CN106300437A - Hydraulic photovoltaic cogeneration method - Google Patents

Abstract

A method for combined hydropower and photovoltaic power generation in hydropower stations. The invention belongs to the technical field of electric power generation, and in particular relates to a method for combining photovoltaic and hydraulic power to generate electricity by utilizing the water surface of a hydropower station. This method is to deploy distributed photovoltaic power generation devices on the water surface of the hydropower station reservoir, and the direct current generated by the inverter is converted into sine wave alternating current with the same frequency and phase as the power grid, and the operation mode of the hydroelectric generator set and photovoltaic power generation equipment is controlled through the centralized control room , use the computer monitoring system and power generation in the centralized control room, and adjust the load of the hydro-generator unit in real time through its automatic control system (AGC). Then it is sent to the grid substation through the main transformer. The invention is simple and easy to implement, can make full use of the huge reservoir area, and solve the technical problems of unstable output of photovoltaic power generation and inability to continuously operate on the grid.

Description

Hydropower photovoltaic combined power generation method in hydropower station

technical field

The invention belongs to the technical field of electric power generation, and in particular relates to a method for combining photovoltaic and hydraulic power to generate electricity by utilizing the water surface of a hydropower station.

Background technique

Solar energy in Yunnan Province is the renewable energy with the greatest development potential. The unique natural resources, the foundation for industrial development, and the recent support from the government have laid a solid foundation for the development of solar energy. Located in the central part of the Yunnan-Guizhou Plateau, Yunnan has an average annual sunshine of 2,400 hours and uniform distribution of sunshine resources throughout the four seasons. As early as the end of the 1980s, the sales and application of solar technology products ranked first in the country, and the penetration rate of solar water heaters in Kunming has reached Nearly 30%, saving about 80,000 tons of standard coal for the country every year, reducing 11,100 tons of carbon dioxide emissions and 445 tons of sulfur dioxide emissions.

Yunnan Province divides the solar energy resources of each county. The annual sunshine energy per square meter reaches 6,000 megajoules, and there are 12 counties with sunshine hours of 2,300 hours, mainly concentrated in central Yunnan. There are 59 counties that are better. The annual sunshine energy per square meter is 5000-6000 megajoules, and the number of sunshine hours reaches 2000-2300. More than half of the 125 counties in the province have relatively good development conditions. In addition, there are 32 counties that can be developed, and 22 counties with poor development conditions.

Existing solar power generation devices have low light energy density, power generation efficiency is closely related to weather conditions such as seasons, day and night, and cloudy or sunny. The annual operating hours are 1500-2500. The probability of off-grid accidents caused by intermittent changes in light is high, which affects the peak regulation and frequency regulation of the power grid. Large-scale application of solar energy has become a technical bottleneck for the safe and stable operation of the power grid. As the traditional power generation form of the power grid, hydropower has a strong automatic adjustment capability and can absorb some intermittent energy such as solar energy and wind energy. The combination of hydropower and photovoltaics avoids this problem and improves the reliability of photovoltaic power generation.

Solar power generation devices need to occupy a huge area of land. In the case of very scarce arable land resources, large-scale construction is almost impossible in areas other than deserts. However, the construction of hydropower stations will submerge a large amount of land. At present, after the completion of hydropower stations, the huge reservoir area is almost unused, and the utilization rate of resources is very low. The combination of reservoirs and photovoltaics has produced the effect of "negatives make positives", and the land problem for photovoltaic power generation has been effectively resolved.

Nalan Hydropower Station is located in Mengla Township, Jinping County, Honghe Prefecture, Yunnan Province, with plenty of sunlight. Because photovoltaic power generation has the characteristics of safety and reliability, no noise, no pollution, energy available everywhere, no mechanical rotating parts, low failure rate, easy maintenance, unattended, short station construction period, no need to erect transmission lines, and convenient integration with buildings, etc. . The solar panels of the photovoltaic power generation system are installed on the water surface of the Nalanku area where there is no shelter at any time of the year. The photovoltaic system and hydroelectric generating units are integrated into the Yunnan power grid to realize combined solar and hydroelectric power generation, making up for the shortcomings of insufficient hydropower generation in dry seasons, insufficient photovoltaic stability and regulation performance, and large land resource occupation. It is an excellent hydropower generation operation mode.

Compared with the present invention, there are the following differences in the relevant technology retrieval situation of Chinese patent documents.

1. Invention of "A Solar Pumped Storage Combined Power Generation System" (Application No. 02134734.4), the technical solution of this invention is to convert solar energy into heat to produce steam, and then use the steam to drive a pump to pump water for energy storage. According to the needs of the grid, the water turbine unit Unified power generation, this technology converts energy forms multiple times through solar energy, thermal energy, steam, water pumps, and water turbines.

2. The utility model (application number 200820185104.4) of "Omnidirectional High Efficiency Concentrating Solar Hydropower Integrated Power Generation Device" is an omnidirectional concentrating solar power generation system, including concentrators, solar power generation units, and heat exchangers. The solar power generation unit includes several series-connected cells and grid-connected inverter power installed on the same heat exchanger, and the DC high-voltage output terminal formed by several series-connected cells is connected to the input terminal of the grid-connected inverter power supply to form an independent overall structure A solar power generation unit; a concentrator composed of a spherical cavity lens and a concentrating funnel is arranged above several series-connected cells, focusing omnidirectional sunlight on several series-connected cells, and the heat exchanger is installed in the water tank In the upper part, the hot water exchanged by the heat exchanger is recycled and reused. This technology fails to make full use of the huge reservoir area. This technology does not solve the technical problem that the output of photovoltaic power generation is unstable and cannot be continuously operated on the grid.

3. The invention of "Corrugated Tile Concentrating Solar Energy Hydropower Integrated Building Module" (application number 201010125392.6) is a corrugated tile concentrating solar hydropower integrated building module. Several series-connected cells are installed on the heat exchanger to form an independent structure The solar power generation unit, the DC high voltage output end formed by several solar power generation units in series is connected to the input end of the grid-connected inverter power supply to form a solar power generation grid-connected system with an independent overall structure, and the sun's rays are focused on several On the cells connected in series, the solar tracker is omitted, the amount of solar cells is reduced, the heat dissipation system is used in conjunction, the hot water is recycled, and the combination with the building realizes the integration of solar water heating and power generation. This technology is a combination of solar water heaters and photovoltaic grid-connected The combination of power generation has not yet solved the technical problem of unstable output of photovoltaic power generation and inability to continuously operate on the grid.

4. The utility model of "A Generating Device for Small Hydropower Station Using Wind Energy and Solar Energy Integrated Power Generation" (application number 200920101784.1) consists of a rodless cylinder, a pressurized tank, an air pipe, an air bag, an air bag bracket, a one-way breathable membrane, a one-way Gas valve, solar water heater hot water tank, easy-to-vaporize liquid tank, piston, air inlet, exhaust port, one-way valve, liquid inlet, liquid outlet, liquid return pipe, air pressure valve, gas storage (liquid) tank , air motor and generator; use water energy, solar energy and wind energy to convert into heat energy to drive the rodless cylinder and air bag to generate compressed air and water, generate high pressure through the pressurized tank, and drive the generator to generate electricity through the air motor. Pressurized tanks, solar water heaters, liquid tanks, gas storage tanks, gas motors, and generators have repeatedly converted energy forms, resulting in large energy losses.

5. The utility model of "A Solar Hydropower Cogeneration Equipment" (Application No.: 201120171058.4,) includes a solar power generation system and a seawater desalination system; the solar power generation system includes: a dish-type solar concentrating system that focuses sunlight on its absorber, The absorber absorbs radiation and heats the circulating fluid; the low-parameter turbogenerator unit generates power under the drive of the heated circulating fluid; the double-layer active disc solar seawater desalination device, the lower layer introduces exhaust steam from the steam turbine to heat the upper seawater; the circulating pump , pump the low-temperature and low-pressure circulating fluid after heat exchange to the absorber; the seawater desalination system includes: seawater supply pump, the filter screen is set at the inlet of the seawater supply pump, and the seawater is pumped to the double-layer active disc solar seawater desalination device The upper layer simultaneously generates electricity and desalinates seawater. This technology converts the energy form multiple times through the dish solar concentrating system-absorber-heating circulating fluid-low-parameter turbo-generator set, but it still hasn't solved the problem of intermittent and unstable power generation of solar power generation devices, and the energy consumption loss is relatively large .

Contents of the invention

The technical problem to be solved by the present invention is to provide a hydropower photovoltaic combined power generation method of a hydropower station, which can make full use of the huge reservoir area and solve the technical problem of unstable photovoltaic power generation output and inability to continuously operate on the grid.

The technical solution adopted to realize the object of the present invention is: a distributed photovoltaic power generation device is arranged on the water surface of the reservoir of the hydropower station, and the direct current generated by the inverter is converted into a sine wave alternating current with the same frequency and phase as the power grid, and the water wheel is controlled through the centralized control room The operation mode of the generator set and photovoltaic power generation equipment uses the computer monitoring system and power generation in the centralized control room, and adjusts the load of the hydroelectric generator set in real time through its automatic control system (AGC). Merged into the outlet bus of the combined power generation unit, and then sent to the grid substation through the main transformer.

The solar power generation device and the hydroelectric generating set are respectively provided with a power meter at an outlet for respective measurement.

The installation angle of the battery panels of the photovoltaic power generation device is 60 degrees, and the control, inverter and energy storage system of the photovoltaic power generation device are placed in the equipment room.

This project is designed as an independent photovoltaic system, and the solar panels of the photovoltaic power generation system are installed on the water surface of the reservoir area without shelter at any time of the year. Photovoltaic systems are used to supply small loads with electricity. In order to reduce the line loss caused by the excessive current of the DC terminal, the system uses 220V DC to connect to the inverter to output AC.

The solar power generation device and the hydro-generator set are respectively equipped with a power meter at the gateway for separate measurement, and the hydro-generator set is controlled through the AGC (automatic power generation device) in the centralized control room. Power generation at the same time, at this time, the centralized control room controls the operation of the hydro-generator set to meet the peak-shaving and frequency-regulation requirements of the power grid; when the sun is sufficient in the dry season, the solar power generation device gives priority to power generation, and the hydro-generator set shuts down to store water. The generator set generates electricity to balance the missing solar power; when the hydroelectric generator set is out of service, the solar power generation device supplies the backup power for the power generation system plant.

The beneficial effects of the present invention are as follows.

① Reduce investment and operating costs. The reservoirs of hydropower stations have been fully utilized, which solves the problems of ordinary photovoltaic power stations occupying a lot of land resources and inconvenient inspection and maintenance traffic. At the same time, the sharing of resources such as sending lines, control equipment, and maintenance personnel can greatly reduce investment and save costs. According to calculations, if a 3 million-kilowatt hydro-photovoltaic combined power station is built, preliminary calculations can save 3.6 billion yuan in arable land occupation fees.

②Improve the regulation performance and stability of the power grid. Through the centralized control room AGC (automatic power generation control device) to control the hydroelectric generator set and solar power generation device to jointly dispatch power generation, use the same transmission line to supply power to the grid, the two are redundantly configured, and the main and auxiliary conversion of hydraulic power and photovoltaic power in flood seasons and dry seasons, at the same time Photovoltaics compensate for the need for regulation accuracy in hydroelectric power generation. The combined power station can realize the balance and stability of the output load, and meet the requirements of the power grid for peak regulation and frequency regulation.

③ Improve economic benefits. Combined dispatching of solar and hydropower, when solar power is generated in the dry season, the hydro turbine generator can be shut down to store water and store energy; in the flood season, hydropower is the mainstay, photovoltaics are combined with peak regulation, and the optimal operation method can increase the utilization hours of the power station by more than 1,000 hours.

④ Save natural resources. The coverage of solar panels reduces the evaporation of the water surface of the reservoir and improves the utilization rate of water resources. If a 3 million-kilowatt solar-hydraulic combined power generation system is built, it can reduce water evaporation by 80 million tons per year based on the annual average evaporation of 1000 mm in Yunnan, or 5 cubic meters per year. Calculation of kilowatt-hour water consumption can increase power generation by 16.5 million kWh.

⑤ Safety and environmental protection. As a combination of two clean energy sources, the invention is helpful to control greenhouse gas and reduce carbon dioxide emission. In China's high-carbon energy structure, 70%-80% of electricity is fueled by coal, and every 1 kWh of electricity produces 860 grams of carbon dioxide. In 2013, the country's carbon dioxide emissions exceeded 9 billion tons. If a 3 million kilowatt hydro-photovoltaic combined power generation system is built, 6 billion kilowatt-hours of electricity can be generated in 2000 utilization hours, and 5.16 million tons of carbon dioxide emissions can be reduced.

Description of drawings

Fig. 1 is a schematic diagram of the working principle of the present invention.

Referring to Fig. 1, the present invention uses a large-capacity solar power generation device installed on the water surface of a hydropower station reservoir, and collectively imports the direct current generated by a plurality of solar power generation devices into an inverter to convert it into a sine wave alternating current with the same frequency and phase as the power grid. The transformer is integrated into the outlet bus of the power generation device through the gateway electricity meter, and the water turbine generator set and the solar power generation device are equipped with a gateway electricity meter to measure the electricity respectively, and the voltage is boosted by the main transformer and sent to the grid. Through the AGC (automatic generation control) device of the hydroelectric generator set, the combined power generation of the solar power generation device and the hydroelectric generator is implemented. This power generation method improves the power generation capacity of the combined power station, does not increase the short-circuit capacity of the power grid, and can avoid the impact of the inverter side network fault on the generator, and meets the requirements of power flow distribution, relay protection and reactive power control of the power system.

The solar power generation device and the hydroelectric generator set are controlled to generate electricity through the centralized control room. When the water volume and sunlight are sufficient, the solar power generation device and the hydroelectric generator set generate electricity at the same time. At this time, the hydroelectric generator set can be put into the AGC (automatic generation control) device to meet Requirements for peak regulation and frequency regulation of the power grid; when the sun is sufficient in the dry season, the solar power generation device will give priority to power generation, and the hydroelectric generator unit will stop to store water. When the hydroelectric generating set is out of service, the solar power generating device provides the backup power for the power generation system. In this method, solar power generation devices and hydroelectric generators are jointly dispatched, and the defects of intermittent power generation of photovoltaic and solar thermal power generation, and the failure of hydroelectric generating units to continuously operate on the grid in dry seasons are balanced in a relatively stable state, and the power balance is realized in the combined power generation system. Balanced and stable transmission meets the requirements of power grid peak regulation and frequency regulation, and creates conditions for large-scale utilization of solar energy while increasing hydroelectric power generation capacity in dry seasons.

The above flow chart is only for clearly illustrating the implementation manner, but not limiting the implementation manner. For those of ordinary skill in the art, on the basis of the above description, other changes or changes in different forms can also be made, and all implementation modes are not exhausted here. However, the obvious changes or changes derived therefrom still fall within the scope of protection of the present invention.

The following table is the application data of the present invention in Nalan, Mengla Township, Jinping County, Honghe Prefecture, Yunnan Province, and the monthly meteorological data in the hydropower solar photovoltaic measurement area is shown in the following table:

Solar radiation data table (terrestrial):

.

Solar radiation data table (water surface):

.

Related parameters:

.

Calculation of power generation

The data obtained from the weather station are the solar radiation on the horizontal plane, which needs to be converted into the radiation on the inclined surface of the photovoltaic array to calculate the power generation.

For a photovoltaic array fixedly installed at a certain inclination angle, the received solar radiation energy is related to the inclination angle, and the simpler empirical formula for calculating the radiation amount is:

Rβ＝S×[sin(α+β)/sinα]+D

In the formula: Rβ——the total solar radiation on the tilted photovoltaic array surface

S ——direct solar radiation on the horizontal plane

D - the amount of scattered radiation

α——The altitude angle of the sun at noon

β——Inclination angle of photovoltaic array.

Power generation on land:

.

Surface power generation (calculated based on level value):

.

Claims (3)

1. hydraulic photovoltaic cogeneration method, it is characterized in that: lay distribution type photovoltaic power generation device at the Hydropower Plant Reservoir water surface, the unidirectional current sent is converted into and electrical network same frequency through inverter, synchronous sine wave alternating current, turbine-generator units and the photovoltaic power generation equipment method of operation is controlled by centralized control room, utilize computer supervisory control system and the generated energy of centralized control room, turbine-generator units load is regulated in real time by its automatic control system, two kinds of TRTs are incorporated to combined power generation device outlet bus respectively after special booster transformer boosts, again through main transformer pushing electric network transformer station.

2. the hydraulic photovoltaic cogeneration method as described in claim 1, is characterized in that: device of solar generating and turbine-generator units are respectively arranged with critical point voltameter and measure respectively.

3. the hydraulic photovoltaic cogeneration method as described in claim 1, is characterized in that: cell panel setting angle is 60 degree, and the control of photovoltaic power generation apparatus, inversion and energy-storage system are placed in equipment room.