• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.11
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• pp.1526-1532
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• 2014

The Electronic Interlocking unit in railway signalling system is safety-related facilities to determine route and speed for train running. In particular, the SSI(Solid State Interlocking) is Electronic Interlocking unit for high-speed railway, and it performs safety-critical function by MPM(Micro-Processor Module). Meanwhile, MPM is composed of the PES(Programmable Electronic System)-based system, and the PES-based system in railway safety-related facilities should be implemented by complying with the safety requirements defined in IEC 62425 and IEC 61508. In this paper, we performed modeling of failure rate and reliability for MPM implemented by fault tolerance methods and analyzed functional safety for MPM. Moreover, we determined SIL(Safety Integrity Level) for MPM according to the safety requirements defined in IEC 61508 based on an analyzed functional safety.

• Journal of Applied Reliability
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• v.14 no.1
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• pp.81-91
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• 2014

The IEC 61508 standard was established to specify the functional safety of E/E/PE safety-related systems. Safety life cycle to provide the framework and direction for the application of IEC 61508 is included in this standard. In this paper, we describe overviews, objects, scopes, requirements and activities of each phase in safety life cycle. In addition, we introduce safety integrity level(SIL) which is used for verifying the safety integrity requirements of E/E/PE system and perform a case study to estimate hardware SIL by FMEDA. The SIL is evaluated by two criteria. One of them is the architectural constraints which restrict the maximum SIL by combination of SFF and HFT. The other is the probability of failure which is classified into PFD and PFH based on frequency of demand and calculated by safe or dangerous failure rates.

• IE interfaces
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• v.25 no.4
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• pp.405-415
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• 2012

The reliability performance measures for low and high or continuous demand modes of operation of safety instrumented systems(SISs) are examined and compared by analyzing the official definitions in IEC 61508 standard. This paper also presents a status of common cause factor(CCF) models used in IEC 61508 and problems relating CCF modelling are discussed and ideas to solve these ones are suggested. An example with mixed M-out-of-N architecture is carried out to illustrate the proposed methods.

• Journal of Applied Reliability
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• v.16 no.3
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• pp.231-237
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• 2016

Purpose: It is not easy to suggest a quantitative data related to safety analysis. The objective of this paper is to propose a method of Safety Integrity Level (SIL) analysis and to suggest a SIL analysis result for single station controller in nuclear power plant based on IEC 61508. Methods: The Failure Modes and Effects Diagnostic Analysis (FMEDA) and average probability of failure on demand (PFD) are used for SIL assessment. Results: A SIL of single station controller is evaluated 4 by a reliability analysis results and PFD. Conclusion: A SIL analysis method and result for single station controller based on IEC 61508 are proposed in this paper. It can applicable for a manufacturer data in safety-related system.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.21-26
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• 2005

The recent developments in the field of reliability and safety is the realisation that these aspects are not only a function of the product but also of the organisation realising this product. Comparing with old DIN 0801 and new method IEC61508, quantitative analysis is required at not only product's quality but also organization's level. Product's life cycle also should be evaluated by analyzing relevant or maturity of business processes. This paper shows the necessity for an analysis on all aspects in a safety certification process, and presents an overview of the available tools and techniques for the various quadrants. Especially, tools and techniques for IEC61508 quadrant C are unavailable currently. Therefore, this paper propose the method which improves the maturity of an organization on reliability management.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.8
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• pp.1169-1176
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• 2013

PES have been recently required to implement railway industry for its application flexibility. The PES should be commensurated with railway safety requirements. It achieved its safety through redundant PES. The redundant systems run with voting functions. The successful major voting result becomes the output of the redundant system. The redundant system have to be synchronized to vote each output results. This paper proposed an algorithm for synchronizing and a voter. The proposed algorithm and the voter are verified using simulation.

• IE interfaces
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• v.25 no.4
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• pp.376-381
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• 2012

As the number, complexity and interaction of electrical, electronic and programmable electronic (E/E/PE) systems increase, a growing emphasis has been placed on the concept of functional safety during product development. IEC 61508 provides guidelines and standardized procedures in the development of reliable and dependable E/E/PE systems to assure functional safety. Determining risk classes (i.e., safety integrity levels, SILs) associated to a specific E/E/PE item may be recognized as one of the most crucial activities in the product development per IEC 61508 since SILs are used to specify necessary safety requirements for achieving an acceptable residual risk. This article presents a case study on the assessment of SILs applying failure modes, effects and diagnostic analysis (FMEDA) from which failure rates may be derived for each important failure category by combining a standard FMEA with online diagnostic techniques.

• International journal of advanced smart convergence
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• v.12 no.3
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• pp.233-243
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• 2023

In modern society, since the expansion of the e-commerce market and the spread of the pandemic, face-to-face business are gradually changing to non-face-to-face. In the logistics industry, the demand for unmanned courier storage is increasing due to lack of loading space from urbanization and courier theft accidents. As the demand for unmanned parcel lockers increases, improved functions such as food storage and efficient space loading are required. This study develops an integrated model-based evaluation procedure of product based on performance factors according to the IEC 61508 standard for newly unmanned parcel storage devices with active loading technology, and derive Critical Technology Element based on the product's core functions and performance goals. As proposing these research, We expect improve the safety and reliability of development targets by identifying and evaluating elements.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.6
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• pp.447-460
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• 2012

In this study, the shutdown system of the fuel gas supply system is designed based on the Safety Integrity Level of IEC 61508 and IEC 61511. First of all, the individual risk($10^{-4}$/year) and the risk matrix which are the risk acceptance criteria are set up for the qualitative risk assessment such as the HAZOP study. The natural gas leakage at the gas supply pipe is identified as the highest risk among the hazards identified through the HAZOP study and as a safety instrumented function the shutdown function for leakage was defined. SIL 2 and PFD($2.5{\cdot}10^{-3}$) for the shutdown function are determined by the layer of protection analysis(LOPA). The shutdown system(SIS) carrying out the shutdown function(SIF) is verified and designed according to qualitative and quantitative requirements of IEC 61508 and IEC 61511. As a result of SIL verification and SIS conceptual design, the shutdown system is composed of two gas detectors voted 1oo2, one programmable logic solver, and two shutdown valve voted 1oo2.

• Journal of the Korean Institute of Gas
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• v.21 no.2
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• pp.32-40
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• 2017

Safety Instrumented Systems (SIS) have wide application area. They are of vital importance at process plants to detect the onset of hazardous events, for instance, a release of some hazardous material, and for mitigating their consequences to humans, material assets, and the environment. The integrated safety systems, where electrical, electronic, and/or programmable electronic (E/E/PE) devices interact with mechanical, pneumatic, and hydraulic systems are governed by international safety standards like IEC 61508. IEC 61508 organises its requirements according to a Safety Life Cycle (SLC). Fulfilling these requirements following the SLC can be complex without the aid of SIS supporting tools. This paper presents simple SIS support tool which can greatly help the user to implement the design phase of the safety lifecycle. This tool is modelled in the form of Android application which can be integrated with a Web-based data reading and modifying system. This tool can reduce the computation time spent on the design phase of the SLC and reduce the possible errors which can arise in the process. In addition, this paper presents an optimization approach to SISs based on cost measures. The multi-objective genetic algorithm has been used for the optimization to search for the best combinations of solutions without enumeration of all the solution space.