Lightning protection and overvoltage protection? - Part 1

It is known that lightning poses a threat not only to our lives but also to our property. It is also a primary source of overvoltage. Their electrical charges can reach millions or even billions of volts, with strengths ranging from 10,000 to 200,000 amperes. However, lightning strikes represent only a part of all transient events that can occur in a building structure.

Transient processes can be caused by external sources such as lightning and internal sources. Therefore, every building, structure, and construction requires not only a reliable system to protect against lightning but also protection from overvoltage.

This brings us to the question: "What is the difference between these two systems and how do they work together?" In this article, we will explore them and help you understand how they function.

Lightning Protection:

As we have previously shared with you, the role of this system is simple - to protect any structure from a direct lightning strike. To achieve this, lightning rods are installed in the most suitable position to capture the charge during a direct lightning hit. This position is chosen based on the architectural design of the building, roof characteristics, and equipment located on it.

The rest of the system is designed to safely transfer the energy from the strike to the ground as efficiently and safely as possible. To achieve this, the system has various components:

• Lightning rods, which capture the strike.
• Conductors that provide the most direct path for directing the charge to the ground.
• Grounding system, ensuring a safe path for the current to reach the ground.
• Bonding, designed to reduce the possibility of voltage differences that pose a significant risk to the safety of structures and people.

Overvoltage Protection:

The design of this system aims to protect electrical systems and equipment from overvoltage and transient events. It limits transient voltages and redirects currents that could threaten the equipment safely to the ground.

Transient processes can be caused by:

• Lightning - the most serious form of externally generated strikes.
• Switching electrical loads within the facilities, such as motors, lighting, heating systems, and office equipment.

This system employs at least one nonlinear component that switches between high and low resistance at different voltages. Under normal working voltages, the system has high resistance and doesn't affect the equipment. When a transient voltage occurs above the trigger threshold, it switches to a conductive state and diverts the charge back to the source or the ground.

This limits the voltage amplitude to a safe level for consumers and systems. Once the transient process is over, the system automatically returns to its initial state.

These are some characteristics of the two systems that are important to know. In the next part of the article, we will continue with the comparison and help you differentiate between them.