Study On Monitoring System Of Urban Gas Transmission And Distribution Station

Zigong City, a gas transmission station during the current is still in a state of no monitor systems, collect process parameters of this transmission stations entirely reply on manual by regular inspections. In the aspect of gas temperature, pressure and flow detection, this transmission stations still use traditional thermometers, pressure gauges, dual bellows differential pressure gauge and standard orifice.This detection method is backward technology, greatly influenced by man-made factors, and low accuracy. In the aspect of gas pressure control, the operator still rely on manual regulator to control the pressure of gas. The manual regulator contains many shortcomings, such us Labor-intensive, low accuracy and poor real-time. These seriously affects the gas transmission station in aspects of reliable and stable distributing gas.This topic of this thesis comes from an Automation technology reconstruction project of a gas transmission station in Zigong city. The thesis first studied the process characteristics of the gas transmission, analyzed the deficiencies, and proposed improvement program in the sensor, control valve, adding devices and other aspects.This thesis summarized signals according to the monitoring requirements of signal transmission stations, designed the hierarchical structure of monitoring system of the gas distribution station. Secondly, this paper selected the hardware of monitoring system, Introduced the main PLC hardware. Then, described the communication design of scene measuring appliance, equipment and PC and PLC controller.this paper Used STEP7programming software to structure the hardware and network, completed the written of data collecting procedures of PLC.Then, against the characteristics of the natural gas pipeline outlet pressure control nonlinear, time-varying, vulnerable to interference, this paper decided to adopt PID controller based on parameter fuzzy self-modify and completed the design of the controller and the control programs of PLC. To verify the correctness of the controller, this paper established a mathematical model for the gas pipeline system, and simulated the controlled system and the whole system by MATLAB simulation software.Finally, it can achieve the process by the screen display of control configuration, parameter setting, alarms, trends, reports, and user management functions by configuration of Force Control software.