CN105226628B - A kind of direct-flow distribution system - Google Patents
A kind of direct-flow distribution system Download PDFInfo
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- CN105226628B CN105226628B CN201510612889.3A CN201510612889A CN105226628B CN 105226628 B CN105226628 B CN 105226628B CN 201510612889 A CN201510612889 A CN 201510612889A CN 105226628 B CN105226628 B CN 105226628B
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Abstract
The invention discloses a kind of direct-flow distribution system, including at least one DC distribution subsystem and new energy distribution subsystem, DC distribution subsystem and new energy electric power distribution network system are connect with DC bus.DC distribution subsystem includes：Current conversion station and dc switch；New energy distribution subsystem includes：Commutator transformer and dc switch.Wherein, dc switch is connect with DC bus.The electric energy of AC distribution net is converted into direct current by current conversion station and dc switch, and the electric energy of new energy power distribution network is switched to by direct current by commutator transformer and dc switch, electric energy is conveyed eventually by DC bus.For alternating-current system in compared with the existing technology, this system, which can be realized, smoothly accesses new energy power distribution network, and the system may include multiple DC distribution subsystems, can extend in this way.
Description
Technical Field
The invention relates to the technical field of electric power, in particular to a direct-current power distribution system.
Background
With the aggravation of energy crisis and the increasingly serious environmental pollution, clean energy technologies such as renewable energy and the like are being developed and utilized greatly in China. However, as the utilization scale of renewable energy sources such as wind energy, solar energy and the like is gradually enlarged, the large-scale new energy access realized by adopting the traditional alternating current power system faces many problems due to the characteristics of distribution, intermittence and the like, for example, the impact is large when the new energy is accessed. Meanwhile, as seen from the development direction of smart grids at home and abroad, the development of renewable energy sources enables the power supply on the user-side power grid, namely the distribution grid, to be highly decentralized. Therefore, in the future, urban power distribution networks face the problem of wide access of a large number of distributed power supplies and microgrid systems containing new energy power supplies, and the problem will bring many technical difficulties to the existing alternating current power distribution networks.
Meanwhile, the shortage of urban power transmission corridors, the continuous and rapid increase of loads and the continuous improvement of the power supply reliability requirements of users make the meeting of the urban load center requirements and the continuous supply of high-quality and reliable electric energy to the users face more and more difficulties and challenges. Therefore, accelerating the development of the urban power grid and ensuring the safety and reliability of power supply become an urgent and arduous task. At present, the power supply mode of the urban power grid mainly adopts a high-medium voltage alternating current system containing overhead lines for power supply, and the central areas of some large and medium cities adopt underground alternating current cables for power supply. The high-voltage alternating-current cable power supply solves the problems of lack of power transmission corridors, incoordination between power facilities and urban landscapes and the like in an urban power grid to a certain extent, but is still limited by factors such as power supply distance and stability of an alternating-current system.
Therefore, the technical staff in the field need to solve the problem of how to overcome the impact of the traditional alternating current power system in large-scale new energy access and how to improve the power supply distance and the system operation stability to meet the development requirement of the urban power grid.
Disclosure of Invention
The invention aims to provide a direct-current power distribution system which is used for overcoming the impact and the development limitation of an urban power grid when a traditional alternating-current power system is accessed to a large-scale new energy source.
In order to solve the technical problem, the invention provides a direct current power distribution system, which comprises at least one direct current power distribution electronic system and a new energy power distribution subsystem, wherein the direct current power distribution electronic system and the new energy power distribution subsystem are both connected with a direct current bus, and the direct current power distribution subsystem comprises:
the converter station is connected with an alternating current power grid through an alternating current bus and an alternating current transformer and is used for converting alternating current into direct current;
a DC switch connecting the converter station and the DC bus;
the new energy power distribution subsystem comprises:
the direct current transformer is connected with the new energy power distribution network and used for performing voltage conversion on the direct current of the new energy power distribution subsystem;
and the direct current switch is connected with the direct current transformer and the direct current bus.
Preferably, the method comprises the following steps: the system comprises a first direct current distribution electronic system, a second direct current distribution electronic system and a third direct current distribution electronic system.
Preferably, the converter station of the first dc power distribution system adopts a three-phase half-bridge cascaded voltage source converter, and the three-phase half-bridge cascaded voltage source converter specifically includes: the three-phase half-bridge modules adopt a three-phase six-bridge arm structure, and each bridge arm is at least connected with an IGBT (insulated gate bipolar translator) with a first backward diode in series;
the direct current output side of the three-phase half-bridge module is connected with a capacitor, a resistor and a diode in parallel in sequence, and the anode of the direct current output side is connected with a second IGBT with a reverse diode in series;
the second IGBT with the backward diode is arranged between the resistor and the diode, an emitter of the second IGBT with the backward diode is connected with a cathode of the diode and used as a direct current positive electrode port of the three-phase half-bridge module, and an anode of the diode is connected with a positive electrode of the direct current output side and used as a direct current positive electrode port of the three-phase half-bridge module.
Preferably, the converter station of the second dc power distribution subsystem adopts a hybrid modular multilevel converter and has a three-phase six-leg structure, each leg of the;
wherein the half-bridge sub-module comprises: the IGBT module comprises a first IGBT with a reverse diode, a second IGBT with a reverse diode and a first capacitor, wherein a collector electrode of the first IGBT with the reverse diode is connected with one end of the first capacitor, the other end of the first capacitor is connected with an emitter electrode of the second IGBT with the reverse diode to be used as a low-voltage end of the half-bridge sub-module, and the emitter electrode of the first IGBT with the reverse diode is connected with the collector electrode of the second IGBT with the reverse diode to be used as a high-voltage end of the half-bridge sub-module;
the full-bridge-like submodule comprises: the IGBT module comprises a third IGBT with a backward diode, a fourth IGBT with a backward diode, a fifth IGBT with a backward diode, a second capacitor and a diode, wherein a collector electrode of the third IGBT with a backward diode is connected with a cathode of the diode and one end of the second capacitor, an emitter electrode of the third IGBT with a backward diode is connected with a collector electrode of the fourth IGBT with a backward diode to serve as a high-voltage end of the full-bridge-like sub-module, an emitter electrode of the fourth IGBT with a backward diode is connected with an emitter electrode of the fifth IGBT with the other end of the second capacitor, and an anode of the diode is connected with a collector electrode of the fifth IGBT with a backward diode to serve as a low-voltage end of the full-bridge-like sub-module.
Preferably, the converter station of the third dc power distribution subsystem adopts a half-bridge type modular multilevel converter and has a three-phase six-leg structure, each leg of the leg of;
wherein the half-bridge sub-module comprises: the IGBT module comprises a first IGBT with a reverse diode, a second IGBT with a reverse diode and a first capacitor, wherein a collector electrode of the first IGBT with the reverse diode is connected with one end of the first capacitor, the other end of the first capacitor is connected with an emitter electrode of the second IGBT with the reverse diode to serve as a low-voltage end of the half-bridge sub-module, and the emitter electrode of the first IGBT with the reverse diode is connected with the collector electrode of the second IGBT with the reverse diode to serve as a high-voltage end of the half-bridge sub-module.
Preferably, the method further comprises the following steps:
and one end of the direct current breaker is connected with the direct current bus, and the other end of the direct current breaker is connected with the converter station of the third direct current power distribution subsystem.
Preferably, the dc circuit breaker is a hybrid dc circuit breaker.
Preferably, the direct current transformer is an input-series output-parallel full-bridge direct current transformer.
The direct current power distribution system comprises at least one direct current power distribution electronic system and a new energy power distribution subsystem, wherein the direct current power distribution subsystem and the new energy power distribution subsystem are connected with a direct current bus. The direct current distribution subsystem includes: a converter station and a dc switch; the new forms of energy distribution subsystem includes: a DC transformer and a DC switch. Wherein, the direct current switches are all connected with the direct current bus. The electric energy of the alternating-current power distribution network is converted into direct current through the converter station and the direct-current switch, the electric energy of the new-energy power distribution network is converted into direct current through the direct-current transformer and the direct-current switch, and finally the electric energy is transmitted through the direct-current bus. Compared with the alternating current power distribution system in the prior art, the system can realize smooth access of the new energy power distribution network, and the system can comprise a plurality of direct current power distribution subsystems, so that the system can be expanded.
Drawings
In order to illustrate the embodiments of the present invention more clearly, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings can be obtained by those skilled in the art without inventive effort.
Fig. 1 is a block diagram of a dc power distribution system according to the present invention;
fig. 2 is a structural diagram of a three-phase half-bridge cascaded voltage source converter according to the present invention;
FIG. 3 is a block diagram of a half-bridge sub-module according to the present invention;
FIG. 4 is a block diagram of a full bridge sub-module according to the present invention;
fig. 5 is a structural diagram of a hybrid dc circuit breaker according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without any creative work belong to the protection scope of the present invention.
The core of the invention is to provide a direct current power distribution system.
In order that those skilled in the art will better understand the disclosure, the invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
The utility model provides a direct current power distribution system, includes at least one direct current distribution electronic system and new forms of energy distribution subsystem, and direct current distribution subsystem and new forms of energy distribution subsystem all are connected with the direct current generating line, and direct current distribution subsystem includes:
the converter station is connected with an alternating current power grid through an alternating current bus and an alternating current transformer and is used for converting alternating current into direct current;
a DC switch connecting the converter station and the DC bus;
the new energy power distribution subsystem comprises:
the direct current transformer is connected with the new energy power distribution network and used for performing voltage conversion on the direct current of the new energy power distribution subsystem;
and the direct current switch is connected with the direct current transformer and the direct current bus.
Fig. 1 is a structural diagram of a dc power distribution system according to the present invention. For clarity of illustration of the different dc power distribution subsystems, they are indicated with different numbers in fig. 1. For example, 3 dc power distribution subsystems, namely, a first dc power distribution subsystem 10, a second dc power distribution subsystem 20, and a third dc power distribution subsystem 30, may be included. The first dc distribution system 10 comprises a first converter station 100 and a first dc switch 101. The first converter station 100 is connected to the ac power grid 1 via an ac busbar and an ac transformer 102. The second dc power distribution subsystem 20 comprises a second converter station 200 and a second dc switch 201. The second converter station 200 is connected to the ac power grid 2 via an ac busbar and an ac transformer 202. The third dc power distribution subsystem 30 comprises a third converter station 300 and a dc breaker 301. The third converter station 300 is connected to the ac power grid 3 via an ac bus and an ac transformer 302.
The new energy power distribution subsystem 40 includes: a dc transformer 400 and a third dc switch 401.
As shown in fig. 1, the first dc switch 101, the second dc switch 201, the dc breaker 301, and the third dc switch 401 are all connected to a dc bus.
In specific implementation, the first converter station, the second converter station, the third converter station and the fourth converter station are used for mutual conversion between alternating current and direct current and are conversion interfaces between an alternating current system and a direct current system; the first to third direct current switches are used for isolation, do not have the capacity of cutting off current, are arranged at the positions, and are used for forming obvious physical intervals among all converter stations, the direct current transformer and the direct current bus for system cutting, so that partial operation and maintenance are facilitated. The direct current breaker has direct current cutting-off capability and is used for quickly isolating the third converter station from the direct current bus under the condition of system failure; the dc transformer has direct conversion capability of high/low dc voltage for connecting dc system interconnections between different dc voltage levels.
The dc power distribution system shown in fig. 1 has a wide range of ac/dc and new energy interconnection capabilities, and at the same time, has a fast fault isolation and clearing capability.
The direct-current power distribution system provided by the invention converts the electric energy of the alternating-current power distribution network into the direct current through the converter station and the direct-current switch, converts the electric energy of the new energy power distribution network into the direct current through the direct-current transformer and the direct-current switch, and finally transmits the electric energy through the direct-current bus. Compared with the alternating current power distribution system in the prior art, the system can realize smooth access of the new energy power distribution network, and the system can comprise a plurality of direct current power distribution subsystems, so that the direct current power distribution system can be easily expanded.
Fig. 1 includes 3 ac power grids, and therefore, there are 3 corresponding dc power distribution subsystems, which may be a first dc power distribution subsystem, a second dc power distribution subsystem, and a third dc power distribution subsystem. It should be noted that fig. 1 is only a specific application scenario, and does not represent only 3. The direct current transformer can be an input-series output-parallel full-bridge direct current transformer.
As a preferred embodiment, the converter station of the first dc distribution system adopts a three-phase half-bridge cascaded voltage source converter, and the three-phase half-bridge cascaded voltage source converter specifically includes: the three-phase half-bridge modules adopt a three-phase six-bridge arm structure, and each bridge arm is at least connected with an IGBT (insulated gate bipolar translator) with a first backward diode in series;
the direct current output side of the three-phase half-bridge module is connected with a capacitor, a resistor and a diode in parallel in sequence, and the anode of the direct current output side is connected with a second IGBT with a reverse diode in series;
the second IGBT with the backward diode is arranged between the resistor and the diode, an emitting electrode of the second IGBT with the backward diode is connected with a cathode of the diode and used as a direct current positive electrode port of the three-phase half-bridge module, and an anode of the diode is connected with a positive electrode of the direct current output side and used as a direct current positive electrode port of the three-phase half-bridge module.
Fig. 2 is a structural diagram of a three-phase half-bridge cascaded voltage source converter according to the present invention. As shown in fig. 2, the three-phase half-bridge module 50 has a three-phase six-leg structure, and the first IGBTs with reverse diodes, which are labeled G51, G52, G53, G54, G55, and G56, are connected in series to 6 legs. A capacitor C51, a resistor R51 and a diode V51 are connected in parallel in sequence on the dc output side of the three-phase half-bridge module 50, and a second IGBT with a backward diode, denoted by the reference G57, is connected in series on the positive electrode of the dc output side.
The resistor R51 and the diode V51 form a resistor G57, the emitter of the resistor G57 is connected to the cathode of the diode V51, and serves as a dc positive terminal of the three-phase half-bridge module, and the anode of the diode V51 is connected to the positive terminal of the dc output side, and serves as a dc positive terminal of the three-phase half-bridge module.
It should be noted that the number Nv of the three-phase half-bridge modules satisfies the following relation:
wherein, UdcFor the DC voltage of a DC distribution network, UvThe DC voltage is output by the three-phase half-bridge module.
As a preferred embodiment, the converter station of the second dc power distribution subsystem adopts a hybrid modular multilevel converter, and has a three-phase six-leg structure, each leg includes a plurality of half-bridge submodules and a plurality of full-bridge-like submodules, and each leg is connected in series with an inductor. Because the three-phase six-bridge arm structure is similar to that of a three-phase half-bridge cascading voltage source type current converter, the invention only provides the structural diagrams of a half-bridge sub-module and a full-bridge-like sub-module.
Fig. 3 is a structural diagram of a half-bridge sub-module provided in the present invention. As shown in fig. 3, the half-bridge sub-module includes: the IGBT with the first backward diode is marked with G61, the IGBT with the second backward diode is marked with G62, and a first capacitor C61. The collector of G61 is connected to one end of a first capacitor C61, the other end of the first capacitor C61 is connected to the emitter of G62 as the low voltage end of the half-bridge sub-module, and the emitter of G61 is connected to the collector of G62 as the high voltage end of the half-bridge sub-module.
Fig. 4 is a structural diagram of a full-bridge sub-module according to the present invention. As shown in fig. 4, the full-bridge-like sub-module includes: the IGBT with the third backward diode is marked as G71, the IGBT with the fourth backward diode is marked as G72, the IGBT with the fifth backward diode is marked as G73, a second capacitor C71 and a diode V71. The collector of G71 is connected with the cathode of diode V71 and one end of second capacitor C71, the emitter of G71 is connected with the collector of G72 as the high-voltage end of the full-bridge-like submodule, the emitter of G72 is connected with the emitter of G73 and the other end of C71, and the anode of diode V71 is connected with the collector of G73 as the low-voltage end of the full-bridge-like submodule.
It should be noted that each bridge arm contains the number N of half-bridge submoduleshAnd the number M of full-bridge-like submoduleshAll are natural numbers greater than 0. The following expression can be obtained:
wherein, UcRated capacitor voltage, U, for half-bridge or full-bridge-like sub-modulesmAnd outputting the amplitude of the phase voltage for the alternating current side of the hybrid modular multilevel converter. Compared with half-bridge submodules, the full-bridge-like submodules have higher manufacturing cost and higher loss, so the principle of minimizing the number of the full-bridge-like submodules is met. According to the principle, the number M of the full-bridge-like sub-modules can be obtainedhThe relation of (1):
wherein,is greater thanIs the smallest integer of (a) or (b),the total number of the bridge arm sub-modules,and k is the ratio of the maximum bearable voltage of the capacitor of the quasi-full-bridge submodule to the rated voltage. The number N of half-bridge sub-moduleshThe following relation is satisfied:
Nh＝Ns-Mh。
in a preferred embodiment, the converter station of the third dc power distribution subsystem adopts a half-bridge type modular multilevel converter, and has a three-phase six-leg structure, each leg includes a plurality of half-bridge submodules, and each leg is connected in series with an inductor.
Wherein, half-bridge submodule includes: the IGBT module comprises a first IGBT with a backward diode, a second IGBT with a backward diode and a first capacitor, wherein a collector electrode of the first IGBT with the backward diode is connected with one end of the first capacitor, the other end of the first capacitor is connected with an emitter electrode of the second IGBT with the backward diode to be used as a low-voltage end of the half-bridge sub-module, and the emitter electrode of the first IGBT with the backward diode is connected with the collector electrode of the second IGBT with the backward diode to be used as a high-voltage end of the half-bridge sub-module.
Since the three-phase six-leg structure of the half-bridge type modular multilevel converter is the same as that of the three-phase six-leg structure of the three-phase half-bridge cascaded voltage source type converter, and the structure of the half-bridge sub-module is the same as that of the half-bridge sub-module of the hybrid type modular multilevel converter, further description is omitted here.
When the third converter station adopts a half-bridge type modular multilevel converter and is of a three-phase six-bridge-arm structure, the third direct-current power distribution subsystem further comprises a direct-current circuit breaker.
As shown in fig. 1, one end of the dc breaker 301 is connected to the dc bus, and the other end is connected to the converter station of the third dc power distribution subsystem 30.
The dc breaker 301 is a hybrid dc breaker.
The direct-current power distribution network needs to have certain breaking capacity and short circuit with high breaking speed to quickly isolate faults, and the safe and stable operation of the power grid is guaranteed. Meanwhile, the breaker is required to have low loss and high reliability, and the operation of a direct current distribution network cannot be influenced by the fault of the breaker. Therefore, compared with the existing direct current breaker technology, the hybrid direct current breaker is more suitable for the requirement of a direct current distribution network. The hybrid direct current circuit breaker can achieve quick fault isolation and reduce operation loss.
Fig. 5 is a structural diagram of a hybrid dc circuit breaker according to the present invention. As can be seen from fig. 5, the hybrid dc circuit breaker mainly includes a high-speed mechanical switch D1, an on-state valve set Q1 composed of a fully-controlled power electronic device, a current-limiting valve set Q2 composed of a fully-controlled power electronic device, and a zinc oxide arrester MOV. K1 and K2 are isolation switches. Under normal conduction, current flows through the high speed mechanical switch D1 and the on valve set Q1 with very low on losses. The flow restrictor set Q2 is in a latched state; under normal breaking condition, the high-speed mechanical switch D1, the on-state valve group Q1 and the flow-limiting valve group Q2 are all in breaking state. The high-speed mechanical switch D1 and the current-limiting valve group Q2 bear fracture voltage; and (3) a fault switching process: when a fault is detected, the on-state valve group Q1 is firstly separated, the current is transferred to the branch of the current-limiting valve group Q2, the high-speed mechanical switch D1 is rapidly separated in zero current, the current-limiting valve group Q2 is disconnected, and the zinc oxide arrester MOV plays a role in limiting voltage and absorbing fault current energy.
Because the half-bridge type modular multilevel converter does not have the self-clearing capability of direct current faults, the cooperation of a direct current breaker is needed to realize the rapid isolation of the faults.
In order to make those skilled in the art understand the dc distribution network system provided by the present invention, the following method for isolating the system in case of a fault is given.
The method comprises the following steps:
(1) when a fault occurs at the side of the alternating current power grid 1 where the first converter station is located, the three-phase half-bridge cascade voltage source type converter in the first converter station is locked, when the current flowing through the first direct current switch is reduced to a certain value, the first direct current switch is disconnected, and a fault point is isolated from the direct current power distribution system.
(2) When the alternating current network 2 side where the second converter station is located has a fault, the hybrid modular multilevel converter in the second converter station is locked first, and when the current flowing through the second direct current switch is reduced to a certain value, the second direct current switch is disconnected, and the fault point is isolated from the direct current distribution system.
(3) When a fault occurs at the side of the alternating current power grid 3 where the third converter station is located, the half-bridge type modular multilevel converter in the third converter station is locked firstly, then a disconnection signal is applied to the direct current circuit breaker, and after the direct current circuit breaker is disconnected, a fault point is isolated from the direct current power distribution system.
(4) When the new energy distribution subsystem side where the transformer station is located breaks down, the direct current transformer in the transformer station is directly locked, when the current flowing through the third direct current switch is reduced to a certain value, the third direct current switch is disconnected, and the fault point is isolated from the direct current distribution system.
(5) When the direct current bus has a fault, corresponding converters in the first to third converter stations are quickly locked, and meanwhile, the direct current transformer is locked and a disconnection signal is applied to the direct current breaker. And after the first to third direct current switches and the direct current breaker are disconnected, the fault is isolated. At the moment, the corresponding converters in the first to third converter stations are unlocked in a constant direct-current voltage and constant alternating-current voltage/reactive power mode, and are used for adjusting the system stability of the alternating-current power grids 1 to 3.
The dc power distribution system provided by the present invention is described in detail above. The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to assist in understanding the method and its core concepts. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.
Claims (1)
1. The utility model provides a direct current power distribution system, its characterized in that includes that 3 direct currents distribute electronic system and new forms of energy distribution subsystem, specifically is first direct current distribution electronic system, second direct current distribution electronic system and third direct current distribution subsystem, direct current distribute electronic system with new forms of energy distribution network subsystem all is connected with the direct current generating line, direct current distribution subsystem includes:
the converter station is connected with an alternating current power grid through an alternating current bus and an alternating current transformer and is used for converting alternating current into direct current;
a DC switch connecting the converter station and the DC bus;
the new energy power distribution subsystem comprises:
the direct current transformer is connected with the new energy power distribution network and used for performing voltage conversion on the direct current of the new energy power distribution subsystem;
a DC switch connecting the DC transformer and the DC bus;
wherein the direct current switch is used for physical isolation and system cutting;
the converter station of the first direct current distribution system adopts a three-phase half-bridge cascade type voltage source converter, and the three-phase half-bridge cascade type voltage source converter specifically comprises: the three-phase half-bridge modules adopt a three-phase six-bridge arm structure, and each bridge arm is at least connected with an IGBT (insulated gate bipolar translator) with a first backward diode in series;
the direct current output side of the three-phase half-bridge module is connected with a capacitor, a resistor and a diode in parallel in sequence, and the anode of the direct current output side is connected with a second IGBT with a reverse diode in series;
the IGBT with the second backward diode is arranged between the resistor and the diode, the emitter of the IGBT with the second backward diode is connected with the cathode of the diode and used as a direct current positive electrode port of the three-phase half-bridge module, and the anode of the diode is connected with the positive electrode of the direct current output side and used as a direct current positive electrode port of the three-phase half-bridge module;
the converter station of the second direct current power distribution subsystem adopts a mixed type modular multilevel converter and is of a three-phase six-bridge-arm structure, each bridge arm comprises a plurality of half-bridge sub-modules and a plurality of similar full-bridge sub-modules, and each bridge arm is connected with an inductor in series;
wherein the half-bridge sub-module comprises: the IGBT module comprises a first IGBT with a reverse diode, a second IGBT with a reverse diode and a first capacitor, wherein a collector electrode of the first IGBT with the reverse diode is connected with one end of the first capacitor, the other end of the first capacitor is connected with an emitter electrode of the second IGBT with the reverse diode to be used as a low-voltage end of the half-bridge sub-module, and the emitter electrode of the first IGBT with the reverse diode is connected with the collector electrode of the second IGBT with the reverse diode to be used as a high-voltage end of the half-bridge sub-module;
the full-bridge-like submodule comprises: the IGBT module comprises a third IGBT with a reverse diode, a fourth IGBT with a reverse diode, a fifth IGBT with a reverse diode, a second capacitor and a diode, wherein a collector electrode of the third IGBT with the reverse diode is connected with a cathode of the diode and one end of the second capacitor, an emitter electrode of the third IGBT with the reverse diode is connected with a collector electrode of the fourth IGBT with the reverse diode to serve as a high-voltage end of the full-bridge-like sub-module, an emitter electrode of the fourth IGBT with the reverse diode is connected with an emitter electrode of the fifth IGBT with the reverse diode and the other end of the second capacitor, and an anode of the diode is connected with a collector electrode of the fifth IGBT with the reverse diode to serve as a low-voltage end of the full-bridge-like sub-module;
the converter station of the third direct current power distribution subsystem adopts a half-bridge type modular multilevel converter and is of a three-phase six-bridge-arm structure, each bridge arm comprises a plurality of half-bridge sub-modules, and each bridge arm is connected with an inductor in series;
wherein the half-bridge sub-module comprises: the IGBT module comprises a first IGBT with a reverse diode, a second IGBT with a reverse diode and a first capacitor, wherein a collector electrode of the first IGBT with the reverse diode is connected with one end of the first capacitor, the other end of the first capacitor is connected with an emitter electrode of the second IGBT with the reverse diode to be used as a low-voltage end of the half-bridge sub-module, and the emitter electrode of the first IGBT with the reverse diode is connected with the collector electrode of the second IGBT with the reverse diode to be used as a high-voltage end of the half-bridge sub-module;
further comprising:
one end of the direct current breaker is connected with the direct current bus, and the other end of the direct current breaker is connected with a converter station of the third direct current power distribution subsystem;
the direct current breaker is a hybrid direct current breaker;
the direct current transformer is an input-series output-parallel full-bridge direct current transformer.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201510612889.3A CN105226628B (en) | 2015-09-23 | 2015-09-23 | A kind of direct-flow distribution system |
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| US9041248B2 (en) * | 2011-01-18 | 2015-05-26 | Siemens Aktiengesellschaft | Control of the distribution of electric power generated by a wind farm between an AC power transmission link and a DC power transmission link |
| CN104022527A (en) * | 2014-05-16 | 2014-09-03 | 国家电网公司 | DC micro grid system |
| CN104184138A (en) * | 2014-08-21 | 2014-12-03 | 南京南瑞继保电气有限公司 | Method for one end of multi-end flexible direct-current power transmission system to exit from operation system |
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