Effect of short-circuit current and conductor spacing on the thermal effects of AC fault arcs and conclusions for the selection of personal protective equipment

Status:

ongoing

Aims:

Regardless of technical, organizational, and personal protective measures, fault arcs can never be completely ruled out when working on live equipment or near live parts. Since arc flashes can cause severe burns and even death, wearing appropriate personal protective equipment against arc flashes (PPEgA) is essential for all live-line work activities.

When selecting the appropriate PPEgA, the electrical network parameters as well as the geometric conditions at the potential fault location must be taken into account. DGUV Information 203-077 describes a corresponding procedure based on the standardized box test according to IEC 61482-1-2.

However, investigations in low-voltage DC systems show that short-circuit currents exceeding 7 kA and electrode distances below 30 mm can result in significantly higher thermal loads than those simulated in the box test.

The research project aims to clarify how prospective short-circuit current and electrode spacing influence the thermal effects of AC fault arcs and how this information can be used to derive a more precise selection of suitable PPE.

Activities/Methods:

• Design of the required test setup and test procedure
• Metrological investigations (Part 1) in the range of prospective short-circuit currents of Ik ≤ 7 kA in the arc fault laboratory at the Technical University of Ilmenau
• Evaluation of the metrological investigations in the arc fault laboratory at TU Ilmenau
• Metrological investigations (Part 2) in the range of prospective short-circuit currents from 7 kA < Ik ≤ 20 kA in an external testing laboratory
• Evaluation of all metrological investigations and conclusions for the selection of arc fault protection devices
• Preparation of the final report

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