As we all know, photovoltaic power generation system uses solar energy to generate electricity. In order to better absorb solar energy, the main parts of photovoltaic power generation system are installed in the open air, with a large distribution area. In addition, photovoltaic modules and supports are conductors, which makes the photovoltaic system very attractive to lightning, and has the potential of direct and indirect lightning strikes.
At the same time, the photovoltaic power generation system has a direct connection with the relevant electrical equipment and buildings, so if the photovoltaic system is struck by lightning, it may also affect the relevant equipment, buildings and electrical loads.
In order to avoid the damage caused by lightning strike to the photovoltaic power generation system as much as possible, it is necessary to set up lightning protection and grounding system for protection.
We recommend that you avoid the damage to the photovoltaic system caused by lightning strikes from the following aspects:
1. Site selection of power station
The selection of the construction site of the photovoltaic power generation system or power station should avoid building the photovoltaic power station in the location where lightning is easy to occur and vulnerable to lightning.
2. Arrangement of lightning rod
The layout of lightning rod should not only consider the photovoltaic system equipment into the protection scope, but also try to avoid the projection of lightning rod on the photovoltaic array components.
3. Layout of down lead
The PV building integrated power generation system generally uses the structural reinforcement in the building as the down lead.
If there is no lightning protection down lead for the building, it is necessary to set up a special down lead for the photovoltaic power generation system, and try to use more than two down leads uniformly arranged to introduce the lightning current into the ground.
The shunting effect of multiple downleads can reduce the lead voltage drop of downleads, reduce the risk of side strike, and reduce the magnetic field intensity generated by the downlead leakage.
4. Add lightning protection device
The lightning protection device (surge protector) is installed on the system circuit step by step to implement multi-level protection, so that the lightning stroke or switch surge current can be discharged when passing through the multi-level lightning protection device.
Generally, DC lightning arrester is used in the DC line of photovoltaic power generation system, and AC lightning arrester is used in the AC line after inversion.
5. Independent grounding of all metal parts
In order to prevent the lightning induced electromagnetic pulse from generating potential difference and fault voltage between different metal objects of the photovoltaic system, and thus endangering the whole system equipment, it is necessary to adopt common grounding devices for lightning protection grounding, electrical equipment grounding, safety grounding, and solar cell anti-static grounding of the photovoltaic building integrated power generation system.
6. Reduce the probability of being struck by lightning
For both ground and roof photovoltaic power generation systems, the component array of the system should be within the protection range of lightning protection devices. Generally, the photovoltaic array installed on the roof of the building can make full use of the external lightning protection system of the original building.
If the original building has no grounding device or the grounding device does not meet the requirements of the photovoltaic power generation system, it is necessary to reset the lightning rod and grounding system.
The frame and PV support of the PV module shall be reliably equipotentially connected with the lightning rod and grounding system, and connected with the grounding system of the original building, so as to minimize the probability of the PV system being struck by lightning and protect the power generation efficiency of the PV module.
