Integrated power supply system of transformer substation

Abstract

The utility model discloses an integrated power supply system of a transformer station, and relates to the technical field of power supply systems of transformer stations. The system comprises an alternating current power supply subsystem, a direct current power supply subsystem and a UPS (Uninterrupted Power Supply) subsystem, the ATS alternating current switching device is connected with the first direct current feeder line through the alternating current feeder line and the AC / DC rectifying unit in sequence; one end of the fuse is connected with the first direct-current feeder, and the other end is connected with the second direct-current feeder; the first end of the DC / DC conversion unit is connected with the storage battery pack, the second end is connected with the second DC feeder, and the third end is connected with the communication DC feeder; and the input end of the DC / AC inverter unit is connected to the second DC feeder line, and the output end of the DC / AC inverter unit and the output end of the AC / AC unit are connected to the UPS feeder line, so that the problem of unstable DC feeder line voltage caused by wide voltage conversion range of a storage battery pack and battery aging can be solved under the conditions of AC incoming line fault and storage battery power supply.

Description

Technical Field

[0001] The utility model relates to the technical field of substation power supply systems, and particularly to an integrated substation power supply system. Background Art

[0002] This section aims to provide background or context for the embodiments of the utility model described in this article. The descriptions herein are not admitted to be prior art merely because they are included in this section.

[0003] With the intensification of substation equipment and the intelligence of operation and maintenance management, the substation power supply system tends to be integrated, designed by a single manufacturer, and a set of battery packs are shared by the DC subsystems to supply power to devices such as lighting, protection, measurement and control, and communication in the substation. When the AC power supply of the integrated power supply system fails, the battery pack directly discharges to the 220V DC load. However, during the discharge process, the voltage conversion range of the battery pack is relatively large, and there is a problem of voltage reduction caused by battery aging, which affects the normal operation of the DC load in the substation.

[0004] During the discharge process of the battery pack in the integrated power supply system, its voltage conversion range is relatively large. In addition, as the number of battery cycles increases, the battery gradually ages, resulting in a decrease in its output voltage, thereby affecting the voltage on the 220V DC feeder. Too high or too low voltage on the 220V DC feeder will affect the normal operation of the DC loads (such as protection, measurement and control devices) connected thereto. Summary of the Utility Model

[0005] Embodiments of the utility model provide an integrated substation power supply system to solve the problem of unstable DC feeder voltage caused by the wide voltage conversion range of the battery pack and battery aging when the AC incoming line fails and the battery supplies power. The system includes:

[0006] An AC power supply subsystem, a DC power supply subsystem, and a UPS (Uninterrupted Power System) power supply subsystem; the AC power supply subsystem includes an ATS (Automatic Transfer Switch) AC switching device and an AC feeder; the DC power supply subsystem includes an AC (Alternating current) / DC (Direct current) rectification unit, a first DC feeder, a fuse, a second DC feeder, a battery pack, a DC / DC conversion unit, and a communication DC feeder; the UPS power supply subsystem includes a DC / AC inversion unit, an AC / AC unit, and an uninterrupted power system UPS feeder;

[0007] The ATS AC switching device is sequentially connected to the first DC feeder through the AC feeder and the AC / DC rectification unit; one end of the fuse is connected to the first DC feeder, and the other end is connected to the second DC feeder;

[0008] The first end of the DC / DC conversion unit is connected to the battery pack, the second end is connected to the second DC feeder, and the third end is connected to the communication DC feeder;

[0009] The input end of the DC / AC inversion unit is connected to the second DC feeder, and the output end and the output end of the AC / AC unit are both connected to the UPS feeder.

[0010] Compared with the prior art, the beneficial effects of the present utility model are as follows: The present utility model includes an AC power supply subsystem, a DC power supply subsystem, and a UPS power supply subsystem; the AC power supply subsystem includes an automatic transfer switch ATS AC switching device and an AC feeder; the DC power supply subsystem includes an AC / DC rectification unit, a first DC feeder, a fuse, a second DC feeder, a battery pack, a DC / DC conversion unit, and a communication DC feeder; the UPS power supply subsystem includes a DC / AC inversion unit, an AC / AC unit, and an uninterruptible power supply system UPS feeder; the ATS AC switching device is sequentially connected to the first DC feeder through the AC feeder and the AC / DC rectification unit; one end of the fuse is connected to the first DC feeder, and the other end is connected to the second DC feeder; the first end of the DC / DC conversion unit is connected to the battery pack, the second end is connected to the second DC feeder, and the third end is connected to the communication DC feeder; the input end of the DC / AC inversion unit is connected to the second DC feeder, and the output end and the output end of the AC / AC unit are both connected to the UPS feeder, which can solve the problem of unstable DC feeder voltage caused by the wide voltage conversion range of the battery pack and battery aging in the case of AC incoming line failure and battery power supply. Description of the Drawings

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings. In the drawings:

[0012] Figure 1 It is a schematic diagram of an integrated substation power supply system provided in an embodiment of the present utility model;

[0013] Figure 2 It is a schematic diagram of a specific example of an integrated substation power supply system provided in an embodiment of the present utility model;

[0014] Figure 3Schematic diagram of a specific example of an integrated power supply system for a substation provided in an embodiment of the present invention;

[0015] Figure 4 Schematic diagram of a specific example of an integrated power supply system for a substation provided in an embodiment of the present invention;

[0016] Figure 5 Schematic diagram of a specific example of an integrated power supply system for a substation provided in an embodiment of the present invention.

[0017] Among them, 1 - ATS AC switching device; 2 - AC feeder; 3 - AC / DC rectification unit; 4 - first DC feeder; 5 - fuse; 6 - second DC feeder; 7 - battery pack; 8 - DC / DC conversion unit; 9 - first disconnecting switch; 10 - second disconnecting switch; 11 - third disconnecting switch; 12 - communication DC feeder; 13 - battery inspection device; 14 - DC / AC inverter unit; 15 - AC / AC unit; 16 - UPS feeder; 17 - monitoring module. Detailed implementation manners

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer and more understandable, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Herein, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but do not limit the present invention.

[0019] In the technical solutions of this application, the acquisition, storage, use, processing, etc. of data all comply with the relevant regulations of laws and regulations.

[0020] The term "and / or" in this article merely describes an association relationship and indicates that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the term "at least one" in this article means any one of multiple types or any combination of at least two of multiple types. For example, including at least one of A, B, and C may represent including any one or more elements selected from the set composed of A, B, and C.

[0021] In the description of this specification, the terms "including", "comprising", "having", "containing", etc. are all open-ended terms, meaning including but not limited to. The description with reference to terms such as "one embodiment", "one specific embodiment", "some embodiments", "for example", etc. means that the specific features, structures or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. The order of steps involved in each embodiment is used to schematically illustrate the implementation of the present application, and the order of steps is not limited and can be adjusted appropriately as needed.

[0022] In recent years, with the intensification of substation equipment and the intelligence of operation and maintenance management, the substation power supply system tends to be integrated, designed by a single manufacturer, and at the same time, the DC subsystem shares a set of battery packs to supply power to devices such as lighting, protection, measurement and control, and communication in the substation. When the AC power supply of the integrated power supply system fails, the battery pack directly discharges to the 220V DC load. However, during the discharge process, the voltage conversion range of the battery pack is relatively large, and there is also a problem of voltage reduction caused by battery aging, which affects the normal operation of the substation DC load. And too high or too low voltage of the 220V DC feeder will affect the normal operation of the DC loads (such as protection, measurement and control devices) connected thereto.

[0023] Figure 1 The following is a schematic diagram of an integrated substation power supply system provided in an embodiment of the present invention. As Figure 1 shown, the integrated substation power supply system includes: an AC power supply subsystem, a DC power supply subsystem, and a UPS power supply subsystem; the AC power supply subsystem includes an automatic transfer switch ATS AC switching device 1 and an AC feeder 2; the DC power supply subsystem includes an AC / DC rectification unit 3, a first DC feeder 4, a fuse 5, a second DC feeder 6, a battery pack 7, a DC / DC conversion unit 8, and a communication DC feeder 12; the UPS power supply subsystem includes a DC / AC inverter unit 14, an AC / AC unit 15, and an uninterruptible power supply system UPS feeder 16;

[0024] The ATS AC switching device 1 is sequentially connected to the first DC feeder 4 through the AC feeder 2 and the AC / DC rectification unit 3; one end of the fuse 5 is connected to the first DC feeder 4, and the other end is connected to the second DC feeder 6;

[0025] The first end of the DC / DC conversion unit 8 is connected to the battery pack 7, the second end is connected to the second DC feeder 6, and the third end is connected to the communication DC feeder 12;

[0026] The input end of the DC / AC inverter unit 14 is connected to the second DC feeder 6, and the output ends of both the output end of the DC / AC inverter unit 14 and the AC / AC unit 15 are connected to the UPS feeder 16.

[0027] Figure 2 It is a schematic diagram of a specific example of an integrated power supply system for a substation provided in an embodiment of the present invention. As Figure 2 shown, in one embodiment, the DC power supply subsystem further includes a battery inspection device 13; the battery inspection device 13 is connected to the battery pack 7 and is used for measuring the voltage of the battery pack 7.

[0028] As Figure 2 shown, in one embodiment, the integrated power supply system for a substation further includes: a monitoring module 17, which is respectively connected to the AC feeder 2, the AC / DC rectifier unit 3, and the battery pack 7; the monitoring module 17 is used for monitoring the AC feeder 2, the AC / DC rectifier unit 3, and the battery pack 7. The monitoring scope of the monitoring module 17 includes but is not limited to the current of the AC feeder 2, the AC / DC rectifier unit 3, the battery pack 7, and the battery inspection device 13.

[0029] The first DC feeder 4 can be a 220V first DC feeder, the second DC feeder 6 can be a 220V second DC feeder, the AC feeder 2 can be a 380V AC feeder, and the communication DC feeder 12 can be a 48V communication DC feeder.

[0030] In one embodiment, the other end of the ATS AC switching device 1 connected to the AC feeder 2 can be connected to a 380V AC input, the input end of the AC / AC unit 15 can be connected to the AC input, and the UPS output can be connected to the UPS feeder 16.

[0031] Figure 3 It is a schematic diagram of a specific example of an integrated power supply system for a substation provided in an embodiment of the present invention. As Figure 3 shown, in one embodiment, the DC power supply subsystem further includes a first knife switch 9, a second knife switch 10, and a third knife switch 11; the first end of the DC / DC conversion unit 8 is connected in series with the battery pack 7 through the first knife switch 9, the second end is connected to the second DC feeder 6 through the second knife switch 10, and the third end is connected to the communication DC feeder 12 through the third knife switch 11; the first knife switch 9, the second knife switch 10, and the third knife switch 11 are respectively used to connect or disconnect the first end, the second end, and the third end of the DC / DC conversion unit 8 from the connection devices.

[0032] In one embodiment, when the power of the battery pack 7 is lower than the actual capacity of the battery pack 7, the states of the first knife switch 9, the second knife switch 10, and the third knife switch 11 are closed. The second end of the DC / DC conversion unit 8 is the input end, the first end and the third end are the output ends, and the second DC feeder 6 is used to supply power to the battery pack 7 and the communication load.

[0033] In one embodiment, when the absolute value of the difference between the power of the battery pack 7 and the actual capacity of the battery pack 7 is lower than a preset threshold, the first switch 9 is in the open state, the second switch 10 and the third switch 11 are in the closed state, the second end of the DC / DC conversion unit 8 is the input end, the third end is the output end, and the second DC feeder 6 is used to supply power to the communication load.

[0034] In one embodiment, when the AC / DC rectification unit 3 fails, the first switch 9, the second switch 10, and the third switch 11 are in the closed state, the first end of the DC / DC conversion unit 8 is the input end, the second end and the third end are the output ends, and the battery pack 7 is used to supply power to the DC load and the communication load.

[0035] In one embodiment, the voltage level of the battery pack 7 is 220V or 110V; the voltage conversion range of the DC / DC conversion unit 8 corresponds to the voltage level of the battery pack 7.

[0036] Figure 4 It is a schematic diagram of a specific example of an integrated substation power supply system provided in the embodiments of the present invention. As Figure 4 shown, the ATS AC switching device 1 is connected to the 380V AC feeder 2 and is connected to the first DC feeder 4 through the AC / DC rectification unit 3; one end of the fuse 5 is connected to the 220V first DC feeder 4, and the other end is connected to the 220V second DC feeder 6; the first port of the DC / DC conversion unit 8 is connected in series with the battery pack 7 through the first switch 9, its second port is connected to the 220V second DC feeder 6 through the second switch 10, and the third port is connected to the 48V communication DC feeder 12 through the third switch 11; the input end of the DC / AC inversion unit 14 is connected to the 220V second DC feeder 6, and its output end and the output end of the AC / AC unit 15 are both connected to the UPS feeder 16; the monitoring range of the monitoring module 17 includes but is not limited to the 380V AC feeder 2, the AC / DC rectification unit 3, the current of the battery pack 7, the battery inspection device 13, etc.

[0037] Figure 5 It is a schematic diagram of a specific example of an integrated substation power supply system provided in the embodiments of the present invention. As Figure 5 shown, in one embodiment, the integrated substation power supply system supplies power to the 220V DC load through the second DC feeder 6 and supplies power to the 48V communication load through the communication DC feeder 12.

[0038] In one embodiment, the DC / DC conversion unit 8 includes a plurality of bidirectional three-port DC / DC converters; the plurality of bidirectional three-port DC / DC converters are connected in parallel, and the first ends, second ends, and third ends of the plurality of bidirectional three-port DC / DC converters are respectively connected together.

[0039] In one embodiment, the number of bidirectional three-port DC / DC converters is n, and n = n1 + n2, where:

[0040]

[0041] where n1 is the number of basic modules and n2 is the number of additional modules; the basic module is the converter unit in the bidirectional three-port DC / DC converter that can meet the rated operation of the load, that is, the bidirectional three-port DC / DC converter for daily work; the additional module is the converter unit additionally added in the bidirectional three-port DC / DC converter with a certain margin for safety and maintenance purposes, that is, the standby bidirectional three-port DC / DC converter that does not participate in daily work and is put into work when the basic module fails or the load suddenly increases; P O,DC is the total DC load power; P O,TX is the total communication load power; P 2,max and P 3,max are the output powers corresponding to the maximum efficiency of the second end and the third end of the bidirectional three-port DC / DC converter respectively; ceil is the ceiling function, ceil(x) = a, where x < a < x + 1 and a ∈ Z.

[0042] To reduce the energy loss of the battery pack and improve the power density of the power supply system, n bidirectional three-port DC / DC converters are connected in parallel for the DC / DC conversion unit 8. The number of bidirectional three-port DC / DC converters needs to be determined according to the power levels of the 220V DC load and the 48V communication load, and a certain margin is reserved. For example, if the total power of the 220V DC load is 50kW, the total power of the 48V communication load is 3kW, and the output powers corresponding to the highest efficiency of the second end and the third end of a single bidirectional three-port converter are 20kW and 0.5kW respectively, then

[0043] The specific working mode of the integrated substation power supply system is as follows:

[0044] During normal operation, 380V alternating current is converted into 220V direct current through the AC / DC rectification unit. If the actual power of the battery pack 7 is lower than the actual capacity, the first switch 9, the second switch 10, and the third switch 11 are all closed. The second end of the DC / DC conversion unit 8 is used as the input end, and the first end and the third end are used as the output ends. The 220V second DC feeder 6 supplies power to the battery pack 7 and the 48V communication load; if the actual power of the battery pack 7 is close to the actual capacity, the first switch 9 is opened, the second switch 10 and the third switch 11 are all closed. The second port of the DC / DC conversion unit 08 is used as the input end, and the third port is used as the output end. The 220V second DC feeder 6 supplies power to the 48V communication load.

[0045] When the AC power supply of the substation is lost or the AC / DC rectifier unit 3 fails, the first switch 9, the second switch 10, and the third switch 11 are all closed. The first port of the DC / DC conversion unit 8 serves as the input end, and the second port and the third port are the output ends. The battery pack 7 supplies power to the 220V DC load and the 48V communication load.

[0046] In summary, compared with the prior art, the beneficial effects of the present utility model are as follows: The present utility model includes an AC power supply subsystem, a DC power supply subsystem, and a UPS power supply subsystem; the AC power supply subsystem includes an automatic transfer switch ATS AC switching device and an AC feeder; the DC power supply subsystem includes an AC / DC rectifier unit, a first DC feeder, a fuse, a second DC feeder, a battery pack, a DC / DC conversion unit, and a communication DC feeder; the UPS power supply subsystem includes a DC / AC inverter unit, an AC / AC unit, and an uninterruptible power supply system UPS feeder; the ATS AC switching device is sequentially connected to the first DC feeder through the AC feeder and the AC / DC rectifier unit; one end of the fuse is connected to the first DC feeder, and the other end is connected to the second DC feeder; the first end of the DC / DC conversion unit is connected to the battery pack, the second end is connected to the second DC feeder, and the third end is connected to the communication DC feeder; the input end of the DC / AC inverter unit is connected to the second DC feeder, and the output ends of the output end and the AC / AC unit are both connected to the UPS feeder. It can solve the problem of unstable DC feeder voltage caused by the wide voltage conversion range of the battery pack and battery aging in the case of AC incoming line failure and battery power supply.

[0047] The specific advantages of the integrated power supply system of the substation proposed in the embodiment of the present utility model are as follows:

[0048] 1. In the case of AC incoming line failure and battery power supply, it solves the problem of unstable DC feeder voltage caused by the wide voltage conversion range of the battery pack and battery aging, adds a DC / DC module, and stabilizes the DC feeder voltage at 220V.

[0049] 2. Adopting a bidirectional three-port DC / DC converter, compared with the two-stage DC / DC module method (that is, on the basis of the existing integrated power supply system, adding a DC / DC module between the battery pack and the 220V DC feeder, and then converting it to 48V by the DC / DC conversion device originally connected to the 220V DC feeder), the energy loss of the battery pack is lower, the power density is higher, and at the same time, the voltage requirement for the battery pack is reduced. In addition, when the battery pack has a low power level, it can be charged to ensure that the battery pack has sufficient power at all times.

[0050] 3. Considering different working conditions of the integrated power supply system, a knife switch is configured for each port of the bidirectional three-port DC / DC converter to ensure that the corresponding port is put into or withdrawn from operation.

[0051] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present utility model. It should be understood that the above are only specific embodiments of the present utility model and are not used to limit the protection scope of the present utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. An integrated power supply system for a substation, characterized in that, Including: An AC power supply subsystem, a DC power supply subsystem, and a UPS power supply subsystem; The AC power supply subsystem includes an automatic transfer switch ATS AC switching device (1) and an AC feeder (2); the DC power supply subsystem includes an AC / DC rectification unit (3), a first DC feeder (4), a fuse (5), a second DC feeder (6), a battery pack (7), a DC / DC conversion unit (8), and a communication DC feeder (12); the UPS power supply subsystem includes a DC / AC inversion unit (14), an AC / AC unit (15), and an uninterruptible power supply system UPS feeder (16); The ATS AC switching device (1) is sequentially connected to the first DC feeder (4) through the AC feeder (2) and the AC / DC rectification unit (3); one end of the fuse (5) is connected to the first DC feeder (4), and the other end is connected to the second DC feeder (6); The first end of the DC / DC conversion unit (8) is connected to the battery pack (7), the second end is connected to the second DC feeder (6), and the third end is connected to the communication DC feeder (12); The input end of the DC / AC inversion unit (14) is connected to the second DC feeder (6), and the output ends of the DC / AC inversion unit (14) and the AC / AC unit (15) are both connected to the UPS feeder (16).

2. The integrated power supply system for a substation according to claim 1, wherein The DC power supply subsystem further includes a battery inspection device (13); the battery inspection device (13) is connected to the battery pack (7) and is used for measuring the voltage of the battery pack (7).

3. The integrated power supply system for a substation according to claim 2, characterized in that, Also including: A monitoring module (17) is respectively connected to the AC feeder (2), the AC / DC rectification unit (3), and the battery pack (7); The monitoring module (17) is used for monitoring the AC feeder (2), the AC / DC rectification unit (3), and the battery pack (7).

4. The integrated power supply system for a substation according to claim 1, wherein, The DC power supply subsystem further includes a first disconnecting switch (9), a second disconnecting switch (10), and a third disconnecting switch (11); the first end of the DC / DC conversion unit (8) is connected in series with the battery pack (7) through the first disconnecting switch (9), the second end is connected to the second DC feeder (6) through the second disconnecting switch (10), and the third end is connected to the communication DC feeder (12) through the third disconnecting switch (11); the first disconnecting switch (9), the second disconnecting switch (10), and the third disconnecting switch (11) are respectively used to connect or disconnect the first end, the second end, and the third end of the DC / DC conversion unit (8) from the connected devices.

5. The integrated power supply system for a substation according to claim 4, wherein When the power of the battery pack (7) is lower than the actual capacity of the battery pack (7), the states of the first disconnecting switch (9), the second disconnecting switch (10), and the third disconnecting switch (11) are closed, the second end of the DC / DC conversion unit (8) is the input end, the first end and the third end are the output ends, and the second DC feeder (6) is used to supply power to the battery pack (7) and communication loads.

6. The integrated power supply system for a substation according to claim 4, wherein When the absolute value of the difference between the power of the battery pack (7) and the actual capacity of the battery pack (7) is lower than a preset threshold, the state of the first disconnecting switch (9) is open, the states of the second disconnecting switch (10) and the third disconnecting switch (11) are closed, the second end of the DC / DC conversion unit (8) is the input end, the third end is the output end, and the second DC feeder (6) is used to supply power to communication loads.

7. The integrated power supply system for a substation according to claim 4, wherein When the AC / DC rectification unit (3) fails, the first switch (9), the second switch (10), and the third switch (11) are in the closed state. The first end of the DC / DC conversion unit (8) is the input end, and the second end and the third end are the output ends. The battery pack (7) is used to supply power to the DC load and the communication load.

8. The integrated power supply system for a substation according to claim 1, wherein, The voltage level of the battery pack (7) is 220V or 110V; the voltage conversion range of the DC / DC conversion unit (8) corresponds to the voltage level of the battery pack (7).

9. The integrated power supply system for a substation according to claim 1, characterized in that The integrated substation power supply system supplies power to the DC load through the second DC feeder (6) and supplies power to the communication load through the communication DC feeder (12).

10. The integrated power supply system for a substation according to claim 1, characterized in that, The DC / DC conversion unit (8) includes a plurality of bidirectional three-port DC / DC converters; the plurality of bidirectional three-port DC / DC converters are connected in parallel, and the first ends, the second ends, and the third ends of the plurality of bidirectional three-port DC / DC converters are respectively connected together.

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