3 best practices for arc flash protection in medium voltage equipment
Credit to Author: Juha Rintala| Date: Tue, 19 Dec 2017 14:00:34 +0000
The first post in this series outlined the goals and standards for arc flash protection, while the second described the impact of an arc flash on medium voltage (MV) equipment and switchboards.
Here, I’ll talk about some of the best practices panel builders need to follow to ensure that arc flash protection works. After all, the best way to ensure an arc flash has little effect is to make sure any arc flash and its impact are minimized.
Follow the standard – That seems obvious but in practice can be challenging. Panel builders must adhere to the standard, and the switchgear equipment and component supplier(s) must do the same. The best approach is to work with suppliers that have the necessary expertise and certifications.
Ensure arc flash mitigation is “designed in” – Bus and transformer differential protection can substantially reduce the potential for arc flash damage. For instance, replacing a transformer protecting fuse with a circuit breaker and fast arc flash protection that can bring down the hazard risk category, in part by clearing line side faults without delay. Panel builders should institute such practices, thereby reducing the available incident energy, its duration, or both.
Use arc-protection and arc-resistant switchgear – This can come in the form of sensors that detect arcing faults through fault current and the resulting light. By doing so, the time to clear a fault is reduced to tens of milliseconds, with this ultrafast reaction mitigating any arc flash that does develop.
Arc resistant switchgear is structurally strong and has built-in pressure-relief mechanisms. Together these eliminate or minimize the chance for an explosion, thereby saving equipment as well as helping prevent downtime and injury. Such switchgear can be an important part of arc flash mitigation.
The next post in the series will look at the role of testing and commissioning. In the meantime, you can learn more in our free white paper, “Evaluating the Arc-Flash Protection Benefits of IEC 61850 Communication.”
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