Main wiring circuit for enhancing reliability of direct-current power supply system of urban rail transit

Abstract

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.

Description

TECHNICAL FIELD

[0001] The utility model relates to rail transit power supply system technical field, concretely related to a kind of main wiring circuit that enhances the reliability of urban rail transit direct current power supply system. BACKGROUND

[0002] With the sustained development of domestic rail transit, urban rail transit line is built more and more dense, in the face of increasingly dense rail transit vehicles and station operation work needs, the importance and stability of urban rail transit power supply system for urban rail transit is increasingly prominent. At present, urban rail power supply system distributes medium voltage power through medium voltage network (AC10kV, AC20kV, AC35kV), sets multiple step-down substations and traction and step-down hybrid substations along the line to transform power form for station and locomotive traction use. The step-down substation is through the step-down transformer arranged in the substation to step down the introduced medium voltage to AC0.4kV commonly used for industrial and civil use, and distribute to the power load in the station for use; the traction and step-down hybrid substation, in addition to supplying AC0.4kV power to the power load in the station, also transforms the introduced medium voltage into DC1500 or DC750 power commonly used by urban rail transit train through the traction transformer and rectifier in the substation.

[0003] For example, Figure 2 The current typical urban rail transit power supply system traction step-down hybrid substation main wiring diagram. The medium voltage system part adopts single bus section form. Under normal working conditions, the bus tie opens, and the AC medium voltage first and second section buses operate separately. The distribution transformers providing 0.4kV power for the distribution system in the substation are respectively mounted on the medium voltage first and second section buses, and do not affect each other, and are mutually main and backup, and jointly supply power to the station distribution system; the rectifier transformers of the DC system part for locomotive power supply are mounted on the same section bus (the first section bus is mounted on the second section bus, and the station is mounted on the first section bus, which is beneficial to the power balance of the whole power supply system), and the 1# and 2# rectifier transformers are a group with phase shift angles of +7.5° and -7.5°, which split the medium voltage into 24-pulse AC through two Y, Δ connection split windings, which not only improves the reliability of the rectifier unit, but also reduces the reverse input harmonic of the rectifier unit to the medium voltage system. Then, through two rectifiers, DC single bus is output, and power is distributed through DC circuit breaker, and then power is supplied to the locomotive. Figure 2

[0004] The arrangement principle of urban rail transit traction substation generally follows the following principles (taking 1500V system as an example): 1) the minimum voltage level of traction network is not less than 1000V; 2) the traction network belongs to particularly important load in primary load, so if voltage is too low or power loss occurs, power supply needs to be supported; 3) the voltage between steel rail and ground needs to meet the requirements of GB50157 and other specifications.​

[0005] Based on the above principles, and after power supply simulation calculations, such as Figure 3 As shown, traction substations are typically arranged as follows, depending on the line conditions: the distance between traction substations, Lcb and Lab, is approximately 2-3 km, ensuring that when traction substation B is out of service, its two adjacent traction substations, A and C, can simultaneously provide power to traction substation B from both sides. The distance between these two sides is generally no more than 6 km. The distance Lab from the end traction substation to its adjacent traction substation is generally less than 2 km, and the distance Lam from the end of the line to the end of the line is generally no more than 1 km, ensuring that when traction substation A is out of service, traction substation B provides power to the end of the line from one side. Multiple traction substations are arranged along the line to meet the power supply needs of the locomotive throughout its operation.

[0006] In practical engineering, traction substations are generally built together with the station to maximize the use of station resources and reduce civil engineering investment. However, the location of civil engineering substations may not necessarily meet the power supply requirements for vehicle traction, such as... Figure 3 As shown, if the locations of traction substations A and B are not well selected, such as when crossing rivers or tunnels with complex geological conditions, or if traction substation A is the end traction substation of this phase of the line and the distance to the end of this phase of the line, Lam, traction substations A and B can meet the traction power supply needs of trains under bilateral power supply. However, when traction substation A withdraws from power supply and traction substation B supplies power to the Lab+Lam power supply arm at the end of the line, it may cause the traction network voltage to be lower than the design standard of 1000V during peak hours of train operation, or the rail-to-ground potential to exceed the operating requirements of GB50157.

[0007] To address the aforementioned issues, the current common design solution is to add a section traction substation between traction substations A and B, or between the traction substation and the end of the line, in the ventilation shaft or under the bridge deck. This reduces the distance for unilateral power supply from traction substations A and B or the end of the line. When traction substation A is withdrawn, the section traction substation at ventilation shaft B can supply power to the end of the line, or ventilation shaft A and traction substation B can form a bilateral power supply. The traction substation at ventilation shaft A reduces its distance to the end of the line for unilateral power supply, thus meeting the locomotive traction power supply requirements.

[0008] However, while the above solution can solve the power supply quality problem, the addition of traction substations in the section will increase the investment in civil engineering and equipment. In addition, the addition of traction substations may cause engineering and technical problems due to the expansion of ventilation shafts in the civil engineering section, and may also cause policy problems such as planning and land acquisition.

[0009] No effective solutions have yet been proposed to address the problems in the relevant technologies. Utility Model Content

[0010] The utility model provides a kind of main wiring circuit for enhancing the reliability of urban rail transit direct current power supply system to overcome the above technical problems existing in prior art.

[0011] For this purpose, the utility model adopts the following specific technical solutions:

[0012] A kind of main wiring circuit for enhancing the reliability of urban rail transit direct current power supply system, comprising:

[0013] Main and backup medium-voltage AC bus, used as the main channel of power transmission, connecting transformer, power supply unit, ensure the stable supply of power;

[0014] Main and backup DC bus, used as the transmission path of DC power, connecting rectifier unit output and rail transit equipment;

[0015] Transformer unit, for converting medium-voltage AC into power suitable for DC system;

[0016] Medium-voltage power supply unit, for protecting the safety of urban rail transit direct current power supply system by cutting off power connection when circuit failure or maintenance;

[0017] DC power supply unit, for protecting DC circuit, ensure the safety of urban rail transit direct current power supply system;

[0018] Rectifier unit, for converting AC into DC to supply DC bus, meet the DC power demand of urban rail transit direct current power supply system.

[0019] Further, the main and backup medium-voltage AC bus is composed of medium-voltage AC bus AC_A and medium-voltage AC bus AC_B;The main and backup DC bus is composed of DC bus DC_A and DC bus DC_B.

[0020] Further, the medium-voltage power supply unit includes medium-voltage circuit breaker 101A, medium-voltage circuit breaker 102A, medium-voltage circuit breaker 103, medium-voltage circuit breaker 101B, medium-voltage circuit breaker 102B, medium-voltage circuit breaker 301, medium-voltage circuit breaker 302, medium-voltage circuit breaker 401, medium-voltage circuit breaker 402, medium-voltage disconnector 101A1, medium-voltage disconnector 101A2, medium-voltage disconnector 101B1, medium-voltage disconnector 101B2, medium-voltage disconnector 102A1, medium-voltage disconnector 102A2, medium-voltage disconnector 102B1, medium-voltage disconnector 102B2, medium-voltage disconnector 3011, medium-voltage disconnector 3012, medium-voltage disconnector 3021, medium-voltage disconnector 3022, medium-voltage disconnector 4011 and medium-voltage disconnector 4012.

[0021] The one end of the medium voltage circuit breaker 101A is connected with the one end of the medium voltage disconnector 101A1 and the one end of the medium voltage disconnector 101A2 respectively, the other end of the medium voltage disconnector 101A1 is connected with the medium voltage AC bus AC_B, and the other end of the medium voltage disconnector 101A2 is connected with the medium voltage AC bus AC_A;

[0022] The one end of the medium voltage circuit breaker 102A is connected with the one end of the medium voltage disconnector 102A1 and the one end of the medium voltage disconnector 102A2 respectively, the other end of the medium voltage disconnector 102A1 is connected with the medium voltage AC bus AC_B, and the other end of the medium voltage disconnector 102A2 is connected with the medium voltage AC bus AC_A;

[0023] The medium voltage AC bus AC_A is connected with the medium voltage AC bus AC_B through the medium voltage circuit breaker 103;

[0024] The one end of the medium voltage circuit breaker 101B is connected with the one end of the medium voltage disconnector 101B1 and the one end of the medium voltage disconnector 101B2 respectively, the other end of the medium voltage disconnector 101B1 is connected with the medium voltage AC bus AC_A, and the other end of the medium voltage disconnector 101B2 is connected with the medium voltage AC bus AC_B;

[0025] The one end of the medium voltage circuit breaker 102B is connected with the one end of the medium voltage disconnector 102B1 and the one end of the medium voltage disconnector 102B2 respectively, the other end of the medium voltage disconnector 102B1 is connected with the medium voltage AC bus AC_A, and the other end of the medium voltage disconnector 102B2 is connected with the medium voltage AC bus AC_B.

[0026] Further, the transformer unit is composed of a transformer T1, a transformer T2, a transformer T3 and a transformer T4;

[0027] The one end of the transformer T1 is connected with the one end of the medium voltage circuit breaker 401, the other end of the medium voltage circuit breaker 401 is connected with the one end of the medium voltage disconnector 4011, and the other end of the medium voltage disconnector 4011 is connected with the medium voltage AC bus AC_A;

[0028] The one end of the transformer T2 is connected with the one end of the medium voltage circuit breaker 402, the other end of the medium voltage circuit breaker 402 is connected with the one end of the medium voltage disconnector 4021, and the other end of the medium voltage disconnector 4021 is connected with the medium voltage AC bus AC_B;

[0029] One end of the transformer T3 is connected with one end of the medium voltage circuit breaker 301, the other end of the medium voltage circuit breaker 301 is connected with one end of the medium voltage disconnector 3011 and one end of the medium voltage disconnector 3012 respectively, the other end of the medium voltage disconnector 3011 is connected with the medium voltage AC bus AC_B, and the other end of the medium voltage disconnector 3012 is connected with the medium voltage AC bus AC_A;

[0030] One end of the transformer T4 is connected with one end of the medium voltage circuit breaker 302, the other end of the medium voltage circuit breaker 302 is connected with one end of the medium voltage disconnector 3021 and one end of the medium voltage disconnector 3022 respectively, the other end of the medium voltage disconnector 3021 is connected with the medium voltage AC bus AC_B, and the other end of the medium voltage disconnector 3022 is connected with the medium voltage AC bus AC_A.

[0031] Further, the DC power supply unit comprises a DC circuit breaker 201, a DC circuit breaker 202, a DC circuit breaker 201, a DC circuit breaker 203, a DC circuit breaker 211, a DC circuit breaker 212, a DC circuit breaker 213, a DC circuit breaker 214, a DC disconnector 2011, a DC disconnector 2012, a DC disconnector 2021, a DC disconnector 2022, a DC disconnector 2111, a DC disconnector 2112, a DC disconnector 2131, a DC disconnector 2132, a DC disconnector 2121, a DC disconnector 2122, a DC disconnector 2141, a DC disconnector 2142, a DC disconnector 2311, a DC disconnector 2321 and a DC disconnector 2331.

[0032] The other end of the DC disconnector 2311 is connected with one end of the DC disconnector 2331, the other end of the DC circuit breaker 201 is connected with one end of the DC disconnector 2011 and one end of the DC disconnector 2012 respectively, the other end of the DC disconnector 2011 is connected with the DC bus DC_B, and the other end of the DC disconnector 2012 is connected with the DC bus DC_A.

[0033] The other end of the DC disconnector 2321 is connected with the other end of the DC disconnector 2331, the other end of the DC circuit breaker 202 is connected with one end of the DC disconnector 2021 and one end of the DC disconnector 2022 respectively, the other end of the DC disconnector 2021 is connected with the DC bus DC_A, and the other end of the DC disconnector 2022 is connected with the DC bus DC_B.

[0034] One end of the DC circuit breaker 211 is connected with one end of the DC disconnector 2111 and one end of the DC disconnector 2112 respectively, the other end of the DC disconnector 2111 is connected with the DC bus DC_B, and the other end of the DC disconnector 2112 is connected with the DC bus DC_A;

[0035] One end of the DC circuit breaker 213 is connected with one end of the DC disconnector 2131 and one end of the DC disconnector 2132 respectively, the other end of the DC disconnector 2131 is connected with the DC bus DC_B, and the other end of the DC disconnector 2132 is connected with the DC bus DC_A;

[0036] One end of the DC circuit breaker 212 is connected with one end of the DC disconnector 2121 and one end of the DC disconnector 2122 respectively, the other end of the DC disconnector 2121 is connected with the DC bus DC_A, and the other end of the DC disconnector 2122 is connected with the DC bus DC_B;

[0037] One end of the DC circuit breaker 214 is connected with one end of the DC disconnector 2141 and one end of the DC disconnector 2142 respectively, the other end of the DC disconnector 2141 is connected with the DC bus DC_A, and the other end of the DC disconnector 2142 is connected with the DC bus DC_B;

[0038] The DC bus DC_A and the DC bus DC_B are further connected through the DC circuit breaker 203.

[0039] Further, the rectifier unit is composed of a rectifier D1 and a rectifier D2;

[0040] The AC input end of the rectifier bridge D1 is connected with the other end of the transformer T3, and the DC output end of the rectifier bridge D1 is connected with one end of the DC disconnector 2311 and one end of the DC circuit breaker 201 respectively;

[0041] The AC input end of the rectifier bridge D2 is connected with the other end of the transformer T4, and the DC output end of the rectifier bridge D2 is connected with one end of the DC disconnector 2321 and one end of the DC circuit breaker 202 respectively.

[0042] Further, the transformer T1 and the transformer T2 are both double-winding transformers, and the transformer T3 and the transformer T4 are both three-winding transformers.

[0043] Further, the medium-voltage AC bus AC_A and the medium-voltage AC bus AC_B are respectively placed in different air chambers to ensure electrical isolation from each other.

[0044] The utility model discloses the beneficial effect is:

[0045] 1) the utility model discloses the power supply system traction substation main wiring diagram can enhance the reliability of traction substation own power supply from the angle of not power maintenance, main spare redundancy support and saving power supply system investment, solve the problem of urban rail transit power supply system excessively dependent " big bilateral " power supply mode support power, the traction substation site selection difficulty, increase investment etc.

[0046] 2) the utility model discloses the whole substation direct current part and alternating current part are all configured according to main spare bus scheme, and the power supply reliability is high, and the operation is convenient and flexible, since direct current and alternating current part are configured with main spare redundancy design scheme, any group bus or equipment failure can be supported by switching operation, and it is convenient to not power maintenance and expansion, and can flexibly respond to the demand of various operation modes of the system.

[0047] 3) the utility model discloses can reduce the technical, economic and policy difficulty brought by newly set traction substation under the condition of appropriately increasing traction substation equipment investment, to improve the reliability of substation itself as the guarantee, also can reach the continuity and standby redundancy requirement of the power supply of the particularly important load required by specification, reduce the various technical problems brought by big bilateral power supply, effectively reduce the difficulty of traction substation arrangement. BRIEF DESCRIPTION OF DRAWINGS

[0048] In order to more clearly illustrate the technical scheme in the embodiment of the utility model or prior art, the following will briefly introduce the drawing needed to be used in the embodiment, and obviously, the drawing in the following description is only some embodiments of the utility model, and for those skilled in the art, other drawings can also be obtained according to these drawings without creating creative labor.

[0049] Figure 1 It is a main wiring circuit diagram for enhancing the reliability of urban rail transit direct current power supply system according to the utility model embodiment;

[0050] Figure 2 It is a typical urban rail transit power supply system traction step-down hybrid substation main wiring schematic diagram;

[0051] Figure 3 It is a traction substation position relationship simplified schematic diagram. DETAILED DESCRIPTION

[0052] To further illustrate the embodiments, the utility model provides has the drawing, these drawings are part of the utility model disclosure content, it mainly used to illustrate the embodiment, and can cooperate the related description of the specification to explain the operation principle of the embodiment, cooperate with reference to these contents, the person skilled in the art should be able to understand other possible implementation ways and the advantages of the utility model, the components in the drawing are not drawn according to scale, and similar component symbols are usually used to indicate similar components.

[0053] According to the embodiment of the utility model, a main wiring circuit for enhancing the reliability of the urban rail transit DC power supply system is provided.

[0054] The utility model will be further illustrated by combining with the drawings and specific embodiments, as shown in the drawings, according to the main wiring circuit for enhancing the reliability of the urban rail transit DC power supply system of the utility model embodiment, comprising: Figure 1

[0055] The main and standby medium-voltage AC bus is used as the main channel for power transmission, and is connected with the transformer and the power supply unit to ensure stable power supply.

[0056] The main and standby DC bus is used as the transmission path for DC power, and is connected with the rectifier unit output and the rail transit equipment.

[0057] The transformer unit is used to convert medium-voltage AC power into power suitable for the DC system.

[0058] The medium-voltage power supply unit is used to protect the safety of the urban rail transit DC power supply system by cutting off the power connection when the circuit fails or is under maintenance.

[0059] The DC power supply unit is used to protect the DC circuit and ensure the safety of the urban rail transit DC power supply system.

[0060] The rectifier unit is used to convert AC power into DC power to supply the DC bus and meet the DC power demand of the urban rail transit DC power supply system.

[0061] Specifically, the main and standby medium-voltage AC bus is composed of a medium-voltage AC bus AC_A and a medium-voltage AC bus AC_B, which are respectively placed in different air chambers to ensure electrical isolation from each other.

[0062] The main and standby DC bus is composed of a DC bus DC_A and a DC bus DC_B.

[0063] ​The medium voltage power supply unit comprises a medium voltage circuit breaker 101A, a medium voltage circuit breaker 102A, a medium voltage circuit breaker 103, a medium voltage circuit breaker 101B, a medium voltage circuit breaker 102B, a medium voltage circuit breaker 301, a medium voltage circuit breaker 302, a medium voltage circuit breaker 401, a medium voltage circuit breaker 402, a medium voltage disconnector 101A1, a medium voltage disconnector 101A2, a medium voltage disconnector 101B1, a medium voltage disconnector 101B2, a medium voltage disconnector 102A1, a medium voltage disconnector 102A2, a medium voltage disconnector 102B1, a medium voltage disconnector 102B2, a medium voltage disconnector 3011, a medium voltage disconnector 3012, a medium voltage disconnector 3021, a medium voltage disconnector 3022, a medium voltage disconnector 4011 and a medium voltage disconnector 4012;

[0064] The transformer unit is composed of a transformer T1, a transformer T2, a transformer T3 and a transformer T4, wherein the transformer T1 and the transformer T2 are both double-winding transformers, and the transformer T3 and the transformer T4 are both three-winding transformers;

[0065] The direct current power supply unit comprises a direct current circuit breaker 201, a direct current circuit breaker 202, a direct current circuit breaker 201, a direct current circuit breaker 203, a direct current circuit breaker 211, a direct current circuit breaker 212, a direct current circuit breaker 213, a direct current circuit breaker 214, a direct current disconnector 2011, a direct current disconnector 2012, a direct current disconnector 2021, a direct current disconnector 2022, a direct current disconnector 2111, a direct current disconnector 2112, a direct current disconnector 2131, a direct current disconnector 2132, a direct current disconnector 2121, a direct current disconnector 2122, a direct current disconnector 2141, a direct current disconnector 2142, a direct current disconnector 2311, a direct current disconnector 2321 and a direct current disconnector 2331;

[0066] The rectifier unit is composed of a rectifier D1 and a rectifier D2.

[0067] One end of the medium voltage circuit breaker 101A is connected with one end of the medium voltage disconnector 101A1 and one end of the medium voltage disconnector 101A2 respectively, the other end of the medium voltage disconnector 101A1 is connected with the medium voltage AC bus AC_B, and the other end of the medium voltage disconnector 101A2 is connected with the medium voltage AC bus AC_A;

[0068] One end of the medium voltage circuit breaker 102A is connected with one end of the medium voltage disconnector 102A1 and one end of the medium voltage disconnector 102A2 respectively, the other end of the medium voltage disconnector 102A1 is connected with the medium voltage AC bus AC_B, and the other end of the medium voltage disconnector 102A2 is connected with the medium voltage AC bus AC_A;

[0069] The medium-voltage circuit breaker 103 is connected between the medium-voltage AC bus AC_A and the medium-voltage AC bus AC_B;

[0070] One end of the medium-voltage circuit breaker 101B is connected with one end of the medium-voltage disconnector 101B1 and one end of the medium-voltage disconnector 101B2 respectively, the other end of the medium-voltage disconnector 101B1 is connected with the medium-voltage AC bus AC_A, and the other end of the medium-voltage disconnector 101B2 is connected with the medium-voltage AC bus AC_B;

[0071] One end of the medium-voltage circuit breaker 102B is connected with one end of the medium-voltage disconnector 102B1 and one end of the medium-voltage disconnector 102B2 respectively, the other end of the medium-voltage disconnector 102B1 is connected with the medium-voltage AC bus AC_A, and the other end of the medium-voltage disconnector 102B2 is connected with the medium-voltage AC bus AC_B;

[0072] One end of the transformer T1 is connected with one end of the medium-voltage circuit breaker 401, the other end of the medium-voltage circuit breaker 401 is connected with one end of the medium-voltage disconnector 4011, and the other end of the medium-voltage disconnector 4011 is connected with the medium-voltage AC bus AC_A;

[0073] One end of the transformer T2 is connected with one end of the medium-voltage circuit breaker 402, the other end of the medium-voltage circuit breaker 402 is connected with one end of the medium-voltage disconnector 4021, and the other end of the medium-voltage disconnector 4021 is connected with the medium-voltage AC bus AC_B;

[0074] One end of the transformer T3 is connected with one end of the medium-voltage circuit breaker 301, the other end of the medium-voltage circuit breaker 301 is connected with one end of the medium-voltage disconnector 3011 and one end of the medium-voltage disconnector 3012 respectively, the other end of the medium-voltage disconnector 3011 is connected with the medium-voltage AC bus AC_B, and the other end of the medium-voltage disconnector 3012 is connected with the medium-voltage AC bus AC_A;

[0075] One end of the transformer T4 is connected with one end of the medium-voltage circuit breaker 302, the other end of the medium-voltage circuit breaker 302 is connected with one end of the medium-voltage disconnector 3021 and one end of the medium-voltage disconnector 3022 respectively, the other end of the medium-voltage disconnector 3021 is connected with the medium-voltage AC bus AC_B, and the other end of the medium-voltage disconnector 3022 is connected with the medium-voltage AC bus AC_A;

[0076] Another end of the DC disconnector 2311 is connected with one end of the DC disconnector 2331, another end of the DC disconnector 201 is connected with one end of the DC disconnector 2011 and one end of the DC disconnector 2012 respectively, another end of the DC disconnector 2011 is connected with the DC bus DC_B, and another end of the DC disconnector 2012 is connected with the DC bus DC_A;

[0077] Another end of the DC disconnector 2321 is connected with another end of the DC disconnector 2331, another end of the DC disconnector 202 is connected with one end of the DC disconnector 2021 and one end of the DC disconnector 2022 respectively, another end of the DC disconnector 2021 is connected with the DC bus DC_A, and another end of the DC disconnector 2022 is connected with the DC bus DC_B;

[0078] One end of the DC disconnector 211 is connected with one end of the DC disconnector 2111 and one end of the DC disconnector 2112 respectively, another end of the DC disconnector 2111 is connected with the DC bus DC_B, and another end of the DC disconnector 2112 is connected with the DC bus DC_A;

[0079] One end of the DC disconnector 213 is connected with one end of the DC disconnector 2131 and one end of the DC disconnector 2132 respectively, another end of the DC disconnector 2131 is connected with the DC bus DC_B, and another end of the DC disconnector 2132 is connected with the DC bus DC_A;

[0080] One end of the DC disconnector 212 is connected with one end of the DC disconnector 2121 and one end of the DC disconnector 2122 respectively, another end of the DC disconnector 2121 is connected with the DC bus DC_A, and another end of the DC disconnector 2122 is connected with the DC bus DC_B;

[0081] One end of the DC disconnector 214 is connected with one end of the DC disconnector 2141 and one end of the DC disconnector 2142 respectively, another end of the DC disconnector 2141 is connected with the DC bus DC_A, and another end of the DC disconnector 2142 is connected with the DC bus DC_B;

[0082] The DC bus DC_A and the DC bus DC_B are further connected through the DC disconnector 203;

[0083] The AC input end of the rectifier bridge D1 is connected with the other end of the transformer T3, the DC output end of the rectifier bridge D1 is connected with one end of the DC isolating switch 2311 and one end of the DC circuit breaker 201 respectively;

[0084] The AC input end of the rectifier bridge D2 is connected with the other end of the transformer T4, the DC output end of the rectifier bridge D2 is connected with one end of the DC isolating switch 2321 and one end of the DC circuit breaker 202 respectively.

[0085] In order to better understand the above technical scheme of the utility model, the above technical scheme is described in detail from the circuit principle.

[0086] As Figure 1 The traction step-down hybrid substation main wiring circuit diagram designed by the utility model. With Figure 2 Different from the typical traction hybrid substation main wiring diagram, the utility model is designed as double busbar form in the traction step-down hybrid substation medium voltage busbar and DC busbar.

[0087] The AC medium voltage circuit breaker is numbered as 101A, 101B, 102A, 102B, 301, 302, 401, 402, 103, and is used for breaking the power supply in the fault and normal working state. 101A1, 101A2, 101B1, 101B2, 102A1, 102A2, 102B1, 102B2, 3011, 3012, 3021, 3022, 4011, 4021 are medium voltage isolating switches, which cannot break the current and are used for isolating the power supply during maintenance.

[0088] The medium voltage circuit breaker 401 is connected in series with the medium voltage disconnector 4011, the medium voltage circuit breaker 402 is connected in series with the medium voltage disconnector 4021, and are connected to the AC_A and AC_B medium voltage AC bus respectively, and the A and B bus are respectively arranged in different air chambers to ensure electrical isolation. The bus interconnection medium voltage circuit breaker 103 is in the open state under normal working condition, when one power supply loses power, the loss of power circuit breaker is locked, the incoming line is closed, and the A and B bus are quickly supported by the fast closing of the circuit breaker. The medium voltage disconnector 101A1 and 101A2 are connected to the medium voltage circuit breaker 101A through the disconnector bus T in the switch cabinet, and the three devices form a medium voltage power supply unit in the same medium voltage switch cabinet air chamber. The same switch combination also includes the medium voltage circuit breaker 102A and the medium voltage disconnector 102A1, 102A2, the medium voltage circuit breaker 101B and the medium voltage disconnector 101B1, 101B2, the medium voltage circuit breaker 102B and the medium voltage disconnector 102B1, 102B2, the medium voltage circuit breaker 301 and the medium voltage disconnector 3011, 3012, and the medium voltage circuit breaker 302 and the medium voltage disconnector 3021, 3022. When one of the medium voltage power supply units is closed, the other must be open and cannot be grounded, and the breaking of the circuit breaker is free, such as the 101A, 101A1 and 101A2 medium voltage power supply unit, 101A1 is closed, and 101A2 is in the open position. The operation logic of other medium voltage power supply units is consistent with that of the 101A, 101A1 and 101A2 medium voltage power supply unit. The disconnector in the incoming and outgoing line power supply unit also has a interlocking relationship, when 101A1 or 102A1 is in the closed position, only 101B2 or 102B2 is allowed to be closed, when 101A2 or 102A2 is in the closed position, only 101B1 or 102B1 is allowed to be in the closed position, to avoid phase-to-phase short circuit caused by power from different power supply systems.

[0089] The DC circuit breakers are numbered as 201, 202, 211, 212, 213, 214, 203, 2011, 2012, 2021, 2022, 2112, 2111, 2132, 2131, 2122, 2121, 2142, 2141, 2311, 2321, 2331, and the DC disconnectors are numbered as 2011, 2012, 2021, 2022, 2112, 2111, 2132, 2131, 2122, 2121, 2142, 2141, 2311, 2321, 2331.

[0090] The direct current system is provided with two direct current buses DC_A and DC_B which are independently insulated and installed. The direct current disconnecting switches 2011 and 2012 are connected to the circuit breaker through the direct current disconnecting switch bus T in the direct current switch cabinet. The direct current disconnecting switches 2011 and 2012 are a group of direct current power supply units. The same power supply unit also comprises the direct current disconnecting switches 2021 and 2022, the direct current disconnecting switches 2112 and 2111, the direct current disconnecting switches 2132 and 2131, the direct current disconnecting switches 2122 and 2121, and the direct current disconnecting switches 2041 and 2042. Under normal conditions, when one of the direct current disconnecting switches is closed, the other direct current disconnecting switch is not allowed to be closed. For example, when 2011 is closed, 2012 is not allowed to be closed. Two groups of rectifier units supply power to the direct current buses DC_A and DC_B. The direct current circuit breaker 203 is closed, and the two direct current buses are connected, thereby reducing the output direct current pulse current and voltage. In order to reduce the leakage of the direct current device frame and cause the entire direct current system to exit, a plurality of frame leakage protection devices are arranged, which are respectively DC_+A section bus, DC_+B section bus, 1# rectifier D1, 2# rectifier D2, 201, 211, 212 group circuit breaker room, 202, 213, 214 group circuit breaker room, and 203 circuit breaker room. The negative electrode cabinet through which the return cable passes first is provided with two negative busbars. The direct current disconnecting switch 2331 is used for electrically isolating the two negative busbars. Under normal conditions, the direct current disconnecting switch is closed. When a fault occurs, the direct current disconnecting switch is opened. DC_-A and DC_-B are connected in series into the rectifier unit through the direct current disconnecting switch 2311 and the direct current disconnecting switch 2321, so that the rectifier unit can be maintained when the rectifier unit is maintained. The devices in the inter-group frame leakage protection are independently insulated, so that when the direct current system leaks, the range of power failure is not expanded.

[0091] In summary, by means of the above technical scheme of the utility model, through the design of the power supply system traction substation main wiring diagram, the reliability of the traction substation itself power supply can be enhanced from the aspects of non-stop maintenance, standby redundancy support and power supply system investment saving, the problems of difficult selection of the traction substation site, increased investment and the like caused by excessive dependence of the urban rail transit power supply system on the "big bilateral" power supply mode are solved, and the utility model has high popularization and application value in the field of urban rail transit power supply systems in China.

[0092] In addition, the entire direct current part and alternating current part of the utility model are configured according to the main and standby bus scheme, the power supply reliability is high, and the operation is convenient and flexible. Since the main and standby redundant design scheme is configured for the direct current part and the alternating current part, any group of bus or equipment fault can be supported by switching operation, non-stop maintenance and expansion are facilitated, and the system can flexibly cope with the demand under various operation modes.

[0093] In addition, the utility model can reduce the technical, economic and policy difficulties brought by newly setting traction substation under the condition of properly increasing traction substation equipment investment, guarantees the reliability of the substation itself, can also reach the sustainability and standby redundancy requirement of supplying power to particularly important load required by the specification, reduces various technical problems brought by large bilateral power supply, and effectively reduces the difficulty of traction substation arrangement.

[0094] The above merely describes the preferred embodiments of the utility model and is not used to limit the utility model, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. A main wiring circuit for enhancing the reliability of DC power supply systems for urban rail transit, characterized in that, Comprise: The main and standby medium-voltage AC bus is used as the main channel for power transmission, connecting the transformer and power supply unit to ensure stable power supply; The main and standby DC bus is used as the transmission path for DC power, connecting the rectifier unit output and rail transit equipment; The transformer unit is used to convert medium-voltage AC power into power suitable for the DC system; The medium-voltage power supply unit is used to protect the safety of the urban rail transit DC power supply system by cutting off the power connection during circuit failure or maintenance; The DC power supply unit is used to protect the DC circuit and ensure the safety of the urban rail transit DC power supply system; The rectifier unit is used to convert AC power into DC power to supply the DC bus and meet the DC power demand of the urban rail transit DC power supply system.

2. The main wiring circuit for enhancing the reliability of a DC power supply system of urban rail transit according to claim 1, characterized in that, The main and standby medium-voltage AC bus is composed of medium-voltage AC bus AC_A and medium-voltage AC bus AC_B; the main and standby DC bus is composed of DC bus DC_A and DC bus DC_B.

3. The main wiring circuit for enhancing the reliability of a DC power supply system of urban rail transit according to claim 2, characterized in that, The medium-voltage power supply unit includes medium-voltage circuit breakers 101A, 102A, 103, 101B, 102B, 301, 302, 401, 402, medium-voltage disconnecting switches 101A1, 101A2, 101B1, 101B2, 102A1, 102A2, 102B1, 102B2, 3011, 3012, 3021, 3022, 4011, and 4012; One end of the medium-voltage circuit breaker 101A is connected to one end of the medium-voltage disconnecting switch 101A1 and one end of the medium-voltage disconnecting switch 101A2, the other end of the medium-voltage disconnecting switch 101A1 is connected to the medium-voltage AC bus AC_B, and the other end of the medium-voltage disconnecting switch 101A2 is connected to the medium-voltage AC bus AC_A; One end of the medium-voltage circuit breaker 102A is connected to one end of the medium-voltage disconnecting switch 102A1 and one end of the medium-voltage disconnecting switch 102A2, the other end of the medium-voltage disconnecting switch 102A1 is connected to the medium-voltage AC bus AC_B, and the other end of the medium-voltage disconnecting switch 102A2 is connected to the medium-voltage AC bus AC_A; The medium-voltage AC bus AC_A is connected to the medium-voltage AC bus AC_B through the medium-voltage circuit breaker 103; One end of the medium-voltage circuit breaker 101B is connected to one end of the medium-voltage disconnecting switch 101B1 and one end of the medium-voltage disconnecting switch 101B2, the other end of the medium-voltage disconnecting switch 101B1 is connected to the medium-voltage AC bus AC_A, and the other end of the medium-voltage disconnecting switch 101B2 is connected to the medium-voltage AC bus AC_B; One end of the medium-voltage circuit breaker 102B is connected with one end of the medium-voltage disconnector 102B1 and one end of the medium-voltage disconnector 102B2 respectively, the other end of the medium-voltage disconnector 102B1 is connected with the medium-voltage AC bus AC_A, and the other end of the medium-voltage disconnector 102B2 is connected with the medium-voltage AC bus AC_B.

4. The main wiring circuit for enhancing the reliability of a DC power supply system of urban rail transit according to claim 3, characterized in that, The transformer unit is composed of a transformer T1, a transformer T2, a transformer T3 and a transformer T4; One end of the transformer T1 is connected with one end of the medium-voltage circuit breaker 401, the other end of the medium-voltage circuit breaker 401 is connected with one end of the medium-voltage disconnector 4011, and the other end of the medium-voltage disconnector 4011 is connected with the medium-voltage AC bus AC_A; One end of the transformer T2 is connected with one end of the medium-voltage circuit breaker 402, the other end of the medium-voltage circuit breaker 402 is connected with one end of the medium-voltage disconnector 4021, and the other end of the medium-voltage disconnector 4021 is connected with the medium-voltage AC bus AC_B; One end of the transformer T3 is connected with one end of the medium-voltage circuit breaker 301, the other end of the medium-voltage circuit breaker 301 is connected with one end of the medium-voltage disconnector 3011 and one end of the medium-voltage disconnector 3012 respectively, the other end of the medium-voltage disconnector 3011 is connected with the medium-voltage AC bus AC_B, and the other end of the medium-voltage disconnector 3012 is connected with the medium-voltage AC bus AC_A; One end of the transformer T4 is connected with one end of the medium-voltage circuit breaker 302, the other end of the medium-voltage circuit breaker 302 is connected with one end of the medium-voltage disconnector 3021 and one end of the medium-voltage disconnector 3022 respectively, the other end of the medium-voltage disconnector 3021 is connected with the medium-voltage AC bus AC_B, and the other end of the medium-voltage disconnector 3022 is connected with the medium-voltage AC bus AC_A.

5. The main circuit of claim 4, wherein, The DC power supply unit comprises a DC circuit breaker 201, a DC circuit breaker 202, a DC circuit breaker 201, a DC circuit breaker 203, a DC circuit breaker 211, a DC circuit breaker 212, a DC circuit breaker 213, a DC circuit breaker 214, a DC disconnector 2011, a DC disconnector 2012, a DC disconnector 2021, a DC disconnector 2022, a DC disconnector 2111, a DC disconnector 2112, a DC disconnector 2131, a DC disconnector 2132, a DC disconnector 2121, a DC disconnector 2122, a DC disconnector 2141, a DC disconnector 2142, a DC disconnector 2311, a DC disconnector 2321 and a DC disconnector 2331. One end of the DC disconnector 201 is connected with one end of the DC disconnector 2011 and one end of the DC disconnector 2012 respectively, the other end of the DC disconnector 2011 is connected with the DC bus DC_B, and the other end of the DC disconnector 2012 is connected with the DC bus DC_A. The other end of the DC disconnector 2321 is connected with the other end of the DC disconnector 2331, one end of the DC disconnector 202 is connected with one end of the DC disconnector 2021 and one end of the DC disconnector 2022 respectively, the other end of the DC disconnector 2021 is connected with the DC bus DC_A, and the other end of the DC disconnector 2022 is connected with the DC bus DC_B. One end of the DC disconnector 211 is connected with one end of the DC disconnector 2111 and one end of the DC disconnector 2112 respectively, the other end of the DC disconnector 2111 is connected with the DC bus DC_B, and the other end of the DC disconnector 2112 is connected with the DC bus DC_A. One end of the DC disconnector 213 is connected with one end of the DC disconnector 2131 and one end of the DC disconnector 2132 respectively, the other end of the DC disconnector 2131 is connected with the DC bus DC_B, and the other end of the DC disconnector 2132 is connected with the DC bus DC_A. One end of the DC disconnector 212 is connected with one end of the DC disconnector 2121 and one end of the DC disconnector 2122 respectively, the other end of the DC disconnector 2121 is connected with the DC bus DC_A, and the other end of the DC disconnector 2122 is connected with the DC bus DC_B. One end of the DC disconnector 214 is connected with one end of the DC disconnector 2141 and one end of the DC disconnector 2142 respectively, the other end of the DC disconnector 2141 is connected with the DC bus DC_A, and the other end of the DC disconnector 2142 is connected with the DC bus DC_B. The DC bus DC_A and the DC bus DC_B are further connected through the DC disconnector 203.

6. The main wiring circuit for enhancing the reliability of a DC power supply system of urban rail transit according to claim 5, characterized in that, The rectification unit is composed of a rectifier D1 and a rectifier D2; One end of the DC disconnector 201 is connected with one end of the DC disconnector 2011 and one end of the DC disconnector 2012 respectively, the other end of the DC disconnector 2011 is connected with the DC bus DC_B, and the other end of the DC disconnector 2012 is connected with the DC bus DC_A. One end of the DC disconnector 202 is connected with one end of the DC disconnector 2021 and one end of the DC disconnector 2022 respectively, the other end of the DC disconnector 2021 is connected with the DC bus DC_A, and the other end of the DC disconnector 2022 is connected with the DC bus DC_B.

7. The main circuit of claim 4, wherein, The transformer T1 and the transformer T2 are double-winding transformers, and the transformer T3 and the transformer T4 are three-winding transformers.

8. The main wiring circuit for enhancing the reliability of a DC power supply system of urban rail transit according to claim 2, characterized in that, The medium-voltage AC bus AC_A and the medium-voltage AC bus AC_B are respectively arranged in different air chambers to ensure electrical isolation from each other.

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