Electrical equipment connected to power networks can be exposed to transient overvoltages caused by lightning strikes and switching operations. Surge arresters are commonly used to help limit these voltage surges.
Basic Operating Principle
Under normal system voltage, a surge arrester has a high resistance and carries only a small current.
When a transient overvoltage occurs, its electrical characteristics allow surge current to flow through the arrester toward the grounding system. This helps limit the voltage applied to protected equipment.
Common Applications
Surge arresters are commonly installed near equipment that needs protection, including transformers, switchgear, transmission lines, and substation equipment.
Their exact location depends on the system configuration and insulation coordination requirements.
Selection Considerations
Selecting a surge arrester requires consideration of the system voltage and grounding arrangement, continuous operating voltage, rated voltage, discharge characteristics, environmental conditions, and the insulation level of the equipment being protected.
The grounding connection is also important because the surge current needs an effective path to earth.
Protection Requires System-Level Design
A surge arrester should not be selected as an isolated component. Its characteristics and installation should be coordinated with the protected equipment and the overall insulation system.
For high voltage surge arresters and other electrical equipment used in power systems, MinRong Electric provides products for substation and power distribution applications.
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