CN211183434U - Double-end direct current power distribution system - Google Patents
Double-end direct current power distribution system Download PDFInfo
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- CN211183434U CN211183434U CN201922002824.3U CN201922002824U CN211183434U CN 211183434 U CN211183434 U CN 211183434U CN 201922002824 U CN201922002824 U CN 201922002824U CN 211183434 U CN211183434 U CN 211183434U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
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Abstract
The application discloses bi-polar direct current distribution system includes: the power distribution line comprises a distribution line body, a transmitting end converter for rectifying power frequency alternating current into direct current, a receiving end converter for inverting the direct current into alternating current and a main controller; a first line section for connecting a power supply end is arranged at one end of the distribution line body, and a second line section for connecting a user end is arranged at the other end of the distribution line body; the sending end converter is connected in parallel with two ends of the first line section, and the output end and the input end of the sending end converter are respectively connected with two ends of the first line section through a first switching circuit breaker; the output end and the input end of the receiving end converter are respectively connected with the two ends of the second line section through a second switching circuit breaker; the first line section and the second line section are respectively provided with a third switching circuit breaker in series; the first switching circuit breaker, the second switching circuit breaker and the third switching circuit breaker are all electrically connected with the main controller. And the voltage qualification rate of the end user is improved.
Description
Technical Field
The application relates to the technical field of electric power, especially, relate to a bi-polar direct current distribution system.
Background
The existing low-voltage three-phase alternating-current power distribution system, such as a 400V three-phase alternating-current power distribution system, has a large line voltage drop under a heavy load if the power supply radius is large (exceeding 2.5km), which easily causes the low voltage (lower than 160V) of a user at the end of a line, affects the normal operation of electrical equipment, and causes low-voltage problem complaints.
In order to solve the above technical problems, the existing solutions mainly include: (1) newly building a 10kv line, and additionally arranging a power distribution station area; however, the method has huge investment, and the lines span mountainous areas, which are easily affected by the vegetation in the mountainous areas, and the operation and maintenance work in the later period is difficult. (2) Installing a low-voltage line voltage regulator; although the voltage can be raised by about 20% by the method, the output qualified rate of the voltage of the user at the tail end of the line is still low, and the problem of low voltage cannot be fundamentally solved.
SUMMERY OF THE UTILITY MODEL
In order to solve the problems of large power supply radius and low voltage caused by difficulty in a newly-built distribution area, the application aims to provide a double-end direct-current power distribution system which can reduce the line voltage drop and improve the qualification rate of the voltage of a terminal user.
To achieve the above technical object, the present application provides a double-ended dc power distribution system, including: the power distribution line comprises a distribution line body, a transmitting end converter for rectifying power frequency alternating current into direct current, a receiving end converter for inverting the direct current into the power frequency alternating current and a main controller;
a first line section for connecting a power supply end is arranged at one end of the distribution line body, and a second line section for connecting a user end is arranged at the other end of the distribution line body;
the sending end converter is connected in parallel with two ends of the first line section, and the output end and the input end of the sending end converter are respectively connected with two ends of the first line section through a first switching circuit breaker;
the receiving-end converter is connected in parallel with two ends of the second line section, and the output end and the input end of the receiving-end converter are respectively connected with two ends of the second line section through a second switching circuit breaker;
third switching circuit breakers are respectively arranged on the first line section and the second line section in series;
the first switching circuit breaker, the second switching circuit breaker and the third switching circuit breaker are all electrically connected with the main controller.
Furthermore, the two first switching circuit breakers and the two second switching circuit breakers are in synchronous linkage fit.
Furthermore, the two third switching breakers are in synchronous linkage fit with each other.
Further, the transmitting end converter and the receiving end converter are diode clamp type three-level converters.
Further, when the first switching circuit breaker and the second switching circuit breaker are closed and the third switching circuit breaker is opened, the distribution line body is in a direct current working mode that the rated voltage of a direct current bus is 750V.
Furthermore, when the first switching circuit breaker is disconnected with the second switching circuit breaker and the third switching circuit breaker is closed, the distribution line body is in an alternating current working mode.
Further, the device also comprises a first mounting cabinet;
the sending end converter, the first switching circuit breaker and the third switching circuit breaker are all installed in the first installation cabinet.
Further, the first mounting cabinet is mounted on the wire pole frame close to the power supply end.
Further, the device also comprises a second mounting cabinet;
the receiving end converter, the second switching circuit breaker and the other third switching circuit breaker are all installed in the second installation cabinet.
Further, the second mounting cabinet is mounted on the electric wire pole frame close to the user end.
According to the technical scheme, the sending end converters are connected in parallel at two ends of the first line section of the power transmission line, the receiving end converters are connected in parallel at two ends of the second line section of the power transmission line, the first switching circuit breaker and the second switching circuit breaker are arranged and used for respectively controlling the on-off of the sending end converters and the receiving end converters, and the third switching circuit breaker is arranged and used for respectively controlling the on-off of the first line section and the second line section. When the switching circuit breaker is used, the main controller can control the first switching circuit breaker and the second switching circuit breaker to be closed, and the third switching circuit breaker is opened; alternating current from the power supply end can be converted into direct current to realize direct current transmission, and the alternating current is converted into alternating current through the current receiving converter when the alternating current is transmitted to a second line section and is transmitted to a user end; and the voltage drop of the line is reduced by using direct current transmission, and the qualification rate of the voltage of a terminal user is improved. And utilize first switching circuit breaker, second switching circuit breaker and third switching circuit breaker can realize exchanging the nimble switching use of transmission of electricity with direct current, improve the convenience that distribution lines used.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive exercise.
Fig. 1 is a schematic diagram of an equivalent model of a first switching circuit breaker, a second switching circuit breaker and a third switching circuit breaker of a double-ended dc power distribution system, which are all in an open state, provided in the present application;
fig. 2 is a schematic diagram of an equivalent model of an ac transmission condition of a double-ended dc distribution system provided in the present application;
fig. 3 is a schematic diagram of an equivalent model of a dc transmission condition of a double-ended dc distribution system provided in the present application;
fig. 4 is a schematic diagram of a diode-clamped three-level converter for a double-ended dc power distribution system as provided herein;
FIG. 5 is a graph of three phase voltage and current waveforms for a double ended DC power distribution system provided herein switching from AC to DC operation in a first application;
FIG. 6 is a graph of three phase voltage and current waveforms for a double ended DC power distribution system provided herein switching from DC mode to AC mode in a second application scenario;
in the figure: 1. a transmission line; 11. a first line segment; 12. a second line segment; 21. a sending end converter; 22. a receiving-end converter; 31. a first switching breaker; 32. a second switching breaker; 33. a third switching breaker; 41. a power supply terminal; 42. and a user side.
Detailed Description
The technical solutions of the embodiments of the present application will be described clearly and completely with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without any creative effort belong to the protection scope of the embodiments in the present application.
In the description of the embodiments of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing the embodiments of the present application and simplifying the description, but do not indicate or imply that the referred devices or elements must have specific orientations, be configured in specific orientations, and operate, and thus, should not be construed as limiting the embodiments of the present application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the embodiments of the present application, it should be noted that the terms "mounted," "connected," and "connected" are used broadly and are defined as, for example, a fixed connection, an exchangeable connection, an integrated connection, a mechanical connection, an electrical connection, a direct connection, an indirect connection through an intermediate medium, and a communication between two elements, unless otherwise explicitly stated or limited. Specific meanings of the above terms in the embodiments of the present application can be understood in specific cases by those of ordinary skill in the art.
The embodiment of the application discloses a double-end direct current power distribution system.
Referring to fig. 1 to fig. 3, an embodiment of a dual-terminal dc power distribution system provided in the embodiment of the present application includes:
the power distribution line comprises a distribution line body 1, a transmitting-end converter 21 for rectifying power frequency alternating current into direct current, a receiving-end converter 22 for inverting the direct current into the power frequency alternating current and a main controller; a first line section 11 for connecting a power supply terminal 41 is arranged at one end of the distribution line body 1, and a second line section 12 for connecting a user terminal 42 is arranged at the other end of the distribution line body; the sending-end converter 21 is connected in parallel with two ends of the first line section 11, and the output and the input end of the sending-end converter 21 are respectively connected with two ends of the first line section 11 through a first switching breaker 31; the receiving-end converter 22 is connected in parallel to two ends of the second line segment 12, and an output end and an input end of the receiving-end converter 22 are respectively connected to two ends of the second line segment 12 through a second switching breaker 32; the first line segment 11 and the second line segment 12 are respectively provided with a third switching breaker 33 in series; the first switching breaker 31, the second switching breaker 32 and the third switching breaker 33 are all electrically connected to the main controller.
Specifically, the distribution line body 1 in the present embodiment may be an existing three-phase four-wire line; in addition, the specific structures of the transmitting-end converter 21 and the receiving-end converter 22 are not limited, and the transmitting-end converter 21 and the receiving-end converter 22 can be used for converting alternating current into direct current and converting direct current into alternating current; in this embodiment, the transmitting-end converter 21 and the receiving-end converter 22 can be directly installed on the original distribution line body, and the direct current transmission system can be constructed by using the original line system, so that the construction cost is low.
As can be seen from the above technical solutions, the sending-end converter 21 is connected in parallel to two ends of the first line segment 11 of the distribution line body 1, the receiving-end converter 22 is connected in parallel to two ends of the second line segment 12 of the distribution line body 1, the first switching breaker 31 and the second switching breaker 32 are arranged to control on/off of the sending-end converter 21 and the receiving-end converter 22 respectively, and the third switching breaker 33 is arranged to control on/off of the first line segment 11 and the second line segment 12 respectively. When in use, the main controller can control the first switching breaker 31 and the second switching breaker 32 to be closed, and the third switching breaker 33 to be opened; the alternating current from the power supply terminal 41 can be converted into direct current to realize direct current transmission, and the alternating current is converted into alternating current by the current receiving converter when the alternating current is transmitted to the second line section 12 and is transmitted to the user terminal 42; and the voltage drop of the line is reduced by using direct current transmission, and the qualification rate of the voltage of a terminal user is improved. In addition, the first switching breaker 31, the second switching breaker 32, and the third switching breaker 33 can be used to switch between ac transmission and dc transmission, thereby improving the convenience of use of the distribution line.
The above is a first embodiment of a dual-terminal dc power distribution system provided in the present application, and the following is a second embodiment of a dual-terminal dc power distribution system provided in the present application, specifically please refer to fig. 1 to 6.
A double-end direct current distribution system comprises a distribution line body 1, a transmitting-end converter 21 used for rectifying power frequency alternating current into direct current, a receiving-end converter 22 used for inverting the direct current into alternating current and a main controller; a first line section 11 for connecting a power supply terminal 41 is arranged at one end of the distribution line body 1, and a second line section 12 for connecting a user terminal 42 is arranged at the other end of the distribution line body; the sending-end converter 21 is connected in parallel with two ends of the first line section 11, and the output and the input end of the sending-end converter 21 are respectively connected with two ends of the first line section 11 through a first switching breaker 31; the receiving-end converter 22 is connected in parallel to two ends of the second line segment 12, and an output end and an input end of the receiving-end converter 22 are respectively connected to two ends of the second line segment 12 through a second switching breaker 32; the first line segment 11 and the second line segment 12 are respectively provided with a third switching breaker 33 in series; the first switching breaker 31, the second switching breaker 32 and the third switching breaker 33 are all electrically connected to the main controller.
Specifically, the transmitting-side converter 21 and the receiving-side converter 22 in this embodiment may both adopt a diode-clamped three-level converter as shown in fig. 4, and correspondingly, a-B-C-N, the positive pole (+), and the negative pole (-) in fig. 4 correspond to the connection terminals of the transmitting-side converter 21 and the receiving-side converter 22 in fig. 1 to 3, respectively. In the installation connection, three terminals a-B-C of the transmitting-side converter 21 are connected to A, B, C three phases of the distribution line body 1, respectively, and the positive terminal thereof is connected to the a phase of the distribution line body 1, the negative terminal thereof is connected to the C phase of the distribution line body 1, and the N terminal thereof is connected to the N line of the distribution line body 1. Accordingly, the receiving-side converter 22 corresponds to this, and three terminals a-B-C of the receiving-side converter 22 are connected to A, B, C three phases of the distribution line main body 1, respectively, and the positive terminal thereof is also connected to the a phase, the negative terminal thereof is also connected to the C phase, and the N terminal thereof is also connected to the N line. Of course, the above connection method is only one embodiment in the present application, and is affected by the phase sequence of the distribution line body 1 in specific applications, and the positive terminals and the negative terminals of the transmitting-side converter 21 and the receiving-side converter 22 only need to be connected to any two non-adjacent phases in the distribution line body 1, and are not necessarily specified to be the a-phase and the C-phase.
In addition, the first switching circuit breaker 31, the second switching circuit breaker 32 and the third switching circuit breaker 33 in this embodiment may be three-phase circuit breakers and are controlled by a main controller, wherein the main controller may be, for example, a P L C controller used in cooperation with the three-phase circuit breaker, and the like, and is not limited specifically.
When the user terminal 42 is powered in the dc operating mode, as shown in fig. 3, the main controller can control the first switching breaker 31 and the second switching breaker 32 to be closed, and the third switching breaker 33 to be opened. When the ac operating mode is used to supply power to the user terminal 42, as shown in fig. 2, the main controller can control the first switching circuit breaker 31 and the second switching circuit breaker 32 to be opened, and the third switching circuit breaker 33 to be closed, so that the transmitting-side converter 21 and the receiving-side converter 22 are in a hot standby state, thereby facilitating subsequent switching. In addition, it should be noted that the three sets of the first switching breaker 31, the second switching breaker 32 and the third switching breaker 33 in the present application cannot be closed at the same time at any time, so as to prevent an electrical short circuit between the ac system and the dc system.
In addition, the distribution line body 1 can select 750V (+ -375V) grades according to the national standard, so that the voltage of a direct current bus when the system is in a direct current working mode is 750V rated; the cross-sectional area of the conductor is then selected according to the load of the user, for example, 120mm is selected according to 20% of the voltage deviation2And the wire with the load distance of 195kW & km is used as the distribution line body 1, so that the power supply radius can be effectively prolonged, and the voltage qualification rate of a terminal user is further ensured. Those skilled in the art can make appropriate changes based on the above without limitation.
As shown in fig. 5 and 6, a/B/C in fig. 5 and 6 are voltage-current waveform diagrams of the a-phase line, the B-phase line, and the C-phase line, respectively. In fig. 5, the middle straight line is used as the mode switching line, the left side of the middle straight line is the three-phase voltage and current waveform diagram in the ac operation mode, and the right side is the three-phase voltage and current waveform diagram in the dc operation mode. In fig. 6, the left side of the middle straight line is the voltage and current waveform diagram in the dc operation mode, and the right side is the voltage and current waveform diagram in the ac operation mode. When the ac operating mode is switched to the dc operating mode, it can be seen that the voltage effective value is increased, so that the receiving voltage of the user terminal 42 can be stable and qualified.
Further, the two first switching breakers 31 and the two second switching breakers 32 are synchronously linked and matched. The first switching circuit breaker 31 and the second switching circuit breaker 32 are synchronously controlled in a linkage manner, so that the sending-end converter 21 and the receiving-end converter 22 can be controlled to be switched on and off simultaneously, and the control is more convenient.
Further, the two third switching breakers 33 are synchronously linked and matched with each other. Similarly, different linkage controls between the third switching breakers 33 are realized, and the control can be more convenient.
Further, a first mounting cabinet (not shown) is also included; the sending-end converter 21, the first switching breaker 31 and a third switching breaker 33 are all installed in the first installation cabinet. Particularly, the first installation cabinet is arranged, so that the sending-end converter 21, the first switching circuit breaker 31 and the third switching circuit breaker 33 can be conveniently and intensively installed, and the subsequent maintenance and management are more convenient.
Further, the first mounting cabinet is mounted on the electric wire pole frame close to the power supply end. When the installation is carried out, the first installation cabinet can be installed on the first wire pole frame close to the power supply end 41; according to the installation arrangement, an additional electric wire pole frame is not needed, the existing electric wire pole frame is directly utilized, and the installation and maintenance cost is saved.
Further, a second mounting cabinet (not shown) is also included; the receiving end converter 22, the second switching breaker 32 and the further third switching breaker 33 are all mounted in a second mounting cabinet. In a similar way, the second installation cabinet is arranged, so that the centralized installation of the receiving-end converter 22, the second switching circuit breaker 32 and the third switching circuit breaker 33 is facilitated, and the subsequent maintenance and management are more convenient.
Further, the second mounting cabinet is mounted on the mast frame near the user end. Similarly, during installation, the second installation cabinet can be installed on the electric wire pole frame close to the user end 42, the electric wire pole frame does not need to be additionally erected, the existing electric wire pole frame is directly utilized, and the installation and maintenance cost is saved.
As can be seen from the above technical solutions, the sending-end converter 21 is connected in parallel to two ends of the first line segment 11 of the distribution line body 1, the receiving-end converter 22 is connected in parallel to two ends of the second line segment 12 of the distribution line body 1, the first switching breaker 31 and the second switching breaker 32 are arranged to control on/off of the sending-end converter 21 and the receiving-end converter 22 respectively, and the third switching breaker 33 is arranged to control on/off of the first line segment 11 and the second line segment 12 respectively. When in use, the main controller can control the first switching breaker 31 and the second switching breaker 32 to be closed, and the third switching breaker 33 to be opened; the alternating current from the power supply terminal 41 can be converted into direct current to realize direct current transmission, and the alternating current is converted into alternating current by the current receiving converter when the alternating current is transmitted to the second line section 12 and is transmitted to the user terminal 42; and the voltage drop of the line is reduced by using direct current transmission, and the qualification rate of the voltage of a terminal user is improved. In addition, the first switching breaker 31, the second switching breaker 32, and the third switching breaker 33 can be used to switch between ac transmission and dc transmission, thereby improving the convenience of use of the distribution line.
While the present invention has been described in detail with reference to the embodiments, it is to be understood that the present invention is not limited to the specific embodiments and applications illustrated in the drawings.
Claims (10)
1. A double ended direct current power distribution system, comprising: the power distribution line comprises a distribution line body, a transmitting end converter for rectifying power frequency alternating current into direct current, a receiving end converter for inverting the direct current into the power frequency alternating current and a main controller;
a first line section for connecting a power supply end is arranged at one end of the distribution line body, and a second line section for connecting a user end is arranged at the other end of the distribution line body;
the sending end converter is connected in parallel with two ends of the first line section, and the output end and the input end of the sending end converter are respectively connected with two ends of the first line section through a first switching circuit breaker;
the receiving-end converter is connected in parallel with two ends of the second line section, and the output end and the input end of the receiving-end converter are respectively connected with two ends of the second line section through a second switching circuit breaker;
third switching circuit breakers are respectively arranged on the first line section and the second line section in series;
the first switching circuit breaker, the second switching circuit breaker and the third switching circuit breaker are all electrically connected with the main controller.
2. The double-ended direct current power distribution system according to claim 1, wherein the two first switching breakers are synchronously coupled with the two second switching breakers.
3. The double ended direct current power distribution system of claim 1, wherein said third switching breakers are synchronized in a ganged relationship.
4. The double ended direct current power distribution system of claim 1, wherein the transmitting side converter and the receiving side converter are diode-clamped three level converters.
5. The double-ended direct current power distribution system according to claim 1, wherein when the first switching breaker and the second switching breaker are closed and the third switching breaker is opened, the distribution line body has a direct current operation mode in which a rated voltage of a direct current bus is 750V (± 375V).
6. The double-ended direct current power distribution system according to claim 1, wherein the first switching breaker is disconnected from the second switching breaker, and the third switching breaker is closed, the distribution line body is in an alternating current operating mode.
7. The double ended direct current power distribution system of claim 1, further comprising a first mounting cabinet;
the sending end converter, the first switching circuit breaker and the third switching circuit breaker are all installed in the first installation cabinet.
8. The double ended direct current power distribution system of claim 7, wherein said first mounting cabinet is mounted to a mast adjacent the power supply end.
9. The double ended direct current power distribution system of claim 1, further comprising a second mounting cabinet;
the receiving end converter, the second switching circuit breaker and the other third switching circuit breaker are all installed in the second installation cabinet.
10. The double ended direct current power distribution system of claim 9, wherein said second mounting cabinet is mounted to a mast adjacent to a customer premises.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201922002824.3U CN211183434U (en) | 2019-11-19 | 2019-11-19 | Double-end direct current power distribution system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201922002824.3U CN211183434U (en) | 2019-11-19 | 2019-11-19 | Double-end direct current power distribution system |
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| CN211183434U true CN211183434U (en) | 2020-08-04 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112909940A (en) * | 2021-03-17 | 2021-06-04 | 广东电网有限责任公司 | AC/DC power supply system and switch switching method based on AC/DC power supply system |
| CN113270941A (en) * | 2021-05-28 | 2021-08-17 | 广东电网有限责任公司 | Low-voltage alternating current-direct current power distribution mode conversion system and time sequence control method and device thereof |
| CN113421170A (en) * | 2021-06-16 | 2021-09-21 | 广东诚誉工程咨询监理有限公司 | Comprehensive optimization management system and method for power engineering quality |
-
2019
- 2019-11-19 CN CN201922002824.3U patent/CN211183434U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112909940A (en) * | 2021-03-17 | 2021-06-04 | 广东电网有限责任公司 | AC/DC power supply system and switch switching method based on AC/DC power supply system |
| CN113270941A (en) * | 2021-05-28 | 2021-08-17 | 广东电网有限责任公司 | Low-voltage alternating current-direct current power distribution mode conversion system and time sequence control method and device thereof |
| CN113421170A (en) * | 2021-06-16 | 2021-09-21 | 广东诚誉工程咨询监理有限公司 | Comprehensive optimization management system and method for power engineering quality |
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