CN209982353U - Non-power frequency transformer structure of AC-DC-AC substation with through same-phase power supply system - Google Patents
Non-power frequency transformer structure of AC-DC-AC substation with through same-phase power supply system Download PDFInfo
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- CN209982353U CN209982353U CN201921119219.8U CN201921119219U CN209982353U CN 209982353 U CN209982353 U CN 209982353U CN 201921119219 U CN201921119219 U CN 201921119219U CN 209982353 U CN209982353 U CN 209982353U
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- 238000000926 separation method Methods 0.000 claims abstract description 12
- 238000002955 isolation Methods 0.000 claims description 8
- 239000003990 capacitor Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000004146 energy storage Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000003137 locomotive effect Effects 0.000 description 1
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Abstract
The utility model discloses a link up no power frequency transformer structure of homophase power supply system AC-DC alternating-current substation, including the many level transverters of modularization, intermediate separation of three-phase electric wire netting side from type DC-DC transverter and the single-phase H bridge cascade connection transverter who pulls the side. The direct current side of the modular multilevel converter at the three-phase power grid side is connected with the high-voltage direct current side of the middle separation type DC-DC converter, and the low-voltage direct current side of the middle separation type DC-DC converter is connected with the H-bridge cascade converter. The structure can realize the non-split-phase through power supply of the electrified railway, can simultaneously cancel an input and output power frequency transformer, and has lower cost.
Description
Technical Field
The utility model relates to a no power frequency transformer's three-phase-single-phase transverter structure, concretely relates to link up no power frequency transformer structure of cophase power supply system AC-DC alternating-current substation.
Background
The two-phase (out-of-phase) power supply system adopted by the existing electrified railway power supply system in China has the problems of electric energy quality mainly based on negative sequence, harmonic wave and reactive power, in particular to the problems of locomotive speed, traction loss, large investment, low reliability and the like caused by an electric phase splitting device. The structure of the current traction power supply system in China is shown in figure 1. Since the power supply arms of adjacent traction substations have certain deviations in voltage phase, amplitude and frequency, an electrical phase splitting device must be arranged between the power supply arms. However, the problems of train speed and traction loss caused by over-neutral section and the defects of large investment, complex structure, low reliability and the like of an electric neutral section device seriously influence the development of high-speed and heavy-duty railway industry in China.
With the rapid development of modern power electronic technology, a brand new thought is provided for solving the problems, and the scheme for realizing power supply and finally comprehensively solving the problem of electric energy quality of the electrified railway is to realize through in-phase power supply, and the structure of the scheme is shown in fig. 2. The amplitude, the phase and the frequency of the output voltage of the adjacent traction substations can meet the condition of in-phase power supply, so that through power supply can be realized among the substations. Therefore, a split-phase device can be omitted between adjacent power supply arms, investment is saved, and development requirements of high-speed and heavy-load electric traction are met. The through same-phase power supply system can realize complete decoupling of a power supply network and a contact network, a filter device and a reactive compensation device are not needed, the whole line can completely cancel electric split phase, the power supply quality, the power supply reliability and the power supply capacity of the contact network and the fault ride-through capacity of the power supply system are improved, the access of energy storage and novel green energy is facilitated, the development prospect is good, and the development trend is in the future.
For the structure of an AC-DC-AC substation of a run-through same-phase power supply system, ABB company provides a diode clamping cascade AC-DC topology, which adopts a special single-phase input/output transformer and has a complex structure and a large number; the Siemens company provides a modular multilevel direct conversion type topology, and a common three-phase input transformer is adopted, so that a single-phase output transformer can be omitted; the Toshiba Japan company proposes H-bridge cascade multiplex AC-DC topology, which adopts special single-phase input and output transformers, and has complex structure and numerous quantity; patent 201110163789.9 discloses a topology of no-output transformer in which N three-phase-single-phase converters are cascaded, and the input side of the power grid needs to use N three-phase step-down transformers; the scholars often propose a modular multilevel AC-DC topology in the research (I) of a novel traction power supply system based on MMC, and the structure adopts a common three-phase input transformer, so that a single-phase output transformer can be omitted. The input and output power frequency transformers cannot be simultaneously cancelled in the AC-DC-AC power substation structures. Patent 201520230853.4 and patent 201510646749.8 disclose a three-phase-single-phase substation structure of the same industrial frequency-free transformer, and the structure uses too many power electronic devices and is expensive in construction cost.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to overcome above-mentioned prior art's shortcoming, proposed one kind and link up the no power frequency transformer structure of homophase power supply system AC-DC alternating-current substation, this structure can realize that electrified railway's no split phase link up the power supply, can cancel input and output power frequency transformer simultaneously, and the cost is lower.
In order to achieve the above object, the structure of the industrial frequency-free transformer for the AC-DC-AC substation with the same-phase power supply system comprises a modular multilevel converter on the side of a three-phase power grid, a middle separation type DC-DC converter and an H-bridge cascade converter on the single-phase traction side. The direct current side of the modular multilevel converter at the three-phase power grid side is connected with the high-voltage direct current side of the middle separation type DC-DC converter, and the low-voltage direct current side of the middle separation type DC-DC converter is connected with the H-bridge cascade converter.
The high-voltage direct current side of each power unit of the intermediate isolation type DC-DC converter is connected in series between a positive direct current bus and a negative direct current bus of the modular multi-level converter on the three-phase power grid side.
The low-voltage direct current side of each power unit of the intermediate isolation type DC-DC converter is connected with an H bridge, and the H bridges of all the power units are cascaded.
The utility model discloses following beneficial effect has:
link up cophase power supply system AC-DC alternating-current substation's no power frequency transformer structure when concrete operation, the modularization multilevel transverter through three-phase electric network side transforms high-voltage electric network side three-phase alternating current voltage into high voltage direct current, recycle the intermediate separation type DC-DC transverter will high voltage direct current voltage converts low voltage direct current voltage into, then for pulling load direct power supply through H bridge cascade transverter, realizes that electrified railway's no phase splitting link up the power supply. The structure can simultaneously cancel the input and output power frequency transformers, reduces the number of power electronic devices used by the substation, and has the advantages of good power quality, small occupied area, low loss and low cost.
Drawings
FIG. 1 is a schematic diagram of a prior art out-of-phase power supply system;
FIG. 2 is a schematic diagram of a conventional feed-through in-phase power supply system;
fig. 3 is a schematic structural diagram of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings:
referring to fig. 3, the no-power-frequency transformer structure of the in-phase power supply system ac-DC-ac substation comprises a modular multilevel converter on the three-phase power grid side, a middle separation type DC-DC converter and an H-bridge cascade converter on the single-phase traction side. The direct current side of the modular multilevel converter at the three-phase power grid side is connected with the high-voltage direct current side of the middle separation type DC-DC converter, and the low-voltage direct current side of the middle separation type DC-DC converter is connected with the H-bridge cascade converter.
Specifically, the modular multilevel converter on the three-phase power grid side is an interface penetrating through an AC-DC-AC substation of a same-phase power supply system and a three-phase power grid, each phase of the modular multilevel converter on the three-phase power grid side comprises an upper bridge arm and a lower bridge arm, and the upper bridge arm and the lower bridge arm are respectively formed by connecting N power submodules in series end to form a chain type multilevel structure, wherein the power submodules SM are of a half H-bridge structure. Different from the traditional voltage source converter topology, the modular multilevel converter on the three-phase power grid side omits a high-voltage direct-current capacitor for intensively storing energy on a direct-current bus, energy storage capacitors are dispersedly arranged in three-phase bridge arms, the head end of a first power module in each phase upper bridge arm is connected to form the anode of a common direct-current bus, the tail end of an Nth power module in each phase lower bridge arm is connected to form the cathode of the common direct-current bus, the tail end of the Nth power module in each phase upper bridge arm and the head end of the first power module in the phase lower bridge arm are respectively connected with an alternating-current reactor L in series, and the alternating-current bus A, B, C is led out from the midpoint of the two alternating-current reactors L.
A high-voltage direct-current side capacitor of each power unit of the middle isolation type DC-DC converter is connected in series between a positive direct-current bus and a negative direct-current bus of the modular multilevel converter on the three-phase power grid side, a low-voltage direct-current side capacitor of the middle isolation type DC-DC converter is respectively and independently connected with an H bridge, and meanwhile, a medium-high frequency transformer is adopted to realize the conversion from high-voltage direct current to low-voltage direct current.
The H bridges connected with each unit in the intermediate isolation type DC-DC converter are connected in series to form an H bridge cascade converter on a single-phase traction side, the H bridge cascade converter is an interface of an AC-DC alternating-current substation and a traction power supply network, traction loads are directly supplied with power through cascade connection of the multi-module H bridges, and an output step-up transformer and a filter are not needed.
Claims (3)
1. A non-power frequency transformer structure of an AC-DC-AC substation of a run-through same-phase power supply system is characterized by comprising a modular multilevel converter at the side of a three-phase power grid, a middle isolation type DC-DC converter and an H-bridge cascade converter at the single-phase traction side, wherein the DC side of the modular multilevel converter at the side of the three-phase power grid is connected with the high-voltage DC side of the middle isolation type DC-DC converter, and the low-voltage DC side of the middle isolation type DC-DC converter is connected with the H-bridge cascade converter.
2. The non-industrial frequency transformer structure of the in-phase power supply system-penetrating alternating current-direct current-alternating current substation according to claim 1, wherein the high-voltage direct current side of each power unit of the middle separation type DC-DC converter is connected in series between a positive direct current bus and a negative direct current bus of the modular multilevel converter on the three-phase power grid side.
3. The non-industrial frequency transformer structure of the AC-DC-AC substation with the same-phase power supply system as the claim 2, wherein the low-voltage DC side of each power unit of the middle-separation type DC-DC converter is connected with an H bridge, and the H bridges of all the power units are cascaded.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921119219.8U CN209982353U (en) | 2019-07-16 | 2019-07-16 | Non-power frequency transformer structure of AC-DC-AC substation with through same-phase power supply system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921119219.8U CN209982353U (en) | 2019-07-16 | 2019-07-16 | Non-power frequency transformer structure of AC-DC-AC substation with through same-phase power supply system |
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| Publication Number | Publication Date |
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| CN209982353U true CN209982353U (en) | 2020-01-21 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201921119219.8U Expired - Fee Related CN209982353U (en) | 2019-07-16 | 2019-07-16 | Non-power frequency transformer structure of AC-DC-AC substation with through same-phase power supply system |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112803789A (en) * | 2021-02-01 | 2021-05-14 | 中科兆和电力技术(山东)有限公司 | Cophase power supply device |
| CN114336641A (en) * | 2022-03-17 | 2022-04-12 | 西南交通大学 | Three-phase power supply ride-through power utilization system and control method |
-
2019
- 2019-07-16 CN CN201921119219.8U patent/CN209982353U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112803789A (en) * | 2021-02-01 | 2021-05-14 | 中科兆和电力技术(山东)有限公司 | Cophase power supply device |
| CN112803789B (en) * | 2021-02-01 | 2022-06-21 | 中科兆和电力技术(山东)有限公司 | Cophase power supply device |
| CN114336641A (en) * | 2022-03-17 | 2022-04-12 | 西南交通大学 | Three-phase power supply ride-through power utilization system and control method |
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Granted publication date: 20200121 Termination date: 20210716 |