A Functional Safety Assessment Methodology for Explosion Protection with Application to a Variable Frequency Drive System

Shiguang Li,Xiaojie Wu

doi:10.3390/en14237872

Abstract

Modern explosion protection equipment, protected by traditional explosion protection technology (as defined by the international electrotechnical commission (IEC) publication IEC60079-ff series standards) and electrical/electronic/programmable electronic (E/E/PE) safety-related systems, is becoming ever more complex in coal mine development and petrochemical industry; thus, the possibility of failures in their operation is also growing. It is well-known that E/E/PE safety-related systems can be used to actively control dangerous sources, with real and expected levels of reliability, if they have been qualified according to the IEC61508-ff series standards. To uniformly evaluate the safety integrity level (SIL) of the explosion protection function of traditional explosion protection technology and E/E/PE safety-related system technology, this study analyzed the ability of these types of protection to remove the ignition risk residual, evaluating the failure rates of safety devices. The key objective of this paper is the presentation of a new equipment protection level (EPL) assessment method for explosion protection equipment based on a functional safety assessment. The method is applied to a variable frequency drive (VFD) system, and the results show that the EPL of the explosion protection equipment evaluated by this method is consistent with the EPL corresponding to the traditional explosion protection type of the IEC60079-ff series standard. Meanwhile, the flexible configuration of explosion protection safety devices and E/E/PE safety-related systems enables explosion protection equipment of different EPL levels to be designed.

Highlights

IntroductionIEC61508-0 introduces the concept of the safety lifecycle, explains the applicability and relevance of electrical/electronic/programmable electronic safety-related systems, clearly puts forward the functional safety of safety-related systems, and details the general procedures and methods for realizing functional safety
Since the introduction of the functional safety international accepted series standardIEC61508-ff, functional safety has gradually formed a complete safety assessment system.IEC61508-0 introduces the concept of the safety lifecycle, explains the applicability and relevance of electrical/electronic/programmable electronic safety-related systems, clearly puts forward the functional safety of safety-related systems, and details the general procedures and methods for realizing functional safety
The European Commission project SAFEC (Contract No CT982255 Determination of safety categories of electrical devices used in potentially explosive atmospheres) advances the safety integrity level (SIL) level functional safety assessment method of electronic/programmable electronic (E/E/PE)

Summary

Introduction

IEC61508-0 introduces the concept of the safety lifecycle, explains the applicability and relevance of electrical/electronic/programmable electronic safety-related systems, clearly puts forward the functional safety of safety-related systems, and details the general procedures and methods for realizing functional safety. On this basis, functional safety standards for specific industrial applications have been published, such as the IEC61511 standard for the process industry, the IEC61513 standard for the nuclear industry, the IEC62061 standard for the mechanical industry, and the international organization for standardization (ISO). Studies the possibility of the safe use of an enhanced light-emitting diode light source in hazardous area Zone 1 (as defined by IEC60079-10-1) based on the functional safety assessment method [5]

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Conclusion