Currently, the solar cell system has been developed by leaps and bounds. both in terms of increased energy production efficiency and a well-designed safety system But if talking about accidents from solar cell systems In most cases it is inevitable. “The fire of the solar panel” which is still happening today. Therefore, it may be questioned whether Is the developed solar cell system enough? In fact, the cause of the solar panel fire is not caused by the solar cell system at all. but caused by other activities that caused a fire in a separate place Because the solar cell system in general when the fire occurred The on-grid inverter will stop working immediately. But the problem is that the solar panels on the roof will continue to produce energy. As a result, the potential of the solar panels in each string can be as high as 600 volts (Vdc), while the on-site power supply voltage is much lower. which in this case resulted in more fires spreading and there is great difficulty in extinguishing fires.

However, a truly good solar cell system Should be able to prevent the occurrence of fire in all cases, such as the Rapid shutdown system that will stop the operation of the entire solar cell system. Including emergency stop of the solar cell panel when there is a fire.

1 Rank of safety solar energy system (Rapid shutdown)

Rapid shutdown system meets National Electrical Code (NEC) 2017 standards from the United States. which sets out the details of the emergency stop system requirements By setting the voltage level conditions around the boundary around the solar panel for a distance of 1 foot (305 mm.) in all directions, which on June 1, 2022, Thailand by the Engineering Institute of Thailand (EIT) will enforce the safety standards. Advanced Security (NEC) in all new solar cell installation projects in Thailand as well. To raise the standard of solar cell system projects in Thailand

Rapid shutdown or emergency shutdown system It is a system that creates a comprehensive safety for the solar cell system. It can reduce the voltage on the DC (direct current) side of the cable outside the array area. The voltage in the array is reduced to 30 volts in less than 30 seconds and the voltage in the array is reduced to 80 volts in 30 seconds, all of which are UL 3741 tested. such as Power Optimizer from the brand SolarEdge

Power Optimizer Inverter supports Rapid Shutdown

Power optimizer is a small inverter that is installed under the solar panel. Instead, it operates as a combination of both a string inverter and a micro-inverter. This system “optimizes” the current and voltage (DC) before sending it to the string inverter to convert it to direct current (AC).

In the event of a fire within the place where the solar cells are installed The firefighters cut the alternating current (AC) circuit, but the main problem is that the direct current (DC) power is often still working. due to exposure to sunlight This is where the danger is. The power optimizer includes SafeDC™ technology to make it safer. If we disconnect the alternating current (AC) circuit, the voltage on the direct current (DC) cable on the roof will drop below 60 volts, meeting NEC’s Rapid Shutdown requirements.

Now, when the DC side voltage is reduced, in addition to allowing firefighters to more easily control the fire. It also protects solar panel installers and system maintenance personnel. from high voltage DC as well.

Compared to the String inverter system, even if the alternating current (AC) circuit is cut off, the direct current (DC) voltage is still high in hundreds of volts. due to receiving solar energy This will not pass the NEC standard in any way and does not support the Rapid Shutdown system.

In summary, in the event of a fire at a solar-installed facility, the Rapid Shutdown system allows firefighters to stop the direct current (DC) supply within the premises. especially on the roof with solar panels This will prevent the fire from spreading further. and allows firefighters to quickly and safely extinguish the burning fire. At this point, the SolarEdge system is considered to meet the needs of customers in every way. It is a technology that is very needed today and we may soon see NEC standards implemented in Thailand. As well, when more and more factories install solar cells Safety must come first. In the future, every factory will definitely have to install solar cells with Rapid Shutdown system.