WO2018012714A1

WO2018012714A1 - Photovoltaic system on water

Info

Publication number: WO2018012714A1
Application number: PCT/KR2017/004124
Authority: WO
Inventors: 안병준
Original assignee: 운지파워텍(주)
Priority date: 2016-07-15
Filing date: 2017-04-18
Publication date: 2018-01-18
Also published as: KR101721372B1

Abstract

The present invention relates to a photovoltaic system on the water. The present invention comprises: a main floating structure floating on a water surface; a photovoltaic device installed in the main floating structure and including solar cell modules; a fixing frame fixed on the ground underwater, and having an upper portion positioned over the water surface; a protective house installed on the upper portion of the fixing frame; a power converting device installed in the protective house and converting DC power generated by the photovoltaic device into AC power to boost the AC power to high voltage; a power transmitting device installed on land and transmitting the high voltage AC power, which is supplied from the power converting device, to a power distributing system; a high voltage cable electrically connecting the power converting device positioned on the water and the power transmitting device installed on land, so as to send the power boosted in the power converting device to the power transmitting device; and a heat exchanging device performing heat exchanging for the inside of the protective house by using water from the underwater zone in which the fixing frame is positioned. According to the present invention, installation costs can be greatly reduced and transmission power loss can be reduced.

Description

Floating Solar Power System

The present invention relates to a water photovoltaic power generation system.

At present, the depletion of hydrocarbon-based fossil energy resources and the increase of greenhouse gases emitted by its use have increased the adverse effects on the global environment and threatened the survival of humankind. Nuclear power generation also has a problem of depletion of resources, as well as the Chernobyl and Fukushima nuclear plants.

For this reason, the use of renewable energy such as solar, wind, tidal power, etc., with no environmental pollution and infinite duration is increasing all over the world. Among the renewable energy, solar energy is distributed evenly in the inhabited place of people all over the world, and solar power is most effective because it converts solar light energy directly into electric energy, while solar light energy has a low energy density and requires a large area. Do.

Until now, photovoltaic power generation facilities have been installed in salt fields, farmland, forests, etc., but in addition to the net function of using renewable energy, they cause other environmental problems such as farmland deforestation and deforestation, and have limited land resources. As they compete, they are not welcomed by local residents and face difficulties due to various complaints. Therefore, research on photovoltaic power generation in desert areas or waters that has limited land resources, does not compete with humans, and has no adverse effects on the environment such as farmland deforestation or deforestation, is being actively applied and partially applied.

A solar power plant installed on the surface of a lake, river, or sea is called a water-based photovoltaic system. It is human-friendly because it does not compete with people and land, and when it is installed in a lake or river, it restricts the entrance of solar energy into the water. By suppressing the temperature rise of the water, it reduces the evaporation amount and helps to preserve the fresh water amount, and reduces the fog damage in the surrounding area. In addition, it is effective to improve water quality by promoting water convection due to the temperature difference caused by the shade of the water photovoltaic power generation system, and it protects fish stocks by providing the place for laying the fish with the shade by the water photovoltaic power generation system. It is nurtured.

1 is a side view showing an example of a conventional water-based photovoltaic system.

As shown in FIG. 1, the water-based photovoltaic system has a floating structure 10 floating on the surface of a lake, a river, or the sea, and the floating structure 10 so as not to move horizontally in accordance with wind or water flow. Mooring device 20 to be fixed to the water surface, the mounting frame 30 is installed on the upper portion of the floating structure 10, a plurality of solar cell modules (M) installed on the mounting frame 30 to produce power from the solar energy (M Photovoltaic device 40 including a), and a power conversion transmission device installed on the land to convert the low-voltage DC power generated by the solar cell modules (M) to AC and boost the power transmission to the power distribution system of the power company ( 50).

The solar cell modules (M) of the photovoltaic device (40) are divided into a plurality of groups so that the solar cell modules (M) of each group are connected in series according to the input voltage of the inverter. Each group is called a solar cell string array, and the direct current power output from the unit solar strings of the solar cell string array is merged in the connection panel.

The power conversion transmission apparatus 50 includes a plurality of inverter units 51 for converting DC power transmitted from the connection panel into AC power, a circuit breaker unit 52 for protecting a load end of the inverter unit 51, and an inverter. Transformer unit 53 for boosting the power converted in the unit 51 to the grid voltage, switch unit 54 for opening and closing the circuit, meter unit 55 for trading power, for power system and protection cooperation A protective relay unit 56, a monitoring unit 57 for monitoring the operating state of the photovoltaic power generation system and the like.

The connection panels of the photovoltaic device 40 are divided into a plurality of groups, and each connection group group is connected to the inverter unit 51 of the power conversion transmission apparatus 50. Each connecting panel of the connecting panel group and the inverter unit 51 are connected by a cable 60, and the cable 60 has waterproofness and flexibility to transmit the combined low voltage direct current power of the connecting panel to the inverter unit 51. A thick special cable is used. That is, one connection panel group is connected to one inverter unit 51 by a plurality of cables 60 (the number of connection panels constituting the connection panel group).

In such a water photovoltaic power generation system, when power is generated in each of the solar cell modules M of the photovoltaic device 40 by sunlight, the DC power generated in each solar cell module M is a unit solar. Flow through the cell strings. DC power flowing through the unit solar cell strings is merged in each access panel for each solar cell string array. The DC power merged in each connection panel is output to each inverter unit 51 of the power conversion transmission apparatus 50 through the cables 60 for each connection panel group. The inverter unit 51 converts the DC power into AC power and boosts the system voltage in the transformer unit 53 to transmit power to the distribution system of the electric power company.

However, in the conventional water-based photovoltaic system as described above, the low-voltage DC power generated in the solar cell modules (M) of the photovoltaic device (40) located in the water is merged in each connection panel to the cables 60 Since a number of special cables are used because it flows to the inverter units 51 of the power conversion transmission apparatus 50 installed on the land, and the photovoltaic device is generally located at the center of the deep lake. The length of 60) is long, and a thick cable is used to transmit the low voltage direct current power incorporated in the connection board to the inverter unit 51.

For this reason, there is a problem that the cost of the cable 60 is greatly increased when installing the water-based photovoltaic system. In particular, if the installation of a large-scale solar power generation system with large power generation capacity, the cost of the cable is greatly increased. I can't do it.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a water photovoltaic system to which a water power conversion device is applied, which greatly reduces installation costs and reduces transmission power loss.

The technical problems to be achieved by the present invention are not limited to the technical problems mentioned above.

In order to achieve the object of the present invention, the main floating structure floating on the water surface; A photovoltaic device installed on the main floating structure and including solar cell modules; A fixed frame fixed to the ground under water, the upper part of which is located on the surface of the water; A protection house installed on an upper portion of the fixed frame; A power converter installed inside the protection house and converting the DC power generated by the photovoltaic device into alternating current and stepping up to a high pressure; A power transmission device installed on land and transmitting high voltage AC power supplied from the power conversion device to a power distribution system; A high voltage cable electrically connected to a power converter located in the water phase and a power transmission device installed on the land to send power boosted by the power conversion device to the power transmission device; There is provided a water-based photovoltaic system including a; heat exchanger for heat-exchanging the inside of the protection house using the water in the fixed frame is located.

In addition, the main floating body structure floating on the water surface; A photovoltaic device installed on the main floating structure and including solar cell modules; A plurality of pillars fixed to the underwater ground; An auxiliary floatation structure floating on the water surface adjacent to the pillars; A lifting device for connecting the pillars and the auxiliary floating structure so that the auxiliary floating structure can move up and down according to the water level; A protection house installed on the auxiliary floating structure; A power converter installed inside the protection house and converting the DC power generated by the photovoltaic device into alternating current and stepping up to a high pressure; A power transmission device installed on land and transmitting high voltage AC power supplied from the power conversion device to a power distribution system; A high voltage cable electrically connected to a power converter located in the water phase and a power transmission device installed on the land to send power boosted by the power conversion device to the power transmission device; There is provided a water-based photovoltaic system including a; heat exchanger for heat-exchanging the inside of the protection house using the water in the fixed frame is located.

The power converter preferably includes an inverter unit and a transformer unit.

The power transmission device preferably includes a meter unit for trading power and a protection relay unit for distribution system and protection coordination.

The heat exchange apparatus includes a fluid circulation pipe installed to circulate water into the water through the protection house through the inside of the protection house, a pump for pumping water in the water so that the water in the fluid circulation pipe circulates, and the protection house. It is preferable to include a heat exchange fin provided in a portion of the fluid circulation pipe located inside the.

A portion of the fluid circulation pipe having the heat exchange fins is preferably bent a plurality of times.

Preferably, the heat exchange fins further include a blowing fan for generating a flow of air.

It is preferable to further include a protective barrier installed on the edge of the fixed frame to surround the protective house.

It is preferable to further include a protective barrier installed at the edge of the auxiliary floating structure to surround the protective house.

It is preferable that a plurality of holes are provided in the protective barrier.

According to the present invention, since the power converter is located in the water adjacent to the photovoltaic device and the power transmission device is installed on land, the length of the low voltage cables for transmitting the DC power generated in the photovoltaic device to the inverter unit of the power converter can be shortened. It is also possible to increase the power to the high voltage in the power converter to transmit the high voltage to the power transmission device installed on the land through the high voltage cable has the effect of reducing the power loss.

In addition, the present invention, the power converter is located in the water adjacent to the photovoltaic device and the power transmission device is installed onshore, the length of the low-voltage cables for transmitting the DC power generated in the photovoltaic device to the inverter unit of the power converter is short In addition, since the high-voltage power boosted by the power converter is connected to the power transmission device by a pair of high-voltage cables (three strands in the case of three-phase power), the use of low-voltage cables is greatly reduced, thereby reducing the installation cost of the solar photovoltaic system. There is a saving effect.

In addition, the present invention has the effect that the low-voltage cables can be wired in the water rather than in the water can be selected freely and the wiring work and maintenance is easy.

In addition, the present invention is to protect the power converter from moisture and salt by the protection house sealed type, it is possible to automatically control the pump and the pump to safe operation management of the power converter in the optimum temperature and humidity, By circulating the lake water in the protection house, there is no need for additional heating and cooling related facilities, so it is possible to operate economic efficiency and safe operation management regardless of the season.

1 is a side view showing an example of a water-based photovoltaic system according to the prior art.

Figure 2 is a side view showing an embodiment of a water-based photovoltaic system according to the present invention.

3 is a side view showing a first embodiment of a power conversion device constituting an embodiment of a water-based photovoltaic system according to the present invention.

4 is a side view showing a second embodiment of a power conversion device constituting an embodiment of a water-based photovoltaic system according to the present invention.

Figure 5 is a side view showing a heat exchanger constituting an embodiment of a water-based photovoltaic system according to the present invention.

Figure 6 is a side view of the heat exchanger fin and the blower of the heat exchanger constituting an embodiment of a water-based photovoltaic system according to the present invention.

7 is a side view showing a first embodiment of the mooring apparatus of the water-based photovoltaic system according to the present invention.

8 is a side view showing a second embodiment of the mooring apparatus of the water-based photovoltaic system according to the present invention.

9 is a side view showing the first embodiment of the mooring apparatus of the water-based photovoltaic system according to the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention. Like elements in the figures are denoted by the same reference numerals wherever possible. In addition, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

Figure 2 is a side view showing an embodiment of a water-based photovoltaic system according to the present invention. As shown in FIG. 2, one embodiment of the water-based photovoltaic power generation system according to the present invention includes a main floatation structure 100, a photovoltaic device 200, an auxiliary floatation structure 300, and a power converter 400. ), The power transmission apparatus 500.

The main floating structure 100 is suspended on the surface of the lake, such as a river, a lake, a dam, or the sea. As an example of the main floating structure 100, the main floating structure 100 includes a plurality of buoyancy materials 110 and a base frame 120 coupled to the upper portions of the buoyancy materials 110. The buoyancy member 110 may be a material that floats in water, such as an empty space or a styropole. Preferably, the mooring device 130 is connected to the main floating structure (100). The mooring device 130 not only restricts the main floating structure 100 from moving in the horizontal direction by the flow of wind or water, but also allows the main floating structure 100 to move freely up and down according to the change in the height of the water surface. As an example of the mooring device 130, the mooring device 130 is an anchor 131 is fixed to the bottom of the river or lake, and the rope 132 connected to the anchor 131 and across the main floating structure 100 And a rope length adjusting device 133 connected to an end of the rope 132. The mooring device 130 may be implemented in various ways.

The photovoltaic device 200 includes solar cell modules (M). The photovoltaic device 200 is installed on the main floating structure 100. The mounting frame 210 is installed on the base frame 120 of the main floating structure 100, and the solar cell modules M are installed on the mounting frame 210. The low voltage cable 220 supplies the power generated by the photovoltaic device 200 to the power converter 400. The unit solar cell strings, which connect the solar cell modules in series, are merged at the junction board. The unit solar cell string is connected to a set number of solar cell modules (M). The connection boards also consist of a set number. The unit solar strings and the connection panels are determined by the inverter input voltage and the power generation capacity of the photovoltaic device.

Auxiliary floating structure 300 is suspended in the water surface. Auxiliary floating structure 300 is preferably located adjacent to the main floating structure (100). As an example of the auxiliary floating structure 300, as shown in FIGS. 3 and 4, the auxiliary floating structure 300 is coupled to the plurality of buoyancy bodies 310 and the buoyancy bodies 310 and is a power converter. The base plate 320 is installed 400, and a protective barrier 330 is coupled to the edge of the base plate 320 in a vertical direction. The buoyancy body 310 may be a member in which an inner space is suspended in water, such as an empty container or a styropole. In another embodiment of the auxiliary floating structure 300, a protective house 340 surrounding the power converter 400 is included. In another embodiment of the secondary floating structure 300, the secondary floating structure 300 may be a barge.

The power converter 400 converts the DC current generated in the photovoltaic device 200 into an AC and boosts it. The power converter 400 includes an inverter unit 410, a transformer unit 430, and preferably further includes a switch unit 440. The inverter unit 410 converts the low voltage direct current supplied by the low voltage cables 230 from the photovoltaic device 200 into AC power. The inverter unit 410 is provided in plurality according to the capacity of the photovoltaic device 200. The transformer unit 430 boosts the AC power converted by the inverter unit 410 to a high voltage. Here, the high voltage does not mean a range of high voltage based on the voltage classification standard of each country, but means a voltage higher than the output voltage of the inverter unit. The breaker unit 420 is connected to the output side of the inverter unit 410 or the transformer unit 430 to protect the equipment by blocking the current when the transient current flows into the inverter unit 410 or the transformer unit 430 Allow the circuit to be disconnected for inspection. The switch unit 440 also protects the circuit by opening and closing the circuit when abnormal power flows in the circuit, and opens and closes the circuit so as to supply or cut off power to the onshore power transmission device. The power converter 400 may further include a monitoring unit.

The power transmission device 500 is installed on land. The power transmission apparatus 500 boosts the high-voltage AC power supplied from the power converter 400 as it is or again, and transmits the power to the distribution system. The power transmission apparatus 500 includes a meter unit 510 for trading power, a protection relay unit 520 for protection coordination with a distribution system, and the like. The power converter 400 and the power transmitter 500 are preferably connected by a high voltage cable 450. That is, the high voltage power boosted by the transformer unit 430 of the power converter 400 is transmitted to the power transmission apparatus 500 through a set of high voltage cables 450, and the high voltage power transmitted to the power transmission apparatus 500 is Power is transmitted to the distribution system via the meter unit 510.

1 and 3, the power converter 400 is preferably located inside the protection house 340. The protection house 340 is installed on the base plate 320 of the auxiliary floating structure 300. When the surface of the water is always waved and storms caused by typhoons and the like, a large wave rises and splashes directly on the power converter 400 or splashing water droplets may intrude into the power converter 400. When water comes into contact with the inverter unit 410 constituting the power converter 400 and the transformer unit 430, a ground fault may occur, and the switch may be cut off or insulation breakdown may cause the device to be burned out. The protection house 340 may be manufactured in various materials, such as a flat roof, a domed roof in addition to the inclined roof. In addition, a container or an iron box may be used as a substitute for the protection house 340. As shown in FIG. 4, a protective barrier 330 may be further provided on an outer surface of the base plate 320 so that a large wave due to the storm does not hit the protective house 340 directly. It is preferable to drill a plurality of small holes in the lower portion of the protective barrier 330 to allow the water to flow out. The protective barrier 330 is preferably installed at a height of 1200MM or more so as to prevent a person from falling during maintenance inspection.

5 is a conceptual diagram illustrating an embodiment of a heat exchanger of the water power conversion device constituting the water photovoltaic power generation system according to the present invention.

As shown in FIG. 5, a heat exchanger 600 using lake water is installed in a protection house 340 in which the power converter 400 is stored. When installing the power converter 400 on the surface of the appeal it is necessary to protect the power converter 400 from moisture and salt. Appeals are always rippled and vaporized from the surface of the water during the day, making them wetter than on land and surrounded by fog at night. This damages the insulation of the inverter unit 410 and the transformer unit 430 constituting the power conversion device 400 to shorten the life of the device, and if a severe ground fault occurs, the switch is cut off or the insulation breakdown may cause damage to the device There is concern. In particular, when the power converter 400 of the photovoltaic facility is installed on the seawall containing salt or when the storm is driven by a typhoon or the like, splashing water droplets caused by large waves and splashes and the salt contained therein are power converters. Intrusion into the interior of the accident further increases the risk of an accident. In order to protect the power converter 400 from such a wet environment and salt, the protection house 340 needs to be sealed. Inverter unit 410 and transformer unit 430 constituting the power converter 400 is a loss occurs during operation and the loss is released as heat. In general, since the efficiency of the inverter unit 410 is about 98% and the efficiency of the transformer unit 430 is about 99%, about 3% of the converted power is lost as heat. In the case of the land, when the power converter 400 starts to operate, the temperature inside the protection house 340 rises, and when the temperature reaches a predetermined value, the hot air in the protection house 340 is discharged to the fans 644a and 644b and cooled. Outside air is supplied through the air inlets 641a and 641b provided on the wall. That is, it is possible to continue the operation of the power converter 400 by suppressing the temperature rise in the room by ventilation.

Meanwhile, when the power converter 400 installed in the water is accommodated in the protection house 340 to protect it from moisture, moisture, and salt, a heat exchanger to cool the heat generated while the power converter 400 is operating is provided. need. At this time, it is very useful to circulate the lake water indoors to use as a heat exchange medium. The lake water has infinite heat capacity compared to the generated heat of the power converter 400 and is cold enough to cool the indoor air so that the power converter 400 operates stably. In general, the upper limit of the operation temperature of the inverter unit 410 is 45 degrees Celsius to 50 degrees Celsius and the temperature of the summer appeal water temperature does not exceed 25 degrees, so the temperature difference is more than 20 degrees and the cooling water in the room for the power converter 400 Means are enough. This is much more economical in terms of installation cost and power than using an electric heat pump (air conditioner). The electric heat pump requires a large amount of power for the compressor to compress the refrigerant gas even though the installation cost is excluded, whereas the heat exchanger using the lake water has no water level difference between the suction side and the discharge side of the lake water. All you need is a pump.

As an example of the heat exchanger, as illustrated in FIGS. 5 and 6, the heat exchanger 600 includes a fluid circulation pipe 620 installed to circulate into the water through the protection house 340 through the water inflow, A pump 630 for pumping water in the water to circulate the water in the fluid circulation pipe 620, and a heat exchange fin 610 provided in a portion of the fluid circulation pipe 620 located inside the protection house 340 ) The portion of the fluid circulation pipe 620 having the heat exchange fins 610 is bent many times. Blowing fan 640 for generating a flow of air to the heat exchange fins 610 is preferably further provided. The pump 630 is preferably located below the water surface, such as using an underwater pump so that no water raising device is required.

On the other hand, the heat exchange device 600 is supplied to the heat inside the protection house 340 because the number of appeal is warmer than the outside air at night time or winter time. Since the power change device 400 located in the water is placed in a harsher environment than the land, it is necessary to protect against moisture not only when driving but also when stopped. When the sun goes down and the temperature goes down, the water vapor condenses on the lake, causing condensation. The power converter 400 is in a wet state close to 100% humidity, and condensation is generated on the components of the power converter 400. Condensation may cause a ground fault and insulation breakdown when the power converter 400 is restarted, and insulation degradation may accumulate even if not immediately caused by an accident, thereby shortening the life of an electric device.

When the heat exchanger 600 using the appealing water is operated at night time or in winter, the appealing water having a relatively higher temperature than the outside air functions as a heating function inside the protection house 340 to dedicate the interior of the power converter 400. It will become wet and prevent condensation on the electric equipment.

Temperature change is also an important factor in determining the life of an electric device. Electric equipment generates heat by loss when driving and cools down to room temperature when it is at rest. Repeated thermal expansion and contraction of the solid insulation material of an electric device causes cracks, and when the cracks are enlarged, the mechanical strength is lost and the insulation distance cannot be maintained, resulting in insulation breakdown such as ground faults and short circuits. Until the breakdown, the heating and cooling cycles and the rate of temperature change are affected by the temperature difference. The power converter 400 of the photovoltaic power generation system is repeatedly exposed to a high temperature state at the time of operation and a low temperature state at the time of stopping, and the lifespan is shorter than that of a general electric device because the temperature difference varies in winter.

When the heat exchanger 600 using the appealing water at night time or winter time is operated, the appealing water having a relatively higher temperature than the outside air functions as a heating function to warm the room in which the power converter 400 is accommodated and the power converter 400 By reducing the temperature difference at the time of operation and stop), it is possible to reduce the number of maintenance check of the device and to extend the life of the power converter 400.

Measure and compare the temperature and humidity of the air and outside air inside the protection house 340 equipped with the power converter 400 to automatically control the pump 630 and the fan 640 by a preset program to control the temperature and humidity. It is desirable to maintain the optimal state and at the same time to reduce the power required to drive the heat exchange device (600). The measured weather information and the operation information of the heat exchanger 600 are transmitted to the land together with the operation information of the power converter 400 and the information obtained from the monitoring equipment of the connection panel, and are configured to receive control commands on the land. desirable. The heat exchanger 600 may be implemented in various forms.

The mooring device 130 is connected to the auxiliary floating structure 300 mounted with the power converter 400. The mooring device 130 not only restricts the auxiliary floating structure 300 to move in the horizontal direction by the flow of wind or water, but also allows the auxiliary floating structure 300 to freely move up and down according to the change in the height of the water surface.

Figure 7 is a side view showing a first embodiment of the mooring device of the water photovoltaic system according to the present invention, the first embodiment of the mooring device 130 is anchored to the bottom of the river or lake 131 and The rope 132 is connected to the anchor 131 and is connected to the auxiliary floating structure 300, and a rope length adjusting device 133 for adjusting the stretching of the rope 132. As a method of adjusting the expansion and contraction of the rope 132, it may be configured in various ways, such as attaching a weight to one end of the rope 132 or installing a hoist. The first embodiment of the mooring device 130 is preferably installed in a deep dam or the sea.

Figure 8 is a side view showing a second embodiment of the mooring device of the water photovoltaic power generation system according to the present invention, the second embodiment of the mooring device 130 is a plurality of pillars 350 to be fixed to the underwater ground And a lifting device connecting the auxiliary floating structure and the plurality of pillars to move the auxiliary floating structure up and down according to the height of the water surface. The lifting device 355 may be a roller mechanism that moves up and down along the guide member. The lifting device can be configured in various ways. Lifting device 355 is preferably configured to be detachable to the auxiliary floating structure 300 or the auxiliary floating structure 300 so that it can be maintained by moving the auxiliary floating structure 300 or the power conversion device 400. In addition, the lifting device 355 is preferably provided with a fixing means for fixing the auxiliary floating structure 300 to a predetermined height. In the second embodiment of the mooring device 130, it is preferable to install the reservoir, the embankment, or the like having a low water depth. The main floatation structure 100 and the auxiliary floatation structure 300 may be connected to each other by a connecting means (not shown). The connecting means can be rope or rod members.

Figure 9 is a side view showing a third embodiment of the mooring device of the water photovoltaic system according to the present invention, the third embodiment of the mooring device 130 is fixed to the underwater ground, the top is fixed on the water surface It includes a frame, the power converter 400 is installed on top of the fixed frame. The fixed frame 360 is preferably located adjacent to the main floating structure (100). As an example of the fixed frame, the fixed frame includes a plurality of piles 350 to be embedded in the ground, and the support plate 360 is coupled to the upper end of the piles 350 to be located on the water surface. The fixed frame and the main floating structure 100 may be connected by a connecting means (not shown).

Hereinafter, the operation and effects of the water-based photovoltaic power generation system according to the present invention.

First, when power is generated in each of the solar cell modules M of the photovoltaic device 200 installed in the main floating structure 100 by sunlight, the DC power generated in each solar cell module M is a unit. Flow through the solar cell strings (201). DC power flowing through the unit solar cell strings 201 is merged in each connection panel 220 for each solar cell string array (A). The DC power merged in each connection panel 220 is connected to each inverter unit 410 of the power converter 400 located in the water so as to be adjacent to the photovoltaic device 200 through the low voltage cables 230 for each connection panel group. It is transmitted. The inverter unit 410 converts the DC power into AC power and boosts the voltage to the high voltage in the transformer unit 430. The high voltage AC power converted by the power converter 400 is transmitted to the power transmission apparatus 500 through the high voltage cable 450, and the high voltage current passed through the power transmission apparatus 500 is transmitted to the power distribution system of the power company.

In the present invention, since the power converter 400 is located in the water adjacent to the photovoltaic device 200, the direct current power generated by the photovoltaic device 200 is transmitted to the inverter unit 410 of the power converter 400. The length of the low voltage cable 230 is shortened to reduce the cost of the cable, and the low voltage cable 230 can be wired to the water phase rather than in the water, thereby making the wiring work easier. In addition, the power generated by the photovoltaic device is converted into high-voltage alternating current in the power converter 400 to transmit the power transmission device 500 installed on the land through the high-voltage cable 450 to reduce the power loss.

In addition, the present invention is housed in a sealed protection house to protect the power converter 400 from splashing water droplets, and the heat generated during the operation of the power converter is cooled by using the appealing water without cooling the ventilation device by the external air, moisture and There is no fear of salt penetration. Since the heat exchanger 600 using the lake water at night time or winter time is converted to a heating function, it prevents condensation damage caused by fog or moisture, and reduces the temperature difference between the operation and the stop of the power converter 400. The life of the component is extended.

Table 1 below illustrates the power cable requirements of the conventional water-based photovoltaic system and the water-based photovoltaic system according to the present invention.

조건Condition	1. 선로긍장 800M 2. 허용전압강하 3%3. 접속반용량 110 Kw 분할1. Line approval 800M 2. Allowable voltage drop 3% 3. 110 Kw partition capacity
전압강하 계산식: E = AL1/ 1000SA; 단상 2선식 = 35.6 3상 3선식 = 30.8 3상 4선식 = 17.8(단상3선식)E: 전압강하(V) L: 변압기 2차측부터의 거리 또는 인입선 접속점(M)I : 전류(A) S: 전선의 단면적(MM2) Dropout formula: E = A L * 1/1000 * SA; Single-phase 2-wire = 35.6 3-phase 3-wire = 30.8 3-phase 4-wire = 17.8 (single-phase 3-wire) E: Voltage drop (V) L: Distance from the secondary side of the transformer or lead-in connection point (M) I: Current (A) S : Cross-sectional area of wire (MM2)
발전용량Power generation capacity	5Mwp5Mwp		20Mwp20Mwp
송전전압Transmission voltage	직류 716VDC 716V	삼상교류 22900VThree Phase Exchange 22900V	직류 716VDC 716V	삼상교류 22900VThree Phase Exchange 22900V
소요케이블Cable	UW-3PN Cable240sq/1C 90가닥UW-3PN Cable240sq / 1C 90 strands	F-CNCV-W Cable60sq/1C 3가닥F-CNCV-W Cable60sq / 1C 3 Strands	UW-3PN Cable240sq/1C 360가닥UW-3PN Cable240sq / 1C 360strands	F-CNCV-W Cable240sq/1C 3가닥F-CNCV-W Cable240sq / 1C 3 Strands
소요배관재Required piping material	ELP PIPE 80C40LINEELP PIPE 80C40LINE	ELP PIPE 125C1LINEELP PIPE 125C1LINE	ELP PIPE 80C160LINEELP PIPE 80C160LINE	ELP PIPE 80C1LINEELP PIPE 80C1LINE

Table 1 is a value calculated by comparing the present invention with the conventional water-based photovoltaic system for the case of 5MW, which can be referred to as medium-scale equipment and 20MW, a large-scale facility, the voltage of the DC low-voltage power of the conventional water-based photovoltaic system is Since the low voltage range is 750V DC, the voltage of the high-voltage AC power of the power conversion equipment of the present invention is 22900V, the distribution system voltage of the Korean electric power company, and the length of the power cable is 800M and the allowable voltage drop is 3% or less under the same conditions. Compared.

As shown in Table 1, in the conventional water-based photovoltaic system, the power cable is required in the 5MW power plant, and 90 strands of 240 mm2 and 40 protective wires are required for 80 mm in diameter, whereas in the water-based photovoltaic system according to the present invention, 60 sq. The protective wire tube also needs only one 125mm diameter. In addition, in the 20MW power plant, the power cable requires 240 mm2 and 360 strands, and the protective cable tubes need 160 diameters of 80 mm, whereas in the water-based photovoltaic power generation system according to the present invention, only three protective wire tubes of 200 mm diameter need one 200 mm diameter. .

As described above, in the water photovoltaic power generation system to which the water power converter of the present invention is applied, since the power converter is located in the water adjacent to the photovoltaic device and the power transmission device is installed on land, the DC power generated in the photovoltaic device The length of the low voltage cables transmitting to the inverter unit of the power converter can be shortened, and the power loss is increased by increasing the voltage from the power converter to the high voltage through the high voltage cable to the power transmission device installed on the land, thereby reducing the power loss. There is.

In addition, since the low-voltage cables can be wired in the water rather than in the water, the cable can be freely selected and the wiring and maintenance can be easily performed.

In addition, the protection house is enclosed to protect the power converter from moisture and salt, and automatically controls the pump and pump to allow the safe operation and management of the power converter with optimum temperature and humidity. By circulating in the house, there is no need for additional heating and heating-related facilities, so it is possible to operate economic efficiency and safe operation management regardless of season.

The water-based photovoltaic system to which the water-power converter according to the embodiment of the present invention is applied is not limited to the configuration and operation of the embodiments described above. The above embodiments may be configured such that various modifications may be made by selectively combining all or part of the embodiments.

Claims

A main floating structure floating on the water surface;

A photovoltaic device installed on the main floating structure and including solar cell modules;

A fixed frame fixed to the ground under water, the upper part of which is located on the surface of the water;

A protection house installed on an upper portion of the fixed frame;

A power converter installed inside the protection house and converting the DC power generated by the photovoltaic device into alternating current and stepping up to a high pressure;

A power transmission device installed on land and transmitting high voltage AC power supplied from the power conversion device to a power distribution system;

A high voltage cable electrically connected to a power converter located in the water phase and a power transmission device installed on the land to send power boosted by the power conversion device to the power transmission device;

And a heat exchanger for heat-exchanging the inside of the protection house using water in the water in which the fixed frame is located.
A main floating structure floating on the water surface;

A photovoltaic device installed on the main floating structure and including solar cell modules;

A plurality of pillars fixed to the underwater ground;

An auxiliary floatation structure floating on the water surface adjacent to the pillars;

A lifting device for connecting the pillars and the auxiliary floating structure so that the auxiliary floating structure can move up and down according to the water level;

A protection house installed on the auxiliary floating structure;

A power converter installed inside the protection house and converting the DC power generated by the photovoltaic device into alternating current and stepping up to a high pressure;

A power transmission device installed on land and transmitting high voltage AC power supplied from the power conversion device to a power distribution system;

A high voltage cable electrically connected to a power converter located in the water phase and a power transmission device installed on the land to send power boosted by the power conversion device to the power transmission device;

And a heat exchanger for heat-exchanging the inside of the protection house using water in the water in which the fixed frame is located.
The water photovoltaic power generation system according to claim 1 or 2, wherein the power converter includes an inverter unit and a transformer unit.
The water photovoltaic system according to claim 1 or 2, wherein the power transmission device includes a meter unit for trading power, and a protection relay unit for distribution system and protection coordination.
According to claim 1 or 2, wherein the heat exchange device is a fluid circulation pipe is installed so that the water in the water flows through the inside of the protection house and the water circulation pipe, and the water in the water so that the water in the fluid circulation pipe circulates A water-based photovoltaic power generation system comprising a pump for pumping water and heat exchange fins provided in a portion of a fluid circulation pipe located inside the protection house.
6. The water photovoltaic power generation system according to claim 5, wherein the portion of the fluid circulation pipe provided with the heat exchange fins is bent a plurality of times.
6. The water photovoltaic power generation system according to claim 5, further comprising a blower fan that generates a flow of air to the heat exchange fins.
The water photovoltaic system of claim 1, further comprising a protective barrier installed at an edge of the fixed frame to surround the protective house.
3. The water photovoltaic system of claim 2, further comprising a protective barrier installed at an edge of the auxiliary floating structure to surround the protective house.
10. The water photovoltaic power generation system according to claim 8 or 9, wherein a plurality of holes are provided in the protective barrier.