Lightning Arrester: Definition, Working & Location of Lightning Arrester
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FAQ Related to Lightning Arrester
What is the lightning arrester rating and how does it relate to the system it protects?
Q1. What is the lightning arrester rating and how does it relate to the system it protects? The lightning arrester rating refers to its maximum blocking or nominal discharge current. It should be higher than the short-circuit current the system can deliver and also allow for a safety margin of at least 20%. Otherwise, the arrester may not be able to divert large surges harmlessly.
How can you tell if a lightning arrester has failed?
Signs of failure include abnormal tripping of system circuit breakers, loose connections, blown fuse protection, and physical cracks or leaks in the internal insulator or tank housing. Advanced arresters also feature failure indication lamps or potential-free contacts for centralized monitoring.
Are lightning arresters required indoors?
While not as critical as outdoor models, installing surge protection devices at the main breaker panel or wherever power and communication cables enter buildings offers worthwhile safeguards. These take the form of compact plug-in surge protectors or whole-house surge protection systems.
How do you select between gas and dry-type arresters?
Gas or oil-filled arresters work well for medium voltages but require maintenance to replenish fluids. Polymer dry types are self-contained, easier to install in switchgear, and preferred in indoor/clean environments. Voltage class, environment, and space constraints primarily dictate the choice.
Can a lightning arrester be connected in series with the transformer?
No, lightning arresters must never be installed in series with the transformer winding. They work by providing a parallel path to the surge current and connecting it in series would subject the transformer to the full voltage, potentially causing winding damage.