In photovoltaic installations, one of the priorities is to ensure maximum safety for facilities and people staying in them. Equally important is the efficient operation of the installation, which is why they are equipped with so-called surge arresters. What features must an arrester meet and what are the consequences of its absence?
Check surge arresters at the Onninen wholesaler
Photovoltaic installations and their protection with surge arresters
One way to obtain energy from renewable sources is to choose a photovoltaic installation. Their installation is associated with meeting certain requirements, including proper protection of the system, among others against overvoltages. In a system without protection, failure could very easily occur. Regardless of the reason for the overvoltage, it can lead to damage to the panels themselves, as well as inverters, cables, or other elements important for the proper operation.
Protecting a photovoltaic installation from overvoltages is essential due to the specifics of the installation and the location of the panels. Located outside the building, they are exposed to harsh weather conditions. The greatest threat is a lightning strike. It does not have to hit the panels directly, because even a distance of several kilometers can lead to an inductive overvoltage and failure.
Appropriate protection protects the installation from interference occurring in the electrical network. If the PV installation is connected to the electrical network in the building, which makes them vulnerable to failures and overvoltages caused by incorrect operation of devices in the network. The use of appropriate overvoltage protection prevents failures and high costs of potential repairs.
The mechanism of operation of surge arresters consists in removing excess surge energy from the system in order to protect operating devices and components. This energy is then redirected to the ground. In photovoltaic installations, DC and AC surge arresters are used.
In practice, different types of arresters are used in installations. Depending on the class, these are arresters:
- type 1 – used where the risk of direct lightning strike is high, including systems with external lightning protection;
- type 2 - most often used in photovoltaic installations, where the greatest threat is the so-called inductive overvoltages related to atmospheric discharges or coming from the network;
- Type 3, which are used in conjunction with Type 2 models, their role is to provide additional protection for electronic devices particularly sensitive to voltage spikes.
What features must a surge arrester for PV systems meet?
In photovoltaic installations, special surge arresters are used, which are resistant to high and low temperatures. Due to the fact that photovoltaic panels are installed outside, they are exposed to frost, wind, rain, and in summer also to solar radiation. For this reason, the arresters used must be durable and prepared to work in extreme temperatures. It is assumed that the range should cover the range from -40°C to +85°C.
The second important factor is high impulse strength. The protection must be able to accept an impulse even of a large value, without the risk of damage. This value must be large, in the order of 40 kA, and when a type 1 surge arrester is used - even higher. The safety of the entire system depends on it.
Consequences of not using appropriate PV surge arresters
Overvoltage protection is essential in photovoltaic installations. A sudden increase in parameter values and the occurrence of overvoltage could lead to serious failure of photovoltaics, inverters, cables and connectors.
The occurring overvoltages of the electrical installation create a risk of fire in the panels. This is why it is so important to provide maximum fire protection. It should be remembered that a fire in the panels is also a threat to residential buildings.
For proper protection, a surge arrester is used, adapted to the needs of a specific installation. Its selection must be compatible with the installation's lightning protection system.
The lack of a limiter in electrical installations near photovoltaic panels may lead to a decrease in operating efficiency and power outages.