CN108649577A - A kind of transmission system - Google Patents

A kind of transmission system Download PDF

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Publication number
CN108649577A
CN108649577A CN201810632251.XA CN201810632251A CN108649577A CN 108649577 A CN108649577 A CN 108649577A CN 201810632251 A CN201810632251 A CN 201810632251A CN 108649577 A CN108649577 A CN 108649577A
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CN
China
Prior art keywords
frequency
network
connect
transmission
converter
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN201810632251.XA
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Chinese (zh)
Inventor
葛菁
于弘洋
邓占锋
赵国亮
廖志军
殷平
蔡林海
戴朝波
陆振纲
宋洁莹
祁欢欢
尉志勇
杨士慧
张永征
王英沛
刘依晗
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
State Grid Corp of China SGCC
State Grid Jiangxi Electric Power Co Ltd
Global Energy Interconnection Research Institute
Original Assignee
State Grid Corp of China SGCC
State Grid Jiangxi Electric Power Co Ltd
Global Energy Interconnection Research Institute
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by State Grid Corp of China SGCC, State Grid Jiangxi Electric Power Co Ltd, Global Energy Interconnection Research Institute filed Critical State Grid Corp of China SGCC
Priority to CN201810632251.XA priority Critical patent/CN108649577A/en
Publication of CN108649577A publication Critical patent/CN108649577A/en
Pending legal-status Critical Current

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Classifications

    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00Circuit arrangements for ac mains or ac distribution networks

Abstract

The present invention provides a kind of transmission systems, including:Several first AC/AC converter plants, connect with AC network, and for the first frequency three-phase voltage of AC network to be converted to second frequency three-phase voltage, first frequency is more than second frequency;Power transmission cable is connect with the first AC/AC converter plants and the second AC system, for AC network to be carried out networking.The transmission system promotes the transmission capacity of circuit by using the transmission frequency less than first frequency at double, improves transmission range.

Description

A kind of transmission system
Technical field
The present invention relates to electric system field of power transmission, and in particular to a kind of transmission system.
Background technology
The energy is the important substance basis of socio-economic development, and Speed-up Establishment is safe and reliable, economical and efficient, clean environment firendly Modern energy supply system, it has also become the common strategic objective in countries in the world.In order to effectively solve lack of energy and environmental pollution Problem, development new energy have become reply energy security, environmental pollution, climate change three challenges, realize that human society can be held The only way of supervention exhibition.Wind-power electricity generation is most ripe, on the largest scaleization exploit condition power generation side in new energy power generation technology One of formula.Some regional wind power resources distributions and load center are in contrary distribution, are needed through large capacity long distance power transmission come real Existing resource is distributed rationally.
Existing ac transmission be limited by the transmission power limit, system safety and stability, transmission of electricity corridor and cost of investment etc. because The restriction of element, it is difficult to be adapted to the requirement of long-distance and large-capacity power transmission;It is universal in the occasions such as wind-electricity integration, urban electricity supply at sea Using cable power transmission, cable is there is apparent capacity effect, the Payload energy that can be greatly increased reactive loss, reduce cable Power, while being difficult to carry out reactive-load compensation, transmission distance when relatively long distance cable run is using exchange transmission in cable run midway From limited.
Invention content
Therefore, the technical problem to be solved in the present invention is to overcome transmission system transmission range is short in the prior art to lack It falls into.
For this purpose, the present invention provides the following technical solutions:
The present invention provides a kind of transmission system, including:Several first AC/AC converter plants, connect with AC network, are used for The first frequency three-phase voltage of the AC network is converted into second frequency three-phase voltage, the first frequency is more than described the Two frequencies;Power transmission cable is connect with the first AC/AC converter plants and the second AC system, is used for the AC network Carry out networking.
Optionally, the first AC/AC converter plants include the first AC/AC frequency converters and first switch group, wherein described The input terminal of first AC/AC frequency converters is connect with the AC network, and the output end of the first AC/AC frequency converters is described in First switch group is connect with the power transmission cable.
Optionally, the first AC/AC frequency converters include at least one set of frequency-variable module, and the frequency-variable module includes three changes Frequency unit, the input terminal of the converter unit are connect with the AC network, the output end of the converter unit and described first Switching group connects.
Optionally, the converter unit includes three frequency conversion bridge arms, each described frequency conversion bridge arm includes inductance and H The first end of bridge, the inductance is connect with the first end of H bridges, the input of the second end of the inductance as the frequency conversion bridge arm End, the output end of the second ends of the H bridges as the frequency conversion bridge arm;The input terminal of three frequency conversion bridge arms respectively with it is described A phases, the B phases of AC network are connected with C, and the output end of three frequency conversion bridge arms is connect with the first switch group.
Optionally, the H bridges include at least one full-control type H bridges.
Optionally, the full-control type H bridges include two groups of power electronic devices bridge arms and DC capacitor, two groups of electric power electricity Sub- device bridge arm is connected in parallel, each described power electronic devices bridge arm includes concatenated two power electronic devices, institute DC capacitor is stated to be connected in parallel with the power electronic devices bridge arm.
Optionally, the power electronic devices include insulated gate bipolar transistor and with the insulated gate bipolar crystal The voltage rectifier that pipe is connected in parallel.
Optionally, the first switch group is breaker and the disconnecting switch for being set to the breaker both ends.
Optionally, the first frequency is 50Hz, and the second frequency is 50/3Hz.
Optionally, further include:2nd AC/AC converter plants are connect with the power transmission cable and second AC system, For the second frequency three-phase voltage of the AC network to be converted to third frequency three-phase voltage.
Optionally, further include:Several transformers are corresponded with the first AC/AC converter plants, the transformer point It is not connect with the first AC/AC converter plants and the AC network, for adjusting the AC network output voltage;With/ Or, with the 2nd AC/AC converter plants correspond, the transformer respectively with the 2nd AC/AC converter plants and institute The connection of the second AC system is stated, for adjusting the second AC system input voltage.
Technical solution of the present invention has the following advantages that:
1. transmission system provided by the invention, including:Several first AC/AC converter plants, connect with AC network, are used for The first frequency three-phase voltage of AC network is converted into second frequency three-phase voltage, first frequency is more than second frequency;Transmission of electricity Cable is connect with the first AC/AC converter plants and the second AC system, for AC network to be carried out networking.The transmission system The transmission capacity for promoting circuit at double by using the transmission frequency less than first frequency, improves transmission range.
2. transmission system provided by the invention, the first AC/AC converter plants include the first AC/AC frequency converters and first switch Group, wherein the input terminal of the first AC/AC frequency converters is connect with the AC network, the first AC/AC frequency converters it is defeated Outlet is connect by the first switch group with the power transmission cable.First AC/AC frequency converters realize the reduction of frequency, and first opens Pass group realizes flexible variation and the Fault Isolation of networking mode, easy access and maintenance.
3. transmission system provided by the invention, the first AC/AC frequency converters include at least one set of frequency-variable module, the frequency conversion mould Block includes three converter units, and the input terminal of the converter unit is connect with the AC network, the output of the converter unit End is connect with the first switch group.The exportable one group of three-phase low-frequency ac pressure of one group of frequency-variable module, therefore the first AC/AC frequency conversions The exportable multigroup three-phase low-frequency ac pressure of device, and then can be connect with multiple second AC systems, improve the flexibility of networking And convenience.
4. transmission system provided by the invention further includes the 2nd AC/AC converter plants, with the power transmission cable and described Two AC systems connect, for the second frequency three-phase voltage of the AC network to be converted to third frequency three-phase voltage.It is logical The frequency that the 2nd AC/AC converter plants change AC network is crossed, is allowed to preferably match with frequency needed for the second AC system, is increased The flexibility of transmission system is added so that the application scenario of transmission system is more extensive.
5. transmission system provided by the invention, further includes:Several transformers, one by one with the first AC/AC converter plants Corresponding, the transformer is connect with the first AC/AC converter plants and the AC network respectively, for adjusting the exchange Power grid output voltage;And/or corresponded with the 2nd AC/AC converter plants, the transformer is respectively with described second AC/AC converter plants are connected with second AC system, for adjusting the second AC system input voltage.Transformer makes Matching and the 2nd AC/AC frequency conversions dress of AC network and the first AC/AC converter plants can be better met by obtaining transmission system The matching with the second AC system is set, the application flexibility of transmission system is increased.
Description of the drawings
It, below will be to specific in order to illustrate more clearly of the specific embodiment of the invention or technical solution in the prior art Embodiment or attached drawing needed to be used in the description of the prior art are briefly described, it should be apparent that, in being described below Attached drawing is some embodiments of the present invention, for those of ordinary skill in the art, before not making the creative labor It puts, other drawings may also be obtained based on these drawings.
Fig. 1 is the schematic diagram of a specific example of transmission system in the embodiment of the present invention;
Fig. 2 is the schematic diagram of another specific example of transmission system in the embodiment of the present invention;
Fig. 3 is the schematic diagram of another specific example of transmission system in the embodiment of the present invention;
Fig. 4 is the schematic diagram of another specific example of transmission system in the embodiment of the present invention;
Fig. 5 is the schematic diagram of another specific example of transmission system in the embodiment of the present invention;
Fig. 6 is the schematic diagram of another specific example of transmission system in the embodiment of the present invention;
Fig. 7 is the schematic diagram of another specific example of transmission system in the embodiment of the present invention;
Fig. 8 is the schematic diagram of another specific example of transmission system in the embodiment of the present invention;
Fig. 9 is the schematic diagram of another specific example of transmission system in the embodiment of the present invention;
Figure 10 is the schematic diagram of another specific example of transmission system in the embodiment of the present invention;
Figure 11 is the schematic diagram of another specific example of transmission system in the embodiment of the present invention;
Figure 12 is the schematic diagram of another specific example of transmission system in the embodiment of the present invention.
Reference numeral:
1, the first AC/AC converter plants;11, the first AC/AC frequency converters;111, converter unit;1111, inductance;1112、H Bridge;12, first switch group;121, it switchs;2, AC network;3, power transmission cable;4, the second AC system;5, the 2nd AC/AC becomes Frequency device;51, second switch group;52, the 2nd AC/AC frequency converters;6, transformer.
Specific implementation mode
Technical scheme of the present invention is clearly and completely described below in conjunction with attached drawing, it is clear that described implementation Example is a part of the embodiment of the present invention, instead of all the embodiments.Based on the embodiments of the present invention, ordinary skill The every other embodiment that personnel are obtained without making creative work, shall fall within the protection scope of the present invention.
In the description of the present invention, it should be noted that term "center", "upper", "lower", "left", "right", "vertical", The orientation or positional relationship of the instructions such as "horizontal", "inner", "outside" be based on the orientation or positional relationship shown in the drawings, merely to Convenient for the description present invention and simplify description, do not indicate or imply the indicated device or element must have a particular orientation, With specific azimuth configuration and operation, therefore it is not considered as limiting the invention.In addition, term " first ", " second ", " third " is used for description purposes only, and is not understood to indicate or imply relative importance.
In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, term " installation ", " phase Even ", " connection " shall be understood in a broad sense, for example, it may be being fixedly connected, may be a detachable connection, or be integrally connected;It can Can also be electrical connection to be mechanical connection;It can be directly connected, can also indirectly connected through an intermediary, it can be with It is the connection inside two elements, can be wirelessly connected, can also be wired connection.For those of ordinary skill in the art For, the concrete meaning of above-mentioned term in the present invention can be understood with concrete condition.
As long as in addition, technical characteristic involved in invention described below different embodiments non-structure each other It can be combined with each other at conflict.
The present embodiment provides a kind of transmission systems, are applied to electric system AC electricity transmission, as shown in Figure 1, including:
Several first AC/AC converter plants 1, connect with AC network 2, are used for the first frequency three-phase of AC network 2 Voltage is converted to second frequency three-phase voltage, and first frequency is more than second frequency.The transmission system is applied to large capacity over long distances The range of transmission of electricity, first frequency and second frequency determines according to practical application, the preferred scope of first frequency be less than or equal to 75Hz, as long as second frequency is less than first frequency, if first frequency is 60Hz, second frequency can be appointing less than 60Hz One frequency.In the present embodiment, since the work frequency of China's power grid is 50Hz, therefore first frequency is set as 50Hz;Second frequency Rate is set as 50/3Hz;As transmission frequency reduces, cable current increases, and insulation performance declines therewith, is considering it absolutely Use the low frequency power transmission frequency of 50/3Hz, in this way setting that can increase by 3 times of transmission and hold after the influence of many factors such as edge and cost Amount reduces line impedance, increases transmission range.In the present embodiment, as shown in Fig. 2, including two the first AC/AC converter plants 1;Certainly, in other embodiments, can also include three or more, rationally setting as needed.In this implementation In example, as shown in figure 3, the three-phase voltage of AC network is expressed as A phase voltages VA, B phase voltages VBWith C phase voltages VC, above-mentioned The phase difference of three-phase voltage is 120 degree;Transformed three-phase voltage is expressed as first voltage VMA, second voltage VMBWith Three voltage VMC, the phase difference of above-mentioned three-phase voltage is 120 degree.In the present embodiment, AC network can be power plant, substation Or the alternating current of the outputs such as power distribution station, rationally setting as needed.
In the present embodiment, as shown in figure 3, the first AC/AC converter plants 1 include the first AC/AC frequency converters 11 and first Switching group 12, wherein the input terminal of the first AC/AC frequency converters 11 is connect with AC network 2, the first AC/AC frequency converters 11 it is defeated Outlet is connect by first switch group 12 with power transmission cable 3.First switch group is set to the output end of the first AC/AC frequency converters 11 Between power transmission cable 3, on the one hand the networking between AC network is convenient in setting in this way, the switch conduction in first switch group is then AC network accesses transmission system;On the other hand when power transmission cable breaks down, the switch in first switch group is disconnected So that power transmission cable is disconnected with AC network, it is convenient for the maintenance and repair of power transmission cable.First switch group is according to system protection, inspection The demand assignments such as repair.In the present embodiment, first switch group 12 includes at least one set of switch, and each group of switch includes three Switch, each switch include breaker and the disconnecting switch for being set to breaker both ends, i.e., breaker is defeated Enter end to connect with a disconnecting switch, the output end of breaker is connect with a disconnecting switch again, the specific number of switch according to Actual needs rationally setting.In the present embodiment, as shown in figure 5, first switch group 12 includes three groups of switches 121, respectively It is denoted as first group of switch, second group of switch and third group switch, wherein the three-phase voltage output end of the first AC/AC frequency converters 11 It is connect with the first end of first group of switch, the second end of first group of switch is opened with the first end of second group of switch and third group respectively The first end of pass connects, and second group of switch is connected with third group switch in parallel, the second end of second group of switch and one second friendship Streaming system connects, and the second end of third group switch is connect with another second AC system, and the first AC/AC frequency converters 11 can pass through Two groups of switches (second group of switch and third group switch) two second AC systems of connection in parallel.Certainly, in other embodiments In, first group of switch as shown in Figure 5 can also be saved, as needed rationally setting.
First AC/AC frequency converters 11 include at least one set of frequency-variable module, and frequency-variable module includes three converter units 111, is become The input terminal of frequency unit 111 is connect with AC network 2, and the output end of converter unit 111 is connect with first switch group 12.In this reality It applies in example, as shown in figure 4, the first AC/AC frequency converters 11 include one group of frequency-variable module, frequency-variable module includes three converter units 111, converter unit 111 includes three frequency conversion bridge arms, each frequency conversion bridge arm includes inductance 1111 and H bridges 1112, inductance 1111 first end is connect with the first end of H bridges 1112, the input terminal of the second end of inductance 1111 as frequency conversion bridge arm, H bridges Output end of 1112 second end as frequency conversion bridge arm;The input terminal of three frequency conversion bridge arms respectively with the A phases of AC network 2, B phases It is connected with C, the output end of three frequency conversion bridge arms is connect with first switch group 12.First AC/AC frequency converters 11 are containing 9 by grade The bridge arm for joining H bridge modules composition draws three phase low frequency exchange from neutral point.
H bridges 1112 include at least one full-control type H bridges, in the present embodiment, as shown in figure 4, H bridges include a full-control type H bridges, full-control type H bridges include two groups of power electronic devices bridge arms and DC capacitor, and two groups of power electronic devices bridge arms are connected in parallel, Each power electronic devices bridge arm includes concatenated two power electronic devices, DC capacitor and power electronic devices bridge arm It is connected in parallel;Power electronic devices includes insulated gate bipolar transistor (IGBT) and two pole of back-pressure being connected in parallel with IGBT Pipe.Certainly, in other embodiments, power electronic devices can also be metal (metal)-oxide (oxide)-semiconductor (semiconductor) field-effect transistor (MOS) pipe or bipolar transistor (Bipolar Junction Transistor is abbreviated as BJT) etc., rationally setting as needed.The voltage that can bear due to a full-control type H bridge Grade is limited, and the voltage of AC network is higher, therefore multiple full-control type H bridges is needed to be cascaded, as shown in figure 5, H bridges 1112 wrap Two full-control type H bridges are included, in other embodiments, the cascade number of full-control type H bridges can be rationally set as needed.
First frequency three-phase voltage can be converted to a second frequency three-phase voltage, second frequency by one group of frequency-variable module Three-phase voltage is connected to the second AC system by first switch group.When the first switch group 12 being connect with frequency-variable module includes one When group switch 121, one group of frequency-variable module connects second AC system 4, then the first AC/AC frequency converters 11 connect one second AC system 4, such networking the latter AC network connect second AC system, as shown in Figure 4.Connect when with frequency-variable module When the first switch group 12 connect includes at least two groups switch 121, one group of frequency-variable module connects at least two second AC systems 4, Then the first AC/AC frequency converters 11 connect at least two second AC systems 4, and such networking the latter AC network can connect multiple Second AC system;As shown in figure 5, first switch group 12 includes three groups of switches 121, one group of frequency-variable module connects two second friendships Streaming system 4, therefore the first AC/AC frequency converters 11 are connected in parallel two the second AC systems 4.
Certainly, in other embodiments, the first AC/AC frequency converters 11 may include multigroup frequency-variable module, an AC network Multigroup frequency-variable module can be connected.If the first AC/AC frequency converters 11 include two groups of frequency-variable modules, i.e. two groups of frequency-variable module parallel connections connect It connects.When the first switch group 12 being connect with each frequency-variable module includes one group of switch 121, therefore each group of frequency-variable module connection One the second AC system 4, the first AC/AC frequency converters 11 connect two the second AC systems 4, such networking the latter alternating current Net can connect multiple second AC systems, as shown in Figure 6.When the first switch group 12 being connect with each frequency-variable module includes extremely When few two groups of switches 121, each group of frequency-variable module connects at least two second AC systems 4, such networking the latter alternating current Net can also connect multiple second AC systems;As shown in fig. 7, first switch group 12 includes three groups of switches 121, therefore each group of frequency conversion Module connects two the second AC systems 4, and the first AC/AC frequency converters 11 connect four the second AC systems 4.The transmission system Specific network construction form is rationally arranged according to the actual conditions of AC network and the second AC system, as shown in figure 8, the transmission of electricity System includes that four the first AC/AC converter plants form looped network, and specific connection relation refers to attached drawing 8.
Multiterminal low frequency group net operation mode may be implemented by controlling three phase low frequency switch in first AC/AC converter plants 1 Change, including the variation of networking mode and the realization of Fault Isolation function.In multiterminal low frequency networking, first can be passed through AC/AC Frequency Converter Controls adjust trend in networking, realize trend management and control function.
Power transmission cable 3 is connect with the first AC/AC converter plants 1 and the second AC system 4, for carrying out AC network 2 Networking.In the present embodiment, the second AC system can be that transmission line of electricity, substation, change electric line, power distribution station or electricity consumption are set It is standby etc., rationally setting as needed.In the present embodiment, power transmission cable 3 is cable, certainly, in other embodiments, also Can be overhead line etc., rationally setting as needed.
Above-mentioned transmission system is converted to the first frequency three-phase voltage of AC network by the first AC/AC converter plants Second frequency three-phase voltage, first frequency are more than second frequency;It is transmitted to the second AC system by power transmission cable later, this is defeated Electric system promotes the transmission capacity of circuit by using the transmission frequency less than first frequency at double, improves transmission range.This Outside, transformer may be omitted with using low-frequency transmission, further decreases production cost.
In order to increase the networking convenience and operational flexibility of transmission system, on the basis of above-mentioned transmission system, such as Fig. 9 Shown, which further includes:2nd AC/AC converter plants 5 connect with power transmission cable 3 and the second AC system 4, are used for The second frequency three-phase voltage of AC network 2 is converted into third frequency three-phase voltage.In the present embodiment, due to China's power grid Frequency be 50Hz, therefore third set of frequency be 50Hz, certainly, in other embodiments, third frequency can according to second exchange Rationally it is arranged needed for system, third set of frequency is 75Hz if frequency needed for the second AC system is 75Hz;Second exchange system Frequency is that then third set of frequency is 30Hz to 30Hz needed for system.In the present embodiment, as shown in Figure 10, the 2nd AC/AC frequency conversions fill It includes second switch group 51 and the 2nd AC/AC frequency converters 52 to set 5, and power transmission cable 3 becomes by second switch group 51 and the 2nd AC/AC The input terminal of frequency device 52 connects, and the output end of the 2nd AC/AC frequency converters 52 is connect with the second AC system 4.2nd AC/AC frequency conversions The particular circuit configurations of device 52 are similar with the circuit structure of the first AC/AC frequency converters 11, by the input of the first AC/AC frequency converters 11 End and output end exchange can be obtained the 2nd AC/AC frequency converters 52, therefore the circuit structure of the 2nd AC/AC frequency converters 52 is herein no longer It repeats;Second switch group 51 is similar with the particular circuit configurations of first switch group 12, and details are not described herein.In alternating current net side (delivery end) installs the first AC/AC converter plants additional, and three-phase first frequency voltage is converted to the low frequency that frequency is less than first frequency Voltage transmits, and reaches the second AC system (receiving end) and is converted to three-phase third voltage to frequency using the 2nd AC/AC converting means Load power supply is carried out, networking is exchanged to form low frequency multiterminal.It is powered between remote districts or multiple islands using low frequency networking Transmission of electricity transformation is carried out, transmission capacity can be increased, reduces line loss, increases fed distance, saves improvement cost, reduces construction Difficulty.
In order to meet the adjusting between different voltages grade, on the basis of above-mentioned transmission system, as shown in figure 11, this is defeated Electric system further includes:
Several transformers 6 are corresponded with the first AC/AC converter plants 1, and transformer 6 is filled with the first AC/AC frequency conversions respectively 1 and the connection of AC network 2 are set, for adjusting AC network output voltage.In the present embodiment, the first AC/AC converter plants 1 Number is two, therefore the number of transformer 6 is also two;If the voltage of AC network is 220V, by transformer 6 by 220V's Three-phase alternating voltage boosts to 10kV, therefore transformer is step-up transformer, and reconvert is defeated using high voltage at three-phase voltage later Electric line carries out low-frequency transmission, high-tension transmission reduce the material of the thermal losses generated by electric current and reduction long distance power transmission at This.Certainly, in other embodiments, transformer 6 can also boost to different voltage, such as 500kV or 750kV, according to need Rationally to be arranged;Transformer 6 can also be depressurized to different voltages value, if the voltage value of three-phase alternating voltage is 220kV, lead to 110kV, 35kV, 10kV or 220V etc. can be depressurized to by crossing transformer 6, as needed rationally setting.In the present embodiment, Transformer 6 is set between the first AC/AC converter plants 1 and AC network 2, and this set makes the small volume of transformer 6, Cost is relatively low;Certainly, in other embodiments, transformer 6 can also be set to the first AC/AC converter plants 1 and power transmission cable 3 Between, at this point, transformer is low-frequency transformer, frequency is lower, and the volume of transformer is bigger, and cost is also higher, therefore can be according to need Rationally to be arranged.If transmission system voltage and the first AC/AC frequency converters are applicable in, voltage is consistent, and the transformer at the system end can be with It omits, substantially reduces cost.
In order to meet the different voltages grade needed for the second AC system, on the basis of above-mentioned transmission system, such as Figure 12 Shown, transformer 6 can also be set between the 2nd AC/AC converter plants 5 and the second AC system 4, for adjusting alternating current Net is delivered to the ac voltage of the second AC system;This set makes the small volume of transformer 6, cost relatively low.Certainly, In other embodiments, transformer 6 can also be set between power transmission cable 3 and the 2nd AC/AC converter plants 5, as needed Rationally setting.If the second AC system is consistent with the applicable voltage of the 2nd AC/AC frequency converters, the transformer at the system end It can be omitted, further reduce the cost.
Obviously, the above embodiments are merely examples for clarifying the description, and does not limit the embodiments.It is right For those of ordinary skill in the art, can also make on the basis of the above description it is other it is various forms of variation or It changes.There is no necessity and possibility to exhaust all the enbodiments.And thus amplify out it is obvious variation or It changes still within the protection scope of the invention.

Claims (11)

1. a kind of transmission system, which is characterized in that including:
Several first AC/AC converter plants, connect with AC network, are used for the first frequency three-phase voltage of the AC network Second frequency three-phase voltage is converted to, the first frequency is more than the second frequency;
Power transmission cable is connect with the first AC/AC converter plants and the second AC system, for carrying out the AC network Networking.
2. transmission system according to claim 1, which is characterized in that the first AC/AC converter plants include the first AC/ AC frequency converters and first switch group, wherein the input terminal of the first AC/AC frequency converters is connect with the AC network, described The output end of first AC/AC frequency converters is connect by the first switch group with the power transmission cable.
3. transmission system according to claim 2, which is characterized in that the first AC/AC frequency converters include at least one set Frequency-variable module, the frequency-variable module include three converter units, and the input terminal of the converter unit is connect with the AC network, The output end of the converter unit is connect with the first switch group.
4. transmission system according to claim 3, which is characterized in that the converter unit includes three frequency conversion bridge arms, often One frequency conversion bridge arm includes inductance and H bridges, and the first end of the inductance is connect with the first end of H bridges, the inductance Input terminal of the second end as the frequency conversion bridge arm, the output end of the second ends of the H bridges as the frequency conversion bridge arm;
The input terminal of three frequency conversion bridge arms is connected with the A phases of the AC network, B phases and C respectively, three frequency conversions The output end of bridge arm is connect with the first switch group.
5. transmission system according to claim 4, which is characterized in that the H bridges include at least one full-control type H bridges.
6. transmission system according to claim 5, which is characterized in that the full-control type H bridges include two groups of power electronics devices Part bridge arm and DC capacitor, two groups of power electronic devices bridge arms are connected in parallel, each described power electronic devices bridge arm Include concatenated two power electronic devices, the DC capacitor is connected in parallel with the power electronic devices bridge arm.
7. transmission system according to claim 6, which is characterized in that the power electronic devices includes insulated gate bipolar Transistor and the voltage rectifier being connected in parallel with the insulated gate bipolar transistor.
8. according to any transmission systems of claim 2-7, which is characterized in that the first switch group be breaker and It is set to the disconnecting switch at the breaker both ends.
9. according to any transmission systems of claim 1-8, which is characterized in that the first frequency is 50Hz, described the Two frequencies are 50/3Hz.
10. according to any transmission systems of claim 1-9, which is characterized in that further include:
2nd AC/AC converter plants are connect with the power transmission cable and second AC system, are used for the AC network Second frequency three-phase voltage be converted to third frequency three-phase voltage.
11. according to any transmission systems of claim 1-10, which is characterized in that further include:
Several transformers, with the first AC/AC converter plants correspond, the transformer respectively with the first AC/AC Converter plant is connected with the AC network, for adjusting the AC network output voltage;And/or
With the 2nd AC/AC converter plants correspond, the transformer respectively with the 2nd AC/AC converter plants and institute The connection of the second AC system is stated, for adjusting the second AC system input voltage.
CN201810632251.XA 2018-06-19 2018-06-19 A kind of transmission system Pending CN108649577A (en)

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Cited By (6)

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CN110112731A (en) * 2019-05-15 2019-08-09 全球能源互联网研究院有限公司 A kind of transmission system
CN110148945A (en) * 2019-05-15 2019-08-20 全球能源互联网研究院有限公司 A kind of ground connection isolating device based on low frequency power transmission system
CN110148963A (en) * 2019-05-15 2019-08-20 全球能源互联网研究院有限公司 A kind of more converting link AC-AC frequency converters based on energy storage
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CN113381415A (en) * 2021-07-13 2021-09-10 全球能源互联网研究院有限公司 Low-frequency power transmission voltage regulation method and system and electronic equipment

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CN110112731A (en) * 2019-05-15 2019-08-09 全球能源互联网研究院有限公司 A kind of transmission system
CN110148945A (en) * 2019-05-15 2019-08-20 全球能源互联网研究院有限公司 A kind of ground connection isolating device based on low frequency power transmission system
CN110148963A (en) * 2019-05-15 2019-08-20 全球能源互联网研究院有限公司 A kind of more converting link AC-AC frequency converters based on energy storage
CN110148945B (en) * 2019-05-15 2020-09-29 全球能源互联网研究院有限公司 Grounding isolation device based on low-frequency power transmission system
CN110112731B (en) * 2019-05-15 2024-02-13 全球能源互联网研究院有限公司 Power transmission system
CN110571841A (en) * 2019-07-10 2019-12-13 台州宏达电力建设有限公司台州经济开发区运检分公司 Variable frequency power transmission system
WO2021004479A1 (en) * 2019-07-10 2021-01-14 国网浙江省电力有限公司台州供电公司 Variable-frequency power transmission system
WO2021146995A1 (en) * 2020-01-22 2021-07-29 Abb Power Grids Switzerland Ag Apparatus and method of power transmission
CN113381415A (en) * 2021-07-13 2021-09-10 全球能源互联网研究院有限公司 Low-frequency power transmission voltage regulation method and system and electronic equipment

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