Rooftop distributed photovoltaic has been used extensively in Europe, the United States, Australia, China and Japan. As the application closest to the human activity area, more and more emergency crew and firefighters of photovoltaic plants are aware of the potential safety hazards of photovoltaic systems. And how to ensure personal safety, how to prevent the fire risk of photovoltaic facilities, how to ensure that non-professional personnel identify and cut off the risk in the first time, has become a widespread concern of all countries.
Potential safety hazards in photovoltaic system
In fact, the photovoltaic system is not as safe as we think.
We all know that DC isolator is integrated into the solar inverters, but even when the DC isolator is turned off, there will still be up to 600~1500Vdc between the inverter and the PV panels.
As long as there is radiation on the panel, a voltage of 600~1500Vdc will be generated on the DC side. If fire happens in installation without firefighter safety switch, the high voltage DC current inside the panel array or between the panel array and the inverter will threaten the personal safety of firefighters. On the other hand, most of the circuits of photovoltaic plants used 600 ~ 1000V (some even up to 1500V) DC circuit. In an actual power station, DC arcs can be caused by fault such as poor connection, poor contact quality, insulation aging, and damp insulation, etc. Photovoltaic modules continuous generate electricity when a DC fault occurs. The DC current does not have a zero-crossing, so the fault current at the trigger location will persist for a long time and further cause a fire, firefighters may be exposed to very serious potential hazards.
Based on the market demand, PROJOY has successively launched series of firefighter safety switches of String level PEFS-EL and panel level PEFS-PL.
PROJOY firefighter safety switch ensures the safety for Photovoltaic system
Projoy's PEFS-EL series firefighter safety switch is applied to residential PV system or industrial and commercial PV system, its maximum loop voltage can be up to 1500V which meets the requirements of high-power panel.
· Seize the valuable time to put out fire
PEFS series firefighter safety switch matches international standard firefighter working procedure. When a fire occurs in the photovoltaic system, the AC side will be disconnected firstly. Meanwhile, Projoy’s PEFS-EL firefighter safety switch will collect the signal of power outage. If the power outage time exceeds 5 seconds, it will automatically disconnect the isolation switch and then disconnect the DC side, creating a safe environment for firefighters.
On the other hand, relying on advanced temperature sensor to real-time monitoring the temperature inside the enclosure, Projoy’s firefighter safety switch can automatically disconnect the switch if the inside temperature exceeds 70℃.
· l Isolate PV panels completely
The PEFS series use PEDS DC Isolator and can be used directly with PV panels. In case of fire, the firefighter safety switch can rapidly shut down the PV array, without any risk of high DC voltage. If the client wants the entire roof to achieve an even lower DC voltage (e.g. under 80V ~ 120V), it is possible to apply multiple safety switches (one for each 2-3 panels) to ensure maximum safety.
· l Reset automatically
Projoy's PEFS series firefighter safety switch resets automatically. When the AC power supply is turned off (e.g. during a power cut) and then the supply is restored, the PEFS series will reset and connect the circuit quickly and automatically. The client doesn't need to reset it manually each time.
· Requires no additional networking and more stable on-off ability
Compared with common fast isolation devices using remote communication technology in the market, Projoy PEFS series firefighter safety switch is directly controlled by the AC circuit which requires no additional networking. It just uses the existing AC power system. In addition, PEFS does not carry out on-off function through electronic components, but through an isolation switch with arc-extinguishing function, which disconnects the DC circuit directly with much more stability.
· l Prolong the life cycle of solar inverter
When Projoy's PEFS product is installed in the system, in case the AC circuit has no power such as during a power cut, powerline maintenance or grid failure, the DC circuit will be automatically shut down. This will greatly prolong the life of the solar inverters, and makes it safer to repair or replace solar inverters.
· l Use the most popular DC switches
Projoy's PEFS series are equipped with a PEDS DC isolator, which is the most popular PV application DC isolator worldwide. The response time of Projoy's spring mechanism bounce is only 5 milliseconds, which can quickly extinguish the arc. Combined with self-cleaning contacts, the switches have increased durability and safety. For this reason, the PEDS has been selected as the preferred DC switch by many PV inverter manufacturers.
· l Professional DC Isolator manufacturer
PROJOY has rich experience in developing DC switches and has customers worldwide. PROJOY has become the No. 1 company in China developing physical isolation with arc extinguishing capability for direct current without using remote communication technology, effectively ensuring the safety of high DC voltage roofs.
· l 25-year long life design for photovoltaic system
Projoy's PEFS series products use industry level capacitors and motors, and strictly control the internal key components. It can work normally in harsh environments from minus 20°C to 70°C. It is equipped with a waterproof breathable valve to effectively avoid cavity condensation. The designed life span can meet the operation requirements of the photovoltaic system which is 25 years.
With excellent performance, professional after-sales team replies on fast response to solve the customer’s needs, this product sale hot in the European market, get customer praise constantly.
More details can be found on the vide of PROJOY firefighter safety swith: https://youtu.be/kDtmyNxZl1A