Electrical surges occur when the flow of current in a power line increases at certain points. For example, lightning can create an electrical surge. It can fall near a power source and impact the voltage of a power line. Electrical devices like a surge protector can protect against lightning damage by disassembling the equipment from the power source.
What is a surge protector?
It is a protection solution that acts as a screen to protect the power system from surges caused by lightning. The device has two terminals: ground and high voltage. Suppose an electrical surge passes through the surge protector. In this case, a huge current is directed to the insulation and ground terminal to protect the power platform from damage.
Principle of operation of the surge protector
When a power surge or lightning strikes an electrical system, the entire platform and connected electrical devices can be affected because they operate over a fixed voltage range. If devices receive more power than the fixed voltage, they may either explode or be damaged. A surge protector protects electrical devices from damage by preventing excessively high voltage from flowing through the power system.
Thus, a surge protector is a voltage-activated solution, which is exploited to protect computers and other electronic devices against surges or voltage transients in electrical power or data cables, which would be caused by lightning or switching. The surge protector directs the added voltage to the ground wire and prevents it from flowing to the electronic equipment.
Installation of a surge protector
Surge protectors are usually installed near a power meter to protect the electrical system of a building or home from the impact of surges arriving from outside. However, these devices cannot provide complete protection against power surges due to faulty wiring.
Characteristics of surge protectors
A surge protector has the following electrical characteristics:
- When surge arresters above 52 kV are installed, they are powered by discharge meters
- They are connected to earth and phase conductors
- Rated current discharge takes place at values of 5, 10 and 20 kA
- Rated short circuit current
- Maximum continuous operating voltage
- The device has a high power frequency of around 50/60 Hz
- The voltage across the arrester when the flow of energy is stopped after the spark is called resealing voltage.
Types of surge protectors
Surge protectors are classified according to their construction and operation, they are either intermediate, distribution or secondary.
1. Secondary surge arresters
This surge protector uses a supply voltage below 1000 V. It is used to defend against secondary overvoltage. The failure rate of a transformer can be between 0.4 and 1%. Low side overvoltages cause up to 70% of transformer malfunctions. The service transformer has an additional responsibility because it must protect against secondary voltage surges in the house. The use of a secondary surge protector reduces transformer failure rates.
2. Surge protectors for distribution boards
The ratings of these surge protectors range from 1 to 36 kV. They are used in cell-mounted, elbow or oil-filled oil transformers. A normal-duty surge arrester is deployed in applications placed in environments that present less risk of lightning, heavy-duty surge arresters are integrated into systems with a high risk of lightning, riser surge arresters are for their part placed in applications where the distribution line runs from the ceiling to the basement, and finally, distribution surge arresters are used in all overhead systems.
Riser surge protectors can be used to stop the surge experienced by underground cables and equipment.
3. Intermediate surge arresters
This type of surge protector provides enhanced discharged voltages and has the ability to withstand high fault current. Its nominal voltages range from 3 to 120 kV.
4. Station Class Surge Protectors
These surge arresters provide the best expulsion voltages among all surge arresters. They have the ability to withstand high fault currents and handle high voltages. Their nominal voltages range from 3 to 684 kV.
Malfunction on a surge protector
A fault in a surge protector can cause short circuits in homes if moisture or mold affects the device. Moisture can cause discharge by increasing current leakage. A surge protector usually fails due to current penetration, moisture impact and sealing defects.
To conclude this article, we suggest you contact qualified experts for tailored recommendations to define the best electrical solutions based on your individual or business needs.
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