JP2012196118A - Power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power generation system which improves the reliability of power transmission while suppressing the increase of the installation lengths of power transmission lines.SOLUTION: A solar power generation system (power generation system) 1 includes: multiple solar power generation units 10; high voltage power transmission lines 20a and 20b arranged parallel to the multiple solar power generation units 10 and with which the multiple solar power generation units 10 are connected; and switches 23, each of which switches the connection of the solar power generation unit 10 between the high voltage power transmission lines 20a and the high voltage power transmission lines 20b.

Description

  The present invention relates to a power generation system, and more particularly, to a power generation system including a plurality of power generation units and a power transmission line arranged in parallel with the power generation units.

  For example, a solar power generation system (power generation system) using solar energy is generally of a type that generates power by installing a plurality of solar cell modules in an array on one land. In recent years, a large-scale power generation system in which a large amount of this solar cell array is spread over a large amount of land has been attracting attention, and MW (megawatt) -class power generation systems have been installed around the world.

  As described above, when a plurality of solar cell modules are installed in an array on a single land to generate power, the larger the power generation, the larger the land required, making it difficult to secure the land. For example, in the case of a system of about 10 MW, a vast land of about 400 m × 700 m is required.

  In such a system, for example, the system is divided every 1 MW to 2 MW, and solar cell modules are installed in an array for each region. In addition, a primary transformer that boosts the generated power is arranged at the center of each region, and each primary transformer is connected in parallel to one bus or the like. Then, the buses and the like are connected (connected) to the power system, and the generated power is transmitted. In this configuration, each primary transformer is provided with a transmission line for transmitting generated power to a bus or the like, so even if an accident (such as a short-circuit accident or a ground fault) occurs on one transmission line, Transmission of the transmission line is continued.

  On the other hand, a solar power generation system of a type that generates power by arranging solar power generation units (power generation units) composed of a plurality of solar cell modules on an expressway or the like is also known (see, for example, Patent Document 1). . Patent Document 1 discloses a solar power generation system that includes a plurality of solar power generation units configured by a plurality of solar cell modules and a high-voltage power transmission line that transmits power generated by the solar power generation units. Has been. In this solar power generation system, a plurality of solar cell modules are juxtaposed on a high-voltage power transmission line and are elongated.

JP 2010-98797 A

  However, in Patent Document 1, power is transmitted through one high-voltage transmission line, so that when an accident occurs in the high-voltage transmission line, the high-voltage transmission line is completely stopped and power transmission is completely stopped. There is a problem.

  Therefore, it is also conceivable to apply the above-described system in which a power transmission line is provided for each primary transformer to Patent Document 1. That is, it is conceivable to provide a high-voltage transmission line for each photovoltaic power generation unit. However, when power generation is performed in parallel on an expressway or the like, it is necessary to arrange a plurality of solar cell modules in an elongated shape, and one solar power generation unit has a length of, for example, 1000 m. For this reason, when a large number of solar power generation units are arranged along a highway or the like, there is a problem that the wiring length of the high voltage transmission line becomes extremely long.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to improve the reliability of power transmission while suppressing an increase in the length of the power transmission line. Is to provide a simple power generation system.

  To achieve the above object, a power generation system according to the present invention is provided in parallel with a plurality of power generation units including a DC power supply unit that generates power using natural energy and a plurality of power generation units arranged along an elongated path. The first power transmission line and the second power transmission line to which each of the plurality of power generation units is connected, and the first connection switching unit that switches the connection of the power generation unit to the first power transmission line and the second power transmission line.

  In this power generation system, the power transmission path of power can be switched by providing the first power transmission line, the second power transmission line, and the first connection switching unit.

  In the power generation system, the power generation unit may include a conversion unit that converts DC power output from the DC power supply unit into AC power.

  In the power generation system in which the power generation unit includes a conversion unit, the power generation unit includes a transformer that boosts the AC voltage output from the conversion unit, and the first power transmission line and the second power transmission line include a high voltage power transmission line. Good.

  In Japan, a high-voltage transmission line generally means a transmission line with a transmission voltage of 1000 V to 7000 V, but in this specification, a high-voltage transmission line has a transmission voltage of about 1000 V to 35000 V. Refers to the transmission line. For example, in Japan, the distribution lines in the city are high-voltage transmission lines, and the transmission voltage is mainly 6600V.

  In the power generation system in which the first power transmission line and the second power transmission line include a high-voltage power transmission line, preferably, a plurality of power generation units, a plurality of units including a first power transmission line, a second power transmission line, and a first connection switching unit; , A secondary transformer for boosting the AC voltage from the unit, a first special high-voltage transmission line and a second special high-voltage transmission line to which the secondary transformer is connected, a first special high-voltage transmission line and a second special high-voltage transmission A second connection switching unit that switches the connection of the secondary transformer to the electric wire. If comprised in this way, the transmission path of the electric power in an extra high voltage power transmission line can be switched.

  In the present specification, the extra high voltage transmission line refers to a transmission line having a transmission voltage exceeding 7000V. However, the transmission voltage of the extra high voltage transmission line is higher than the transmission voltage of the high voltage transmission line. Examples of the transmission voltage of the extra high voltage transmission line include 22 kV, 33 kV, 66 kV, 77 kV, 110 kV, 154 kV, 275 kV, and 500 kV. Generally, it is 22 kV or 33 kV, but at this level, there are many countries that use distribution lines (high voltage transmission lines). The transmission voltage of the high-voltage tower is 66 kV or 77 kV. In addition, 275 kV and 500 kV are the mainstream for the transmission voltage from nuclear power plants and the like.

  In the power generation system including the secondary transformer, two secondary transformers are provided for each unit, and the low voltage sides of the pair of secondary transformers are connected to the low voltage sides of the pair of secondary transformers. Alternatively, a bypass circuit breaker for disconnecting may be provided.

  In the power generation system in which the power generation unit includes a conversion unit, a plurality of power generation units are connected, and a high voltage transmission line to which an AC voltage output from the conversion unit and boosted by a transformer is supplied, and a high voltage transmission line And a secondary transformer that boosts the AC voltage of the first power transmission line and outputs it to the first power transmission line and the second power transmission line, wherein the first power transmission line and the second power transmission line are the first special high voltage power transmission line and the second special high voltage. Each transmission line may be included.

  In the power generation system including the first special high-voltage transmission line and the second special high-voltage transmission line, AC power from the secondary transformer is converted to DC power and supplied to the first special high-voltage transmission line and the second special high-voltage transmission line. An ACDC conversion unit may be further provided.

  In this case, the ACDC converter preferably includes a thyristor valve.

  In the power generation system, the power generation unit may include a DCDC converter that boosts DC power output from the DC power supply unit.

  In the power generation system in which the power generation unit includes a DCDC converter, the first power transmission line and the second power transmission line may include a high-voltage power transmission line.

  In the power generation system in which the power generation unit includes a DCDC converter and the first power transmission line and the second power transmission line include a high-voltage power transmission line, preferably, the plurality of power generation units, the first power transmission line, the second power transmission line, and the first connection A plurality of units including a switching unit, a secondary DCDC converter that boosts a DC voltage from the unit, a first special high voltage transmission line and a second special high voltage transmission line to which the secondary DCDC converter is connected, and a first special high voltage A second connection switching unit that switches connection of the secondary DCDC converter to the power transmission line and the second extra-high voltage power transmission line. If comprised in this way, the transmission path of the electric power in an extra high voltage power transmission line can be switched.

  In a power generation system in which the power generation unit includes a DCDC converter, a plurality of power generation units are connected, a high voltage transmission line to which a DC voltage boosted by the DCDC converter is supplied, and a DC voltage from the high voltage transmission line is boosted And a secondary DCDC converter that outputs to the first power transmission line and the second power transmission line, and the first power transmission line and the second power transmission line include the first special high-voltage power transmission line and the second special high-voltage power transmission line, respectively. You may go out.

  In the power generation system in which the power generation unit includes a DCDC converter, the DCDC converter preferably includes a step-up chopper circuit.

  In the power generation system including the secondary DCDC converter, the secondary DCDC converter preferably includes a step-up chopper circuit.

  In the power generation system including the first special high voltage transmission line and the second special high voltage transmission line, the first special high voltage transmission line and the second special high voltage transmission line may be overhead transmission lines.

  In the power generation system including the first special high voltage transmission line and the second special high voltage transmission line, the first special high voltage transmission line and the second special high voltage transmission line include the first special high voltage transmission line and the second special high voltage transmission line. An opening / closing station that divides into a plurality of sections may be provided.

  In the power generation system provided with the switching station, the switching station may be configured using a double bus 4 bus tie system or a double bus 2 bus tie system.

  In the power generation system in which the first special high-voltage power transmission line and the second special high-voltage power transmission line are overhead power transmission lines or a power generation system provided with a switch station, the power generation unit boosts DC power output from the DC power supply unit. The DCDC converter may include a boost chopper circuit.

  In the power generation system, preferably, each of the first power transmission line and the second power transmission line has a power transmission capacity that is equal to or greater than a total of the rated power generation capacities of the plurality of power generation units. If comprised in this way, all the electric power generated with the several electric power generation unit can be transmitted by any one of a 1st power transmission line and a 2nd power transmission line.

  In the power generation system including the unit, the first special high-voltage power transmission line, and the second special high-voltage power transmission line, each of the first special high-voltage power transmission line and the second special high-voltage power transmission line preferably has a rated power generation capacity of a plurality of units. The transmission capacity is more than the total. If comprised in this way, all the electric power generated with the some unit can be transmitted by any one of a 1st special high voltage power transmission line and a 2nd special high voltage power transmission line.

  In this case, during normal operation, the electric power generated by the plurality of units may be transmitted through one of the first special high voltage transmission line and the second special high voltage transmission line.

  In the power generation system including the unit, the first special high-voltage transmission line, and the second special high-voltage transmission line, the electric power generated by the plurality of units during normal operation is supplied to the first special high-voltage transmission line and the second special high-voltage transmission line. It may be distributed and transmitted.

  The power generation system may further include a gantry on which the DC power supply unit is installed. In addition, the first power transmission line and the second power transmission line may be attached to a gantry. Furthermore, the first power transmission line and the second power transmission line may be attached to the gantry in a state of being accommodated in the pipeline. In addition, when attaching a 1st power transmission line and a 2nd power transmission line to a mount frame, power cables, such as a CV cable (bridged polyethylene insulation vinyl sheath cable), may be sufficient as a 1st power transmission line and a 2nd power transmission line.

  In the above power generation system, the DC power supply unit preferably includes a solar cell unit that generates power using solar energy.

  As described above, according to the present invention, it is possible to switch the power transmission path by providing the first power transmission line, the second power transmission line, and the first connection switching unit. As a result, even if an accident occurs on one of the first power transmission line and the second power transmission line, the power generated by the plurality of power generation units is transmitted by the other of the first power transmission line and the second power transmission line. Can do. That is, it is possible to suppress power transmission from being completely stopped when an accident occurs, and to improve power transmission reliability.

  Moreover, since it is not necessary to provide a power transmission line for each power generation unit in order to improve the reliability of power transmission, even if a large number of power generation units are installed continuously over a long distance, the wiring length of the power transmission line is long. It can be suppressed.

It is the schematic which showed the whole structure of the solar energy power generation system by 1st Embodiment of this invention. It is the figure which showed the circuit breaker periphery of FIG. It is the figure which showed the structure of the photovoltaic power generation unit of FIG. It is the figure which showed the parallel structure of the strings of FIG. It is the perspective view which showed the example of installation of the solar power generation system of FIG. It is sectional drawing of FIG. It is the perspective view which showed the example of installation of the solar power generation system of FIG. It is the perspective view which showed the example of installation of the solar power generation system of FIG. It is a figure for demonstrating operation | movement of the solar energy power generation system of FIG. It is a figure for demonstrating operation | movement of the solar energy power generation system of FIG. It is the schematic which showed the whole structure of the solar energy power generation system by 2nd Embodiment of this invention. It is the figure which showed a pair of transformer periphery of FIG. It is a figure for demonstrating operation | movement of the solar energy power generation system of FIG. It is a figure for demonstrating operation | movement of the solar energy power generation system of FIG. It is the schematic which showed the whole structure of the solar energy power generation system by 3rd Embodiment of this invention. It is the figure which showed the structure of the intermediate | middle switchyard of FIG. It is the figure which showed the structure of the receiving end of FIG. It is a figure for demonstrating operation | movement of the solar energy power generation system of FIG. It is a figure for demonstrating operation | movement of the solar energy power generation system of FIG. It is a figure for demonstrating operation | movement of the solar energy power generation system of FIG. It is the schematic which showed the whole structure of the solar energy power generation system by 4th Embodiment of this invention. It is the schematic which showed the whole structure of the solar energy power generation system of FIG. It is the schematic which showed the whole structure of the solar energy power generation system by 5th Embodiment of this invention. It is the figure which showed a pair of transformer periphery of the solar energy power generation system by the 1st modification of this invention. It is the figure which showed the structure of the solar energy power generation system by the 2nd modification of this invention. It is the figure which showed the structure of the solar energy power generation system by the 3rd modification of this invention. It is the figure which showed the structure of the intermediate | middle switchyard of the solar energy power generation system by the 4th modification of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
First, with reference to FIGS. 1-8, the structure of the solar power generation system (power generation system) 1 by 1st Embodiment of this invention is demonstrated. Here, a case where the rated power generation capacity of the solar power generation system 1 is about 10 MW will be described.

  As shown in FIG. 1, the solar power generation system 1 includes a plurality of solar power generation units (power generation units) 10 and high-voltage power transmission lines 20 a and 20 b (first power transmission lines) arranged in parallel with the plurality of solar power generation units 10. And a second power transmission line). Moreover, the circuit breaker 21, the switch 22, and the switching switch (1st connection switching part) 23 are provided between the solar power generation unit 10 and the high voltage power transmission line 20a and 20b.

  The solar power generation unit 10 includes a solar cell unit (DC power supply unit) 11 that generates power using solar energy, a conversion unit 12 that converts DC power output from the solar cell unit 11 into AC power, and a conversion unit. 12 and a transformer 13 that boosts the AC voltage output from 12. Moreover, ten photovoltaic power generation units 10 are provided, for example. Further, the solar power generation unit 10 is disposed along, for example, an expressway (elongated route), and the solar cell unit 11 is installed so that the longitudinal direction of the solar cell unit 11 is along a sound insulation wall of the expressway.

  The solar cell unit 11 is a unit in which strings formed by connecting a solar cell module or a plurality of solar cell modules in series are connected in parallel. The detailed structure of the solar cell unit 11 will be described later.

  The conversion unit 12 is a PCS (power conditioner system) such as an inverter device, and one conversion unit 12 is provided for one solar cell unit 11. Moreover, the conversion part 12 is comprised so that the DC voltage output from the solar cell unit 11 may be converted into AC400V.

  The transformer 13 is configured to step up AC400V output from the converter 12 to AC6600V. Further, for example, four converters 12 are connected to the transformer 13 in parallel. The number of conversion units 12 connected to one transformer 13 is set based on the rated capacity of the conversion unit 12, and the rated capacity of the conversion unit 12 is the same as the rated capacity of the transformer 13, for example. In some cases, one converter 12 may be connected to one transformer 13.

  For example, if one transformer 13 having a rated capacity of 1000 kW is provided for four converters 12 having a rated capacity of 250 kW, and ten transformers 13 (solar power generation units 10) are continuously installed, A total of about 10 MW of the solar power generation system 1 is obtained.

  The circuit breaker 21 is automatically opened when an accident (short-circuit accident or ground fault) occurs, and instantaneously interrupts between the transformer 13 (solar power generation unit 10) and the high-voltage power transmission lines 20a and 20b. Is for. The switch 22 is for an operator to open after the circuit breaker 21 is opened to perform maintenance or the like below the circuit breaker 21 (solar power generation unit 10). That is, the switch 22 is for preventing another operator from closing the circuit breaker 21 accidentally and causing an operator to receive an electric shock. 2, the switch 22 is preferably provided on both sides of the circuit breaker 21 (both between the circuit breaker 21 and the switching switch 23 and between the circuit breaker 21 and the transformer 13). However, in this specification, only the switch 22 between the circuit breaker 21 and the switching switch 23 is illustrated for simplification of the drawing. The switching switch 23 is for connecting the transformer 13 (solar power generation unit 10) to one of the high-voltage power transmission lines 20a and 20b.

  Further, for example, an instrument transformer (not shown) is provided between the circuit breaker 21 and the switch 22 for detecting an overcurrent (abnormal current) flowing through the circuit breaker 21 or a ground fault current. Yes. A protection relay (not shown) is connected to the instrument transformer. An instrument transformer and a protection relay are provided for each circuit breaker 21. Further, when an overcurrent or the like flows through the instrument transformer, the protection relay is activated to output a trip signal to the circuit breaker 21. In this way, the protection relay outputs a trip signal when an accident occurs in the high-voltage transmission line 20a or 20b or when the power supply / demand balance with the load is lost and the frequency fluctuation cannot be suppressed. Thus, the circuit breaker 21 is opened and closed. In addition, the connection switching operation of the switching switch 23 after the circuit breaker 21 is automatically opened includes a method of separately providing a control unit (not shown) and automatically operating the switching switch 23 with a motor, Although a method in which a signal is sent from the control unit to the central power supply command station and an operator remotely operates from the central power supply command station is assumed, there is no particular limitation.

  The high-voltage power transmission lines 20 a and 20 b are cables for connecting (collecting) electric power (three-phase 6600 V) from the plurality of transformers 13 in parallel, and are arranged in parallel with the solar power generation unit 10 along the longitudinal direction of the solar cell unit 11. It is installed. The high voltage transmission lines 20a and 20b are installed along a highway, for example, and have a function of transmitting a high voltage output from each transformer 13. In addition, you may comprise so that loads, such as an illumination light, may be installed along a highway, and the generated electric power of the photovoltaic power generation unit 10 may be supplied to a load. Further, the high voltage power transmission lines 20a and 20b may be connected to a power company system. When the solar power generation unit 10 is generating power, the generated power of the solar power generation system 1 is supplied to the load. When the solar power generation unit 10 is not generating power, it receives power supply from the electric power company to the load. You may comprise so that electric power supply may be performed.

  The high voltage transmission lines 20a and 20b each have a transmission capacity of 10 MVA. That is, each of the high-voltage power transmission lines 20a and 20b has a power transmission capacity equal to or greater than the rated power generation capacity of the entire solar power generation system 1 (the total of the rated power generation capacity of the plurality of solar power generation units 10).

  Next, the configuration of the photovoltaic power generation unit 10 will be described with reference to FIGS. 3 and 4. As shown in FIG. 3, the solar power generation unit 10 has, for example, two solar cell modules (for example, thin film solar cell modules) 30 having an output of 140 W connected in series to form strings 31, and 1000 strings 31 are connected in parallel. Is.

  Further, as shown in FIG. 4, in order to connect two solar cell modules 30 in series, a positive terminal of the terminal box 32 of one solar cell module 30 and a negative terminal of the terminal box 32 of the other solar cell module 30. Are connected by a cable 33 to form a string 31. In order to sequentially connect the strings 31 in parallel, the cables 34 connected to the minus terminal of the terminal box 32 of one solar cell module 30 are repeatedly connected via the parallel connection connector 36. Similarly, the connection between the cables 35 connected to the plus terminals of the terminal box 32 of the other solar cell module 30 is repeated via the parallel connection connector 36.

  Further, a backflow prevention diode 37 is installed between the parallel connection connectors 36 that connect the pluses in parallel. The backflow prevention diode 37 has a role of preventing a backflow of current when a part of the solar cell module 30 is shaded or when the power generation amount of the solar cell module 30 is insufficient due to some trouble.

  Then, two sets of two series strings 31 as shown in FIG. 3 that are connected in parallel in the horizontal direction are installed in two sets, and DC power is input to the converter 12 from each through the cable 38. In this way, the solar power generation unit 10 including the solar cell unit 11, the conversion unit 12, and the transformer 13 (see FIG. 1) in which 2000 solar cell modules 30 are connected in 2 series × 1000 parallel is configured. Has been.

  By adopting such a connection structure, parallel connection can be performed only by the parallel connection connector 36, and a generally used connection box or current collection box is not necessary.

  The solar power generation unit 10 (11 × 4 solar cell units) as described above is about 2.8 m × width when a general module of 1.4 m × 1 m is used as the solar cell module 30. It becomes about 1000m × 4. The solar power generation system 1 in which ten solar power generation units 10 are continuously installed has a total length of 40 km, and is arranged in parallel with the solar power generation system 1 (in other words, in parallel with the solar cell module 30). The length of the voltage transmission lines 20a and 20b is also 40 km. In addition, if it is 6600V alternating current, even if it flows through the cable to about 50 km, a power loss does not become a problem practically.

  When the high voltage transmission lines 20a and 20b are installed on a highway, as shown in FIGS. 5 and 6, the high voltage transmission lines 20a and 20b are accommodated inside the pipeline 40, and the road is elevated. You may install in the lower part of the road. If the road is laid on land, it may be installed in the basement on the side. In addition, as shown in FIG. 5, you may install the solar cell unit 11 in the mount frame 41 provided along the road.

  Further, as shown in FIGS. 7 and 8, the pipeline 40 (high voltage power transmission lines 20 a and 20 b) may be attached to the gantry 41. Further, the pipe line 40 is not always necessary, and the high-voltage power transmission lines 20a and 20b may be directly attached to the gantry 41. In addition, since there are many cases where there are no side walls or the like on the highway in the world, and the installation of the gantry 41 is often necessary, the configuration in which the pipe line 40 or the like is attached to the gantry 41 is effective.

  Next, the operation of the solar power generation system 1 will be described with reference to FIGS. 9 and 10. During normal operation (a state in which no accident has occurred), as shown in FIG. 9, the circuit breaker 21 and the switch 22 are closed. Moreover, the switching switch 23 connects the transformer 13 (solar power generation unit 10) alternately to the high-voltage power transmission lines 20a and 20b. As a result, the high voltage transmission lines 20a and 20b transmit 5 MW of power.

  Here, for example, when an accident (such as a short-circuit accident or a ground fault) occurs in the high-voltage power transmission line 20b, a protection circuit (instrument transformer and instrument protection circuit for the photovoltaic power generation unit 10 connected to the high-voltage power transmission line 20b side) A configuration with a protective relay (not shown) detects an accident current, and a trip signal is output to the circuit breaker 21, whereby the circuit breaker 21 is opened. Thereby, the transformer 13 (solar power generation unit 10) connected to the high voltage transmission line 20b is disconnected from the high voltage transmission line 20b.

  And a control signal is output to the motor which drives the switching switch 23 from a control part, and the connection of the switching switch 23 connected to the open circuit breaker 21 switches. Thereafter, the circuit breaker 21 is closed by reclosing. Thereby, as shown in FIG. 10, all the transformers 13 (solar power generation unit 10) are connected to the high voltage power transmission line 20a. For this reason, the high voltage transmission line 20a transmits 10 MW of power until the high voltage transmission line 20b is restored.

  In addition, when an accident occurs, a signal may be transmitted from the control unit to the management device of the maintenance company via the Internet or the like so that the maintenance worker is immediately notified that the accident has occurred.

  Thereafter, when the high-voltage power transmission line 20b is restored, the circuit breaker 21 and the switching switch 23 are reversed in the reverse order due to the operation by the maintenance worker, the remote operation from the central power supply command station, or the driving of the motor by the control unit. Operate. Thereby, the transformer 13 (solar power generation unit 10) is alternately connected to the high-voltage power transmission lines 20a and 20b.

  In the present embodiment, as described above, the high-voltage power transmission line 20a and the high-voltage power transmission line 20b, and the switching switch 23 that switches the connection of the photovoltaic power generation unit 10 to the high-voltage power transmission line 20a and the high-voltage power transmission line 20b. Provide. Thereby, even if an accident occurs on one of the high voltage transmission lines 20a and 20b, the power generated by the plurality of photovoltaic power generation units 10 can be transmitted by the other of the high voltage transmission lines 20a and 20b. it can. That is, it is possible to suppress power transmission from being completely stopped when an accident occurs, and to improve power transmission reliability.

  Moreover, since it is not necessary to provide a high-voltage power transmission line for each photovoltaic power generation unit 10 in order to improve the reliability of power transmission, even when a large number of photovoltaic power generation units 10 are continuously installed over a long distance. And it can suppress that the wiring length of a high voltage power transmission line becomes long.

  In addition, according to the present embodiment, it is possible to supply power to a non-electrified village where infrastructure is not established. Furthermore, by installing the solar power generation system 1 on the expressway, there is no need for a large and cohesive land, and it is easy to install on an existing expressway.

  Further, as described above, each of the high-voltage power transmission lines 20 a and 20 b has a power transmission capacity that is equal to or greater than the total of the rated power generation capacity of the solar power generation unit 10. Thus, even if an accident occurs on one of the high-voltage power transmission lines 20a and 20b, all of the power generated by the plurality of solar power generation units 10 is transmitted by the other of the high-voltage power transmission lines 20a and 20b. be able to.

  In addition, as described above, by providing the mount 41 on which the solar cell unit 11 is installed, the solar cell unit 11 (solar power generation unit 10) can be easily arranged on the highway.

  Further, as described above, if the high-voltage power transmission lines 20a and 20b (pipe lines 40) are attached to the gantry 41, the gantry 41 having the same specification can be continuously connected regardless of whether the highway is an elevated laying or a land laying. The high voltage transmission lines 20a and 20b can be installed. For this reason, even if it is a land laying location, the construction for burying the high-voltage power transmission lines 20a and 20b is not necessary, and the installation cost can be reduced.

(Second Embodiment)
In the second embodiment, a case where power is transmitted using the extra high voltage power transmission lines 120a and 120b, unlike the first embodiment, will be described with reference to FIGS.

  Here, a case where the rated power generation capacity of the solar power generation system (power generation system) 101 is several tens MW or more will be described. Note that, according to the grid connection regulations, when connecting a power larger than 2 MW, it is necessary to link with an extra high voltage.

  As shown in FIG. 11, the solar power generation system 101 includes a plurality of solar power generation units 10, a circuit breaker 21, a switch 22, a switching switch 23, a unit 110 including high-voltage power transmission lines 20a and 20b, and a plurality of solar power generation units. Special high voltage power transmission lines 120a and 120b (first special high voltage power transmission line and second special high voltage power transmission line) provided in parallel with the photovoltaic power generation unit 10 (unit 110). In addition, a secondary transformer 121, a circuit breaker 122, a switch 123, and a switching switch (second connection switching unit) 124 are provided between the unit 110 and the extra high voltage power transmission lines 120a and 120b.

  The unit 110 has a rated power generation capacity of 10 MW, for example, and ten solar power generation units 10 are installed in one unit 110, for example. As a result, the total length of the unit 110 is about 40 km.

  One secondary transformer 121 is provided for each of the high-voltage power transmission lines 20a and 20b. That is, a pair of secondary transformers 121 are provided for one unit 110. The secondary transformer 121 is configured to boost the high voltage supplied from the unit 110 to an extra high voltage (7000 V or more, generally 11 kV to 154 kV). Further, for example, four pairs of secondary transformers 121 (units 110) are continuously installed. Further, the high voltage side (for example, 77 kV) of the pair of secondary transformers 121 is connected in parallel and connected to the circuit breaker 122.

  The circuit breaker 122 is opened automatically when an accident occurs or the like, and instantaneously interrupts the connection between the unit 110 and the extra high voltage transmission lines 120a and 120b. The switch 123 has the same function as the switch 22. Further, the switch 123 is provided on both sides of the circuit breaker 122 similarly to the switch 22, but only the switch 123 between the circuit breaker 122 and the switching switch 124 is illustrated for simplification of the drawing. Yes. The switching switch 124 is for connecting the unit 110 to one of the extra high voltage power transmission lines 120a and 120b.

  For example, a protective circuit having the same function as the protective circuit (instrument transformer and protective relay) of the first embodiment is provided between the circuit breaker 122 and the switch 123. This protection circuit is provided for each circuit breaker 122.

  The extra high voltage power transmission lines 120a and 120b are cables for connecting power from the unit 110 in parallel, and are arranged in parallel to the high voltage power transmission lines 20a and 20b. The extra high voltage power transmission lines 120a and 120b are installed along the highway, for example, like the high voltage power transmission lines 20a and 20b, and have a function of transmitting extra high voltage from each unit 110.

  Each of the extra high voltage power transmission lines 120a and 120b has a power transmission capacity that is equal to or greater than the rated power generation capacity of the entire solar power generation system 101 (the total rated power generation capacity of the solar power generation unit 10 (unit 110)). For example, when four 10 MW units 110 are installed, each of the extra high voltage transmission lines 120a and 120b has a transmission capacity of 40 MVA.

  In the normal operation, a plurality of units 110 may be alternately connected to the extra high voltage power transmission lines 120a and 120b, or all the units 110 may be connected to one side.

  The extra high voltage power transmission lines 120a and 120b may be, for example, CV cables (cross-linked polyethylene insulated vinyl sheath cables). In this case, the CV cables may be installed on the expressway or the gantry 41. Further, the extra high voltage power transmission lines 120a and 120b may be overhead power transmission lines installed in the high voltage steel tower. Moreover, the high-voltage iron tower may be provided integrally with the highway.

  In addition, since the extra high voltage power transmission lines 120a and 120b are long distances, it is necessary to consider the loss due to the charging current. For this reason, when using a CV cable, it is preferable that the extra high voltage power transmission lines 120a and 120b have a length of 100 km or less and the transmission voltage is about 22 kV. When the rated power generation capacity of the unit 110 is 10 MW, the distance (pitch of the unit 110) L1 between the connection positions of the unit 110 and the extra high voltage power transmission lines 120a and 120b is 40 km. In this case, for example, three units 110 may be installed, the total length of the extra high voltage transmission lines 120a and 120b may be 80 km (100 km or less), and the transmission voltage may be 22 kV.

  Further, when increasing the transmission capacity, it is preferable to use an overhead transmission line and set the transmission voltage to a voltage suitable for the transmission capacity (for example, 77 kV or 110 kV when the transmission capacity is about 50 MVA). For example, eight units 110 may be installed, the total length of the extra high voltage power transmission lines 120a and 120b may be 280 km, and the power transmission voltage may be about 77 kV or 110 kV.

  In addition, as shown in FIG. 12, a bypass circuit breaker 125 that connects or disconnects the low voltage sides of the pair of secondary transformers 121 may be provided on the low voltage side of the pair of secondary transformers 121. Circuit breakers 126a and 126b are provided between the bypass circuit breaker 125 and the high voltage power transmission line 20a and between the bypass circuit breaker 125 and the high voltage power transmission line 20b, respectively. For example, the high voltage power transmission lines 20a and 20b are provided with a protection circuit (instrument transformer and protection relay) having the same function as the protection circuit of the first embodiment. Thereby, when an accident current flows through the high-voltage power transmission line 20a or 20b, the circuit breaker 126a or 126b is opened.

  Moreover, although the bypass circuit breaker 125 is provided with a control part and is configured to be automatically operated by a motor therefrom, it is not particularly limited. For example, when an accident occurs in the high-voltage power transmission line 20a, the circuit breaker 126a is opened by the protection circuit. And a bypass circuit breaker 125 is closed by outputting a control signal to a motor which drives bypass circuit breaker 125 from a control part. Thereby, it is possible to distribute the electric power supplied from the high-voltage power transmission line 20b to both of the pair of secondary transformers 121. At this time, since the circuit breaker 126a is open, it is possible to prevent the power of the high voltage transmission line 20b from escaping to the high voltage transmission line 20a via the bypass circuit breaker 125 and the circuit breaker 126a. When the accident of the high voltage transmission line 20a is recovered, the circuit breaker 126a is closed and the bypass circuit breaker 125 is opened by the operation by the maintenance worker, the remote operation from the central power supply command station, or the motor drive by the control unit.

  Other configurations of the second embodiment are the same as those of the first embodiment.

  Next, with reference to FIGS. 13 and 14, the operation of the photovoltaic power generation system 101 when an accident occurs in one of the extra high voltage power transmission lines 120a and 120b will be described.

  First, a case where a plurality of units 110 are alternately connected to the extra high voltage power transmission lines 120a and 120b as shown in FIG. 13 during normal operation will be described. Note that the operation of the solar power generation system 101 in this case is the same as the operation of the solar power generation system 1 of the first embodiment. That is, during normal operation, the circuit breaker 122 and the switch 123 are closed, and the switching switch 124 connects the units 110 to the extra high voltage power transmission lines 120a and 120b alternately.

  Here, for example, when an accident occurs in the extra high voltage transmission line 120b, the protection circuit of the unit 110 connected to the extra high voltage transmission line 120b side detects the accident current, and a trip signal is output to the circuit breaker 122. As a result, the circuit breaker 122 is opened. Thereby, the unit 110 connected to the extra high voltage power transmission line 120b is disconnected from the extra high voltage power transmission line 120b.

  Then, when the control signal is output from the control unit to the switching switch 124, the connection of the switching switch 124 connected to the opened circuit breaker 122 is switched. Thereafter, the circuit breaker 122 is closed by reclosing. Thereby, all the units 110 are connected to the extra high voltage power transmission line 120a.

  After that, when the extra high voltage power transmission line 120b is restored, the circuit breaker 122 and the switching switch 124 are reversed in the reverse order due to the operation by the maintenance worker, the remote operation from the central power supply command station, or the driving of the motor by the control unit. Operate. Thereby, the unit 110 is alternately connected to the extra high voltage power transmission lines 120a and 120b.

  Next, a case where all the units 110 are connected to one of the extra high voltage power transmission lines 120a and 120b (here, the extra high voltage power transmission line 120a) as shown in FIG. 14 during normal operation will be described. During normal operation, the circuit breaker 122 and the switch 123 are closed, and the switching switch 124 connects all the units 110 to the extra high voltage power transmission line 120a.

  Here, when an accident occurs in the extra high voltage power transmission line 120a, the protection circuit of the unit 110 connected to the extra high voltage power transmission line 120a side (the protection circuit of all the units 110) detects the accident current, and the circuit breaker 122 All the circuit breakers 122 are opened by the trip signal being output at. Thereafter, a control signal is output from the control unit to a motor that drives the switching switch 124, whereby the connections of all the switching switches 124 are switched. Then, the circuit breaker 122 is closed by reclosing. Thereby, all the units 110 are connected to the extra high voltage power transmission line 120b.

  After that, when the extra high voltage power transmission line 120a is restored, the circuit breaker 122 and the switching switch 124 are reversed in the reverse order due to the operation by the maintenance worker, the remote operation from the central power supply command station, or the driving of the motor by the control unit. Operate. Thereby, all the units 110 are connected to the extra high voltage power transmission line 120a. Even if the extra high voltage power transmission line 120a is restored, the connection of the unit 110 to the extra high voltage power transmission lines 120a and 120b may not be switched.

  Other operations in the second embodiment are the same as those in the first embodiment.

  In the present embodiment, as described above, the extra high voltage power transmission lines 120a and 120b and the switching switch 124 for switching the connection of the unit 110 (secondary transformer 121) to the extra high voltage power transmission lines 120a and 120b are provided. Thereby, even if an accident occurs on one of the extra high voltage power transmission lines 120a and 120b, the power generated by the plurality of units 110 can be transmitted by the other of the extra high voltage power transmission lines 120a and 120b. As a result, the reliability of power transmission can be further improved.

  In addition, if the bypass circuit breaker 125 is provided on the low voltage side of the pair of secondary transformers 121, when an accident occurs on one of the high voltage transmission lines 20a and 20b, the bypass circuit breaker 125 is closed to thereby increase the high voltage. Electric power (for example, 10 MW) supplied from the other of the transmission lines 20 a and 20 b can be distributed to both of the pair of secondary transformers 121. Thereby, since 5 MW of electric power is supplied to each of the pair of secondary transformers 121, the secondary transformer 121 only needs to have a rated capacity of 5 MW. For this reason, cost can be reduced compared with the case where the rated capacity of each secondary transformer 121 is 10 MW.

  Further, each of the extra high voltage power transmission lines 120 a and 120 b has a power transmission capacity that is equal to or greater than the total of the rated power generation capacities of the plurality of units 110. Thus, even if an accident occurs on one of the extra high voltage power transmission lines 120a and 120b, all of the electric power generated by the plurality of units 110 can be transmitted by the other of the extra high voltage power transmission lines 120a and 120b. .

  Other effects of the second embodiment are the same as those of the first embodiment.

(Third embodiment)
In the third embodiment, referring to FIGS. 15 to 20, unlike the second embodiment, even if an accident occurs in both of the extra high voltage power transmission lines 120a and 120b, the power transmission is prevented from being completely stopped. The case where it does is demonstrated.

  In the photovoltaic power generation system (power generation system) 201 according to the third embodiment, as shown in FIG. ) 210 is provided. Here, a case will be described in which the photovoltaic power generation system 201 (extra high voltage power transmission lines 120a and 120b) is installed over about 2000 km, and the intermediate switchgear 210 is provided every about 500 km.

  The intermediate switching station 210 is provided, for example, at three locations, and the photovoltaic power generation system 201 (extra high voltage transmission lines 120a and 120b) is divided into four sections. Twelve 10 MW units 110 are installed in one section, and the rated power generation capacity of the solar power generation system 201 is 480 MW. When the rated power generation capacity is increased to about 480 MW, the transmission voltage of the extra high voltage transmission lines 120a and 120b is required to be about 154 kV to 275 kV. In the present embodiment, the extra high voltage power transmission lines 120a and 120b are formed by overhead power transmission lines.

  As shown in FIG. 16, the intermediate switchgear 210 is configured using a double bus 2 bus tie system. Specifically, buses 211 and 212 are provided in the intermediate switching station 210. A bus tie 220 is provided on the bus 211, and a right bus (one bus) 211 a and a left bus (other bus) 211 b are connected by the bus tie 220. The bus tie 220 is provided with a circuit breaker 213 and two switches 214 arranged on both sides of the circuit breaker 213. Thereby, the right bus 211a and the left bus 211b can be connected or disconnected. Similarly, a bus tie 221 is provided on the bus 212, and the right bus (one bus) 212 a and the left bus (the other bus) 212 b are connected by the bus 221. The bus tie 221 is provided with a circuit breaker 213 and two switches 214 arranged on both sides of the circuit breaker 213.

  A switch 215, a circuit breaker 216, and disconnectors 217a and 217b are provided between the right (one side) extra high voltage power transmission line 120a and the right buses 211a and 212a. By the disconnectors 217a and 217b, the right extra high voltage power transmission line 120a is connected to the right bus 211a and the right bus 212a so as to be switchable. Similarly, a switch 215, a circuit breaker 216, and disconnectors 217a and 217b are provided between the right extra high voltage power transmission line 120b and the right buses 211a and 212a. A switch 215, a circuit breaker 216, and disconnectors 217a and 217b are provided between the extraordinary high voltage power transmission line 120a on the left side (the other side) and the left side buses 211b and 212b. A switch 215, a circuit breaker 216, and disconnectors 217a and 217b are provided between the extraordinary high voltage power transmission line 120b on the left side (the other side) and the left side buses 211b and 212b.

  Further, a protection circuit having the same function as the protection circuits of the first and second embodiments is provided around each circuit breaker of the intermediate switching station 210. Each protection circuit is controlled by a control unit having the same function as the control units of the first and second embodiments. Note that one control unit may be provided for each protection circuit, or only one control unit may be provided in the intermediate switching station 210. Each protection circuit may be controlled by remote operation from the central power supply command station.

  As shown in FIG. 15, the left ends of the extra high voltage power transmission lines 120 a and 120 b are power receiving ends 230. As shown in FIG. 17, at the power receiving end 230, the extra high voltage power transmission lines 120a and 120b are supplied with electric power to customers through the existing (or newly installed) power transmission lines 240a and 240b.

  Specifically, a switch 231, a circuit breaker 232, and a switching switch 233 are provided at the power receiving end 230 between the extra high voltage power transmission line 120 a and the power transmission lines 240 a and 240 b. With this switching switch 233, the extra high voltage power transmission line 120a is linked to the power transmission line 240a and the power transmission line 240b so as to be switchable. Similarly, a switch 231, a circuit breaker 232, and a switching switch 233 are provided between the extra high voltage power transmission line 120 b and the power transmission lines 240 a and 240 b. With this switching switch 233, the extra high voltage power transmission line 120b is linked to the power transmission line 240a and the power transmission line 240b.

  A protection circuit having the same function as the protection circuits of the first and second embodiments is provided around each circuit breaker at the power receiving end 230. Each protection circuit is controlled by a control unit having the same function as the control units of the first and second embodiments. Note that one control unit may be provided for each protection circuit, or only one control unit may be provided at the power receiving end 230. Each protection circuit may be controlled by remote operation from the central power supply command station.

  The power receiving end 230 may be provided with a transformer (not shown) that steps down the power transmitted through the extra high voltage power transmission lines 120a and 120b to the power transmission voltage (for example, 77 kV) of the power transmission lines 240a and 240b. .

  Note that the intermediate switching station 210 may also be configured to supply power to the consumer, similar to the power receiving end 230. By using the buses 211 and 212, it is possible to supply power from the intermediate switching station 210 relatively easily.

  Other configurations of the third embodiment are the same as those of the first and second embodiments.

  Next, with reference to FIGS. 18-20, the operation | movement of the solar power generation system 201 when an accident generate | occur | produces in both the extra high voltage power transmission lines 120a and 120b is demonstrated. Here, the case where both of the extra high voltage power transmission lines 120a and 120b transmit power during normal operation will be described.

  During normal operation, as shown in FIG. 18, the disconnector 217a connected to the right extra high voltage power transmission line 120a is closed and the disconnector 217b is open. The disconnector 217a connected to the right extra high voltage power transmission line 120b is open and the disconnector 217b is closed. The disconnector 217a connected to the left extra high voltage power transmission line 120b is open and the disconnector 217b is closed. The disconnector 217a connected to the left extra high voltage transmission line 120a is closed and the disconnector 217b is open. The circuit breakers 213 and 216 and the switches 214 and 215 are all closed. Then, power is transmitted by the right extra high voltage power transmission lines 120a and 120b and the left extra high voltage power transmission lines 120a and 120b.

  Here, when an accident occurs in the extra high voltage transmission line 120b in the right section, the protection circuit connected to the extraordinary high voltage transmission line 120b on the right side detects the accident current and is connected to the extra high voltage transmission line 120b on the right side. A trip signal is output to the circuit breaker 216. In addition, when an accident occurs in the extra high voltage transmission line 120a in the left section, the protection circuit connected to the extraordinary high voltage transmission line 120a on the left detects the accident current, and the interruption connected to the extra high voltage transmission line 120a on the left side. A trip signal is output to the device 216. Accordingly, as shown in FIG. 19, the circuit breaker 216 connected to the right extra high voltage power transmission line 120b and the circuit breaker 216 connected to the left extra high voltage power transmission line 120a are opened. And the disconnector 217a connected to the left extra high voltage power transmission line 120b is closed and the disconnector 217b is opened by the driving of the motor by the control unit or the remote operation from the central power supply command station. Thereby, electric power is transmitted by the right extra high voltage power transmission line 120a and the left extra high voltage power transmission line 120b.

  After that, when the right extra high voltage power transmission line 120b and the left extra high voltage power transmission line 120a are restored, the extraordinary high voltage power transmission line on the left side is operated by the maintenance worker, the remote operation from the central power supply command station, or the motor drive by the control unit. The disconnectors 217a and 217b connected to 120b are switched, and the opened circuit breaker 216 is closed.

  On the other hand, when an accident occurs in both of the extra high voltage transmission lines 120a and 120b in the right section, the protection circuit connected to the circuit breaker 213 of the bus tie 220 detects the accident current, and a trip signal is sent to the circuit breaker 213 of the bus tie 220. Is output. In addition, the protection circuit connected to the circuit breaker 213 of the bus tie 221 detects an accident current, and a trip signal is output to the circuit breaker 213 of the bus tie 221. This opens the circuit breakers 213 of the bus ties 220 and 221 as shown in FIG. For this reason, it is possible to prevent an accident from spreading to the left section, and in the left section, power is transmitted by the extra high voltage transmission lines 120a and 120b. After that, when the right extra high voltage power transmission lines 120a and 120b are restored, the circuit breakers 213 of the bus ties 220 and 221 are closed by an operation by a maintenance worker, a remote operation from a central power supply command station, or a motor drive by a control unit.

  In addition, the operation | movement mentioned above at the time of accident occurrence is an example, and it is also possible to prevent the spread of an accident by opening another circuit breaker.

  Other operations in the third embodiment are the same as those in the first and second embodiments.

  In the present embodiment, as described above, the extra high-voltage power transmission lines 120a and 120b are provided with the intermediate bus station 210 of the double bus 2 bus tie system. Thereby, for example, even if an accident occurs in the special high voltage transmission line 120b in the right section and an accident occurs in the special high voltage transmission line 120a in the left section, the special high voltage transmission line 120a on the right side and the special power line on the left side Power transmission can be continued with the high-voltage power transmission line 120b. Further, for example, even when an accident occurs in both of the extra high voltage power transmission lines 120a and 120b in the right section, the accident can be prevented from spreading to the left section. That is, the accident section can be limited to, for example, 500 km. In the left section, power transmission can be continued through the extra high voltage power transmission lines 120a and 120b. Although power transmission reliability is improved by transmitting power through two lines (extra high voltage transmission lines 120a and 120b), accidents occur simultaneously on the two lines when the special high voltage transmission lines 120a and 120b are long distances (for example, 2000 km). There is a case. This embodiment is particularly effective because it is possible to prevent power transmission from being completely stopped even when accidents occur on two lines simultaneously.

  In addition, if a long distance (for example, 2000 km) is connected only by the extra high voltage power transmission lines 120a and 120b without providing the intermediate switching station 210, a protection relay between remote locations may malfunction. However, in this embodiment, by providing the intermediate switching station 210 and separating the extra high voltage power transmission lines 120a and 120b, the protection relay can be set at an appropriate distance, and the protection relay is prevented from malfunctioning. Can do.

  Other effects of the third embodiment are the same as those of the first and second embodiments.

(Fourth embodiment)
In the fourth embodiment, with reference to FIGS. 21 and 22, a case where the extra high voltage power transmission lines 320a and 320b transmit DC power unlike the second embodiment will be described.

  As shown in FIG. 21, the solar power generation system (power generation system) 301 includes a plurality of units 110 and special high-voltage power transmission lines 320 a and 320 b (first special high-voltage power transmission lines and second special high-voltage power transmission lines). High-voltage power transmission line). In addition, a secondary transformer 121, an ACDC converter 312 that converts AC power into DC power, a switch 123, and a switching switch 124 are provided between the unit 110 and the extra high voltage power transmission lines 320a and 320b. . In the solar power generation system 301, for example, several tens or more units 110 are installed.

  The secondary transformer 121 is configured to boost the high voltage supplied from the unit 110 to an extra high voltage of, for example, 500 kV. Further, the high-voltage side (for example, 500 kV) of the pair of secondary transformers 121 is connected in parallel and connected to the ACDC conversion unit 312. The ACDC conversion unit 312 is connected to the extra high voltage power transmission lines 320a and 320b via the switch 123 and the switching switch 124. That is, the present embodiment has a configuration in which the circuit breaker 122 of the second embodiment is replaced with an ACDC converter 312.

  The ACDC conversion unit 312 converts the three-phase AC power output from the secondary transformer 121 into DC power having the same voltage and supplies the converted DC power to the extra-high-voltage power transmission lines 320a and 320b. The ACDC conversion unit 312 is configured by a large-capacity thyristor valve that is a combination of a large number of thyristor elements, for example. In the present embodiment, the rated capacity of the ACDC conversion unit 312 is 10 MW, which is the same as the rated power generation capacity of the unit 110.

  The ACDC conversion unit 312 has a function of automatically stopping when an accident occurs and disconnecting the unit 110 and the secondary transformer 121 from the extra high voltage power transmission lines 320a and 320b. The ACDC conversion unit 312 has a function of detecting the current and stopping the operation of the ACDC conversion unit 312 when an overcurrent (abnormal current), a ground fault current, or the like flows through the ACDC conversion unit 312.

  The extra high voltage power transmission lines 320a and 320b are direct current type power transmission lines. The extra high voltage power transmission lines 320a and 320b are installed over a long distance of 500 km or more (for example, 2000 km), and transmit DC power of 500 kV. It should be noted that a plurality of units 110 may be alternately connected to the extra high voltage power transmission lines 320a and 320b during normal operation, or all the units 110 may be connected to one side.

  The unit 110 may be installed without interruption over the entire length of the extra high voltage power transmission lines 320a and 320b. The unit 110 may be installed along a part of the extra high voltage power transmission lines 320a and 320b. For example, as shown in FIG. 22, there may be a portion where only the extra high voltage power transmission lines 320a and 320b are installed over several hundred km.

  Further, the extra high voltage power transmission lines 320a and 320b are formed by CV cables, for example, and are installed on the highway or the gantry 41. The extra high voltage power transmission lines 320a and 320b may be overhead power transmission lines installed on the high voltage steel tower.

  Other configurations of the fourth embodiment are the same as those of the second embodiment.

  Next, with reference to FIG. 21, operation | movement of the solar power generation system 301 when an accident generate | occur | produces in one of the extra high voltage power transmission lines 320a and 320b is demonstrated.

  First, a case where a plurality of units 110 are alternately connected to the extra high voltage power transmission lines 320a and 320b during normal operation will be described. For example, when an accident occurs in the extra high voltage power transmission line 320b, the ACDC converter 312 connected to the extra high voltage power transmission line 320b detects the accident current and stops its operation. Thereby, the unit 110 connected to the extra high voltage power transmission line 320b is disconnected from the extra high voltage power transmission line 320b.

  Then, when the control signal is output from the control unit to the switching switch 124, the connection of the switching switch 124 connected to the stopped ACDC conversion unit 312 is switched. Thereafter, the operation of the ACDC converter 312 is restarted, whereby all the units 110 are connected to the extra high voltage power transmission line 320a.

  After that, when the extra high voltage power transmission line 320b is restored, the ACDC conversion unit 312 and the switching switch 124 are in the reverse order due to the operation by the maintenance worker, the remote operation from the central power supply command station, or the driving of the motor by the control unit. Works with. Thereby, the unit 110 is alternately connected to the extra high voltage power transmission lines 320a and 320b.

  Next, the case where all the units 110 are connected to one of the extra high voltage power transmission lines 320a and 320b (here, the extra high voltage power transmission line 320a) during normal operation will be described. When an accident occurs in the extra high voltage power transmission line 320a, the ACDC converter 312 (all ACDC converters 312) connected to the extra high voltage power transmission line 320a detects the fault current and stops its operation. Thereafter, a control signal is output from the control unit to a motor that drives the switching switch 124, whereby the connections of all the switching switches 124 are switched. Then, when the operation of the ACDC converting unit 312 is restarted, all the units 110 are connected to the extra high voltage power transmission line 320b.

  Thereafter, when the extra high-voltage power transmission line 320a is restored, the ACDC conversion unit 312 and the switching switch 124 are in the reverse order due to the operation by the maintenance worker, the remote operation from the central power supply command station, or the driving of the motor by the control unit. Works with. Thereby, all the units 110 are connected to the extra high voltage power transmission line 320a. Even if the extra high voltage power transmission line 320a is restored, the connection of the unit 110 to the extra high voltage power transmission lines 320a and 320b may not be switched.

  Next, a case where an accident occurs in the unit 110 will be described. When an accident occurs in the unit 110, the ACDC converter 312 connected to the unit 110 detects the accident current and stops its operation. Thereby, the unit 110 in which the accident has occurred is disconnected from the extra high voltage power transmission line 320a or 320b. At this time, the switching switch 124 is held as it is. That is, the connection switching operation of the switching switch 124 is not performed.

  Thereafter, when the unit 110 is restored, the unit 110 is connected to the extra high voltage power transmission line 320a or 320b by restarting the operation of the ACDC converter 312 by an operation by a maintenance worker or a remote operation from the central power supply command station. The

  The other operations in the fourth embodiment are the same as those in the first and second embodiments.

  In the present embodiment, as described above, the ACDC conversion unit 312 is provided that converts AC power from the secondary transformer 121 into DC power and supplies the DC power to the extra high voltage power transmission lines 320a and 320b. Thereby, since ultra-high voltage and long-distance transmission can be changed to direct current transmission, loss due to charging current can be eliminated and transmission loss can be reduced. More specifically, when performing long-distance power transmission with a power transmission line of, for example, 500 km or more, a resistance loss appears remarkably unless the voltage is increased to about 500 kV. However, when such a long distance is transmitted at 500 kV, a charging current is generated in the transmission line with AC power, resulting in a separate transmission loss. This phenomenon becomes significant when the transmission distance is 2000 km or more when the transmission voltage is 500 kV, for example. The charging current is a phenomenon peculiar to AC transmission, and does not occur in the case of DC transmission. For this reason, by providing the ACDC converting unit 312 and performing direct current power transmission as described above, loss due to charging current can be eliminated, and power transmission loss can be reduced. In addition, although the charging current increases in proportion to the transmission voltage, no charging current is generated in the DC transmission, and therefore, the higher the transmission voltage, the better the loss reduction effect of the DC transmission compared with the AC transmission.

  Further, since the amount of charge current generated increases when a CV cable is used, the CV cable is usually unsuitable for long-distance power transmission. However, as described above, the CV cable can be used regardless of the transmission distance by performing direct current power transmission. Thereby, it is possible to install it inexpensively along a highway etc., without building a high-pressure tower.

  Even when overhead power transmission is performed, the cost of the transmission line per unit length is lower for DC than for three-phase AC. Since the ACDC conversion unit 312 is installed, the cost increases, but the cost of direct current power transmission is lower than the cost of alternating current power transmission at a certain branch point. This branching point is said to be 500 km.

  In addition, as described above, the ACDC conversion unit 312 is configured by a thyristor valve, so that an ultrahigh voltage AC power can be easily converted into a DC power.

  Other effects of the fourth embodiment are the same as those of the first and second embodiments.

(Fifth embodiment)
In the fifth embodiment, referring to FIG. 23, unlike the fourth embodiment, the DC power output from the solar cell unit 11 is supplied to the extra high voltage power transmission lines 320a and 320b without being converted into AC power. Will be described.

  As shown in FIG. 23, the solar power generation system (power generation system) 401 includes a plurality of units 510 and extra high-voltage power transmission lines 320 a and 320 b provided in parallel with the plurality of units 510.

  The unit 510 includes a plurality of photovoltaic power generation units (power generation units) 410, a switch 22, a switching switch 23, and high-voltage power transmission lines 420a and 420b (first power transmission line and second power transmission line) that are direct current transmission lines. Is included. The unit 510 is not provided with the circuit breaker 21. The photovoltaic power generation unit 410 includes a plurality of solar cell units 11 and a DCDC converter 413 that boosts the DC power output from the solar cell unit 11.

  The DCDC converter 413 includes a boost chopper circuit and is configured to boost the DC power output from the solar cell unit 11 to 3000V to 30000V. Further, the DCDC converter 413 has a function of automatically stopping when an accident occurs and disconnecting the photovoltaic power generation unit 410 from the high voltage power transmission lines 420a and 420b. Note that, when an overcurrent (abnormal current), a ground fault current, or the like flows through the DCDC converter 413, the DCDC converter 413 has a function of detecting the current and stopping the operation of the DCDC converter 413.

  Other configurations of the photovoltaic power generation unit 410 and the unit 510 are the same as those of the photovoltaic power generation unit 10 and the unit 110 described above.

  A secondary DCDC converter 521, a switch 123, and a switching switch 124 are provided between the unit 510 and the extra high voltage power transmission lines 320a and 320b. One secondary DCDC converter 521 is provided for each of the high-voltage power transmission lines 420a and 420b. That is, a pair of secondary DCDC converters 521 are provided for one unit 510. The secondary DCDC converter 521 includes a step-up chopper circuit and is configured to step up the high-voltage DC power supplied from the unit 510 to, for example, an extra-high-voltage DC power of 500 kV. Further, the high-voltage side (for example, 500 kV) of the pair of secondary DCDC converters 521 is connected in parallel and connected to the switch 123. In the present embodiment, the rated capacity of the secondary DCDC converter 521 is 10 MW, which is the same as the rated power generation capacity of the unit 510.

  The secondary DCDC converter 521 has a function of automatically stopping when an accident occurs and disconnecting the unit 510 from the extra high voltage power transmission lines 320a and 320b. The secondary DCDC converter 521 has a function of detecting the current and stopping the operation of the secondary DCDC converter 521 when an overcurrent (abnormal current) or a ground fault current flows through the secondary DCDC converter 521.

  Other configurations of the fifth embodiment are the same as those of the fourth embodiment.

  Next, with reference to FIG. 23, operation | movement of the solar power generation system 401 when an accident generate | occur | produces in one of the extra high voltage power transmission lines 320a and 320b is demonstrated.

  First, a case where a plurality of units 510 are alternately connected to the extra high voltage power transmission lines 320a and 320b during normal operation will be described. For example, when an accident occurs in the extra high voltage transmission line 320b, the secondary DCDC converter 521 connected to the extra high voltage transmission line 320b side detects the accident current and stops its operation. Thereby, the unit 510 connected to the extra high voltage power transmission line 320b is disconnected from the extra high voltage power transmission line 320b.

  Then, when the control signal is output from the control unit to the switching switch 124, the connection of the switching switch 124 connected to the stopped secondary DCDC converter 521 is switched. Thereafter, the operation of the secondary DCDC converter 521 is restarted, whereby all the units 510 are connected to the extra high voltage power transmission line 320a.

  After that, when the extra high voltage power transmission line 320b is restored, the secondary DCDC converter 521 and the switching switch 124 are reverse to the above by the operation by the maintenance worker, the remote operation from the central power supply command station, or the driving of the motor by the control unit. Works in order. Thereby, the unit 510 is alternately connected to the extra high voltage power transmission lines 320a and 320b.

  Next, the case where all the units 510 are connected to one of the extra high voltage power transmission lines 320a and 320b (here, the extra high voltage power transmission line 320a) during normal operation will be described. When an accident occurs in the extra high voltage power transmission line 320a, the secondary DCDC converters 521 (all the secondary DCDC converters 521) connected to the extra high voltage power transmission line 320a detect the accident current and stop operating. Thereafter, a control signal is output from the control unit to a motor that drives the switching switch 124, whereby the connections of all the switching switches 124 are switched. Then, by restarting the operation of the secondary DCDC converter 521, all the units 510 are connected to the extra high voltage power transmission line 320b.

  After that, when the extra high voltage power transmission line 320a is restored, the secondary DCDC converter 521 and the switching switch 124 are reverse to the above by the operation by the maintenance worker, the remote operation from the central power supply command station, or the driving of the motor by the control unit. Works in order. Thereby, all the units 510 are connected to the extra high voltage power transmission line 320a. Even if the extra high voltage power transmission line 320a is restored, the connection of the unit 510 to the extra high voltage power transmission lines 320a and 320b may not be switched.

  Next, a case where an accident occurs in the unit 510 will be described. When an accident occurs in the unit 510, the secondary DCDC converter 521 connected to the unit 510 detects the accident current and stops its operation. Thereby, the unit 510 in which the accident has occurred is disconnected from the extra high voltage power transmission line 320a or 320b. At this time, the switching switch 124 is held as it is. That is, the connection switching operation of the switching switch 124 is not performed.

  Thereafter, when the unit 510 is restored, the operation of the secondary DCDC converter 521 is resumed by an operation by a maintenance worker or a remote operation from the central power supply command station, so that the unit 510 is connected to the extra high voltage transmission line 320a or 320b. Is done.

  The operation of the DCDC converter 413 and the switching switch 23 when an accident occurs in one of the high voltage transmission lines 420a and 420b is the secondary DCDC converter when an accident occurs in one of the extra high voltage transmission lines 320a and 320b. The operation is the same as that of 521 and the switching switch 124.

  Other operations in the fifth embodiment are the same as those in the fourth embodiment.

  In the present embodiment, as described above, the DC power output from the solar cell unit 11 is supplied to the extra high voltage power transmission lines 320a and 320b without being converted into AC power. Thereby, since it is not necessary to provide the converter 12 and the ACDC converter 312, the configuration can be simplified and the cost can be reduced.

  Further, as described above, DC power can be easily boosted by configuring DCDC converter 413 and secondary DCDC converter 521 by a boost chopper circuit.

  The other effects of the fifth embodiment are the same as those of the fourth embodiment.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, the present invention includes a configuration in which a storage battery is installed in a solar power generation system and a part of electric power generated during the daytime is stored and consumed at night or when there is insufficient sunlight.

  Further, in the above-described embodiment, the example using the solar cell unit, the solar power generation unit, and the solar power generation system that generate power using solar energy as the DC power supply unit, the power generation unit, and the power generation system has been described. Is not limited to this. For example, the present invention includes power generation using natural energy such as wind power.

  Moreover, in the said 2nd Embodiment, although shown about the example which provided the circuit breaker 122, the switch 123, and the switching switch 124 between a pair of secondary transformer 121 and extra high voltage power transmission line 120a and 120b, The invention is not limited to this. For example, as in the photovoltaic power generation system according to the first modification of the present invention shown in FIG. 24, a circuit breaker 122 and a switch 123 are provided between the secondary transformer 121 and the extra high voltage power transmission line 120a. A circuit breaker 122 and a switch 123 are provided between the device 121 and the extra high voltage power transmission line 120b. In addition, a bypass circuit breaker 125 a that connects or disconnects the high-voltage sides of the pair of secondary transformers 121 is provided on the high-voltage side of the pair of secondary transformers 121. Further, the bypass circuit breaker 125a, the circuit breaker 122, and the switch 123 may constitute a connection switching unit (second connection switching unit) 621 that switches the connection of the unit 110 to the extra high voltage power transmission lines 120a and 120b.

  Moreover, in the said 2nd, 4th and 5th embodiment, although shown about the example which provided both 2 lines of the high voltage power transmission line and the extra high voltage power transmission line, this invention is not limited to this. For example, the high-voltage power transmission line may be one line as in the solar power generation system according to the second modification of the present invention shown in FIG. That is, a plurality of photovoltaic power generation units 10 may be connected to one high voltage transmission line 620. In this case, it is not necessary to provide the switching switch 23 between the switch 22 and the high-voltage power transmission line 620. Between the high voltage transmission line 620 and the extra high voltage transmission lines 120a and 120b (first transmission line and second transmission line), one secondary transformer (transformer) 121, circuit breaker 122, switch 123 Further, a switching switch 124 may be provided. Depending on the circuit configuration, two secondary transformers 121 may be provided between the high voltage power transmission line 620 and the extra high voltage power transmission lines 120a and 120b. Similarly, for example, as in the solar power generation system according to the third modification of the present invention shown in FIG. 26, when performing DC power transmission, one high-voltage power transmission line and two extra high-voltage power transmission lines are used. Good. The same applies to a configuration in which direct current power output from the solar cell unit is transmitted without being converted into alternating current power.

  In the said 3rd Embodiment, although the example which comprised the intermediate | middle switchyard 210 by the double bus 2 bus tie system was shown, this invention is not limited to this. For example, as in the photovoltaic power generation system according to the fourth modification of the present invention shown in FIG. 27, bus ties 222 and 223 are provided between the bus 211 and the bus 212, and the intermediate switching station 210 is formed by a double bus 4 bus tie system. It may be configured. If comprised in this way, the reliability of power transmission can further be improved. Further, the intermediate switching station may be configured by a double bus 1 bus tie system. Moreover, you may comprise an intermediate | middle switchyard by systems other than a bus tie system.

  In the above-described embodiment, an example in which both the high-voltage power transmission lines 20a and 20b transmit power during normal operation has been described. However, the present invention is not limited thereto, and the high-voltage power transmission lines 20a and 20b are not limited thereto. Any one of the above may be configured to transmit power.

  Moreover, in the said embodiment, the 2nd and 3rd modification, although shown about the case where a 1st power transmission line and a 2nd power transmission line were a high voltage power transmission line or a special high voltage power transmission line, this invention is not limited to this, The present invention can also be applied to transmission lines other than high voltage transmission lines and extra high voltage transmission lines.

  Moreover, in the said embodiment, although the example which arrange | positions several electric power generation units along a highway was shown, this invention is not restricted to this. A plurality of power generation units may be arranged along an elongated route such as a road (such as a general road) other than a highway or a railway.

  Further, for example, in the fourth and fifth embodiments, the example in which the extra high voltage transmission line transmits DC power when the extra high voltage of 500 kV or more is transmitted over 500 km or more has been shown. Not limited to. When an extra high voltage of less than 500 kV is transmitted less than 500 km, the extra high voltage transmission line may be configured to transmit DC power.

  In the fifth embodiment, the example in which the DCDC converter and the secondary DCDC converter are configured by the boost chopper circuit has been described. However, the present invention is not limited to this, and the DCDC converter and the secondary DCDC converter are the boost chopper circuit. It may be configured by other than the above.

  Further, a configuration obtained by appropriately combining the configurations of the above-described embodiment and modification examples is also included in the technical scope of the present invention.

1, 101, 201, 301, 401 Solar power generation system (power generation system)
10, 410 Photovoltaic power generation unit (power generation unit)
11 Solar cell unit (DC power supply unit)
12 Converter 13 Transformer 20a, 420a High-voltage transmission line (first transmission line)
20b, 420b High voltage transmission line (second transmission line)
23. Switching switch (first connection switching unit)
40 pipeline 41 gantry 110, 510 unit 120a, 320a extra high voltage transmission line (first extra high voltage transmission line, first transmission line)
120b, 320b extra high voltage transmission line (second extra high voltage transmission line, second transmission line)
121 Secondary transformer 124 Switching switch (second connection switching unit)
125 Bypass circuit breaker 210 Intermediate switching station (switching station)
312 ACDC converter 413 DCDC converter 521 Secondary DCDC converter 620 High voltage power transmission line 621 Connection switching unit (second connection switching unit)

Claims (26)

A plurality of power generation units including a DC power supply unit that generates power using natural energy;
A first power transmission line and a second power transmission line that are arranged in parallel with the plurality of power generation units arranged along an elongated path, and each of the plurality of power generation units is connected;
A first connection switching unit that switches connection of the power generation unit to the first power transmission line and the second power transmission line;
A power generation system comprising:   The power generation system according to claim 1, wherein the power generation unit includes a conversion unit that converts DC power output from the DC power supply unit into AC power. The power generation unit includes a transformer that boosts the AC voltage output from the conversion unit,
The power generation system according to claim 2, wherein the first power transmission line and the second power transmission line include a high-voltage power transmission line. A plurality of units including the plurality of power generation units, the first power transmission line, the second power transmission line, and the first connection switching unit;
A secondary transformer that boosts the AC voltage from the unit;
A first extra high voltage transmission line and a second extra high voltage transmission line to which the secondary transformer is connected;
A second connection switching unit that switches connection of the secondary transformer to the first special high-voltage transmission line and the second special high-voltage transmission line;
The power generation system according to claim 3, further comprising: Two secondary transformers are provided for each unit,
The low-voltage side of the pair of secondary transformers is provided with a bypass circuit breaker that connects or disconnects the low-voltage sides of the pair of secondary transformers. Power generation system. A plurality of power generation units are connected, and a high-voltage transmission line to which an alternating voltage output from the conversion unit and boosted by a transformer is supplied,
A secondary transformer that boosts an alternating voltage from the high-voltage power transmission line and outputs the boosted voltage to the first power transmission line and the second power transmission line;
Further comprising
The power generation system according to claim 2, wherein the first power transmission line and the second power transmission line include a first special high voltage power transmission line and a second special high voltage power transmission line, respectively.   The ACDC conversion part which converts the alternating current power from the said secondary transformer into direct-current power, and supplies it to the said 1st special high voltage power transmission line and the said 2nd special high voltage power transmission line is further provided, It is characterized by the above-mentioned. The power generation system of any one of.   The power generation system according to claim 7, wherein the ACDC converter includes a thyristor valve.   The power generation system according to claim 1, wherein the power generation unit includes a DCDC converter that boosts DC power output from the DC power supply unit.   The power generation system according to claim 9, wherein the first power transmission line and the second power transmission line include a high-voltage power transmission line. A plurality of units including the plurality of power generation units, the first power transmission line, the second power transmission line, and the first connection switching unit;
A secondary DCDC converter that boosts the DC voltage from the unit;
A first extra high voltage transmission line and a second extra high voltage transmission line to which the secondary DCDC converter is connected;
A second connection switching unit that switches connection of the secondary DCDC converter to the first special high-voltage power transmission line and the second special high-voltage power transmission line;
The power generation system according to claim 10, further comprising: A high-voltage power transmission line connected to the plurality of power generation units and supplied with a DC voltage boosted by the DCDC converter;
A secondary DCDC converter that boosts a DC voltage from the high-voltage power transmission line and outputs the boosted voltage to the first power transmission line and the second power transmission line;
Further comprising
The power generation system according to claim 9, wherein the first power transmission line and the second power transmission line include a first special high voltage power transmission line and a second special high voltage power transmission line, respectively.   The power generation system according to claim 9, wherein the DCDC converter includes a step-up chopper circuit.   The power generation system according to claim 11 or 12, wherein the secondary DCDC converter includes a step-up chopper circuit.   The power generation system according to any one of claims 4 to 8, 11, 12, and 14, wherein the first special high-voltage transmission line and the second special high-voltage transmission line are overhead transmission lines.   The first special high-voltage power transmission line and the second special high-voltage power transmission line are provided with a switching station for dividing the first special high-voltage power transmission line and the second special high-voltage power transmission line into a plurality of sections. The power generation system according to any one of claims 4 to 8, 11, 12, 14, and 15.   The power generation system according to claim 16, wherein the switchgear is configured by using a double bus 4 bus tie system or a double bus 2 bus tie system. The power generation unit includes a DCDC converter that boosts DC power output from the DC power supply unit,
The power generation system according to claim 15 or 16, wherein the DCDC converter includes a step-up chopper circuit.   19. The power transmission capacity according to claim 1, wherein each of the first power transmission line and the second power transmission line has a power transmission capacity that is equal to or greater than a total of rated power generation capacities of the plurality of power generation units. Power generation system.   12. The power generation system according to claim 4, wherein each of the first special high-voltage power transmission line and the second special high-voltage power transmission line has a power transmission capacity equal to or greater than a total of the rated power generation capacity of the plurality of units. .   21. The power generation system according to claim 20, wherein the electric power generated by the plurality of units is transmitted through one of the first special high-voltage transmission line and the second special high-voltage transmission line during normal operation.   The electric power generated by the plurality of units during normal operation is distributed and transmitted to the first special high-voltage power transmission line and the second special high-voltage power transmission line. Power generation system.   The power generation system according to any one of claims 1 to 22, further comprising a mount on which the DC power supply unit is installed.   The power generation system according to claim 23, wherein the first power transmission line and the second power transmission line are attached to the gantry.   The power generation system according to claim 24, wherein the first power transmission line and the second power transmission line are attached to the gantry in a state of being housed in a pipeline.   The power generation system according to any one of claims 1 to 25, wherein the DC power supply unit includes a solar cell unit that generates power using solar energy.