3HAC028179-001 DCS control system daily maintenance work

Distributed control system is written in English as DCS, which is the result of the development of computer technology and automation technology. The capacity of the unit continues to increase, and the parameters continue to improve, creating a broad world for DCS applications; With the wide use of DCS system, it provides a strong guarantee for the safe and economic operation of the unit. The control mode of the unit comprehensively reflects the level of automation, so the early thermal automation level is low, the quality of personnel is low, mainly adopts the decentralized local operation mode, the monitoring and operation are scattered on the site, this control mode is only suitable for low parameters, small capacity units, labor intensity, poor safety. (Courtesy of Instrumentation World Network)

3HAC028179-001 After the mid-1950s, it entered the development stage of local control. Due to the operation mode of the unit general mother control, local centralized control mode such as boiler, turbine and water supply deaeration was correspondingly adopted. In the 1960s, electronic computer technology was used in the monitoring and control of thermal power plants, and centralized control of machine, furnace and electricity appeared. In the early 1970s, programmable control capacity (PLC) was developed; With the development of high and new technologies such as control technology, computer technology, communication technology and CRT technology in the 1980s, microcomputer distributed control system (DCS) was developed abroad and successively applied to thermal power plants. In the 1990s, due to the development of microprocessors and their very large scale integrated circuits (VLSI) technology, DCS with the emergence of computer technology, fault-tolerant technology and human-machine interface technology, window technology, interactive graphics, as well as the development of standardized data communication networks and artificial intelligence, DCS has developed to integration and openness.

DCS is widely used in domestic power, petrochemical, food and other industries. Mainly, it has strong versatility, flexible system configuration, perfect control function, convenient data processing, centralized display operation, user-friendly interface, simple and standardized installation, convenient debugging, reliable operation characteristics, with the development of China’s power industry DCS has become a common equipment, whether it is a large unit or a small heating unit, more and more widely used. The corresponding daily maintenance work of its equipment also requires thermal control personnel to change the original way of thinking and adapt to the needs of modern development. The production and maintenance experience in the past few years is described.

1, 3HAC028179-001 process channel failure Process channel failure is the most common I/O card failure: I/O card failure general judgment and treatment, through the system diagnosis, replace the channel or through the replacement of spare parts processing, as for its internal components aging or other causes of damage, the general thermal control personnel is not good to judge. The maintenance of the I/O card is generally handled by the manufacturer, and the current means of thermal control maintenance personnel can not reach the maintenance like the maintenance of conventional instruments. And the manufacturer’s I/O card has been manufactured into an integrated trend, so that only spare parts can be purchased. Fortunately, such failures only occur in the debugging phase, and the probability of occurrence in normal operation is very low.

3HAC028179-001 A component or control equipment failure sometimes can not be directly found by the operator, only abnormal or alarm to notify the thermal control personnel to deal with. In this way, the quality requirements of maintenance personnel and operating personnel should be improved, and the operating personnel should introduce the status before and after the fault in detail to facilitate the thermal control maintenance personnel to quickly and accurately deal with the defect, reduce the expansion of the fault, in addition, many DCS manufacturers in the product promotion are supporting the card hot dial, as the controller, When replacing card parts in operation, we must take safety protection measures otherwise it will cause system changes or load changes, especially digital card parts.