| For gas pipeline design in China,the allocation of standby compressor units of a gas pipeline was usually based on experience,while there was no quantitative analysis to the rationality of the standby schemes.Reasonable compressor unit standby scheme not only can ensure the reliable operation of a gas pipeline,but also achieve the best balance between operational reliability and economy.In this paper,the reliability of compressor unit standby scheme was analyzed based on Markov theory,using failure rate and repair rate of a single compressor to evaluate steady probability of failure state,which was an average probability of compressor system in a certain failure condition under the setting operational schemes.Taking Central-Asia A-B pipeline as an example,the state transition method was used to calculate the steady probability of failure state of one running unit in a station,the failure state of two running units in a station and the failure state of each one running unit in any two stations.SPS software was used to simulate pipeline capacity after different failure conditions under full throughput.The results showed that the decrease of capacity caused by failure of the initial station was greater than that of the downstream station,and the decrease of daily throughput reached 28.7% of full capacity.Assuming that the pipeline allows an annual loss of 5% of the design throughput,stations except initial station that all without standby units are able to reach the setting minimum annual pipeline capacity requirement.Assuming that the pipeline is a public transporter,a series of standby schemes according to influence degree that caused by the failure of different stations were proposed,the recommended scheme was chosen based on net present value considering with investment costs and loss costs,which include cost of pipeline charges and penalty.This paper provides a quantitative method for the allocation of the new pipeline standby schemes,which has a certain guiding significance. |
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