medium voltage busbar contactors Q23, Q13, Q24, and Q28 are all disconnected, the air conditioner HVAC1 in the Mp3 and M3 cars is powered off, and the air conditioner HVAC2 in the Mp3 and M3 cars is still powered on. At the same time, the Mp3 car load contactor Q4 is controlled to keep the fan in the traction converter box of the Mp3 car, the fan in the brake resistor box of the Mp3 car, the fan in the auxiliary electrical box of the charger of the Mp3 car, the fan in the traction auxiliary converter box of the M3 car, the fan in the brake resistor box of the M3 car, and the fan in the reactor box of the M3 car powered on. The entire train loses 1 / 8 of the air conditioning load, and the entire train does not lose critical loads.

[0039] The specific embodiments described above further illustrate the technical problems, technical solutions and beneficial effects solved by the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A three-phase busbar auxiliary grid-connected power supply system for railway vehicles, characterized in that: It includes: The first busbar AC BUSSE1, the second busbar AC BUS SE2, the third busbar AC BUS SE3, the fourth busbar AC BUS SE4, the fifth busbar AC BUSSE5, the first medium-voltage busbar contactor Q23, the second medium-voltage busbar contactor Q24, the third medium-voltage busbar contactor Q13, and the fourth medium-voltage busbar contactor Q28; The first busbar AC BUS SE1 is used to supply power to the first air conditioner HVAC1 of the Tc1 car, the Mp1 car and the M1 car, and the first busbar AC BUS SE1 is connected to the inlet terminal of the first medium-voltage busbar contactor Q23; The second busbar AC BUS SE2 is used to supply power to the second air conditioner HVAC2 of the Tc1 car, the Mp1 car and the M1 car, and the second busbar AC BUS SE2 is connected to the inlet terminal of the second medium-voltage bus contactor Q24; The third busbar AC BUS SE3 is used to supply power to the first air conditioner HVAC1 of the Tc2 car, the Mp2 car, and the M1 car, and the second air conditioner HVAC2 of the Mp3 car. The third busbar AC BUS SE3 is connected to the outlet terminal of the third medium-voltage bus contactor Q13; The fourth busbar AC BUS SE4 is used to supply power to the second air conditioner HVAC2 of the Tc2 car, the Mp2 car, the M2 car and the M3 car, and the fourth busbar AC BUS SE4 is connected to the outlet terminal of the fourth medium-voltage busbar contactor Q28; The fifth busbar AC BUS SE5 is used to supply power to the first air conditioner HVAC1 of the Mp3 car and the first air conditioner HVAC1 of the M3 car. The fifth busbar AC BUS SE5 is respectively connected to the outlet terminal of the first medium-voltage bus contactor Q23, the outlet terminal of the second medium-voltage bus contactor Q24, the inlet terminal of the third medium-voltage bus contactor Q13 and the inlet terminal of the fourth medium-voltage bus contactor Q28.

2. The rail vehicle three-phase busbar auxiliary grid-connected power supply system according to claim 1, characterized in that: It also includes a Tc1 car auxiliary converter box, a Tc1 car air compressor and a Tc1 car load contactor Q1. The output end of the Tc1 car auxiliary converter box is connected to the first bus AC BUS SE1. The Tc1 car air compressor is connected to the first bus AC BUS SE1 and the second bus AC BUS SE2 respectively through the Tc1 car load contactor Q1.

3. The three-phase busbar auxiliary grid-connected power supply system for rail vehicles according to claim 1 is characterized in that: It also includes an Mp1 vehicle traction converter box, an Mp1 vehicle brake resistor box and an Mp1 vehicle load contactor Q2. The Mp1 vehicle brake resistor box is connected to the Mp1 vehicle traction converter box. The Mp1 vehicle traction converter box is respectively connected to the first busbar ACBUS SE1 and the second busbar AC BUS SE2 through the Mp1 vehicle load contactor Q2.

4. The rail vehicle three-phase busbar auxiliary grid-connected power supply system according to claim 1, characterized in that: It also includes an M1 vehicle traction auxiliary converter box, an M1 vehicle brake resistor box, an M1 vehicle reactor box and an M1 vehicle load contactor Q3. The M1 vehicle brake resistor box is connected to the M1 vehicle traction auxiliary converter box, the output end of the M1 vehicle traction auxiliary converter is connected to the second bus ACBUS SE2, the incoming end of the M1 vehicle load contactor Q3 is respectively connected to the first bus AC BUS SE1 and the second bus ACBUS SE2, and the outgoing end of the M1 vehicle load contactor Q3 is respectively connected to the M1 vehicle traction auxiliary converter box and the M1 vehicle reactor box.

5. The rail vehicle three-phase busbar auxiliary grid-connected power supply system according to claim 1, characterized in that: It also includes an Mp3 vehicle charger auxiliary electrical box, an Mp3 vehicle traction inverter box, an Mp3 vehicle brake resistor box and an Mp3 vehicle load contactor Q4. The Mp3 vehicle brake resistor box is connected to the Mp3 vehicle traction inverter box, the incoming line end of the Mp3 vehicle load contactor Q4 is respectively connected to the third bus AC BUS SE3 and the fifth bus AC BUS SE5, and the outgoing line end of the Mp3 vehicle load contactor Q4 is respectively connected to the Mp3 vehicle charger auxiliary electrical box and the Mp3 vehicle traction inverter box.

6. The rail vehicle three-phase busbar auxiliary grid-connected power supply system according to claim 5, characterized in that: The first medium-voltage bus contactor Q23, the second medium-voltage bus contactor Q24, the third medium-voltage bus contactor Q13 and the fourth medium-voltage bus contactor Q28 are all arranged in the auxiliary electrical box of the Mp3 vehicle charger.

7. The rail vehicle three-phase busbar auxiliary grid-connected power supply system according to claim 1, characterized in that: It also includes a Tc2 vehicle auxiliary converter box, a Tc2 vehicle air compressor and a Tc2 vehicle load contactor Q5. The output end of the Tc2 vehicle auxiliary converter box is connected to the third bus AC BUS SE3. The Tc2 vehicle air compressor is respectively connected to the third bus AC BUS SE3 and the fourth bus AC BUS SE4 through the Tc2 vehicle load contactor Q5.

8. The rail vehicle three-phase busbar auxiliary grid-connected power supply system according to claim 1, characterized in that: It also includes an Mp2 vehicle traction converter box, an Mp2 vehicle brake resistor box and an Mp2 vehicle load contactor Q6. The Mp2 vehicle brake resistor box is connected to the Mp2 vehicle traction converter box. The Mp2 vehicle traction converter box is respectively connected to the third busbar ACBUS SE3 and the fourth busbar AC BUS SE4 through the Mp2 vehicle load contactor Q6.

9. The rail vehicle three-phase busbar auxiliary grid-connected power supply system according to claim 1, characterized in that: It also includes an M2 vehicle traction auxiliary converter box, an M2 vehicle brake resistor box, an M2 vehicle reactor box and an M2 vehicle load contactor Q7. The M2 vehicle brake resistor box is connected to the M2 vehicle traction auxiliary converter box, the output end of the M2 vehicle traction auxiliary converter box is connected to the fourth bus ACBUS SE4, the incoming line end of the M2 vehicle load contactor Q7 is respectively connected to the third bus AC BUS SE3 and the fourth bus ACBUS SE4, and the outgoing line end of the M2 vehicle load contactor Q7 is respectively connected to the M2 vehicle traction auxiliary converter box and the M2 vehicle reactor box.

10. The rail vehicle three-phase busbar auxiliary grid-connected power supply system according to claim 1, characterized in that: It also includes an M3 vehicle traction auxiliary converter box, an M3 vehicle brake resistor box, an M3 vehicle reactor box and an M3 vehicle load contactor Q8. The M3 vehicle brake resistor box is connected to the M3 vehicle traction auxiliary converter box, the output end of the M3 vehicle traction auxiliary converter box is connected to the fifth bus AC BUS SE5, the incoming end of the M3 vehicle load contactor Q8 is respectively connected to the fourth bus AC BUS SE4 and the fifth bus AC BUS SE5, and the outgoing end of the M3 vehicle load contactor Q8 is respectively connected to the M3 vehicle traction auxiliary converter box and the M3 vehicle reactor box.

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