Which standard governs the performance of a short circuit study?

The performance of a short circuit study is governed by ANSI/IEEE standard 399, which is also known as the "IEEE Recommended Practice for Industrial and Commercial Power Systems Analysis." This standard provides guidelines for conducting various types of electrical studies, including short circuit analysis, which is essential for understanding the behavior of electrical systems under fault conditions.

Short circuit studies are critical for ensuring the safety and reliability of power systems, as they help determine the fault current levels that can occur during a short circuit event. ANSI/IEEE 399 outlines the necessary calculations, methodologies, and considerations needed to perform these analyses effectively. It also addresses the selection of protective equipment and coordination of protection devices based on the findings from the study, which ultimately helps in designing a robust electrical system.

In contrast, the other choices either pertain to different aspects of electrical systems or do not specifically focus on short circuit studies. For example, IEC 61000 is related to electromagnetic compatibility, and NEMA standards deal with the fit, form, and function of electrical equipment. IEEE standard 99 provides guidance on the protection of electrical equipment but is not specifically dedicated to the performance of short circuit studies. Thus, ANSI/IEEE standard 399 is the most applicable standard for this topic.