Grid-connected and off-grid type wind-solar-hydrogen storage wiring system

Abstract

The utility model discloses a grid-connected and off-grid type wind and light hydrogen storage wiring system, which belongs to the technical field of new energy hydrogen production and comprises a wind power generation system, a photovoltaic power generation system, a water electrolysis hydrogen production system and an energy storage system. The photovoltaic power generation system is inverted by the double-switching combiner box and then is connected to an in-station 35kV bus through a rectifying device III and a transformer in sequence, the 35kV bus is connected to the water electrolysis hydrogen production system through the transformer, a rectifying device I and a double-power-supply switching cabinet in sequence, the 35kV bus is connected to a direct-current bus through the transformer and a rectifying device II, the direct-current bus is provided with an energy storage system, and the energy storage system is connected to the direct-current bus. A wind power generation system is connected to a direct current bus through a double-cut box and a fan rectifier, a photovoltaic power generation system is connected to the direct current bus through a double-cut combiner box and a photovoltaic DC / DC converter, the direct current bus is connected to a water electrolysis hydrogen production system through a hydrogen production DC / DC converter and a double-power-supply switching cabinet, and an in-station 35kV bus is connected with a power grid.

Description

Technical Field

[0001] The utility model belongs to the technical field of new energy hydrogen production, and in particular relates to an off-grid wind-solar hydrogen storage wiring system. Background Art

[0002] At present, the green hydrogen industry is in the early stages of commercialization, and the supporting policies and industrial chain supply are not yet mature, which makes the cost of the whole process of green hydrogen "production + storage + transportation + use" relatively high, and the unit volume cost on the end-user side cannot currently compete with gray hydrogen and blue hydrogen. Low-carbon hydrogen is the focus of the future development of hydrogen energy, especially with the continuous expansion of renewable energy installed capacity, green hydrogen is expected to be applied on a large scale and gradually replace traditional fossil energy.

[0003] According to the calculation results of the International Renewable Energy Agency (IRENA), compared with the electricity price of 0.42 yuan / kWh, the cost of hydrogen production dropped significantly when the electricity price was 0.13 yuan / kWh, and the decline was significantly higher than the cost reduction caused by the reduction in the cost of electrolyzer equipment, that is, the reduction in equipment cost cannot make up for the impact of high electricity prices. Therefore, using the abandoned electricity of new energy to electrolyze water to produce hydrogen has potential benefits for exploring ways to reduce the price of green electricity hydrogen production, improve the regional energy structure, reduce the abandonment of wind and solar power, and increase the local consumption of new energy. It can drive local economic growth and promote the sustainable development of the social economy.

[0004] In addition, with the development and acceleration of the green hydrogen market, the initial investment cost and operation and maintenance costs of each link in the water electrolysis hydrogen production industry chain will decrease accordingly, and the threshold for commercial investment will be further lowered.

[0005] Therefore, it is necessary to combine the technical characteristics of power supply form and load demand, consider the dynamic matching problem of hydrogen production unit and randomness and volatility of renewable energy, and propose a wind, solar, hydrogen and storage integrated energy system and operation strategy that adapts to the development of new energy. Utility Model Content

[0006] The purpose of the utility model is to provide an off-grid wind-solar-hydrogen storage wiring system and operation method, which has good operating reliability and flexibility, significant economic benefits, and is convenient for engineering application and promotion.

[0007] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0008] A grid-connected and off-grid wind-solar-hydrogen-storage wiring system comprises a wind power generation system, a photovoltaic power generation system, a water electrolysis hydrogen production system and an energy storage system. The wind power generation system is connected to a 35kV bus in a station through a double-cut box via a transformer. The photovoltaic power generation system is inverted through a double-cut combiner box and then connected to the 35kV bus in the station through a rectifier device three and a transformer. The 35kV bus is connected to the water electrolysis hydrogen production system through a transformer, a rectifier device one and a dual-power switching cabinet. The 35kV bus is connected to a DC bus through a transformer and a rectifier device two. The DC bus is equipped with an energy storage system. The wind power generation system is connected to the DC bus through a double-cut box via a fan rectifier. The photovoltaic power generation system is connected to the DC bus through a double-cut combiner box via a photovoltaic DC / DC converter. The DC bus is connected to the water electrolysis hydrogen production system through a hydrogen production DC / DC converter through a dual-power switching cabinet. The 35kV bus in the station is connected to the power grid.

[0009] A further improvement of the technical solution of the utility model is that the wind power generation system includes a wind power generator set, the photovoltaic power generation system includes a photovoltaic module, the water electrolysis hydrogen production system includes an electrolyzer and a hydrogen storage tank, and the energy storage system includes an energy storage inverter and an energy storage battery.

[0010] Due to the adoption of the above technical solution, the technical progress achieved by the utility model is:

[0011] The electric energy produced by the wind power generation equipment of the wind power generation system is adjusted through the double-cut box at the outlet of the wind turbine to adjust the system operation mode. In the off-grid mode, the electric energy required for hydrogen production is directly supplied to the DC bus by the wind power generation equipment through the double-cut box and the rectifier, without going through the fan boost transformer to boost the voltage to a high level and then stepping down and rectifying it for power supply, which reduces the electric energy loss and effectively reduces the initial investment cost, making it economical and applicable.

[0012] The electricity produced by the photovoltaic power generation equipment of the photovoltaic power generation system is adjusted through the double-cut junction box at the outlet of the photovoltaic string to adjust the system operation mode. In the off-grid mode, the electricity required for hydrogen production is directly supplied to the DC bus by the photovoltaic power generation equipment through the double-cut junction box and the photovoltaic DC / DC converter, without passing through the inverter and step-up transformer to boost the voltage to a high level and then step down and rectify it to supply power, which reduces the power loss and effectively reduces the initial investment cost, making it economical and applicable.

[0013] The electric energy produced by the wind power generation equipment is adjusted through the double-cut box at the outlet of the wind turbine generator. In the grid-connected mode, the wind power generation equipment is directly connected to the 35kV AC bus in the booster station and then connected to the grid through the double-cut box and the step-up transformer, without going through the AC / DC rectification and DC / AC inverter links. The electric energy required for hydrogen production is obtained by rectifying the 35kV AC bus after voltage reduction. The harmonics generated in the rectification and inversion process of the power components are reduced, and the initial investment cost is effectively reduced, which is economical and applicable.

[0014] The electricity produced by the photovoltaic power generation equipment is adjusted through the double-cut junction box at the outlet of the photovoltaic generator. In the grid-connected mode, the photovoltaic power generation equipment is directly connected to the 35kV AC bus in the booster station through the switching cabinet and the step-up transformer, and is connected to the grid without going through the DC / DC conversion and DC / AC inverter links. The electricity required for hydrogen production is obtained by stepping down the 35kV AC bus and then rectifying it. The harmonics generated in the power component commutation process are reduced, and the initial investment cost is effectively reduced, which is economical and applicable.

[0015] The energy storage system of the present application is directly connected to the DC bus, and the 35kV bus in the station is connected to the DC bus through a transformer and an AC / DC rectifier unit. In off-grid mode, excess wind and light directly store energy in the energy storage system through the DC bus. In grid-connected mode, excess wind and light resources are stored in the energy storage system after voltage reduction and rectification through the 35kV bus in the station. This ensures that wind and light resources can be fully utilized in both grid-connected and off-grid modes, effectively avoiding wind and light abandonment.

[0016] This application sets up a dual power switching cabinet at the front end of the electrolyzer equipment. One of the two power supplies is drawn from the DC bus, and the other is drawn from the 35kV station bus. In the off-grid mode, the wind, light, and storage devices directly power the hydrogen-making electrolyzer equipment through the DC bus, and can directly use the wind and light electricity to produce hydrogen. In the grid-connected mode, the power supply of the hydrogen-making electrolyzer equipment is obtained by stepping down the 35kV bus in the station. This wiring method ensures that wind and light resources can be fully utilized in both grid-connected and off-grid modes, effectively avoiding wind and light abandonment, the economic efficiency of the power station operation is better, and the reliability of the electrolyzer hydrogen production power supply is improved.

[0017] The off-grid wind-solar-hydrogen storage connection system of the present application has good operational reliability and flexibility, and significant economic benefits, and is convenient for engineering application and promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the utility model's off-grid wind-solar hydrogen storage wiring system;

[0019] Among them, 1. Wind turbine generator set, 2. Photovoltaic module, 3. Electrolyzer, 4. Transformer, 5. Power grid, 6. Photovoltaic DC / DC converter, 7. Energy storage system, 8. Rectifier device three, 9. Rectifier device one, 10. Wind turbine rectifier, 11. Rectifier device two, 12. Energy storage converter, 13. Hydrogen production DC / DC converter. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below in conjunction with the embodiments:

[0021] like Figure 1As shown, a grid-connected and off-grid wind-solar-hydrogen-storage wiring system comprises a wind power generation system 1, a photovoltaic power generation system 2, a water electrolysis hydrogen production system 3 and an energy storage system. The wind power generation system 1 is connected to the 35kV bus in the station through a double-cut box via a transformer. The photovoltaic power generation system 2 is inverted through a double-cut combiner box and then connected to the 35kV bus in the station through a rectifier device 3 8 and a transformer. The 35kV bus is connected to the water electrolysis hydrogen production system 3 through a transformer, a rectifier device 1 9 and a dual-power switching cabinet in turn. The 35kV bus is connected to the DC bus through a transformer and a rectifier device 2 11. The DC bus is equipped with an energy storage system. The wind power generation system 1 is connected to the DC bus through a double-cut box via a fan rectifier. The photovoltaic power generation system 2 is connected to the DC bus through a double-cut combiner box via a photovoltaic DC / DC converter 6. The DC bus is connected to the water electrolysis hydrogen production system through a hydrogen production DC / DC converter 13 through a dual-power switching cabinet. The 35kV bus in the station is connected to the power grid 5. The wind power generation system includes a wind power generator set, the photovoltaic power generation system includes a photovoltaic module, the water electrolysis hydrogen production system 3 includes an electrolyzer and a hydrogen storage tank, and the energy storage system includes an energy storage inverter 12 and an energy storage battery 7.

[0022] The operation method of the above-mentioned wind-solar hydrogen storage system is as follows:

[0023] The difference power between the power generated by the wind and solar power generation system (i.e. wind power generation system and photovoltaic power generation system) and the power required by the water electrolysis hydrogen production system is calculated. The difference power is set as P, and the difference power P = wind power generation power + photovoltaic power generation power - hydrogen production power. The rated power of the energy storage battery is set as Pc. When the wind and solar power output meets the needs of the hydrogen production system, that is, P ≥ 0, the following operation mode is adopted:

[0024] Mode 1: The state of charge SOC of the energy storage battery and the hydrogen storage tank are in the normal working range. When P<Pc, the water electrolysis hydrogen production system produces hydrogen through the hydrogen production DC / DC converter 13 while the energy storage battery is charged with the difference power P through the energy storage converter 12;

[0025] Mode 2: The state of charge SOC of the energy storage battery and the hydrogen storage tank are within the normal working range. When P≥Pc, the water electrolysis hydrogen production system still produces hydrogen through the energy storage battery and the rectifier device 9, while the energy storage battery is charged with Pc through the energy storage converter 12, and the wind and solar power generation unit sends the remaining power ΔP=P-Pc to the grid 5;

[0026] Mode 3: The state of charge SOC of the energy storage battery is within the normal working range, the hydrogen storage tank reaches the maximum value, and when P<Pc, the water electrolysis hydrogen production system stops producing hydrogen, and the energy storage battery is charged with the difference power P through the energy storage converter 12;

[0027] Mode 4: The state of charge SOC of the energy storage battery is within the normal working range, the hydrogen storage tank reaches the maximum value, and when P≥Pc, the energy storage battery is charged with Pc through the transformer and the rectifier device 11, and the wind and solar power generation unit sends the remaining power ΔP=P-Pc to the grid 5;

[0028] Mode 5: The hydrogen storage tank is in the normal working range, the energy storage battery state of charge SOC reaches the maximum value, the water electrolysis hydrogen production system produces hydrogen through the transformer 4 and the rectifier device 9, while the wind and solar power generation unit sends the difference power P to the grid 5 through the transformer 4;

[0029] Method six: When the state of charge (SOC) of the hydrogen storage tank and the energy storage battery reaches the maximum value, the water electrolysis hydrogen production system stops producing hydrogen, and the wind and solar power generation units send all the generated power to the power grid 5 through the transformer 4.

[0030] When the output of wind and solar power generation systems does not meet the demand of the hydrogen production system, that is, P < 0, the following operation is adopted:

[0031] Mode 7: The state of charge SOC of the energy storage battery and the hydrogen storage tank are in the normal working range. When -P<Pc, the water electrolysis hydrogen production system produces hydrogen through the converter while the energy storage battery is discharged at the difference power P through the energy storage converter 12;

[0032] Mode 8: The state of charge SOC of the energy storage battery and the hydrogen storage tank are within the normal working range. When -P≥Pc, the energy storage battery is discharged at Pc through the energy storage converter 12, and the water electrolysis hydrogen production system reduces hydrogen production or uses the grid electricity to produce hydrogen through the grid 5, the transformer 4 and the rectifier device 2 11 when the electricity price is low;

[0033] Mode 9: The state of charge SOC of the energy storage battery reaches the minimum value, the hydrogen storage tank is in the normal working range, and the water electrolysis hydrogen production system reduces hydrogen production by charging the energy storage battery through the energy storage converter 12, or uses the grid power 5, transformer 4 and rectifier device 2 11 to charge the energy storage battery and produce hydrogen when the electricity price is low;

[0034] Method 10: When the hydrogen storage tank reaches its maximum value, the water electrolysis hydrogen production system stops producing hydrogen, and the wind and solar power generation unit connects all its power to the grid through transformer 4. The wind and solar power generation unit is a wind power generation system and a photovoltaic power generation system.

[0035] The off-grid mode is similar to the above-mentioned operation mode, with the following differences: when the output of wind and solar power generation systems meets the requirements of hydrogen production power and energy storage batteries, the wind and solar units are not connected to the grid, and the wind turbine power generation unit uses wind turbine pitch angle adjustment to reduce power operation or the photovoltaic power generation unit changes the maximum power tracking mode MPPT to constant voltage mode to maintain system power balance; when the wind and solar power output does not meet the requirements of hydrogen production power or energy storage batteries, hydrogen production is reduced or stopped according to the SOC status of the energy storage batteries.

[0036] An energy optimization management model is established for the off-grid wind-solar-hydrogen storage wiring system of the utility model. Based on the ultra-short-term power forecast information of wind and solar resources, the wind power and photovoltaic power generation power forecast and hydrogen production load forecast in the station are used as data input for the energy management system in the station. In energy optimization management, the changes in renewable energy resources and power plans in the future are predicted, and the output of wind and solar power generation, energy storage and hydrogen production devices are optimized and adjusted. According to the power dispatch instructions issued by the upper power management system, the local equipment of the wind-solar-hydrogen storage system operates stably and reliably under various operating modes.

Claims

1. An off-grid wind-solar-hydrogen storage wiring system, characterized by: The invention comprises a wind power generation system (1), a photovoltaic power generation system (2), a water electrolysis hydrogen production system (3) and an energy storage system, wherein the wind power generation system (1) is connected to a 35 kV bus in a station via a double-cut box via a transformer (4), the photovoltaic power generation system (2) is inverted via a double-cut combiner box and then connected to the 35 kV bus in the station via a rectifier device three (8) and a transformer (4), the 35 kV bus is connected to the water electrolysis hydrogen production system (3) via a transformer (4), a rectifier device one (9) and a dual power supply switching cabinet, and the 35 kV bus is connected to the water electrolysis hydrogen production system (3) via a transformer (4), a rectifier device one (9) and a dual power supply switching cabinet. The kV bus is connected to the DC bus through a transformer (4) and a rectifier device (11). The DC bus is equipped with an energy storage system. The wind power generation system (1) is connected to the DC bus through a double-cut box and a wind turbine rectifier (10). The photovoltaic power generation system (2) is connected to the DC bus through a double-cut junction box and a photovoltaic DC / DC converter (6). The DC bus is connected to the water electrolysis hydrogen production system (3) through a hydrogen production DC / DC converter (13) and a dual power supply switching cabinet. The 35kV bus in the station is connected to the power grid (5).

2. According to claim 1, the off-grid wind-solar-hydrogen storage wiring system is characterized by: The wind power generation system (1) comprises a wind power generator set, the photovoltaic power generation system (2) comprises a photovoltaic module, the water electrolysis hydrogen production system (3) comprises an electrolyzer and a hydrogen storage tank, and the energy storage system comprises an energy storage converter (12) and an energy storage battery (7).

Images