Reliability assessment method for safety instrument system based on Markov model and D-S evidence theory

A technology of safety instrumented system and evidence theory, which is applied in the field of reliability evaluation of industrial safety instrumented system, and can solve the problems of reliability change and no consideration

Inactive Publication Date: 2013-03-13
SOUTHWEST UNIVERSITY
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Problems solved by technology

These methods calculate the safety reliability from different levels, but they all assume each state of the safety instrumented system as a constant, but in actual applications, the state of each equipment and system

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  • Reliability assessment method for safety instrument system based on Markov model and D-S evidence theory
  • Reliability assessment method for safety instrument system based on Markov model and D-S evidence theory
  • Reliability assessment method for safety instrument system based on Markov model and D-S evidence theory

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Embodiment Construction

[0039] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0040] The safety instrumented system reliability assessment method based on Markov model and D-S evidence theory of the present invention comprises five steps altogether: 1: determine the state space according to the redundant structure of safety instrumented system, form an identification framework of state ; 2: According to the characteristics of each state, establish a basic probability assignment function on the power set of the identification framework, and then get the basic probability assignment; 3: Calculate the reliability function and likelihood function according to the basic probability assignment; 4: In the reliability function and Calculate the state transition matrix in the Markov model based on the likelihood function; five: Calculate the average failure time on demand according to the state transition matrix.

[0041] In ...

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Abstract

The invention discloses a reliability assessment method for a safety instrument system based on a Markov model and a D-S evidence theory. The reliability assessment method comprises the following steps: (1) confirming a state space according to a redundant structure of the safety instrument system and forming a discernment frame theta with states; (2) establishing a basic probability assignment function on a discernment frame power set according to various characteristics of the states and further obtaining basic probability assignment; (3) calculating a reliability function and a likelihood function according to the basic probability assignment; (4) calculating a state-transition matrix in the Markov model based on the reliability function and the likelihood function; and (5) calculating average time of failure on demand, applying the D-S evidence theory to the Markov model, calculating upper and lower limits of each state through a reliability function and a likelihood function of the D-S evidence theory, and obtaining the average probability of failure on demand of the safety instrument system. Compared with the former assessment models, the assessment model is more accurate.

Description

technical field [0001] The invention belongs to the field of reliability evaluation of industrial safety instrument systems, and relates to a reliability evaluation method of safety instrument systems based on Markov model and D-S evidence theory. Background technique [0002] Industrial safety instrument system (Safety Instrument System, SIS), also known as safety interlocking system (Safety interlocking System), is mainly the alarm and interlocking part of the factory control system, which implements alarm actions or adjustments or adjustments to the detection results in the control system. Shutdown control is an important part of the automatic control of factories and enterprises. [0003] SIS executes its safety function on time and correctly before dangerous events occur, thereby avoiding or reducing the occurrence of accidents. But the function failure of SIS will lead to its safety function can not be realized. IEC 61508 "Functional Safety of Electrical / Electronic / P...

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Application Information

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IPC IPC(8): G06F19/00
Inventor 潘东波原红丽
Owner SOUTHWEST UNIVERSITY
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