With the drastic decline in photovoltaic panel prices and solar systems’ growing efficiency, we can witness solar installations turning into the world’s fastest-growing renewable energy sources. However, rooftop solar projects are exposed to various elements, and they are vulnerable to lightning strikes, especially in places such as India, where there is a high incidence of lightning. In such situations, solar lightning arresters are crucial equipment.
Here is everything you need to know about the lightning arrester for the solar system.
What is a Lightning Arrester?
A lightning arrester is a safeguarding device installed within a circuit to protect it from damage caused by lightning strikes. These strikes are high transient voltage, isolation arcs and sparks, and surge currents produced by lightning. Lighting arresters are installed to protect the equipment from lightning and send excessive voltage to the ground if needed. In addition, ground wires or earthing can protect electrical systems as well as overhead wires from a direct lightning strike.
In a solar rooftop system, a lightning arrester is a watchman who is alert on all sides, shielding the installation against the destructive force of lightning strikes. On top of this name are surge protectors and lightning diverters, allowing lightning to pass through low-impedance paths instead of bringing excessive electrical surges into the solar panels and their associated electrical equipment. In so doing, they prevent or at least alleviate damage resulting from the tremendous electrical energy released during a lightning strike.
How Does a Lightning Arrester Work?
A lightning arrester – also known as a surge diverter – is used at substations to protect circuits from wave damage. It has the function of leading abnormally high voltage to earth while at the same time keeping power supply continuity. Connected between the line and the earth, lightning arresters work in parallel with equipment at a substation that should not be exposed to risk.
Lighting Arrester Mechanism
In locations near critical equipment or access points, such as an electrical panel or generator, arresters are usually installed. When lightning occurs, the arrester goes to work and directs the bolt away from its target back to the ground, where it can disperse safely.
More importantly, it should be understood that a lightning arrester does not prevent lightning from striking; instead, it actually induces a more restricted and well-managed electric charge. By offering a safe path for lightning to go along, it is able to lead the harmful electricity that would otherwise damage expensive or important electrical equipment into a harmless discharge.
Lightning arresters form an integral part of a total lightning protection system. This provides greatly increased protection against damage. When a travelling wave comes to the arrester, it passes through a predetermined voltage that causes it to flash over and provide a conducting channel for low-impedance waves between line and ground, thus limiting the amount of current to ground and protecting equipment insulations this way.
Types of Lightning Arrester
The high functioning of lightning arresters is complex, and there are many different types out there. The design of each may be different, but its basic concept is the same: to provide a route of low resistance for surges travelling towards the ground. Other names for this device are surge diversion methods and lightning dischargers.
Here are seven types of lightning arresters for solar panels,
Copper Lightning Arrester
A copper lightning arrester is made up of a copper-bonded rod with around 45 or five spikes on top. Voltage spikes from electrical storms are absorbed by it and allowed to pass through the solar system, electrical wiring and any other household devices. The rod’s insides are solid, high-tensile steel with an outer covering of pure copper. Usually, a copper strip or wire connects the lightning arrester to the ground earthing rod so that the surge current can then pass to the ground via the earthing system.
Horn Gap Arresters
This type of lightning arrester is made up of two horn-shaped metal rods arranged so that they cover a small air gap. The gap between the rods can be adjusted, while ceramic insulators underneath the metal rods keep them separated. One side of the horn is connected to the line, and the other via a resistance and choke coil effectively to the ground.
Valve Type Arresters
High power-electrical systems benefit from valve-type lightning arresters, which comprise a series of spark gaps and non-linear resistor plates. When the voltage across the spark gap exceeds a predetermined level, the gap breaks down, and surge current is conducted to earth through the valve assembly.
Metal Oxide Varistor Lightning Arrester
One part of the two parts is a ceramic casing filled with metal-oxide discs. The highly non-linear resistance of metal-oxide material decreases with voltage and effectively protects against surges in this way. These discs are connected in series with equipment being protected, and the entire assembly is earthed.
Hybrid Lightning Arrester
Combining the features of both rod-type and metal oxide varistor lightning arresters, the hybrid lightning arrester provides excellent protection from lightning indifferences. It comprises a metal oxide disc connected in series with a spark gap. If the surge current exceeds the breakdown voltage of the spark gap, then the metal oxide disc takes over and provides additional guard.
Rod-type Lightning Arrester
This is the most common and traditional kind of lighting arrester for solar systems. A metal rod or tube, usually made of copper or aluminium, is suspended on tall buildings or structures. What the rod will do is make it obvious for air molecules (attracting them through corona discharge and ionising them) to provide a low resistance path between the sky and the ground. So it attracts lightning and then acts like a beacon telling where to go when it comes down to the ground.
Multiple Gap Arresters
These arresters are composed of a series of insulated metal cylinders separated by air gaps. The first cylinder is connected to the electric line, while other cylinders are connected to the ground through resistance. Some inter cylinder shunt resistances enterprise is used to protect against surges when there is a voltage mismatch.
Importance of Lightning Arresters in Solar Installations
Lightning arresters protect solar panels against lightning and protect the complicated circuitry of inverters, charge controllers, etc. These components are easy prey for lightning power surges. Dispatching high-voltage surges and sharing them with the collective system’s distributed capacitance, this arrester ensures that regular operations are maintained among its nodes while also avoiding expensive repairs and low-quality machinery.
Also, lightning arresters are compulsory in many areas, for this isn’t just a precautionary measure. Electrical standards and building codes stipulate that lightning protection systems, including arresters, must be provided in order to guarantee fire and injury are not brought on through lightning strikes. Nevertheless, the quiet survival of arresters should not be overlooked in the alternative energy industry.
Advantages and Disadvantages of Lightning Arresters
Because of the use of lightning arresters, there are a number of advantages as well as disadvantages.
Here they are:
Advantages
- Minimises the damage done to property by lightning strokes
- Guards outdoor equipment at substations
- Prevents power surges in outlets
- Reduces interference on the electromagnetic field
- Ease of use
Disadvantages
- Requires more space for installation
- High installation cost and maintenance is a headache.
Surge protectors and lightning arresters are devices specifically designed to absorb voltage surges and protect electronic equipment. It should be noted, however, that these devices cannot replace appropriate grounding. Only if a good grounding system is in place are they effective. Consequently, a good grounding system should be installed either before or at the same time as the power line is put in place because neglecting this very critical component could have the potential to cause safety hazards.
In conclusion, the lightning arrester acts as a silent sentinel, protecting the durability and service life of systems whose prime energy is derived from sunlight. Despite the fact that its role is so little recognised, it’s absolutely vital function in guarding against the destructive fury of nature deserves more attention in the solar technology realm.
