A fuzzy expert system for controlling safety and shutoff valves in gas pressure reduction stations under uncertain conditions

Abstract

Given the increasing use of gas energy and the dependence of large segments of industries and domestic, commercial, and administrative customers on gas energy, the need for sustained monitoring and the avoidance of any interruptions in the provision of gas services is essential and inevitable. One of the vital parts of the gas industry is gas pressure reduction stations, namely CGSs. In this research, a new fuzzy expert system is designed to troubleshoot and control safety and shutoff valves, which are regarded as main elements in controls of the safety of stations. In the presented expert system, the knowledge about the control of the safety and shutoff valves has been obtained from experts and has been entered in a knowledge-base as "if ... then ... else", and CLIPS language has been used for the system implementation. In this system, 164 rules have been utilized. The expert system is designed to be able to make deductions in both certain and uncertain conditions. Decision trees and control flowcharts have been applied in certain conditions. Fuzzy logic and certainty factors have been employed to implement uncertainty conditions in a case study. Concerning the importance of appropriate control of the safety and shutoff valves, increased responsiveness, increased reliability, increased availability, reduced accidents, reduced costs, reduced natural gas loss, and improved safety of the CGSs are expected by the implementation of the fuzzy expert system.