DCS external conditions refer to UPS power supply, computer control system grounding, control room and electronic room environmental requirements, etc. During the installation and commissioning of power plants, these situations are often overlooked due to rush schedules or other factors. However, the external conditions directly threaten the safety and stable operation of DCS. Through the analysis of DCS problems, it can be seen that many accidents, faults, etc. are caused by poor UPS power supply and system grounding. DCS does not have a good grounding system and reasonable cable shielding, which not only causes significant system interference, but also makes it easy for the control system to send signals incorrectly and damage the modules. It can be seen that poor external conditions such as UPS power supply, control system grounding, control room and electronic room environmental requirements pose great risks to the safety and stable operation of DCS after the power plant is put into operation. Therefore, the power supply design of DCS system must have reliable backup means, and the load configuration should be reasonable and have a certain margin; The grounding of the DCS system must strictly comply with technical requirements. All cables entering the DSC system control signal must use shielded cables of qualified quality, and must be laid separately from power cables with good single end grounding; Strict management systems should also be established, such as electronic room entry and exit registration, civilized and hygienic management systems, regular dust removal, daily environmental inspections, regular measurement of DCS system grounding, and testing of DPC redundancy switching, DPU and security power redundancy switching, to ensure good external environmental conditions of DCS. So before the DCS is put into operation, a series of external environmental inspections should be carried out to meet the relevant conditions before powering on and putting it into operation.
1. Pre operation inspection and quality requirements of the system
(1) Appearance inspection and requirements
Before putting into operation, check the temperature, humidity, and cleanliness of the environment where the equipment is located, check that the cable holes between electronic devices are sealed properly, and also check that all power supply fuses meet the requirements. The cabinet numbers and names of each control station cabinet, I/O cabinet, and on-site transition terminal cabinet are clearly marked, and terminal block wiring diagrams are attached. The common power lines, grounding wires, and lighting wires of each control station cabinet, I/O cabinet, and on-site transition terminal cabinet should be connected properly, correctly, and firmly; The attachments are complete and intact. The lighting inside the cabinet is normal. All types of signal wires, signal shielding ground wires, protective ground wires, and power wires entering the intermediate transition terminal cabinet and on-site control station cabinet from the site should be connected properly, correctly, firmly, and aesthetically pleasing; The cable grades and wiring numbers are complete and clear.
(2) Inspection and quality requirements for each workstation
1) For the on-site control station, various signal lines, power lines, and grounding wires entering the on-site control station cabinet from the site should be checked and connected to ensure the integrity of the system and reduce defects.
2) Inspect all power modules, main controller modules, functional modules, and other equipment inside the on-site control station cabinet. They should be fully restored and installed correctly and firmly. All connecting cables and wiring should be connected properly, correctly, firmly, and aesthetically pleasing; The redundant communication cables of each workstation should be connected properly, correctly, firmly, and aesthetically pleasing.
3) Check the data communication lines inside the on-site control station, as well as the communication lines between each on-site control station, and ensure that they are connected properly, correctly, and firmly. All connecting cables and wiring should be connected properly, correctly, and firmly.
4) For functional service stations such as operator stations and engineer stations, the power supply of computers, CRTs, printers, etc. at each station should be checked and connected properly; Also, check that the connection between the dedicated keyboard, mouse or trackball, CRT signal line, and printer signal line with each computer is intact, correct, and in good condition; The redundant data communication lines between various functional service control stations and the communication lines between workstations should be connected properly, correctly, and firmly; Finally, check that the power supply of the large screen monitor and its connection to the computer are intact.
2. System commissioning
After passing the appearance inspection of the system and the necessary inspections of each workstation, prepare for power on.
(1) Power on preparation work
1) Firstly, place all power switches (including cabinet AC power switches and cabinet DC power switches) in the “off” position.
2) Check if there is any miswiring or external power supply voltage caused by misoperation on the power input terminal, and confirm that all cabinets are not powered on.
3) Check if there is any miswiring or external power supply voltage caused by misoperation on the power input terminal, and confirm that all cabinets are not powered on.
4) It is not allowed to directly turn on the power supply without authorization. It is necessary to check that the power circuits of all subsystems related to the DCS system are indeed unmanned, and the condition of all subsystems related to the DCS system allows the system to be powered on; After completing all necessary procedures for operation, power on again.
(2) Operation steps
1) Power on the on-site control station. Turn on the main power switch of the on-site control station, the system power switch, and the on-site power switch in sequence to start the on-site control station, automatically enter the system operation status, and observe the operation status through self diagnosis.
2) Power on each functional service station.
a. Turn on the main power, printer, large screen display, and other power switches, connect the main power supply of each engineer station and historical data station, start each engineer station and historical data station, display on the CRT, enter the operating system, start the application program, and the system will start normally in sequence.