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How does PDU protect equipment from lightning damage?

Date：2025-05-04

Lightning strikes and surges often threaten the safety of electronic equipment. You may not know that instantaneous high voltage can cause equipment damage or even scrap. PDUs help you protect your equipment and avoid these catastrophic consequences through built-in lightning protection and surge protection. Especially in data centers, lightning protection PDUs are a key tool to ensure stable operation of equipment.

Key Points

The PDU protects devices from high voltage damage through built-in lightning protection and surge protection functions, ensuring stable operation of the equipment.

Choosing a PDU that meets international standards can effectively reduce damage to electronic equipment caused by lightning strikes and surges and extend the service life of the equipment.

Regularly check and replace PDU protection components, such as varistors, to ensure their protection effectiveness and avoid equipment failure.

Hazards of lightning strikes and surges

Direct damage to equipment caused by lightning strikes

When lightning strikes a device directly, the instantaneous high voltage is transmitted to the inside of the device through the power line or signal line. This high voltage may cause the circuit board to burn, damage components, or even cause a fire. You may find that the device cannot start at all or has serious malfunctions after the lightning strike. This direct damage is usually irreversible and the repair cost is extremely high.

Effects of Induced Lightning Strike

Even if lightning doesn't strike equipment directly, induced lightning can be a threat. When lightning strikes nearby, the strong electromagnetic field can induce currents around cables or equipment. This induced current can cause voltages inside the equipment to rise momentarily, damaging sensitive electronic components. The effects of induced lightning are often more subtle, but just as dangerous.

Sources and hazards of internal surges

Internal surges are often caused by current fluctuations when equipment is turned on or off. For example, when high-power equipment such as air conditioners or elevators are running, the voltage in the grid may rise momentarily. Although this surge is not as strong as a lightning strike, frequent occurrences can have long-term effects on the life of the equipment. You may notice that the performance of the equipment gradually decreases, which is often the result of internal surges. Using a PDU with strong lightning protection can effectively alleviate these problems.

PDU protection mechanism

Energy Guidance: How to Direct Excess Current to Ground

When lightning strikes or surges occur, the current will instantly increase to dangerous levels. At this time, the PDU quickly guides the excess current to the ground wire through its internal grounding system. The ground wire serves as a "safe exit" for the current and can effectively prevent the current from entering the equipment. You can think of it as a "flood discharge channel" that quickly diverts the current when it is overloaded to protect the equipment from damage.

To achieve this function, PDUs are usually equipped with efficient grounding designs. The material and connection method of the grounding wire directly affect its performance. When choosing a PDU, you can pay attention to whether its grounding system meets international standards, which will determine the reliability of its protection effect.

Voltage limitation: the role of components such as varistors

The varistor is one of the important protective components in the PDU. Its function is to limit the excessive increase of voltage. When the voltage exceeds the safe range, the varistor will quickly reduce its resistance and shunt the excess current to the ground wire. This can prevent the equipment from being damaged due to excessive voltage.

You may be curious about how a varistor works. Its core principle is to use the nonlinear characteristics of the material. When the voltage is normal, the varistor hardly conducts electricity; but when the voltage rises to a certain value, it will quickly conduct and protect the equipment. In this way, the PDU ensures that the equipment can still operate safely during lightning strikes or surges.

Absorption of energy: The process of absorbing surge energy

The absorption of surge energy is another key link in the PDU protection mechanism. The surge protector (SPD) and other components inside the PDU will convert surge energy into heat energy and release it. This process can effectively reduce the impact of surges on equipment.

For example, when a transient high voltage appears on the power grid, the PDU will respond quickly through its internal energy-absorbing elements. These elements absorb the excess energy and prevent it from being transferred to the equipment. You can think of it as a "cushion" that protects the equipment when a surge hits.

Through three mechanisms, namely energy guidance, voltage limitation and energy absorption, PDU can fully guarantee the safety of equipment. Choosing a high-quality PDU can give you more peace of mind when facing lightning strikes and surges.

Key protection components of PDU

Working principle and function of varistor

The varistor is an indispensable protective component in the PDU. Its main function is to limit the excessive increase of voltage and protect the equipment from the impact of surge. When the voltage is within the normal range, the varistor is almost non-conductive and the equipment can operate normally. But when the voltage suddenly rises to a dangerous level, the varistor will quickly reduce its resistance and shunt the excess current to the ground wire.

You can think of a varistor as a "voltage gatekeeper." It monitors voltage changes at all times and takes immediate action if it detects an anomaly. Its core principle is based on the nonlinear properties of the material, which enables it to respond to voltage changes in milliseconds. Through this rapid response, the varistor effectively prevents equipment from being damaged by excessive voltage.

Function of gas discharge tube

The gas discharge tube is another important protective element in the PDU. Its function is to deal with high-energy surges, especially the instantaneous high voltage caused by lightning strikes. When the voltage exceeds the set value, the gas inside the gas discharge tube will be ionized, forming a conductive path to guide the excess current to the ground wire.

The advantages of gas discharge tubes are their high energy tolerance and long life. They are suitable for scenarios that require high-intensity protection, such as data centers or industrial equipment.

When choosing a PDU, you can pay attention to whether it is equipped with a gas discharge tube. This component can provide additional safety for the equipment, especially in areas where lightning is frequent.

How NTC thermistors protect equipment

NTC thermistors are mainly used to suppress surge currents. Their characteristic is that their resistance decreases when the temperature rises. When a device starts, the current usually increases instantly, which may cause a shock to the device. At this time, the NTC thermistor limits the initial current through its high resistance value to protect the device from damage.

As the device runs, the temperature of the NTC thermistor gradually increases, the resistance decreases, and the current can flow normally. This "soft start" mechanism not only extends the service life of the device, but also reduces the burden on the power grid. You can think of it as a "buffer" that provides additional protection when the device starts.

Function and selection of surge protection device (SPD)

Surge protection device (SPD) is one of the most core protection components in PDU. Its main task is to absorb and divert surge energy to prevent equipment from being damaged by instantaneous high voltage. SPD is usually composed of multiple protection components, such as varistors and gas discharge tubes, to achieve multi-level protection.

When choosing an SPD, you need to pay attention to the following key parameters:

1.Maximum discharge current : indicates the maximum surge current that the SPD can withstand.

2.Residual voltage value : refers to the voltage remaining after the surge passes through the SPD. The lower the value, the better.

3.Response time : The reaction speed of the SPD, usually measured in nanoseconds, the faster the better.

parameter	illustrate	Recommended value
Maximum discharge current	The maximum surge current that the SPD can withstand	≥20kA
Residual pressure value	Residual voltage after surge	≤1.5kV
Response time	SPD response speed	≤25ns

Choosing the right SPD can significantly improve the protection capabilities of the PDU. When purchasing, you should choose products that meet international standards based on the actual needs of the equipment and the usage environment.

Through the coordinated work of varistors, gas discharge tubes, NTC thermistors and surge protectors, PDUs can provide comprehensive protection for equipment. These components perform their respective functions and together build a solid "safety barrier".

PDU design and testing standards

Design goals of lightning protection PDU

The design goal of lightning protection PDU is to ensure the safe operation of equipment in the event of lightning strikes and surges. You need to know that the core task of PDU is to quickly respond to voltage anomalies and prevent excessive current from entering the equipment. In order to achieve this goal, the design of PDU will focus on the following aspects:

Efficient grounding system : quickly guides excess current to the ground to avoid equipment damage.

Multi-level protection mechanism : Through the coordinated work of components such as varistors and gas discharge tubes, comprehensive protection is provided.

Durability and reliability : Ensure that the PDU can operate stably under high-frequency use and harsh environments.

When you choose a PDU, you can pay attention to whether it has these design features. These goals are directly related to the safety and service life of the equipment.

Complies with international test standards (such as IEC61000-4-5)

The protection performance of PDU needs to be verified by strict international testing standards. IEC61000-4-5 is one of the most important standards. It mainly tests the performance of PDU under surge current and voltage impact. PDU that passes this standard can effectively deal with the threats brought by lightning strikes and surges.

You can check the product manual or certification mark to confirm whether the PDU complies with the IEC61000-4-5 standard. PDUs that comply with this standard usually have higher safety and reliability.

The function of high temperature fuse protector

The high temperature fuse protector is an important safety device in the PDU. Its function is to prevent the equipment from malfunctioning due to overheating or overloading. When the temperature exceeds the safe range, the fuse protector will automatically cut off the circuit to avoid further damage.

You can think of the high temperature fuse protector as the "last line of defense" for your equipment. It not only protects your equipment, but also prevents potential safety hazards such as fire. Choosing a PDU equipped with a high temperature fuse protector can provide more comprehensive protection for your equipment.

The lightning protection and surge protection functions of PDU are the core of protecting equipment safety. It can effectively reduce the damage of lightning and surge to electronic equipment and extend the life of equipment. It is particularly important to choose high-quality lightning protection PDU that meets international standards. You can ensure that the selected PDU has reliable protection performance by checking the certification mark and product manual.

FAQ

1. How to determine whether a PDU has lightning protection function?

Check the product manual or certification mark. Make sure the PDU complies with international standards (such as IEC61000-4-5) and is equipped with key protection components such as varistors and gas discharge tubes.

2. In what scenarios is the lightning protection PDU suitable?

Lightning protection PDU is suitable for scenarios such as data centers, industrial equipment, and home electronic devices that need to be protected from lightning strikes and surges, especially in areas where lightning strikes are frequent.

Tip : If thunderstorms are frequent in your area, it is particularly important to choose a PDU with strong lightning protection capabilities.

3. Do the protective components of the PDU need to be replaced regularly?

Yes, protective components such as varistors will age. It is recommended to check them every 3-5 years and replace them if necessary to ensure the protective effect.