CN210137183U - Power transmission system - Google Patents
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- CN210137183U CN210137183U CN201920704688.XU CN201920704688U CN210137183U CN 210137183 U CN210137183 U CN 210137183U CN 201920704688 U CN201920704688 U CN 201920704688U CN 210137183 U CN210137183 U CN 210137183U
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Abstract
The utility model discloses a power transmission system, include: the power generation system comprises an offshore power utilization platform, an alternating current system, an offshore power supply platform, a new energy power generation base and a plurality of first AC/AC frequency conversion devices, wherein the first AC/AC frequency conversion devices are used for converting first frequency three-phase voltage in a power transmission line into second frequency three-phase voltage; the plurality of second AC/AC frequency conversion devices are used for converting second-frequency three-phase voltage in the power transmission line into first-frequency three-phase voltage, and the first frequency is smaller than the second frequency; and the power transmission cable is connected with the new energy power generation base and/or the alternating current system and/or the offshore power utilization platform and/or the offshore power supply platform through the first AC/AC frequency conversion device and/or the second AC/AC frequency conversion device respectively. The utility model discloses well transmission of electricity system improves transmission distance through adopting the transmission of electricity frequency that is less than first frequency to promote the transport capacity of circuit at double, utilizes new forms of energy electricity generation base to carry out the network deployment electricity generation simultaneously and can reduce the loss of energy approving, is favorable to the environmental protection construction, and the guarantee resident can healthy life.
Description
Technical Field
The utility model relates to an electric power system transmission of electricity field, concretely relates to transmission of electricity system.
Background
Energy is an important material basis for economic and social development, and the establishment of a safe, reliable, economic, efficient, clean and environment-friendly modern energy supply system is accelerated, so that the energy becomes a common strategic target of all countries in the world. In order to effectively solve the problems of energy exhaustion and environmental pollution, the development of new energy has become three challenges to energy safety, environmental pollution and climate change, and a necessary way for sustainable development of human society is realized. Wind power generation is one of the most mature and scaled power generation modes of a power generation device in new energy power generation technology. In some areas, wind power resource distribution and load centers are reversely distributed, and optimal allocation of resources is required to be realized through large-capacity long-distance power transmission.
At present, in an existing power transmission system, because an offshore platform provides electric energy for electric equipment, fuel oil power generation is usually carried out through oil drilling or coal power generation is carried out through coal mining, and the thermal power generation mode obviously has certain environmental pollution, influences the healthy life of residents, and can cause certain energy consumption on limited energy sources such as oil, coal and the like.
SUMMERY OF THE UTILITY MODEL
Therefore, the embodiment of the utility model provides a technical problem that solve lies in overcoming the remote transmission system of large capacity among the prior art and utilizing the thermal power mode to have certain environmental pollution, influences resident's healthy life to can lead to the fact certain energy resource consumption to limited energy such as oil and coal.
Therefore, the embodiment of the utility model provides a following technical scheme:
an embodiment of the utility model provides a power transmission system, include:
the offshore power utilization platform is used for providing electric energy for offshore power utilization equipment;
the alternating current system is used for supplying electric energy to electric equipment on the land;
the offshore power supply platform is used for providing electric energy for the offshore power utilization platform or carrying out communication networking with the communication system;
the new energy power generation base is used for providing electric energy for the offshore power utilization platform and the offshore power supply platform;
the first AC/AC frequency conversion devices are used for converting the first frequency three-phase voltage in the power transmission line into a second frequency three-phase voltage;
a plurality of second AC/AC frequency conversion devices for converting the second frequency three-phase voltage in the power transmission line into the first frequency three-phase voltage, the first frequency being less than the second frequency;
and the power transmission cable is connected with the new energy power generation base and/or the alternating current system and/or the offshore power utilization platform and/or the offshore power supply platform through the first AC/AC frequency conversion device and/or the second AC/AC frequency conversion device respectively.
Optionally, the new energy generation site comprises a plurality of offshore wind power plants and/or a plurality of offshore solar power plants and/or a plurality of offshore tidal power plants.
Optionally, each of the first AC/AC frequency conversion devices includes a first AC/AC frequency converter and a first switch set.
Optionally, each of the second AC/AC frequency conversion devices includes a second AC/AC frequency converter and a second switch set.
Optionally, the first AC/AC frequency converter and each of the second AC/AC frequency converters include at least one set of frequency conversion modules, and the frequency conversion modules include three frequency conversion units.
Optionally, the frequency conversion unit includes three frequency conversion bridge arms, each of the frequency conversion bridge arms includes an inductor and an H-bridge, a first end of the inductor is connected to a first end of the H-bridge, a second end of the inductor is used as an input end of the frequency conversion bridge arm, and a second end of the H-bridge is used as an output end of the frequency conversion bridge arm;
the input ends of the three frequency conversion bridge arms are respectively connected with the phase A, the phase B and the phase C of the new energy power generation base, and the output ends of the three frequency conversion bridge arms are connected with the switch group.
Optionally, the H-bridge comprises at least one fully-controlled H-bridge.
Optionally, the fully-controlled H-bridge includes two sets of power electronic device bridge arms and a dc capacitor, the two sets of power electronic device bridge arms are connected in parallel, each power electronic device bridge arm includes two power electronic devices connected in series, and the dc capacitor is connected in parallel with the power electronic device bridge arm.
Optionally, the power electronic device comprises an insulated gate bipolar transistor and an anti-parallel diode connected in parallel with the insulated gate bipolar transistor.
Optionally, the first switch group and the second switch group are circuit breakers and isolating switches arranged at two ends of the circuit breakers.
The embodiment of the utility model provides a technical scheme has following advantage:
the utility model provides a power transmission system, include: the power generation system comprises an offshore power utilization platform, an alternating current system, an offshore power supply platform, a new energy power generation base and a plurality of first AC/AC frequency conversion devices, wherein the first AC/AC frequency conversion devices are used for converting first frequency three-phase voltage in a power transmission line into second frequency three-phase voltage; the plurality of second AC/AC frequency conversion devices are used for converting second-frequency three-phase voltage in the power transmission line into first-frequency three-phase voltage, and the first frequency is smaller than the second frequency; and the power transmission cable is connected with the new energy power generation base and/or the alternating current system and/or the offshore power utilization platform and/or the offshore power supply platform through the first AC/AC frequency conversion device and/or the second AC/AC frequency conversion device respectively. The utility model discloses well transmission of electricity system improves transmission distance through adopting the transmission of electricity frequency that is less than first frequency to promote the transport capacity of circuit at double, utilizes new forms of energy electricity generation base to carry out the network deployment electricity generation simultaneously and can reduce the loss of energy approving, is favorable to the environmental protection construction, and the guarantee resident can healthy life.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the technical solutions in the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic view of a first configuration of a power transmission system according to an embodiment of the invention;
fig. 2 is a schematic view of a second structure of a power transmission system according to an embodiment of the present invention;
fig. 3 is a schematic view of a third structure of a power transmission system according to an embodiment of the present invention;
fig. 4 is a fourth schematic structural diagram of a power transmission system according to an embodiment of the present invention;
fig. 5 is a fifth structural schematic diagram of a power transmission system according to an embodiment of the present invention;
fig. 6 is a sixth schematic structural diagram of a power transmission system according to an embodiment of the present invention.
Reference numerals:
1-a new energy power generation base; 2-an offshore power supply platform; 3-offshore power utilization platform;
4-an alternating current system; 5-a first AC/AC frequency conversion device; 6-a second AC/AC frequency conversion device;
7-a power transmission cable; 8-a transformer; 51-a first AC/AC frequency converter;
52-a first switch set; 61-a second AC/AC frequency converter; 62-a second switch set;
511-a frequency conversion unit; 5111-inductance; 5112-H bridge.
Detailed Description
The technical solutions of the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings, and it is to be understood that the described embodiments are only some embodiments, but not all embodiments, of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
In the description of the embodiments of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are only for convenience of describing the embodiments of the present invention and simplifying the description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the embodiments of the present invention, it should be noted that unless explicitly stated or limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; the two elements may be directly connected or indirectly connected through an intermediate medium, or may be communicated with each other inside the two elements, or may be wirelessly connected or wired connected. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Furthermore, the technical features mentioned in the different embodiments of the invention described below can be combined with each other as long as they do not conflict with each other.
Example 1
An embodiment of the utility model provides a power transmission system is applied to electric power system alternating current transmission, as shown in fig. 1, include: the system comprises a new energy power generation base 1, an offshore power supply platform 2, an alternating current system 4, an offshore power utilization platform 3, a plurality of first AC/AC frequency conversion devices 5, a plurality of second AC/AC frequency conversion devices 6 and a power transmission cable 7, wherein,
the offshore power utilization platform 3 is used for providing electric energy for offshore power utilization equipment. The offshore power platform 3 is mainly installed on each island or island, and is used for performing production operations or other activities, for example: the offshore power utilization platform 3 can be used for exploiting oil on the island through oil drilling, the offshore power utilization platform 3 can also be used for exploiting coal resources on the island, and the offshore power utilization platform 3 needs to provide electric energy for electric equipment for production operation when the production operation is carried out. Because the sea islands are usually distributed in a relatively dispersed manner, and a certain distance also exists between the islands, in order to realize long-distance power transmission between the offshore power platforms 3 on the islands, the offshore power platforms 3 can be powered to perform low-frequency power transmission transformation, so that the transmission capacity can be increased, the transmission distance can be increased, the transformation cost can be saved, and the construction difficulty can be reduced, wherein the offshore power platforms 3 in the embodiment supply power to the electrical equipment in the offshore area.
And the alternating current system 4 is used for supplying electric energy to electric equipment on the land. The ac system 4 can be a land-based substation and/or power station and/or distribution substation, which primarily supplies electrical energy to land-based consumers, for example; the electricity consumption of the residents on the land is mainly supplied by the alternating current system 4. The distance between this alternating current system 4 and the offshore platform on sea is far away, is located the both sides of island respectively, and it is hopeful to separate the sea, carries out the low frequency transmission transformation through alternating current system 4 and offshore power supply platform 2 on the land and marine new forms of energy electricity generation base 1 on the sea, can increase transport capacity, increases transport distance, saves the transformation cost, reduces the construction degree of difficulty.
And the offshore power supply platform 2 is used for providing electric energy for the offshore power utilization platform 3 or carrying out communication networking with the communication system 4. The offshore power supply platform 2 is equivalent to a transformer substation arranged on a sea island, relays the electric energy output by the new energy power generation base 1, can transfer the electric energy output by the new energy power generation base 1 to the offshore power utilization platform 3 for use on one hand, and can perform alternating current networking with the alternating current system 4 on the other hand, so that the electric energy output by the offshore new energy power generation base 1 can be fully used.
The new energy power generation base 1 is used for providing electric energy for the offshore power utilization platform 3 and the offshore power supply platform 2. The new energy power generation base 1 can be a plurality of offshore wind power generation stations and/or a plurality of solar power generation stations and/or a plurality of tidal power generation stations, as the new energy power generation base 1 belongs to renewable energy sources, which are inexhaustible, comprehensively utilizes new energy sources such as wind energy, solar energy or tidal energy, can reduce consumption of other energy sources, can save other energy sources to a great extent, and the wind energy, the solar energy or the tidal energy belongs to clean energy sources, has less environmental pollution and is beneficial to ensuring healthy life of residents, therefore, the new energy power generation base 1 is utilized to collect power generation, can save energy sources and is beneficial to environmental protection construction. The frequency of the electric energy output by the new energy power generation base 1 is low-frequency.
In the present embodiment, as shown in fig. 2, the three-phase voltages of the new energy power generation base 1 are represented as a-phase voltages V, respectivelyAVoltage V of phase BBAnd a C-phase voltage VCThe phase difference of the three-phase voltage is 120 degrees; the converted three-phase voltages are respectively expressed as first voltages VMAA second voltage VMBAnd a third voltage VMCThe phase difference of the three-phase voltage is 120 degrees. In this embodiment, the new energy power generation base 1 is generally installed on an island, and outputs electric energy to the offshore power supply platform 2 and the offshore power utilization platform 3 by collecting electric energy output from the new energy power generation base 1.
In fig. 1, a plurality of first AC/AC frequency conversion devices 5 are used for converting a first frequency three-phase voltage in a power transmission line into a second frequency three-phase voltage, and the first frequency is smaller than the second frequency. In fig. 1, a first AC/AC frequency conversion device 5 is disposed between the offshore power supply platform 2 and the new energy power generation base 1, and is configured to convert a first frequency three-phase voltage output by the new energy power generation base 1 into a second frequency three-phase voltage, that is, to output electric energy output by the new energy power generation base 1 to the offshore power supply platform 2 at a low frequency; in fig. 1, a first AC/AC frequency conversion device 5 is disposed between the new energy power generation base 1 and the offshore power utilization platform 3, and is configured to convert a first frequency three-phase voltage output by the new energy power generation base 1 into a second frequency three-phase voltage, that is, to output electric energy output by the new energy power generation base 1 to the offshore power utilization platform 3 at a low frequency; in fig. 1, a first AC/AC frequency conversion device 5 disposed between the offshore power supply platform 2 and the offshore power utilization platform 3 is configured to convert a first frequency three-phase voltage converted by a second AC/AC frequency conversion device 6 disposed therebetween into a second frequency three-phase voltage, that is, low-frequency electric energy converted by the offshore power supply platform 2 is output to the offshore power utilization platform 3; in fig. 1, two first AC/AC frequency conversion devices 5 are disposed between the offshore power supply platform 2 and the AC system 4, wherein a second AC/AC frequency conversion device 6 is disposed near the offshore power supply platform 2, and is configured to convert the first frequency three-phase voltage converted by the second AC/AC frequency conversion device 6 disposed therebetween into a second frequency three-phase voltage, that is, to output the low-frequency electric energy converted by the offshore power supply platform 2 to the AC system 4, and wherein a second AC/AC frequency conversion device 5 is disposed near the AC system 4, and is configured to convert the first frequency three-phase voltage converted by the second AC/AC frequency conversion device 6 disposed therebetween into a second frequency three-phase voltage, that is, to output the low-frequency electric energy converted by the AC system 4 to the offshore power supply platform 2. The power transmission system in this embodiment is applied to large-capacity long-distance power transmission, the ranges of the first frequency and the second frequency are determined according to practical application, the preferred range of the first frequency is a low-frequency power transmission frequency of 50/3Hz, the second frequency is 75Hz or less, the first frequency is only required to be less than the second frequency, for example, the second frequency is 60Hz, and the first frequency can be any frequency less than 60 Hz. In the embodiment, because the power frequency of the power grid in China is 50Hz, the second frequency is 50Hz after frequency conversion; the first frequency was set to 50/3 Hz; with the increase of the transmission frequency, the current of the cable increases, the insulation performance is reduced, the 50/3Hz low-frequency transmission frequency is adopted after the influence of various factors such as insulation, cost and the like is comprehensively considered, and therefore the transmission capacity can be increased by 3 times, the line impedance is reduced, and the transmission distance is increased.
And the plurality of second AC/AC frequency conversion devices 5 are used for converting the second frequency three-phase voltage in the power transmission line into the first frequency three-phase voltage, and the first frequency is smaller than the second frequency. In fig. 1, two second AC/AC frequency conversion devices 6 are disposed between the offshore power supply platform 2 and the AC system 4, wherein the second AC/AC frequency conversion device 6 located beside the offshore power supply platform 2 is configured to convert a second frequency three-phase voltage output by the offshore power supply platform 2 into a first frequency three-phase voltage, that is, convert a power frequency output by the offshore power supply platform 2 into a low frequency, and wherein the second AC/AC frequency conversion device 6 located beside the AC system 4 is configured to convert the second frequency three-phase voltage output by the AC system 4 into the first frequency three-phase voltage, and convert the power frequency output by the AC system 4 into the low frequency.
In the present embodiment, as shown in fig. 2, each first/AC inverter device includes a first AC/AC inverter 51 and a first switch group 52. In fig. 1, for a first AC/AC frequency converter 5 disposed between a new energy power generation base 1 and an offshore power supply platform 2, an input end of a first AC/AC frequency converter 51 is connected to the new energy power generation base 1, and an output end of the first AC/AC frequency converter 51 is connected to the offshore power supply platform 2 through a first switch group 52 and a power transmission cable 7; the first AC/AC frequency conversion device 5 is arranged between the new energy power generation base 1 and the offshore power utilization platform 3, the input end of a first AC/AC frequency converter 51 of the first AC/AC frequency conversion device is connected with the new energy power generation base 1, and the output end of the first AC/AC frequency converter 51 of the first AC/AC frequency conversion device is connected with the offshore power utilization platform 3 through a first switch group 52 and a power transmission cable 7; the first AC/AC frequency conversion device 5 is arranged between the offshore power utilization platform 3 and the offshore power supply platform 2, the input end of a first AC/AC frequency converter 51 of the first AC/AC frequency conversion device is connected with the offshore power supply platform 2 through a second AC/AC frequency conversion device 6, and the output end of the first AC/AC frequency converter 51 of the first AC/AC frequency conversion device is connected with the offshore power utilization platform 3 through a first switch group 52 and a power transmission cable 7; the first AC/AC frequency conversion device 5 is arranged between the offshore power supply platform 2 and the AC system 4 and is positioned beside the AC system 4, the input end of a first AC/AC frequency converter 51 of the first AC/AC frequency conversion device is connected with the offshore power supply platform 2 through a second AC/AC frequency conversion device 6, and the output end of the first AC/AC frequency converter 51 of the first AC/AC frequency conversion device is connected with the AC system 4 through a first switch group 52 and a power transmission cable 7; and the first AC/AC frequency conversion device 5 is arranged between the offshore power supply platform 2 and the AC system 4 and is positioned beside the offshore platform, the input end of the first AC/AC frequency converter 51 is connected with the AC system 4 through the second AC/AC frequency conversion device 6, and the output end of the first AC/AC frequency converter 51 is connected with the offshore power supply platform 2 through the first switch group 52 and the power transmission cable 7. The first switch group 52 is arranged between the output end of the first AC/AC frequency converter 51 and the power transmission cable 7, so that on one hand, networking between alternating current grids of the power transmission system is facilitated, and when the switches in the first switch group 52 are turned on, the new energy power generation base 1 or the offshore power supply platform 2 or the alternating current system 4 is connected into the power transmission system; on the other hand, when the transmission cable 7 has a fault, the disconnection of the switch in the first switch group 52 can disconnect the transmission cable 7 from the new energy power generation base 1 or the offshore power supply platform 2 or the alternating current system 4, which is convenient for the maintenance and repair of the transmission cable 7. The first switch group 52 is allocated according to the requirements of system protection, maintenance and the like. In this embodiment, first switch group 52 includes at least a set of switch, and each group switch includes three switch, and each switch wherein all includes the circuit breaker and sets up in the isolator at circuit breaker both ends, and the input and an isolator of circuit breaker are connected promptly, and the output of circuit breaker is connected with an isolator again, and the concrete number of switch is rationally set up according to actual need can.
In the present embodiment, as shown in fig. 3, each second AC/AC frequency conversion device 6 includes a second AC/AC frequency converter 61 and a second switch group 62, wherein the second AC/AC frequency conversion device 6 disposed between the offshore power supply platform 2 and the AC system 4 and beside the offshore power supply platform 2 has an input end of the second AC/AC frequency converter 61 connected to the offshore power supply platform 2 and an output end of the second AC/AC frequency converter 61 connected to the AC system 4 through the second switch group 62, the power transmission cable 7 and the first AC/AC frequency conversion device 5. For the second AC/AC frequency conversion device 6 disposed between the offshore power supply platform 2 and the AC system 4 and beside the AC system 4, the input end of the second AC/AC frequency converter 61 is connected to the AC system 4, and the output end of the second AC/AC frequency converter 61 is connected to the offshore power supply platform 2 through the second switch group 62, the power transmission cable 7 and the first AC/AC frequency conversion device 5. In this embodiment, as shown in fig. 5, the first switch group 52 includes three groups of switches, which are respectively referred to as a first group of switches, a second group of switches, and a third group of switches, wherein a three-phase voltage output end of the first AC/AC frequency converter 51 is connected to a first end of the first group of switches, a second end of the first group of switches is connected to a first end of the second group of switches and a first end of the third group of switches, respectively, the second group of switches and the third group of switches are connected in parallel, a second end of the second group of switches is connected to one second offshore power supply platform 2, a second end of the third group of switches is connected to another offshore power supply platform 2, and the first AC/AC frequency converter 51 can be connected to the two offshore power supply platforms 2 through two groups of switches (the second group of switches and the.
The first AC/AC frequency converter 51 or the second AC/AC frequency converter 61 includes at least one set of frequency conversion modules, as shown in fig. 4, the frequency conversion module in the first AC/AC frequency converter 51 includes three frequency conversion units, an input end of the frequency conversion unit is connected to the AC power grid of the new energy power generation base 1 or the offshore power supply platform 2 or the AC system 4, and an output end of the frequency conversion unit is connected to the switch set. In this embodiment, as shown in fig. 4, the first AC/AC frequency converter includes a set of frequency conversion modules, each of which includes three frequency conversion units, each of which includes an inductor and an H-bridge, a first end of the inductor is connected to a first end of the H-bridge, a second end of the inductor is used as an input end of the frequency conversion bridge, and a second end of the H-bridge is used as an output end of the frequency conversion bridge; the input ends of the three frequency conversion bridge arms are connected with the phase A, the phase B and the phase C of the new energy power generation base 1. Of course, the input ends of the three frequency conversion bridge arms can also be connected with the A phase, the B phase and the C phase of the offshore power supply platform 2 or the alternating current system 4. The output ends of the three frequency conversion bridge arms are connected with a switch group, and the switch group is connected with the offshore power utilization platform 3. In fig. 4, the first AC/AC frequency converter 21 contains 9 legs consisting of cascaded H-bridge modules, from which a three-phase low-frequency alternating current is drawn from a neutral point.
The H-bridge includes at least one fully-controlled H-bridge, and in this embodiment, as shown in fig. 4, the H-bridge includes one fully-controlled H-bridge, the fully-controlled H-bridge includes two sets of power electronic device bridge arms and a dc capacitor, the two sets of power electronic device bridge arms are connected in parallel, each power electronic device bridge arm includes two power electronic devices connected in series, and the dc capacitor is connected in parallel with the power electronic device bridge arms; the power electronic device includes an Insulated Gate Bipolar Transistor (IGBT) and an anti-parallel diode connected in parallel with the IGBT. Of course, in other embodiments, the power electronic device may also be a metal-oxide-semiconductor (MOS) field effect transistor (MOS) or a Bipolar Junction Transistor (BJT), and the like, and may be configured as needed. Since one fully-controlled H-bridge can bear a limited voltage class and the voltage of the ac power grid is high, multiple fully-controlled H-bridges are required to be cascaded, as shown in fig. 5, the H-bridge includes two fully-controlled H-bridges 2112.
In other embodiments, the first AC/AC inverter 51 may include multiple sets of inverter modules, for example; the first AC/AC frequency converter 51 comprises two groups of frequency conversion modules, i.e. two groups of frequency conversion modules are connected in parallel.
The first AC/AC frequency conversion device 5 or the second AC/AC frequency conversion device 6 can realize the change of the low-frequency networking operation mode between the multi-terminal alternating current system 4 and the offshore power supply platform 2 by controlling the three-phase low-frequency switch, and the change of the networking mode and the realization of the fault isolation function are included. In the multi-terminal low-frequency network, the power flow in the network can be regulated by controlling the first AC/AC frequency converter 51 or the second AC/AC frequency converter 61, so that the power flow control function is realized.
And the power transmission cable 7 is connected with the new energy power generation base 1 and/or the alternating current system 4 and/or the offshore power utilization platform 3 and/or the offshore power supply platform 2 through the first AC/AC frequency conversion device 5 and/or the second AC/AC frequency conversion device 6. The function of the power transmission cable 7 is to establish a connection relationship among the new energy power generation base 1, the offshore power supply platform 2, the offshore power utilization platform 3, and the ac system 4 in order to realize the function of low-frequency transmission.
In the power transmission system in this embodiment, the first frequency three-phase voltage in the power transmission line is converted into the second frequency three-phase voltage by the plurality of first AC/AC frequency conversion devices 5, and the second frequency three-phase voltage in the power transmission line is converted into the first frequency three-phase voltage by the plurality of second AC/AC frequency conversion devices 6, where the first frequency is smaller than the second frequency; and then low frequency transmission is performed through the power transmission cable 7, and the power transmission system improves the transmission distance by multiplying the transmission capacity of the line by the power transmission frequency lower than the first frequency.
In order to satisfy the adjustment between different voltage levels, on the basis of the above power transmission system, as shown in fig. 6, the power transmission system further includes: a plurality of transformers 6 arranged in the transmission line for adjusting an input voltage or an output voltage of the transmission line. In fig. 6, a transformer 6 disposed between the new energy power generation base 1 and the first AC/AC frequency conversion device 5 is used to adjust the output voltage of the new energy power generation base 1, and in fig. 6, a transformer 6 disposed between the second AC/AC frequency conversion device 6 and the first AC/AC frequency conversion device 5 is used to adjust the output voltage after frequency conversion of the offshore power supply platform 2 or the AC system 4. For example: the voltage of the new energy power generation base 1 is 220V, the three-phase alternating-current voltage of 220V is boosted to 10kV through the transformer 6, so the transformer 6 is the step-up transformer 6, then the three-phase voltage is converted into the three-phase voltage, the low-frequency transmission is carried out by adopting the high-voltage transmission line, and the high-voltage transmission reduces the heat loss caused by current and reduces the material cost of long-distance transmission. Of course, in other embodiments, the transformer 6 may also be boosted to a different voltage, for example: 500kV or 750kV, and can be reasonably set as required; the transformer 6 can also step down to different voltage values, for example, the voltage value of the three-phase alternating-current voltage is 220kV, and the voltage can be reduced to 110kV, 35kV, 10kV or 220V through the transformer 6, and the voltage can be reasonably set according to needs.
The embodiment of the utility model provides an in power transmission system, through the electric energy of the marine new forms of energy electricity generation base 1 output of comprehensive utilization, give marine power supply platform 2 or marine power consumption platform 3 with its long-range low frequency transmission, then, carry out the low frequency network deployment with the help of marine power supply platform 2 and AC system 4, can make the new forms of energy of marine new forms of energy electricity generation base 1 output obtain make full use of, and then practiced thrift the consumption of other energy, bring very big facility for marine power consumption platform 3, the phenomenon of marine power consumption platform 3 because of the electric energy lack influences its normal work has been avoided.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications can be made without departing from the scope of the invention.
Claims (10)
1. A power transmission system, comprising:
the offshore power utilization platform is used for providing electric energy for offshore power utilization equipment;
the alternating current system is used for supplying electric energy to electric equipment on the land;
the offshore power supply platform is used for providing electric energy for the offshore power utilization platform or carrying out communication networking with the communication system;
the new energy power generation base is used for providing electric energy for the offshore power utilization platform and the offshore power supply platform;
the first AC/AC frequency conversion devices are used for converting the first frequency three-phase voltage in the power transmission line into a second frequency three-phase voltage;
a plurality of second AC/AC frequency conversion devices for converting the second frequency three-phase voltage in the power transmission line into the first frequency three-phase voltage, the first frequency being less than the second frequency;
and the power transmission cable is connected with the new energy power generation base and/or the alternating current system and/or the offshore power utilization platform and/or the offshore power supply platform through the first AC/AC frequency conversion device and/or the second AC/AC frequency conversion device respectively.
2. An electric power transmission system according to claim 1, characterized in that the new energy power generation base comprises a plurality of offshore wind power plants and/or a plurality of offshore solar power plants and/or a plurality of offshore tidal power plants.
3. The power transmission system of claim 1, wherein each of the first AC/AC frequency conversion devices comprises a first AC/AC frequency converter and a first switch set.
4. A power transmission system according to claim 3, characterized in that each of said second AC/AC frequency conversion means comprises a second AC/AC frequency converter and a second switch group.
5. The power transmission system of claim 4, wherein the first AC/AC frequency converter and each of the second AC/AC frequency converters comprise at least one set of frequency conversion modules, the frequency conversion modules comprising three frequency conversion units.
6. The power transmission system according to claim 5, wherein the frequency conversion unit comprises three frequency conversion bridge arms, each of which comprises an inductor and an H-bridge, a first end of the inductor being connected to a first end of the H-bridge, a second end of the inductor being an input end of the frequency conversion bridge arm, and a second end of the H-bridge being an output end of the frequency conversion bridge arm;
the input ends of the three frequency conversion bridge arms are respectively connected with the phase A, the phase B and the phase C of the new energy power generation base, and the output ends of the three frequency conversion bridge arms are connected with the switch group.
7. The power transmission system of claim 6, wherein the H-bridge comprises at least one fully-controlled H-bridge.
8. The power transmission system of claim 7, wherein the fully-controlled H-bridge comprises two sets of power electronics legs connected in parallel, each of the power electronics legs comprising two power electronics in series, and a DC capacitor connected in parallel with the power electronics legs.
9. The power transmission system of claim 8, wherein the power electronics device comprises an insulated gate bipolar transistor and an anti-parallel diode connected in parallel with the insulated gate bipolar transistor.
10. The power transmission system of claim 4, wherein the first and second switch sets are circuit breakers and disconnectors disposed across the circuit breakers.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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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 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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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 |
| 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 |
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