How to choose a string level rapid shut down switch?

Addtime:2021,06,04

As a low-carbon renewable energy, solar energy is not only rich in resources, pollution-free to the environment, but also an energy that humans can freely use. Therefore, solar energy has become the focus of attention with its unique advantages, and the installation of solar energy systems has also increased year by year. As the power generation application closest to the human activity area, how to ensure personal safety, how to prevent the fire risk of photovoltaic installations, and how to ensure that non-professionals recognize and cut off the risks in the first time have become widespread concerns in the photovoltaic industry.


For photovoltaic systems, there are two major safety hazards: "DC high voltage risk" and "rescue risk". In a traditional string system, the voltage of the entire string can generally reach a high voltage of 600V to 1000V. Due to the loose contacts of the photovoltaic module joints, poor contact, dampness of the wires, and rupture of the insulation, the strings can easily cause DC arcing and cause fires. On the other hand, when a fire accident occurs due to arcing or external reasons, the solar panels on the DC side will generate electricity as long as there is light, so high voltage always exists. Therefore, firefighting is very dangerous. Firefighters cannot rescue the scene and can only control the fire from a distance. At the same time, intelligent operations such as intelligent monitoring, controlling access and disconnection of photovoltaic power generation systems are also a direction and trend of the current industry development. Therefore, in order to improve the safety of photovoltaic systems, NEC2017 (U.S. Electrotechnical Act 2017) proposes rapid shutdown (RS)requirements for photovoltaic systems.


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Quick shutdown is the concept of photovoltaic power plant safety protection introduced from the National Electrical Code (NEC). The concept of quick shutdown is proposed to protect firefighters, installation and maintenance personnel of photovoltaic power plants. Therefore, the National Electrotechnical Code NEC2014 clearly requires that photovoltaic power plants need to have a rapid shutdown capability at the panel level to provide the best system safety. The quick-shut-off start switch needs to be installed in a place that can be reached at any time outside the building and equipped with a quick-shut-off indicator, so that timely measures can be taken.


The design service life of photovoltaic systems is as long as 25 years. At the same time, the number of household distributed projects is increasing rapidly, which puts forward high requirements for the safe and stable operation of photovoltaic power stations. A complete safety protection mechanism will greatly reduce major risks such as fires in the long-term operation of photovoltaic power stations.


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At this time, Aswich developed and launched the ERS series rapid shut down switch(RS switch). After installing the Aswich RS switch, firefighters can remotely turn off the AC power before extinguishing the fire. The quick-shutoff switch will automatically disconnect the internal DC isolation switch after collecting the signal from the power grid. Because the quick turn-off switch is close to the photovoltaic module, it will also directly cut off the DC current, creating a safe fire-fighting environment for firefighters, reducing the economic loss of the fire, and ensuring the safety of the photovoltaic power station. At the same time, the fire safety switch has an automatic reset function. If the AC power supply is disconnected (such as a power failure) and the power supply is restored, the ERS series fire safety switch can be automatically closed. There is no need to manually reset each time.


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10 reasons to choose Aswich ERS series Rapid Shut Down Switch: 

1. It is applicable to a wide range of voltage and current, suitable for photovoltaic systems of 600V~1500V, 9A~55A, and a single switch can turn off up to 5 strings of current at the same time 

2. Wider range of AC voltage:  100~270Vac

3. Use internal motor drive to disconnect. It can be turned off by an AC switch, or it can be turned off remotely 

4.LED indicator, ON or OFF can be easily identify status

5.IP66 level, suitable for outdoor installation fully

6.Knock outs | Cable glands | MC4 connectors optional/1m AC cable optional, Convenient for customers to install

7.Equipped with breathing valve to avoid condensation inside the enclosure

8. Low noise when running, which does not affect people's normal life

9.Built-in temperature sensor, Shut down automatically exceeding 80°C

10.Modular design of product components, fast and convenient after-sale service。


How to choose suitable model of ERS series rapid shutdown switch:

1. Confirm the voltage and current required by the photovoltaic system

2. interface requirement: Knock outs | Cable glands | MC4 connectors optional

3. 1 meter AC cable required or not

4. 1~ 5 strings available


Aswich is a manufacturing plant with more than 40 years of production experience. Its push-button switches, universal changeover switches, DC isolating switches, MCCB and circuit breakers are exported to many countries and regions. With excellent cost performance, excellent product quality and quick after-sales response, this product has been selling well and has been continuously praised by customers.


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