Safety integrity level identification method and device for rail traffic signal system

Abstract

The invention provides a safety integrity level identification method and device for a rail traffic signal system. The method comprises the following steps that: the risk mitigation factors of a functional module to be identified on a train are obtained, wherein the risk mitigation factors comprise at least hazard exposure possibility, accident occurrence reduction possibility and accident consequence reduction possibility; target statuses corresponding to each risk mitigation factor of the functional module to be identified and the target types of hazard consequences are determined; and the target safety integrity level of the functional module to be identified is identified according to the target statuses and the target types. According to the safety integrity level identification method and device for the rail traffic signal system of the invention, when the safety integrity level of the functional module to be identified is determined, the considered risk mitigation factors are more comprehensive, not only the accident occurrence reduction possibility is considered, but also the accident consequence reduction possibility is considered; the final hazard consequences are determined on the basis of protection measures; and since consideration is better based on actual conditions, and the safety integrity level of the functional module to be identified can be determined more accurately, and driving safety can be improved.

Description

technical field [0001] The invention relates to the field of train safety, in particular to a method and device for identifying a safety integrity level of a rail transit signal system. Background technique [0002] Currently, a matrix method or a graph method is mostly used to analyze the safety integrity level (Safety Integrity Level, SIL for short) of a safety-related functional module in a system. [0003] 1. Matrix method [0004] Table 1 is a matrix for determining the SIL of a functional block. The possibility of harm and the severity of the consequences of the functional module to be identified in the event of functional failure, the matrix method is to use the brainstorming method to qualitatively determine the SIL of the device or functional module. In general, the possibility of hazard occurrence can be divided into three types: high, medium, and low, and the severity of the hazard can be divided into three types: major, serious, and minor, forming a 3×3 matrix ...

AI Technical Summary

Problems solved by technology

[0011] The existing matrix method only defines the safety integrity level based on the severity of the hazard and the possibility of occurrence, without considering the risk mitigation factors. The failure of some functions leads to a high original risk level of the hazard, but other functions of the system may respond to this Hazards have a protective effect, if these are not taken into account, directly assigned according to the above matrix, may lead to the defined safety integrity level being too high

Moreover, the existing highest level SIL3 defined is mainly aimed at electrical, electronic and programmable electronic systems, which are used in the field of industrial control equipment and are not suitable for rail transit signal systems.

[0012] Although the existing graph method considers risk mitigation factors, the risk level should be determined by the probability of risk occurrence and the severity of risk consequences. The graph method only considers the avoidance of the probability of risk occurrence, and does not consider the reduction in the severity of consequences. In the case of the situation, the event tree analysis is directly done from the severity of the original consequences; secondly, due to the limitation of using the event tree, only two situations are not comprehensive enough to distinguish between the hazard exposure time and the probability of avoiding the hazard

[0013] Therefore, the SIL determined for the functional modules to be identified based on the above-mentioned matrix method and graph method is not consistent with the SIL required in practical applications, which may lead to potential safety hazards in the light rail traffic signal system

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