ANALYSIS OF EMERGENCY FAILURE OF LONG-TERM OPERATED GAS PIPELINES

Abstract

At present, the uninterrupted supply of natural gas to consumers is the key to the stability of the Russian economy. The gas transmission system of Gazprom PJSC is at the stage of long-term operation, demanding significant investments to maintain it in an efficient condition. In this connection, the problems of accidents statistical data analysis are impor- tant to maintain the gas transportation system in the conditions of long- term operation. The article analyzes the distribution of accidents on the main gas pipe- lines along the distance from the compressor station. The sample size was 169 accidents occurred on 56 gas pipelines with a nominal diameter of DN 700-1400 for a ten-year period. It is obtained that the nature of the distribution function of the failure distribution obeys the Weibull law. Results analysis made it possible to establish that the probability distribution function of Weibull's failure- free operation describes the experimental data of the probability of fail- ure-free operation quite accurately. The root-mean-square relative error was 2.28 %. The difference between the empirical (obtained from experimental data) and the theoretical functions of the probability of failure-free operation can be traced with considerable run-up of gas pipelines in the period when the risks of sudden failures increase. The paper proposes a three-parameter Gompertz function for character- izing the probability of trouble-free operation of main gas pipelines, which allows to take into account the real aging processes and operating conditions of gas pipelines. A comparative analysis of the theoretical distributions under consideration was made. An analysis of the results obtained showed that the probability distribu- tion function of Gompertz's fail-safe operation describes experimental data with a mean-square relative error of 2.14 %. Thus, the Gompertz distribution is 0.2 % more accurate than the Weibull distribution.