How critical are wind solar hybrid systems to modern communications?
As mobile phone users increase, there are higher requirements for wireless signal coverage.
In some rural areas and remote mountainous areas, if the power supply of telecommunications base stations is not effectively guaranteed, there will be no signal. Your mobile phone will not be able to make calls or access the Internet.
In the past, diesel generators were used for emergency power supply. However, due to transportation and diesel shortages, electricity costs will be higher.
To provide a scientific power supply solution for telecommunications base stations, it is recommended to choose solar and wind energy.
This will provide a stable 24-hour uninterrupted power supply for the base stations.
1-Why was wind solar hybrid power generation technology born?
Traditional solar power generation alone does not provide enough power.
Solar power generation only works under sunlight, and the power generation effect is better in summer than in winter. A cloudy or rainy day will weaken or even stop solar power generation, affecting the base station’s power supply.
This type of problem also exists in solar energy storage systems used in homes, factories, hospitals, etc.
Wind power generation needs to generate electricity normally when the wind speed reaches 5m/s, regardless of whether it is rainy or cloudy.
These two renewable energy sources have their drawbacks, but if they are combined, they will break down barriers and realize 24-hour uninterrupted power generation.
Then, the application of wind solar hybrid systems to generate electricity at communication base stations can effectively improve the comprehensive utilization of wind and solar energy.
Realizing an all-weather power supply for communication base stations improves signal facilities’ stability and sustainability.
2-Composition and working principle of wind solar hybrid systems
Wind & solar hybrid power generation consists of wind turbines, controllers, inverters, photovoltaic arrays (solar panels), battery packs (lithium batteries or gel batteries), DC and AC loads, etc.
Wind turbines convert kinetic energy into electrical energy, and solar panel array components use the photoelectric principle to convert solar energy into electrical energy.
Among them, the battery pack plays a crucial role in storing electrical energy during system operation. When the sun and wind are sufficient, the remaining electrical energy will be converted into storage.
At night, when the photovoltaic module generates insufficient power, the battery provides power for electrical equipment.
The hybrid controller continuously adjusts to changes in sunlight intensity and load.
When the power is sufficient, the controller will transmit the generated power to the load, and the remaining power will charge the battery.
If the power generation cannot meet the power needs of the base station, the controller can effectively control the battery to supply power to the load.
3-Requirements of solar and wind energy system technology in communication base stations
(1) Requirements for power supply stability
Communication base stations and related equipment require continuous operation 24 hours a day. Only a continuous power supply from the power generation system can effectively ensure mobile phone users’ normal use.
In the wind solar hybrid system, the power generation effect of wind turbines is very sensitive to the utilization rate of wind energy, and sometimes there is the problem of unstable power generation.
Therefore, technicians must use the wind turbine’s power generation as a reference point when conducting system stability assessments.
In the wind-solar complementary power supply system, energy storage equipment capacity should be increased as much as possible to fully ensure stable power supply operation.
(2) Equipment operating power requirements
As the number and capacity of communication equipment increases, the power of the entire power supply system is also developing and transforming towards high-power operation.
However, base stations are difficult to establish in some remote areas.
When installing the power supply system at the same time, there are still restrictions on the construction site, site selection, and equipment installation.
This makes it very difficult to install large turbines near base stations.
Therefore, technicians must conduct comprehensive research to understand the local installation environment. They must then recommend whether you use a horizontal axis or a vertical axis wind turbine to meet the energy needs of the communication base station operation.
For example, the 25kw wind and solar hybrid system project uses vertical axis wind turbines to provide power to local communication and broadcasting stations. — You can click on the orange text to learn more about this project.
(3) Requirements for power generation system controllers
The solar and wind energy system controller is the core of its power generation system and determines the system’s operating status.
The controller’s operating range can improve wind turbine efficiency. It protects the power system.
When an abnormality occurs in the wind power supply system, the controller will respond promptly to protect the generator set during high-speed operation.
At the same time, the controller can also adjust the power supply operation range of wind turbines and solar energy settings. It can apply complementary power sources to improve communication base stations’ stability.
4-How to design a wind & solar hybrid system for telecommunications base stations?
General telecommunications base station loads include signal processing, receiving equipment, and temperature control equipment to control and regulate temperature.
Signal processing equipment accounts for about 50% of the total electricity consumption, and computer room air conditioners account for about 40% of the total electricity consumption.
Most base stations rely on UPS power systems. The power supply system is connected in parallel with the battery to continuously power the equipment. The system power exceeds the base station’s operation.
In this process, energy is consumed, but costs are also increased.
Since the power generation of the wind-solar hybrid system is based on solar and wind energy resources, the power generation of wind turbines and photovoltaic arrays is determined based on meteorological resource data.
Wind turbines and solar energy convert renewable resources into electricity.
When the wind speed changes, the turbine power also changes.
Photovoltaic modules also change power with radiation.
Reduce costs by meeting the needs of the power supply system, a combined power supply system consisting of wind turbines and battery panels.
Where power is provided, the hybrid power supply system is double-fused, doubling the system output. Rechargeable batteries can reduce backup power consumption compared to wind or solar systems.
In a hybrid solar pv and wind energy system, solar energy data, wind resource data, and battery design must be completed. System simulation analysis is necessary to derive system modeling to meet requirements.
Solar power generation during the day can reduce battery charge and discharge times and extend service life.
The wind power generation system can be operated at night or on rainy days, making up for solar power generation limitations.
Take a certain communication base station as an example.
Assumption: The maximum peak power consumption of telecommunications base stations is no more than 3KW, and the total designed power supply requirement is 6KW.
To establish this base station, a cabinet air conditioner must be equipped for heat dissipation. The next step is the calculation process.
Solar capacity calculation
Using the solar radiation data of the meteorological software METEONORM7, the query data are as follows:
Explanation: According to the above data, the amount of solar radiation shows that the average annual sunshine hours in this area are 1908 hours, and the average sunshine duration is 5.23 hours.
The effective sunshine hours for calculating the power supply system configuration are 5.23 hours. This value is effective when the solar array elevation angle is 40 degrees.
Solar power generation in the wind-solar hybrid integrated power supply system: S (solar) = ɳ×t×P×N/J
S (solar) = solar module calculations;
J = Redundancy coefficient. This time the value is 1.1, which is about 10% redundancy;
P = power generation of a single module. This time 440Wp;
t = local effective sunshine time, which is 5.23 hours as found through query;
ɳ = Partial working efficiency of solar modules, solar module redundancy coefficient is 0.85;
Formula description: According to the following configuration formula, the entire system has t hours of effective sunshine every day
The calculation results are as follows:
S light = ɳ×t×P×N/J = 0.85×5.23×440×40/1.1 = 71.1KW
Wind power generation calculation
Assumption: The base station is located in an area where the maximum wind force can reach levels 7-8, the maximum wind speed can reach 30m/s, and there is no typhoon in the area.
You can check your local wind speed through the meteorological department’s statistical data and enter the specific installation address.
Calculation formula for wind power generation in a wind-solar hybrid integrated power supply system:
S wind = ɳ×t×P
S wind = wind power calculation;
ɳ = wind starting efficiency, 70% based on weather conditions;
t = local annual average effective hours, generally calculated as 8128 hours;
P = the rated power of a wind turbine (KW);
S wind = ɳ×t×P=70%×(8128/365) ×5= 77.9KW
The total capacity throughout the day is the sum of S light + S wind capacity. This is, the total planned capacity is 155KW, which meets the 144KW (6kw*24h) power supply demand of the site.
Battery capacity calculation
Formula: Q=KIT/η[1-0.006(25-t)]
Q = battery capacity
K = insurance coefficient (generally between 1 and 1.25), this time the value is 1.0;
I = load current, 3000W load, current rounded up to 63A (3000/48=62.5A);
T = Maximum continuous power supply time of the battery. This time it is set to 8 hours of backup, with a value of 8;
η = Battery depth of discharge coefficient or DOD. The value is 0.5.
t = ambient temperature, so this time the battery operating temperature is -15°C; the calculation results are as follows:
Q=KIT/η[1-0.006(25-t)] =KxIxT/ηx[1-0.006(25-T)] =1072.34Ah
Therefore, if you choose the gel battery specification, a single cell is 2V500Ah, and 24 cells are connected in series to form a group. This is a total of 2 groups, 48 cells, forming 1000Ah/48V.
If lithium batteries are recommended at 48kwh.
Based on the current analysis of the future power demand of the base station, the power consumption of communication equipment, lighting, and other instruments is around 3000W.
In addition, wind and solar hybrid systems are regulated by the power supply system.
The power control system requires an inverter to provide power supplies for air conditioning, lighting equipment, and other equipment. It also requires a management cabinet system and a remote monitoring system.
Management cabinet equipment should include AC and DC power distribution cabinets, wind energy, and solar energy control modules.
Communication between the remote power monitoring system and the monitoring center is realized using the operator’s 4G-5G network.
5 – How do you install a wind and solar hybrid system?
Based on the photovoltaic panel array, it is installed on the ground and faces south.
A cement foundation supports the PV panel array.
Due to the system installation location, brackets with anti-corrosion properties are used.
Wind resistance requires each pillar to form an interconnected network structure, and the cement foundation and brackets should be connected and fixed by bolts.
The battery is installed indoors on a battery rack.
Make sure the wind turbine head tower is fixed with cable stays by analyzing the environmental conditions at the installation site.
To achieve increased wind collection, the wind turbine head is fixed to a tower to avoid mountains.
The solar control box rack is fixed to the ground. Due to its small size, the wind energy controller can be fixed to the wall to save space.
For specific installation details, click on the orange font to jump to the corresponding article.
Conclusion
To sum up, mobile technology is developing faster, and mobile base stations are spreading around every corner. However, due to regional economic and power laying reasons in some areas, they cannot cover remote areas.
Therefore, to ensure stable and reliable power supply operation during communication base stations, new energy sources need to be developed and applied.
With the development of wind and solar hybrid systems, their practical applications will no longer be limited to remote areas in the future.
For example, small-sized vertical spiral axis wind turbines can be used and installed on the roofs and balconies of ordinary civilian houses (apartments).
Energy applications need to complete the urban base station power supply.
At present, wind and solar hybrid power supply systems require higher requirements for base station power.
To implement new energy development, our team will continue to conduct technical research in the future.
