Dual-current power supply structure, control method and control system for electrified railway substations

Abstract

The present invention provides a dual-current power supply structure, control method, and control system for an electrified railway substation. The structure includes: a first traction substation, a second traction substation, a first AC busbar, a second AC busbar, a DC busbar, a substation, and a measurement and control system; the output end of the grid substation is connected to the input end of the first traction substation and the input end of the second traction substation, respectively; the output end of the first traction substation is connected to the substation via the first AC busbar; the output end of the second traction substation is connected to the substation via the second AC busbar; the substation is connected to the measurement and control system; and the measurement and control system is connected to the DC busbar. The present invention can optimize the grid voltage balance at the end of the power supply arm of the traction power supply system. By controlling the power transmission between the first AC busbar, the second AC busbar, and the DC system, power can be redistributed, effectively optimizing the grid voltage balance problem at the end of the power supply arm of the electrified railway.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrified railway traction power supply, and in particular relates to a dual-current power supply structure, a control method and a control system for an electrified railway substation. Background Art

[0002] Currently, AC traction power supply systems in my country's rail transit system utilize 27.5kV or 55kV single-phase AC power, while DC traction power supply systems generally utilize 1500V or 750V DC power. Due to these differences in power supply standards, the two traction power supply systems generally utilize independent single-standard power supplies.

[0003] With the development and construction of rail transit, the transportation network is complicated, and it is inevitable that there will be coexistence of AC traction power supply system and DC traction power supply system in some places. The traditional single power supply system can no longer meet the needs of dual-current power supply. The dual-current traction power supply system can be used in areas where there is a transition between AC electric traction vehicles and DC urban rail vehicles. Furthermore, locomotives of different voltage levels and current systems produced by my country's locomotive and vehicle manufacturing enterprises also require different traction power supply systems to provide power for debugging and testing. The construction of a dual-current traction power supply system can enable it to supply power to both AC electric traction vehicles and DC urban rail vehicles, making the operation as efficient and economical as possible, reducing duplicate construction as much as possible, and avoiding huge waste of resources. Therefore, it is necessary to study the dual-current traction power supply scheme.

[0004] In AC electrified railways, there are electrical phase separations in the sections, and the DC power supply system is connected to the AC power supply system through a converter. If the traction network voltage is too high, the train's regenerative braking will fail, and if it is too low, it will lead to insufficient traction power for the train. Summary of the Invention

[0005] In order to overcome the above technical defects, the first aspect of the present invention provides a dual-current power supply structure for an electrified railway substation, comprising: a first traction substation DCSa, a second traction substation DCSb, a first AC bus AB1, a second AC bus AB2, a DC bus DB, a substation, and a measurement and control system MCS;

[0006] The output terminal of the grid substation is connected to the input terminal of the first traction substation DCSa and the input terminal of the second traction substation DCSb respectively;

[0007] The output end of the first traction substation DCSa is connected to the substation via the first AC bus AB1;

[0008] The output end of the second traction substation DCSb is connected to the substation via the second AC bus AB2;

[0009] The sub-area is connected to the measurement and control system MCS;

[0010] The measurement and control system MCS is connected to the DC bus DB.

[0011] As a further improvement of the present invention, the partition includes: an SPC single-phase power converter SPC, and the SPC single-phase power converter SPC includes: a first matching transformer MT1, a second matching transformer MT2, a first AC-DC-AC converter 1, and a second AC-DC-AC converter 2;

[0012] The primary side of the first matching transformer MT1 is connected to the first AC bus AB1 and the rail R, and the primary side of the second matching transformer MT2 is connected to the second AC bus AB2 and the rail R;

[0013] The DC side of the first AC-DC-AC converter 1 and the DC side of the second AC-DC-AC converter 2 are both connected in parallel to the DC bus DB.

[0014] As a further improvement of the present invention, the measurement and control system MCS includes: a first voltage transformer PT1, a second voltage transformer PT2, a voltage transmitter VD, a first current transformer CT1, a second current transformer CT2, a shunt RW and a controller CD;

[0015] The first current transformer CT1 is connected in series to the first AC bus AB1, and the second current transformer CT2 is connected in series to the second AC bus AB2;

[0016] The first voltage transformer PT1 is connected in parallel between the first AC busbar AB1 and the rail R, the second voltage transformer PT2 is connected in parallel between the second AC busbar AB2 and the rail R, and the rail R is grounded;

[0017] One end of the DC busbar DB is connected in series with the shunt RW, and the other end is connected in parallel with the voltage transmitter VD and then connected to the rail R;

[0018] The signal input end of the controller CD is respectively connected to the measurement signal output ends of the first voltage transformer PT1, the second voltage transformer PT2, the voltage transmitter VD, the first current transformer CT1, the second current transformer CT2, and the shunt RW, and the signal output end of the controller CD is connected to the control end of the SPC single-phase power converter.

[0019] A second aspect of the present invention provides a control method applied to the above-mentioned dual-current power supply structure of the electrified railway substation, comprising the steps of:

[0020] Obtain the grid voltage U1 at the end of the first AC bus power supply arm and the grid voltage U2 at the end of the second AC bus power supply arm;

[0021] Calculate the AC load power P on the first AC busbar power supply arm A , AC load power P on the second AC busbar power supply arm B , DC load power P L ;

[0022] Set the voltage difference reference value U at the end of the power supply arm ε , it is stipulated that the load power is positive when the train is in traction condition and negative when the train is in regenerative braking condition;

[0023] If P L =0, when |U1-U2|≤U ε There is no need to control the transfer active power of the SPC single-phase power converter SPC, and the traction power flows from the first traction substation and the second traction substation to the train respectively. When |U1-U2|>U ε When the SPC single-phase power converter is controlled to transmit power from the first AC bus (P B -P A ) / 2 to the second AC bus;

[0024] If P L >0, when P A ≥0,P B ≥0, control the SPC single-phase power converter to transmit power (P B +P L -P A ) / 2, power is transmitted from the second AC bus through the second AC-DC converter (P A +P L -P B ) / 2; when P A ≤0, P B ≤0, control the SPC single-phase power converter to transmit traction power (|P L |+|P A |-|P B | / 2, power is transmitted from the second AC bus through the second AC-DC converter (|P L |+|P B |-|P A | / 2; when P A <0,P B >0, control the SPC single-phase power converter to transmit power (|P L |+|P B |-|P A| / 2, power is transmitted from the second AC bus through the second AC-DC converter (|P L |+|P A |-|P B | / 2; when P A >0,P B <0, control the SPC single-phase power converter to transmit power (|P L |-|P B |-|P A | / 2, power is transmitted from the second AC bus through the second AC-DC converter (|P L |+|P A |+|P B | / 2;

[0025] If P L <0, when P A ≤0,P B ≤0, control the SPC single-phase power converter to transmit power (|P B |+|P L |-|P A | / 2, power is transmitted to the second AC bus through the second AC-DC converter (|P A |+|P L |-|P B | / 2; when P A >0,P B ≤0, control the SPC single-phase power converter to transmit power (|P B |+|P L |+|P A | / 2, transmits power to the second AC bus through the second AC-DC converter (|P L |-|P B |-|P A | / 2; when P A ≤0,P B >0, control the SPC single-phase power converter SPC to transmit power (|P L |-|P B |-|P A | / 2, transmits power (|P B |+|P L |+|P A | / 2; when P A >0,P B >0, control the SPC single-phase power converter to transmit power (|P L |+|PA |-|P B | / 2, transmits power to the second AC bus through the second AC-DC converter (|P L |+|P A |-|P B | / 2;

[0026] If P A =0,P B =0,P L ≠0, control the SPC single-phase power converter to transmit power P from the first AC bus and the second AC bus through the first AC-DC-AC converter 1 and the second AC-DC-AC converter. L / 2.

[0027] The third aspect of the present invention provides a control system, which includes a processor and a memory, wherein the memory stores at least one instruction, at least one program, code set or instruction set, and the at least one instruction, at least one program, code set or instruction set is loaded and executed by the processor to implement the control method as described in claim 5.

[0028] Compared with the prior art, the present invention has the following beneficial effects: it can optimize the grid voltage balance at the end of the power supply arm of the traction power supply system; by controlling the power transmission between the first AC bus, the second AC bus, and the DC system, it can redistribute power so that the output of the first traction substation and the second traction substation are the same after distribution, reducing the difference between the voltage at the end of the first AC bus power supply arm and the voltage at the end of the second AC bus power supply arm, and effectively optimizing the problem of grid voltage balance at the end of the power supply arm of the electrified railway. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, wherein:

[0030] Figure 1 This is a schematic structural diagram of the dual-current power supply structure of the electrified railway sub-station described in Example 1;

[0031] Figure 2 Schematic diagram of the topological structure of the AC-DC-AC converter described in Example 1 and Example 2;

[0032] Figure 3 This is a schematic diagram of the structure of the dual-current power supply structure of the electrified railway sub-station described in Example 2;

[0033] Figure 4 This is a schematic diagram of the structure of the control system described in Example 4. DETAILED DESCRIPTION

[0034] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0035] Example 1

[0036] This embodiment provides a dual-current power supply structure for electrified railway substations, which is applicable to AC traction power supply systems where the traction network power supply mode is direct supply mode or direct supply mode with return line, such as Figure 1 As shown, it includes: a first traction substation DCSa, a second traction substation DCSb, a first AC bus AB1, a second AC bus AB2, a DC bus DB, a substation, and a measurement and control system MCS; the output end of the grid substation is connected to the input end of the first traction substation DCSa and the input end of the second traction substation DCSb respectively; the output end of the first traction substation DCSa is connected to the substation through the first AC bus AB1; the output end of the second traction substation DCSb is connected to the substation through the second AC bus AB2; the substation is connected to the measurement and control system MCS; and the measurement and control system MCS is connected to the DC bus DB.

[0037] Furthermore, the partition includes: an SPC single-phase power converter SPC, and the SPC single-phase power converter SPC includes: a first matching transformer MT1, a second matching transformer MT2, a first AC-DC converter 1, and a second AC-DC converter 2; the primary side of the first matching transformer MT1 is connected to the first AC bus AB1 and the rail R, and the primary side of the second matching transformer MT2 is connected to the second AC bus AB2 and the rail R; the DC side of the first AC-DC converter 1 and the DC side of the second AC-DC converter 2 are both connected in parallel to the DC bus DB.

[0038] Furthermore, the measurement and control system MCS includes: a first voltage transformer PT1, a second voltage transformer PT2, a voltage transmitter VD, a first current transformer CT1, a second current transformer CT2, a shunt RW and a controller CD; the first current transformer CT1 is connected in series to the first AC bus AB1, and the second current transformer CT2 is connected in series to the second AC bus AB2; the first voltage transformer PT1 is connected in parallel between the first AC bus AB1 and the rail R, and the second voltage transformer PT2 is connected in parallel between the second AC bus AB2 and the rail R, and the rail R is grounded; one end of the DC bus DB is connected in series with the shunt RW, and the other end is connected in parallel with the voltage transmitter VD and then connected to the rail R; the signal input end of the controller CD is respectively connected to the measurement signal output ends of the first voltage transformer PT1, the second voltage transformer PT2, the voltage transmitter VD, the first current transformer CT1, the second current transformer CT2 and the shunt RW, and the signal output end of the controller CD is connected to the control end of the SPC single-phase power converter.

[0039] Example 2

[0040] This embodiment provides another dual-current power supply structure for electrified railway substations, such as Figure 2 As shown, the difference between it and embodiment 1 is that the traction network power supply mode of this embodiment is AT (autotransformer power supply mode), and the power supply mode of this embodiment is provided with a first AT station and a second AT station. The first AT station AT1 is provided with a first autotransformer AT1, and the second AT station is provided with a second autotransformer AT2. The first autotransformer AT1 and the second autotransformer AT2 are connected in parallel between the first AC bus AB1, the second AC bus AB2 and the negative feeder F, and the primary sides of the first autotransformer AT1 and the second autotransformer AT2 are respectively It is connected to the first AC bus AB1 and the negative feeder F or the second AC bus AB2 and the negative feeder F; the midpoints of the first autotransformer AT1 and the second autotransformer AT2 are connected to the rail R; the first voltage transformer PT1 is connected in parallel between the first AC bus AB1 and the negative feeder F, and the second voltage transformer PT2 is connected in parallel between the second AC bus AB2 and the negative feeder F; the primary side of the first matching transformer MT1 is connected to the first AC bus AB1 and the negative feeder F, and the primary side of the second matching transformer MT2 is connected to the second AC bus AB2 and the negative feeder F.

[0041] Example 3

[0042] This embodiment provides a control method that utilizes active power compensation to reasonably distribute the power of the DC system and the two AC system power supply arms, thereby optimizing the grid voltage balance level at the end of the power supply arm. The method is applied to the dual-current power supply structure of the electrified railway substation of Embodiment 1 or Embodiment 2, and includes the following steps:

[0043] The voltage U1 at the end of the first AC busbar AB1 power supply arm and the grid voltage U2 at the end of the second AC busbar AB2 power supply arm are obtained through the measurement and control system MCS;

[0044] Calculate the AC load power P on the first AC bus AB1 power supply arm A , AC load power P on the second AC bus AB2 power supply arm B , DC load power P L ;

[0045] Set the voltage difference reference value U at the end of the power supply arm ε , it is stipulated that the load power is positive when the train is in traction condition and negative when the train is in regenerative braking condition;

[0046] If P L =0, when |U1-U2|≤U εThere is no need to control the transfer active power of the SPC single-phase power converter SPC, and the traction power flows from the first traction substation DCSa and the second traction substation DCSb to the train. When |U1-U2|>U ε When the SPC single-phase power converter SPC is controlled to transmit power (P B -P A ) / 2 to the second AC bus AB2;

[0047] If P L >0, when P A ≥0,P B ≥0, control the SPC single-phase power converter SPC to transmit power (P B +P L -P A ) / 2, power (P A +P L -P B ) / 2; when P A ≤0, P B ≤0, control the SPC single-phase power converter SPC to transmit traction power (|P L |+|P A |-|P B |) / 2, power (|P L |+|P B |-|P A |) / 2; when P A <0,P B >0, control SPC to transmit power (|P) from AC bus AB1 through the first AC-DC converter 1 L |+|P B |-|P A | / 2, power is transmitted from the second AC bus AB2 through the second AC-DC converter 2 (|P L |+|P A |-|P B |) / 2; when P A >0,P B <0, control the SPC single-phase power converter SPC to transmit power (|P L |-|P B |-|P A |) / 2, power (|P L |+|P A |+|PB |) / 2;

[0048] If P L <0, when P A ≤0,P B ≤0, control the SPC single-phase power converter SPC to transmit power (|P B |+|P L |-|P A |) / 2, transmits power (|P) to the second AC bus AB2 through the second AC-DC converter 2 A |+|P L |-|P B |) / 2; when P A >0,P B ≤0, control the SPC single-phase power converter SPC to transmit power (|P B |+|P L |+|P A |) / 2, and transmits power (|P L |-|P B |-|P A |) / 2; when P A ≤0,P B >0, control the SPC single-phase power converter SPC to transmit power (|P L |-|P B |-|P A |) / 2, and transmits power (|P B |+|P L |+|P A |) / 2; when P A >0,P B >0, control the SPC single-phase power converter SPC to transmit power (|P L |+|P A |-|P B |) / 2, and transmits power (|P L |+|P A |-|P B |) / 2;

[0049] If P a =0,P B =0,P L≠0, control the SPC single-phase power converter SPC to transmit power P from the first AC bus AB1 and the second AC bus AB2 through the first AC-DC-AC converter 1 and the second AC-DC-AC converter 2. L / 2.

[0050] Example 4

[0051] This embodiment provides a control system, such as Figure 4 As shown, the computer device includes a processor and a memory, wherein the memory stores at least one instruction, at least one program, code set or instruction set, and the at least one instruction, at least one program, code set or instruction set is loaded and executed by the processor to implement the control method of Example 1.

[0052] The processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0053] The memory can be used to store computer programs or modules. The processor implements various functions of the control method by running or executing the computer programs or modules stored in the memory, and calling the data stored in the memory. The memory can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, at least one application required for a function (such as a sound playback function, an image playback function, etc.); the data storage area can store data created based on the use of the mobile phone (such as audio data, a phone book, etc.). In addition, the memory can include a high-speed random access memory and can also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage device.

[0054] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

[0055] From the above embodiments, it can be seen that the beneficial effects of the present invention are:

[0056] First, the present invention optimizes the voltage balance at the end of the traction power supply arm. By controlling the power transmission between the first AC bus, the second AC bus, and the DC system, a single-phase power converter (SPC) can redistribute power so that the outputs of the first traction substation (DCSa) and the second traction substation (DCSb) are the same. This reduces the difference between the voltage at the end of the first AC bus arm and the voltage at the end of the second AC bus arm, effectively optimizing the voltage balance at the end of the electrified railway arm.

[0057] Second, the present invention can realize the simultaneous power supply of AC and DC, and the two power supply systems share power supply equipment, effectively reducing the construction area and cost of the sub-stations;

[0058] 3. The present invention can realize the controllable DC voltage of the DC system, and the regenerative energy generated by the DC system can be fed back to the power supply system. That is, when PL is less than 0, the DC system train is in a regenerative braking condition, and the regenerative power is transmitted to the first AC bus through the first AC-DC-AC converter, and is transmitted to the second AC bus through the second AC-DC-AC converter.

[0059] 4. The present invention can realize the mutual utilization of train regenerative energy between the DC system and the AC system, thereby improving the utilization rate of regenerative energy.

[0060] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A dual-current power supply structure for an electrified railway substation, characterized in that: include: First traction substation, second traction substation, first AC busbar, second AC busbar, DC busbar, substation, measurement and control system; The output terminal of the grid substation is connected to the input terminal of the first traction substation and the input terminal of the second traction substation respectively; The output end of the first traction substation is connected to the substation via the first AC bus; The output end of the second traction substation is connected to the substation via the second AC bus; The sub-area is connected to the measurement and control system; The measurement and control system is connected to the DC bus; The partition includes: an SPC single-phase power converter, and the SPC single-phase power converter includes: a first matching transformer, a second matching transformer, a first AC-DC-AC converter, and a second AC-DC-AC converter; The primary side of the first matching transformer is connected to the first AC bus and the rail, and the primary side of the second matching transformer is connected to the second AC bus and the rail; The DC side of the first AC-DC-AC converter and the DC side of the second AC-DC-AC converter are both connected in parallel to the DC bus; The measurement and control system includes: a first voltage transformer, a second voltage transformer, a voltage transmitter, a first current transformer, a second current transformer, a shunt RW and a controller; The first current transformer is connected in series to the first AC bus, and the second current transformer is connected in series to the second AC bus; The first voltage transformer is connected in parallel between the first AC busbar and the rail, the second voltage transformer is connected in parallel between the second AC busbar and the rail, and the rail is grounded; One end of the DC bus is connected in series with the shunt, and the other end is connected in parallel with a voltage transmitter and then connected to the rail; The signal input end of the controller is respectively connected to the first voltage transformer, the second voltage transformer, the voltage transmitter, the first current transformer, the second current transformer, and the measurement signal output end of the shunt, and the signal output end of the controller is connected to the control end of the SPC single-phase power converter; The system further comprises: a first autotransformer and a second autotransformer, wherein the first autotransformer and the second autotransformer are connected in parallel between the first AC bus, the second AC bus and the negative feeder, and the primary sides of the first autotransformer and the second autotransformer are connected to the first AC bus and the negative feeder or the second AC bus and the negative feeder, respectively; the midpoints of the first autotransformer and the second autotransformer are connected to the rails; the first voltage transformer is connected in parallel between the first AC bus and the negative feeder, and the second voltage transformer is connected in parallel between the second AC bus and the negative feeder; the primary side of the first matching transformer is connected to the first AC bus and the negative feeder, and the primary side of the second matching transformer is connected to the second AC bus and the negative feeder.

2. A control method, characterized in that: The dual-current power supply structure for an electrified railway substation as claimed in claim 1 comprises the following steps: Get the grid voltage at the end of the first AC busbar power supply arm , the grid voltage at the end of the second AC busbar power supply arm ; Calculate the AC load power on the first AC busbar power supply arm , AC load power on the second AC busbar power supply arm , DC load power ; Set the reference value of the voltage difference at the end of the power supply arm , it is stipulated that the load power is positive when the train is in traction condition and negative when the train is in regenerative braking condition; like ,when There is no need to control the transfer active power of the SPC single-phase power converter, and the traction power flows from the first traction substation and the second traction substation to the train. When the SPC single-phase power converter is controlled to transmit power from the first AC bus To the second AC bus; like ,when , , control the SPC single-phase power converter to transmit power from the first AC bus through the first AC-DC converter , power is transmitted from the second AC bus through the second AC-DC converter ;when , , control the SPC single-phase power converter to transmit traction power from the first AC bus through the first AC-DC converter , power is transmitted from the second AC bus through the second AC-DC converter ;when , , control the SPC single-phase power converter to transmit power from the first AC bus through the first AC-DC converter , power is transmitted from the second AC bus through the second AC-DC converter ;when , , control the SPC single-phase power converter to transmit power from the first AC bus through the first AC-DC converter , power is transmitted from the second AC bus through the second AC-DC converter ; like ,when , , control the SPC single-phase power converter to transmit power to the first AC bus through the first AC-DC converter , transmits power to the second AC bus through the second AC-DC converter ;when , , control the SPC single-phase power converter to transmit power to the first AC bus through the first AC-DC converter , transmits power to the second AC bus through the second AC-DC converter ;when , , control the SPC single-phase power converter to transmit power to the first AC bus through the first AC-DC converter , transmits power to the second AC bus through the second AC-DC converter ;when , , control the SPC single-phase power converter to transmit power to the first AC bus through the first AC-DC converter , transmits power to the second AC bus through the second AC-DC converter ; like , , , control the SPC single-phase power converter to transmit power from the first AC bus and the second AC bus through the first AC-DC converter and the second AC-DC converter .

3. A control system, characterized in that: The control system includes a processor and a memory, wherein the memory stores at least one instruction, at least one program, code set or instruction set, and the at least one instruction, at least one program, code set or instruction set is loaded and executed by the processor to implement the control method as described in claim 2.

Images