1 Condition of the thermal control system before transformation The two units of Huaneng Nanjing Power Plant are all 320MW supercritical DC coal-fired generators imported from the former Soviet Union. The model of the boiler is IIII-1000-25-545KT. The storage system of the pulverizing system and the turbine model For K-320-23.5-4, equipped with a 100% load steam pump and a 65% load steam pump.
The thermal control system of the unit has a low level of automation and many intermediate links. The logic control components are not only diverse, but also have a very large number; the components work under the influence of the gold temperature, and the adjustment quality is relatively poor. The function of the control system is not easy to upgrade or expand; spare parts are scarce and expensive. Therefore, the original control system has seriously affected the safe and stable operation of the unit. After bidding, it was decided to use the HIACS-5000M distributed control system (DCS) provided by Beijing Hitachi Control Systems Co., Ltd. The power plant, Northeast Electric Power Research Institute, Beijing Hitachi, and Xi'an Thermal Power Research Institute jointly assumed the transformation.
2 The principle of system transformation is to reduce the investment and workload of the transformation. Based on the full digestion and absorption of the original system design experience, the original long cabinet and some cables are used to transfer the original cabinet to the middle terminal cabinet. The control strategy is based on the original design. At the same time, the configuration of the control logic is required to fully reflect the advanced nature of the transformation, improve the automation level of the unit, reduce the work intensity of the operating personnel, and reserve the necessary safety operation backup means when a major fault occurs.
After the transformation, all functions of the original control system must be fully realized. Dismantle the original protection, interlocking and adjustment cabinets, retain local transmitters and actuators, use some imported transmitters and actuators for some important analog measurement points and automatic adjustment mechanisms. The original generator coil and iron core temperature inspection device was changed to remote data acquisition and DCS communication; the control panel dial was redesigned and replaced. The electrical system switches, alarms, and control methods were unchanged, but some of the electrical controls were incorporated into the new system.
3 HIACS-5000M System Introduction HIACS-5000M distributed control system consists of 7 operator stations (POC - processoperationcontrolstion), 1 engineer workstation (EWS - engineeringworkingststion), 1 historical data station (HDS - historicaldatastation), 3 lasers The printer (PRS - printerrecordstation) consists of two large screen displays. The POC, EWS, and HDS are connected to the high-speed fiber ring network FDDI through a dedicated network access device, LanBox. The network's transmission speed is 100 Mbit/s, and it is connected to the plant management information system (MIS) through routers.
The entire control system is divided into multiple sub-systems according to the production process, and 16 R600C controllers complete the characters. The R600C controller is the basic controller in the system. The redundant dual CPU and I/O module form a high-performance controller. Its CPU uses a 32-bit RISC high-speed processor clocked at 100MHz. The 16 R600C controller functions are divided into: turbine speed control (OPC), self-start control (AUT), unit protection (BTS), side-wind smoke system (FDA), side B side smoke system (FDB), lower fuel system (BMB), Coordination System (CCS), Upper Fuel System (BMA), Milling System (MIL), Desuperheated Water System (STM), Deoxygenation Feedwater System (FWP) Bypass, Heater System (HBP), Oil, Condensate, desalinated water system (AUA), closed cold water, vacuum. Flange, Axial Heating System (AUB), 2 Data Acquisition Stations (DAA).
The POC software system is divided into application software and system software. POC application software is divided into offline configuration tools and online operating programs. Configuration tools include databases, system screens, graphics, reports, device operations and other configurations. The online running software includes a series of necessary functions such as unit status, equipment, parameter display, alarm display, SOE, accident recall, equipment operation and printing.
The system configuration software has the following functions: 1 monitoring function, online monitoring of control logic, trends, etc., and online adjustment and simulation of relevant control parameters; 2 programming functions, providing programming logic of the control logic, program compilation, PI/O logic, 3 program maintenance, logic program download, controller status display and change, etc. 4 System login, related to program registration, system configuration setting, TASK login, transfer connection table setting, etc.; 5 function management , Dual controller generation, etc.
4 After the transformation of the system functions DCS completed the main control functions include: boiler furnace safety monitoring, sequence control, coordinated control, analog regulation and control, electro-hydraulic regulation, data acquisition.
Boiler furnace safety monitoring systems include furnace purging, MFT (main fuel trip), load shedding to 65% and 30% protection, oil leak testing, fuel allowance, and safety gate control. The condition of the trigger MFT of the original control system and the control logic remain the original design, and on the basis of this increase the boiler loses all the material protection. Turbine protection is divided into unit protection, shutdown protection, 65% protection, 30% protection, power outage and steam feed pump protection, and heating 0S water level protection. The combination of the TSI transformation of the unit has increased the shaft vibration and wave vibration protection of the unit.
In the process of configuration design of the sequential control system, in addition to retaining the interlock of the original design, the focus will be placed on the function design of the main equipment and the functional design of the group operation. A functional group was designed for start/stop of important auxiliary equipments such as boiler auxiliary equipment, pulverizing system, oil gun and powder feeder, and other startup and adjustment processes, such as boiler water preparation, fuel leakage test, and A and B side lifts. Automatic load/cutting for the loader, etc., and functional groups were also designed.
The unit coordination control system and the simulation closed-loop sub-control system total 91 control loops, including: unit unit control, water supply control, fuel control, air supply control, induced draft control, primary bellows pressure control, heater water level control and other circuits.
The DEH part of this transformation is based on the original design, meets the requirements of the regulations, satisfies the power amplifier interface, and enhances the degree of automation. It increases the segmentation, anti-slicing, and ATC functions of the original system. A total of 8 working conditions are designed under the ESC mode: speed, valve position, power, holding pressure 1 (including RB), holding pressure 2, segmentation, anti-slicing, and coordination. The cutting and counter-cutting conditions are new. Increased operating conditions. In terms of functions, functions such as ATC, primary frequency modulation, and line valve testing have been added. According to the operating characteristics of the unit, functions such as unit RB, unit anti-overspeed, on-line valve activity testing, etc. have been further improved; in terms of DEH protection function, the When 103%, 110% and 114% overspeed or load rejection pre-turn protection.
The online functions of the DAS system include all screen call, operation, alarm, and printing functions that the operator can perform. Its functions are divided into the following areas: screen display, CRT operation, alarm monitoring, trend display, group display, list display and printing, accident recall, print request, historical trend, historical data display and printing, operator Operation records, hard copy, task switching of the printer, performance index calculation.
The calculation of economic and technical indicators is a key project for the transformation of DAS functions, especially in the current situation where the power industry is bidding on the Internet. It is of great significance to reduce the cost of electricity production and increase the competitive power of competitive bidding. The calculation results serve as the basis for the assessment of our factory economic indicators. The system is equipped with flexible calculation management software, which mainly has the following functions: 1 The comparison between the designed value of the performance calculation and the actual calculated value yields the deviation and its effect on the heat consumption rate and coal consumption. The operating personnel can perform the displayed results. Analysis, to make the unit run in the best state; 2 Calculated by the boiler thermal efficiency, turbine generator cycle thermal efficiency and plant power consumption calculation of the unit's net heat rate; 3 using the input-output method to calculate the turbine generator control Cycle performance, the obtained data and the main steam temperature, pressure and exhaust pressure and other deviations are corrected: 4 Calculate the efficiency of the turbine by baking, and give the efficiency of the high pressure cylinder, medium pressure cylinder and low pressure cylinder, 5 input - Output and heat loss methods to calculate the boiler efficiency, and list the amount of controllable heat loss and the amount of uncontrollable heat loss, 6 using the end-to-end difference and approximation method to calculate the feedwater heater efficiency, 7 using the "Heat Exchange Association standards (HEIS )"Condenser cleaning coefficient provided to calculate condenser efficiency; 8 Calculate air preheater efficiency using capacity balance principle; 9Use main and re-steam temperature, Main steam inlet Force, condenser pressure, water temperature, water temperature of each heater outlet, end the difference, the degree of subcooling, the excess air deviation, a deviation rated thermal efficiency and thermal efficiency, and calculates the cost due to the deviation.
5 System Operation After the DCS transformation of Unit 1, its controllability, reliability, and economical efficiency have been greatly improved compared with those before the transformation. The unit's main protection investment rate has remained at 100%, and the automatic investment rate has remained at around 95%. Resumption of the use of the previously released "down load to 65% protection", and has used the opportunity to mediate the trial, the dynamic process completely without the need for operator intervention, can smoothly reduce load: through the measurement point and the replacement of the executing agency, vote Using the automatic function of sending and attracting wind that has never been put into before, the operation is in good condition at present; CCS and various functional groups can basically guarantee the unit in the coordinated working condition, the range of change is 180MW to 310MW, and the parameters of the unit are stable and smooth. There is no need to Excessive manipulation and intervention. The new automatic increase/decrease feeder function group can guarantee that the unit is in the range of 180MW-310MW in the AGC working condition, and there is no need to run the personnel to cast/cut feeder.
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