Protection Against Lightning on Solar Systems


Solar power systems are at risk from thunderstorms. The cumulonimbus cloud layer contains many positive and negative charges, resulting in many electric dipoles and multipoles due to the separation of positive and negative charges.

How Does Lightning Cause Damage?

Damage to Solar Panels

PV solar panels are the most valuable and essential part of photovoltaic power generation equipment since they provide the source of the electricity generated. Sunlight becomes electricity through the conversion of its radiant energy. Due to the fact that solar panels are mounted on open fields, they are extremely vulnerable to lightning, which results in the failure of the system as a whole.

Damage to Solar Charge Controller

A solar charge controller safeguards the battery from overcharging and overdischarge by controlling the battery's working state. Solar charge controllers can be damaged by lightning or overvoltage, resulting in a charging system that keeps charging, but a discharging system that keeps charging whenever it is damaged, or a charging system that cannot charge, while the discharging system is always in the discharging state. Equipment cannot be used in best case, or the battery breaks, damaging the entire system and causing casualties in worst case.

Damage to Batteries

For storing electrical power with solar photovoltaic devices, typically lead-acid batteries, nickel-hydride batteries, nickel-cadmium batteries or lithium batteries are used. In the event of lightning strikes, overvoltage can cause damage to the battery, shorten its life cycle, or even cause the battery to explode, posing a greater threat to safety.

Damage to Inverter

From the solar photovoltaic power generation equipment, the inverter can convert direct current power into alternating current power. An inverter that is damaged cannot accept voltage input from the user load or cannot invert voltage. The solar photovoltaic panel will generate DC voltage that will be directly used by the load. Solar panels would be burned once their voltage is too high.

Lightning Protection for Solar Power System

Current methods of connecting electrical equipment to the ground are most effective and common. There are four aspects to grounding: equipment, body, lead-in wire, and earth. The grounding of an electrical system is essential to lightning protection.
Some of the popular grounding methods include:

Common Grounding

The grounding body must first be placed in the bottom of a hole with a diameter of 30 cm and then salt needs to be spread on the bottom. Using the PVC pipes to cover the grounding bodies, fill in the gaps with soil and compact it, adding gravel afterward and then watering them to reinforce the groundings. In the same way, ground other grounding bodies by arranging an isosceles triangle and connecting them with copper wires 1.5cm in diameter inside the photovoltaic field.
The metal equipment, lightning protection devices, and inverters of all photovoltaic power station equipment can therefore all be directly connected to the grounding system. Grounding can simply serve as ground protection and neutral line. When lightning strikes, it works as a lightning protection grounding device.

Single Point Grounding

Despite being relatively fixed in position, the poles in a photovoltaic field are often struck by lightning due to the influence of the geographical environment. To protect these poles, a lightning protection device needs to be installed separately.

Combined Grounding

Grounding devices that combine grounding bodies provide lightning protection. In terms of lightning protection, this kind of arrangement can be by ring, square, radial, etc. The actual distance between two grounding bodies should not be shorter than 3m so as to avoid the mutual shielding effect of the grounding bodies when arranged in a ring. Grounding bodies must have galvanized angle steel reinforced at their upper ends, and distances from the ground must be less than 1 meter.