Arc flash protection
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An electric arc short-circuit is an infrequent switchgear fault where an explosion-like heat and pressure effect may cause extensive material damage and jeopardize the safety of operational staff. The goal of arc flash protection is to detect the arc and minimize its burning time thus protecting people and property. The burning time is usually minimized by cutting off the current path feeding the arc. |
The best way to restrict damage from an arc short-circuit is to limit the arc burning time. The burning time can be limited by tripping off the breaker that is feeding the arc current. This will effectively limit both direct and indirect damage. Short arc burning times are critical, especially when the arc develops during work on the switchgear.
Fast protection
When the conventional protection coordination principle based on time-grading or blocking is used, the traditional protection systems may not provide fast enough protection against substation faults. Further, high-impedance type of earth-faults may prolong operation of earth-fault relays and lead to a significant release of arcing energy. These facts pose a considerable risk to life and property.
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Total fault clearing time typically:
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Total fault clearing time typically:
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Resistance earthed network
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Resistance earthed network
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Typically the burning time of an arc fault should be limited to less than 100 ms in order to avoid major damage. Burning times of nearly half a second will most certainly cause considerable damage in the switchgear
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The operation times in critical arc situations are significantly reduced by implementing VAMP arc protection system.
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