In recent years, fire accidents in photovoltaic power plants have occurred frequently. In August 2014, a rooftop photovoltaic power station in Wuhan caught fire, and the roof of the color steel tile was burned through several large holes, and the equipment in the plant was burned down, resulting in heavy losses; In May 2015, the roof of Apple's factory in Mesa, Arizona, which Apple has been proud of, suddenly caught fire, and the fire started with photovoltaic modules on the roof of the building. In October 2023, a fire broke out at a photovoltaic enterprise in Gaoyou Guoji Industrial Concentration Zone, Yangzhou City, and the entire plant was burned down; In February 2024, a devastating fire broke out in a £70 million warehouse in the UK where photovoltaic modules were installed on the roof...... Once a serious accident such as fire occurs in a photovoltaic power station, it will not only affect the safety of the power station, but also cause harm to the plant facilities and personnel below the power station. Safety has become the primary consideration of photovoltaic power plants.
Photovoltaic power station fire extinguishing system scheme
There are many reasons for fire accidents in photovoltaic power stations, such as aging or failure of equipment and cables, resulting in short circuits; Improper selection and installation of fuses and circuit breakers, resulting in DC arcing; There is a lot of bird droppings on the PV module panels, which causes the hot spot effect, which leads to the partial burning of the battery and even fires. There is a lot of dust inside the combiner box, and the internal electronic components have poor heat dissipation and short circuit, which leads to the hot melt combustion of the insulating layer of the wire, and ignites the dust and fibers accumulated on the wire, thus causing fire accidents.
First of all, let's talk about what a photovoltaic power station is, in fact, a photovoltaic power station is a device that uses the photovoltaic effect to convert solar energy into electrical energy. So what are the components of photovoltaic power stations and how does it work? And what is the reason for the frequent fires in photovoltaic power plants? The following Nianhai Fire will give you a detailed introduction.
1. The components of a photovoltaic power station can be briefly described as follows:
1. Solar panels: Solar panels are the core components of photovoltaic power plants, and their main role is to convert solar energy into electricity.
2. Inverter: The inverter is mainly used to convert the direct current signal emitted by the solar panel into an alternating current signal, so that it can be easily transmitted to the grid or used for local power supply.
3. Capacitors and inductors: Capacitors and inductors are generally used to balance the frequency of an alternating current signal and the peak of the current.
4. Power grid: A power grid is a network that transmits the electrical energy generated by a photovoltaic power station to the place where it is needed to supply electricity.
5. Grid-side transformer: Grid-side transformer is mainly used to increase the output voltage and connect to the grid.
6. Auxiliary equipment: including rectifiers, controllers, protection equipment, monitoring equipment and other equipment used to control, protect and monitor the operation of photovoltaic power plants.
2. The working principle of photovoltaic power station can be briefly described as follows:
1. Sunlight irradiation: When sunlight hits a solar panel, it excites electrons, causing electrons to jump into conductors, a phenomenon known as the photovoltaic effect.
2. Direct current generation: The wires in the panels are connected to an inverter, which converts direct current (DC) into alternating current (AC) for use in homes or industries, thus making solar power generation available to users on the grid.
3. Grid power supply: The electricity generated by the photovoltaic power station will be sent to the grid for users to use. If more electricity is generated in the PV plant than needed, the surplus electricity can be sold to the power company and distributed to other users.
3. Solar panel fire extinguishing system scheme
(1) Causes of solar panel fire:
1. Quality problems of solar panels: Some solar panels have hidden quality hazards in the production process, such as poor materials, poor welding, etc., which are prone to failure and short circuit during use.
2. High temperature environment: In a sunny and high temperature environment, solar panels will generate a lot of heat. If the heat is not dissipated properly, it can cause the temperature inside the solar panel to be too high, which can cause a fire.
3. Junction box problem: The junction box of the solar panel may be aging and short circuit due to quality problems, improper installation or long use time, which will cause fire.
4. System design problems: the design of the solar system is unreasonable, such as the layout of the modules is too close, resulting in poor heat dissipation; Or the solar street light is designed with too much power to exceed the capacity of the panel, which can cause a fire.
5. External factors: such as excessive dust on the surface of solar panels, which leads to the aggravation of the hot spot effect; Or there are flammable debris near the solar panel, and accidentally touching the solar panel can cause a fire.
Photovoltaic power station fire extinguishing system scheme
In fact, 40% of the fires in photovoltaic power stations are caused by DC arcs, because there are thousands of joints in the entire power station, and any loose joint may cause DC arcs, and as soon as there is an arc, it will cause fires, which is very clear. In addition to the selection of high-quality modules, inverters, cables, connectors, combiner boxes, ......, it is also necessary to install automatic fire extinguishing devices for the photovoltaic system.
(2) Solution: Configure a small hot aerosol fire extinguishing device
1. It is a small fire extinguishing device suitable for small spaces.
2. No need for external power supply, small size, easy to install, can be fixed with screws L-shaped, or directly fixed with 3M glue, without damaging the cabinet in the protection area.
3. Long service life, standby time up to 5 years.
4. The temperature of the nozzle is not more than 75°C, which does not affect the surrounding objects.
Application scenario: Small hot aerosol fire extinguishing device is mainly used in important cabinet equipment such as substation and distribution room, electronic equipment room, generator room, uninterruptible UPS room, communication room, high and low voltage distribution cabinet, signal base station cabinet, cable shaft and other important cabinet equipment.
Photovoltaic power station fire extinguishing system scheme
Fourth, box-type transformer fire extinguishing system scheme
(1) Causes of box-type transformer fire:
1. Short circuit in winding: Short circuit in box-type transformer winding is one of the main causes of misfire. A short circuit in the windings generates a large amount of current, which causes the temperature to rise, which eventually leads to a misfire.
2. Insulation aging: The insulation of the transformer will inevitably be affected by the environment and pressure during use, resulting in aging. When the insulation deteriorates severely, there is a risk of misfire.
3. Running too long with no load: When the box-type transformer runs in the no-load state for a long time, it will produce too high induced voltage and induced current, which will cause the risk of fire.
4. Leakage: The leakage of the box-type transformer is also one of the causes of fire. Leakage can lead to overloading of the circuit, which in turn increases the temperature of the windings, accelerates insulation aging, and can ultimately lead to the risk of fire.
(2) Solution: heptafluoropropane fire detector tube fire extinguishing device
1. Alarm and fire extinguishing in one, point-to-point fire extinguishing, a fire extinguishing device suitable for fire extinguishing in small spaces.
2. No need for any power supply and fire alarm controller.
3. The design is simple, the installation is simple, it does not occupy the user's limited space, and there is no need to set up a cylinder room.
4. It is very close to the protective object, with high fire extinguishing efficiency and low cost.
Application scenarios: The fire detector tube fire extinguishing device is mainly suitable for small space substation and distribution cabinets, electronic equipment rooms, meter wave machine rooms, uninterruptible UPS rooms, relay rooms, cable cross dense and intermediate joints, elevator control cabinets, wire and cable troughs or bridges with slot boxes, special or important cabinet equipment with relatively sealed shells in gas places, etc.
Photovoltaic power station fire extinguishing system scheme
According to the cause of the fire in the photovoltaic power station, we can divide different protection space areas, and we can also configure a responsive fire extinguishing system scheme. However, there is no special fire protection design specification for photovoltaic power stations, and the fire extinguishing system scheme on the market is also designed according to the existing area.