Abstract: This article comprehensively introduces the automatic control system test and on-site instrument joint calibration work in the early stage of the construction and commissioning of the Sulige Natural Gas Processing Plant, and puts forward the problems that need attention in the system test work, and provides reliability for the normal operation and on-site production of the system after it is put into operation. Assure.
The Sulige Natural Gas Processing Plant is equipped with an automatic control system during construction. The system is functionally divided into the following three parts: DCS system for monitoring and control of production and operation data, and fire and combustible gas detection in the treatment plant FGS system, ESD system used to handle emergency shutdown and safe shutdown under factory accidents.System testing is a comprehensive test of the system hardware integrated in accordance with the design drawings and the control program written in accordance with the control plan to ensure that the components of the entire system operate well and that the control program fully conforms to the design plan.The instrument joint calibration is based on the preliminary test of the system, the field instrument linkage test of the entire automatic control system, and the software configuration of the human-computer interaction interface is tested to ensure that the field instrument works normally and can be in accordance with the control plan. The requirements for process control, fault alarm and safety cut-off.The three components of the automatic control system: the detection unit, the processing unit, and the execution unit respectively play the roles of eyes, brains and hands in the production and operation of the processing plant, that is, various transmitters on site transmit various physical parameters to the central control room. , Sent to the automatic control system controller to participate in the analysis and calculation of the control logic, and according to the results of the calculation, various types of actuators adjust and control the on-site process.1 Automatic control system test1.1 FATThe FAT (Factory Acceptance Test) factory acceptance test is a preliminary test for the system control unit, that is, the automatic control system cabinet, before the system hardware is integrated in the integrator’s factory and sent to the installation site. This test is mainly carried out on the functions, stability and usability of the system.1.2 Communication network testThe communication network is an important part of the automatic control system, which is responsible for the transmission of data and instructions between the various components of the automatic control system.The purpose of testing the communication network is to determine whether the IP address of the control system of each device is configured correctly, whether the communication network is reliable, and whether the network structure is reasonable, etc.1.3 Software configuration testThe software configuration test needs to be combined with the on-site instrument joint calibration. When various instruments, valves, and transmitters are used in the joint calibration field, check the value, status, and commands on the human-computer interaction interface (hollow process monitoring screen). No, so as to carry out a comprehensive proofreading of the upper computer system configuration and the lower computer system configuration.Through the test of the system configuration software, it is ensured that the on-site instrument data, valves and valve actions are consistent with the instructions displayed and issued by the central control room. Software configuration testing is a necessary condition to ensure remote monitoring of various instruments and valves on site.1.4 Failure response testThe automatic control system of the treatment plant needs to achieve a certain degree of protection for on-site production and operation in the event of a system failure. The fault response test is to artificially create fault conditions for various faults that may occur in the system, check the working status of the system, and understand whether the system affects on-site production under various fault conditions.The purpose of the corresponding fault test is to check whether the automatic control system has the fault tolerance required by the design, and to accumulate experience in troubleshooting and problem solving. When the system has a problem, the system maintainer can solve the problem as soon as possible.2 Field instrument joint schoolThe purpose of instrument joint school is to ensure that the on-site instruments are in normal working condition, and to ensure that the information obtained by the personnel in the central control position is consistent with the on-site production situation. This is an important prerequisite for the automatic control system to exert its remote central control.2.1 Transmitter joint calibrationTransmitter joint calibration method: Since all the transmitters used in Sulige Natural Gas Processing Plant support HART protocol, the HART function of FLUKE 744 can be used to provide HART protocol current signal on the meter head of the field instrument. Check the display value of the corresponding control point on the central control screen to see if it can correspond to the analog signal given on the spot, so as to test a single transmitter.2.2 Joint calibration of level gaugesThere is a magnetic floating ball in the pontoon of the magnetic flap level gauge, which floats up and down according to the level of the liquid. The remote transmission mechanism beside the pontoon induces magnetism and converts it into the corresponding current signal through the current transmission module. Control room. The joint calibration method of this type of level gauge is: place a magnet on a scale of the remote transmission mechanism of the level gauge to simulate a magnetic float. On the monitoring screen of the central control room, you can observe whether the displayed value is consistent with the scene. Joint school of level gauges.2.3 Joint schools of implementing agenciesThe actuators of the treatment plant are divided into electric actuators, pneumatic shut-off valve actuators, and regulating valves. The joint school of the actuator is mainly to check whether the on-off state and opening state of the valve on the central control screen are consistent with the scene, and whether the actions of the on-site actuator are consistent with the commands given by the central control.Therefore, the joint calibration method is for the central control to give a switch command or valve opening command to a certain actuator. The on-site personnel observe whether the corresponding valve has an action and whether the action is consistent, whether the on-site valve status is consistent with the feedback received by the central control Just be consistent.2.4 Control circuit and interlock logic testThe automatic control system of the treatment plant has a large number of control programs and logics, which are used to control each control loop and interlock. The control loop is to ensure the normal production and operation process. The principle of the control loop and the interlock logic test is to create a certain control. Under the condition of the normal operation of the loop, switch the execution unit to the normal operation state, and then destroy the normal condition, and observe whether the actuator performs the corresponding action according to the design of the control scheme.To test whether the interlock value setting in the interlock logic is correct, you can use the interval continuous value function of FLUKE 744 to test.3 concluding remarksSystem testing and instrument joint calibration are extremely important links before the automatic control system is put into operation, and it is directly related to the stability and reliability of the system after it is put into operation. Therefore, the system test and instrument joint calibration should be planned and prepared in advance, combined with the treatment plant process control plan and emergency shutdown plan for comprehensive and detailed testing, and the test records should be collected and organized to automatically control the treatment plant after it is put into production. The normal and stable operation of the system is guaranteed.
Post time: 21-09-21