Recently, a construction worker at the Changhong project in Zhongshan was killed by a DC electric shock while connecting the array of components. The specific cause is under investigation.
On May 26, 2015, Apple's rooftop solar panel plant in Arizona, USA, caught fire and thick smoke blew up on the scene. The fire department dispatched more than 100 firefighters to control the fire for 30 minutes.
In 2014, a Queensland company sold DC switches with potential safety hazards, and the user’s rooftop solar system triggered at least 70 fires. In China, the phenomenon of fire at the power station due to the quality of the DC switch also occurs from time to time.
Photovoltaic power plant engineering is a complicated and large-scale system project, and any link in it may lead to safety accidents. Therefore, the frequent outbreak of quality problems in photovoltaic power plants will undoubtedly reduce the power generation of the power plant. In recent years, frequent accidents of photovoltaic power plants have also forced us to re-examine. The more reliable the equipment, the lower the end-to-end cost of the power plant. In addition to the core components such as PV modules and inverters that pose a threat to the quality of the power station, the small part of the PV DC switch also plays a crucial role in the smooth operation of the PV power plant.
The important role of photovoltaic DC switch
It is understood that at present, when some manufacturers select components for inverters, combiner boxes, etc., in pursuit of low cost, it is very common to use AC circuit breakers on the DC side. The arc extinguishing capacity of these AC switches and the rated load cutoff are very common. The power is far from enough, and it easily leads to overheating, leakage and sparks. In severe cases, even if the power station catches fire, the operating voltage of the photovoltaic DC switch is high, and the DC current has no zero crossing point. The arc system is more difficult to break off than the AC system. These will also increase the risk of electric shock and fire accidents. Therefore, in the photovoltaic power plant system, the photovoltaic DC switch plays an important role!
Suzhou Puzhao is the only genuine PV DC switch manufacturer in China that can provide various types of DC switches, which can be applied to various applications, including built-in/external locking DC switches, from the installation and debugging process. From the perspective of security, this type of switch has the following characteristics:
1. In the process of installation and debugging of the construction, the DC switch is in the "off" state. At this moment, the DC switch can be locked and locked in the "off" state to prevent someone from misoperation, resulting in an accident.
2. The true DC switch, spring storage force, arc extinguishing grid, grounding of the shell and other designs make the shutdown time less than 5ms, and the arc extinguishing effect is better, effectively preventing the occurrence of accidents such as electric leakage and fire.
3. Imported material, 2.5mm shell thickness, 3mm seal thickness, IP66 protection grade, -25 °C ~ +70 °C working temperature, almost suitable for all types of alpine, high heat, high humidity, acidity, partial alkali, partial salt And other harsh environment.
4. Maximum 1500V working voltage, maximum support 6-channel MPPT design, a variety of models available for a variety of junction box, inverter and other electrical equipment.
5. For the quality of photovoltaic DC switch products, excellent suppliers, high-quality materials, rigorous design, strict quality inspection standards are indispensable.
6. Projoy-related products have been rigorously tested by TUV/UL and other testing organizations, passed and obtained certifications, and have undergone double tests of the experiment and the market.
New intelligent fire protection linkage switch can achieve double isolation
In addition, Promega is also actively developing a new type of intelligent fire protection linkage switch. This DC switch is connected to the AC switch through a separate cable. When the AC power is disconnected, the DC side relay will lose due to the AC signal and it will automatically shut off. The open DC side circuit plays a role of double isolation of the DC/AC circuit. The fireproof linkage switch has the following characteristics:
1. More secure
The firefighters can directly control the AC distribution box so that the AC switch and the DC switch are disconnected, so that all the AC cables and DC cables will be cut off and the power can be completely de-energized to ensure safety.
2. DC switch disconnection is more convenient and quick
Solar panels are generally installed on the roof, and DC switches are installed as close to the solar panels as possible. Firefighters do not need to climb rock to achieve rapid and effective double disconnection of AC and DC circuits.
3. Reduce the DC voltage
Rooftop PV system DC voltage is generally 150V ~ 800V, the same group of battery panels can be connected in series with a number of DC switches, when the switch is disconnected, the system DC voltage is "split" into several segments, thereby greatly reducing the high DC system voltage The risk, and in the fire can be directly sprayed.
4. Easy and quick installation
The firefighters can directly control the AC distribution box so that the AC switch and the DC switch are disconnected, so that all the AC cables and DC cables will be cut off and the power can be completely de-energized to ensure safety. When the utility power is restored, the DC switch will automatically turn on and return to the on state.
The reliability and stability of photovoltaic DC switches are not only related to the safe and reliable operation of photovoltaic power distribution systems, but also to the stable power generation and benefits of the photovoltaic industry. The philosophy of the switch is: Switch to Safety! He is safer!
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