Photovoltaic Power Generation Systems and Lightning Protection Measures for Photovoltaic SPD

Since the main components of the solar photovoltaic power generation system are outdoors, they are prone to lightning strikes or high-voltage surge induction, causing equipment damage. This article will discuss photovoltaic SPD lightning protection measures from the ways lightning surges enter and solutions.

Ways Lightning Surges Enter a Photovoltaic Power Generation System

Ground Potential Rebound Voltage Invasion

When lightning strikes a lightning rod, a radial potential distribution is generated near the grounding body of the lightning rod, and the ground potential of the grounding body of the electronic equipment close to it will be counter-attacked, and the invasion voltage can be as high as tens of thousands of volts. This situation invades the photovoltaic system through the grounding body, causing severe damage.

Solar Array DC Input Line Invasion

This invasion route is divided into two situations:

When the solar array is struck directly by lightning, the strong lightning voltage will break through the adjacent soil or DC input cable sheath, causing lightning pulses to invade the photovoltaic system.

When a charged cloud discharges to the ground, the entire photovoltaic array, like a huge circular antenna, induces an overvoltage of several thousand volts, which is introduced through the DC input line, causing damage to the photovoltaic system equipment connected to that line.

Photovoltaic System Output Power Line Invasion

When power supply equipment and power lines are struck by lightning, the lightning overvoltage on the power line can average tens of thousands of volts. The output line is also a primary factor introducing remote lightning, and the lightning pulse invades photovoltaic microelectronic devices and systems along the power line, delivering a devastating blow to the system equipment.

Lightning Protection Measures and Photovoltaic SPD Requirements for Photovoltaic Power Generation Systems

Selection and Arrangement of Lightning Protection Devices

Site selection and layout

In locations and situations prone to lightning strikes, avoid choosing a construction site for the solar photovoltaic power generation system or power station. Avoid the lightning rod's shadow falling on the solar cell array components.

Lightning rods, lightning belts, and lightning nets

Depending on the site conditions, different protection measures such as lightning rods, lightning belts, and lightning nets can be used to protect against direct lightning strikes and reduce the probability of strikes. Use as many uniformly arranged down conductors as possible to guide the lightning current into the ground. Multiple down conductors’ shunting effect can reduce the lead voltage drop of the down conductor, reduce side flash risks, and lower the magnetic field intensity generated by the down conductor discharge.

Equipotential Connection of Metal Objects

To prevent lightning induction, all metal objects in the entire photovoltaic power generation system, including the battery module frame, equipment, cabinet/shell, metal conduits, etc., should be connected equipotentially with the combined grounding body and grounded independently. The equipotential connection of the photovoltaic system can effectively reduce the harm caused by lightning induction.

Photovoltaic SPD's Multi-level Protection

Install lightning protection devices in stages in the system circuit to implement multi-level protection, allowing surge or switch surges to discharge through multi-stage lightning protection devices. The DC line part of the photovoltaic power generation system generally uses DC power lightning protectors, and the AC line part after inversion uses AC power SPD . The application of photovoltaic SPD in solar photovoltaic power generation systems can greatly enhance the system's lightning protection capability.

Photovoltaic SPD Selection

Choosing the right photovoltaic SPD is key to ensuring the effectiveness of lightning protection.  Photovoltaic SPD should have the following features:

High discharge capacity

 It can effectively discharge large current lightning pulses.

Low residual voltage level

The residual voltage to the device during discharge should be as low as possible to protect the equipment from damage.

Durability

Photovoltaic SPD should have a long service life and maintain effective protection performance during multiple lightning strikes.

Through reasonable lightning protection measures and selecting proper photovoltaic SPD, solar photovoltaic power generation systems can effectively avoid damage caused by lightning surges and ensure the stable operation of the system. If you have any needs or questions about photovoltaic SPD, please feel free to contact us.