Research Of Speed Control Of Pig For Long Distance Natural Gas Pipeline

Pipeline,an important equipment for the transportation of oil and gas resources,the safety of it is increasingly concerned by the society.It's an extremely important measure to ensure the safety of pipeline that pipeline integrity management.Inside,pipeline detection is an important technique for pipeline integrity management.In order to solve the problem of the pipe wall thinning and the crack,which are caused by pipeline corrosion and stress concentration,the inline inspection is the universal means in the world.In-line inspection is a method for quantitative detection of pipeline defects,which is used the PIG with the device that can collect and record pipeline information in real time and without influence for pipeline operation.It's important significance in guaranteeing the safety of pipeline operation,especially in long pipelines that obtain the scientific information of pipeline integrity management from in-line inspection.It's the key of in-line inspection that control the speed of PIG and it's the precondition to ensure the integrity and effectiveness of the data from inspection.So in this thesis,the researches,which is related with the speed control principle,the control strategy and the control algorithm of PIG for long distance pipeline are carried out.Based on these theories,the hardware and software of the speed control system of the PIG are researched.The major contents of the research are listed as follows:(1)Technical investigation aiming at the research about the PIG for Long Distance Natural Gas Pipeline.The research status of speed control of PIG is illustrated.In addition,the technical route are put forward,which is according to the problem and deficiency of speed control of PIG.(2)Research on the model of PIG for long distance natural gas pipeline.The speed control principle of the PIG is clarified,which is combined with the structure composition and the working principle of PIG.Based on these,the fluid dynamic submodel and the friction submodel of the cups are established by numerical simulation.Thus,the speed control simulation model of PIG is built.(3)Research on the strategy of speed control of PIG for long distance natural gas pipeline.Based on the actual working conditions of PIG,the target of speed control of PIG is established.Also,the speed controllers of PID algorithm and fuzzy PID algorithm,with combining the speed control model of PIG are designed.And then,simulation and performance analysis of speed control algorithm of PIG for long distance natural gas pipeline.Based on the simulation model of speed control of PIG,the simulation of analysis of the speed algorithm of PIG is carried out.The ability of the dynamic response of the control algorithm is evaluated,when PIG is in launch,uphill and downhill.And the stability of the control algorithm is evaluated,when the system is interference by step,sine and square wave signal.(5)Development of speed control system of PIG.First of all,the general scheme of control system of PIG is proposed.And then,the hardware and software system of PIG are designed,which is combined with fuzzy PID control algorithm.(6)Development and test of electrical system for PIG for long distance natural gas pipeline.Based on the overall scheme of the electrical system of PIG,the compoments selection and system integration of the electrical system are completed.And the performance test and analysis of the electrical system are carried out.Eventually,the algorithm of the speed control system and the electrical system function of the PIG are verified.