Arc-Flash Hazard Calculations in LV and MV DC Systems Part—II: Analysis
Arc-Flash Hazard Calculations in LV and MV DC Systems Part—II: Analysis
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低压和中压直流系统中的弧闪危害计算第二部分：分析
DOI：
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发表时间：
2014
影响因子：
4.4
通讯作者：
J. Das
中科院分区：
文献类型：
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作者：
J. Das
基于本文第一部分的短路计算结果，演示了直流系统中电弧闪光危险的计算。与交流系统非常相似，电弧电流与短路电流不同。美国国家消防协会 2012 年方法建议将电弧电流取为计算出的直流短路电流的 50%，并计算持续时间为 2 秒的弧闪危险。这两个概念都有很大缺陷，并且会给出不准确的结果。还必须了解直流系统中的短路保护。半导体器件的能量允许通过承受能力非常小，并受到快速熔断半导体熔断器或直流断路器的保护，这些熔断器或直流断路器可以阻止预期的短路电流并将入射能量释放限制在很小的值。本文计算了示例案例中的电弧闪光危险，以演示低压和中压直流系统的计算方法。
Based on the results of the short-circuit calculations in Part I of this paper, the calculation of the arc-flash hazard in dc systems is demonstrated. Much like ac systems, the arcing currents are not the same as the short-circuit currents. The National Fire Protection Association 2012 methodology recommends that the arcing current be taken as 50% of the calculated dc short-circuit current and that the arc-flash hazard be calculated for a time duration of 2 s. Both these concepts are much flawed and will give inaccurate results. It is also imperative to appreciate the short-circuit protection in dc systems. Semiconductor devices have very little energy let-through withstand capability and are protected with fast-acting semiconductor fuses or dc circuit breakers that may arrest the prospective short-circuit current and limit the incident energy release to a small value. This paper calculates the arc-flash hazard in specimen cases to demonstrate the methodology of the calculations in low-voltage and medium-voltage dc systems.