Conveyor Pulley Conveyor Pulley,Drum Conveyor Pulley,Conveyor Driving Pulley,Rubber Belt Conveyor Pulley Hebei Juxin Conveyor Engineering Co., Ltd , https://www.juxinconveyor.com
In the automatic case, the operator mainly performs various operations through the operator station. Operation instructions are transmitted from the operator station to the control DPU, and output control is performed by the I/O card. The unit status and results are displayed on the CRT. EH hydraulic system includes oil supply system, oil pipeline, oil motive, emergency security system and so on. The unit adopts high-pressure anti-combustion oil, and the oil motive adopts the unilateral oil-injection method, that is, the valve is opened by the pressure oil and closed by the spring force to ensure the reliable closing of the valve. Critical security systems include OPC solenoid valves, AST solenoid valves, and diaphragm valves. When the OPC solenoid valve is energized, the OPC safety oil leaks and all the regulating valves are closed. When the AST solenoid valve is de-energized, the AST safety oil is drained off, and the OPC safety oil is also released. All valves are closed and the system shuts down. Baoding Thermal Power Plant DEH system control valves include: two high main doors (TV), four high-profile doors (GV), three intermediate doors (IV), two low-key doors (LV), one middle door (EOV) and one A total of 13 low-ejection doors (EIV) are used. Through the control of these doors, a series of functions such as turbine speed control, lift load, and extraction of low and medium pressure cylinders are accomplished.
2 System Composition and Functions 2.1 System Configuration The digital electro-hydraulic control system of the DEH-IIIA steam turbine consists of the following components:
2.1.1 DEH control cabinet 01 - control computer A (DPU11) and B (DPU31). Logical control and PID operations, and communication control with the lower computer, including the valve control card. 11 VCC boards accept host commands or manual operator commands (via hard disk) to control 11 adjustable valves; two extraction valves (EOV, EIV) are 4-20ma signal controlled air control doors.
02 cabinet - basic control analog, digital input and output terminal board.
2.1.2 Operator stations include: IPC, CRT, printer, touch keyboard. The operator station performs the DEH control operation, image display, alarm, recall, status display, etc., and is the man-machine interface between the operator and the DEH-IIIA.
2.1.3 Engineer Station includes: IPC, printer. The DEH-IIIA is configured, modified, adjusted and maintained by the engineering station. Run the same software as the operator station. The configuration is the same and can be used as a backup.
2.1.4 Manual operation The manual operation of DEH is a backup mode of operation of the DEH. When a pair of redundant DPUs are faulty, the operation can be maintained by waiting for the system to be resumed. It is also possible to switch to manual operation for safety reasons when the operator station fails.
2.1.5 Hydraulic Pressure (EH Section)
â—EH oil supply system (tank and oil pipeline)
â— There are 2 main engine oil engines, 4 high-pressure engine oil governors, 3 medium-pressure engine oil governors and 2 low-pressure engine oil governors.
â— OPC, AST protection system control block.
2.2 Main functions of the system The DEH-IIIA system has functions such as automatic adjustment, program control, monitoring, and protection. Its main functions are as follows:
2.2.1 Operation Modes The DEH-IIIA has three operation modes: operator automatic operation - main operation mode; remote control automatic mode; manual operation.
2.2.2 Load Control Loops Three types of loop control: power loop, adjustment level pressure loop, and frequency modulation loop.
2.2.3 Turbine speed control After the turbine is gated, the door is fully opened and the main valve is fully closed. The high-pressure main valve controls the speed. After the speed reaches 2950 RPM, the valve is switched and the speed is adjusted by the door.
2.2.4 Automatic Contemporaneous Control After the turbine speed reaches 3000 RPM, the DEH receives the automatic synchronization command and controls the turbine to the synchronous speed and is ready for grid connection.
2.2.5 Coordination Control The DEH accepts the CCS instruction to control the turbine load and the unit is in coordinated control mode.
2.2.6 After the medium and low-pressure extraction steam control units are connected to the grid, the DEH can be injected with medium-pressure extraction when the load is greater than 30MW in the automatic mode, and the low-pressure extraction can be used when the load is greater than 60MW.
2.2.7 Single/Multi-Valve Control Provides valve management functions, single-valve/multi-valve switching, throttling and nozzle adjustment.
2.2.8 Valve Test Online valve testing can be performed on each valve.
2.2.9 OPC control with overspeed protection and overspeed protection test.
2.2.10 Turbine program control start Under the condition of automatic, and the external measuring point is correct, program control start mode can be selected.
2.2.11 Communication with DAS or DCS systems for data sharing.
2.2.12 main valve, adjust the tightness test, check the valve is tight.
2.2.13 friction inspection function.
3 system function debugging 3.1 Valve feedback zero adjustment DEH control of the turbine mainly through the two main valves, four high-profile doors, three medium-adjusting doors, two low-profile doors to achieve, so the valve opening requirements are very high. Each valve design has two instructions and two feedbacks. When each valve command is zero, the feedback of each valve is adjusted to 0.002mm. Zero adjustment ends.
3.2 Valve sluggish rate Based on the importance of each valve, the valve position command and feedback must not only track well, but there can not be a large deviation between the valve opening process and the closing process under the same command conditions. The sluggish rate of each valve was tested before the unit started and the test results were normal.
3.3 friction inspection boiler ignition, the main steam temperature, main steam pressure to meet the rush conditions, and the disc drive input, the operator selects the automatic mode, after the turbine is unloaded, press the main valve control button, and then press the friction check button, friction The check lamp is on, indicating that the DEH is in a friction check mode. The DEH automatically sets the target value to 500r/m, lights up and automatically rushes to raise speed, and the rate of rise is 100r/m. When the rotation speed rises to 500r/m, the target value of DEH is set to 0, the unit idles and is checked by the operator. After the inspection is completed, press the friction check button to exit the “friction checkâ€. The test situation is consistent with the design and the friction check function is normal.
3.4 Speed ​​Control After the friction inspection is completed, the unit enters the up speed phase. In the automatic mode, the turbine is gated and the gate is fully opened after the gate is opened. The operator selects “main valve controlâ€, the high-profile door is fully opened, the target value is set to 600r/m, and the “Continue†key is pressed. Automated rotation. DEH internally set the rate of rise to 100r/m/min. The operator can set the rate of rise according to the turbine's state of revolution. The maximum rate of rise is 300r/m/min.
The speed was increased to 600r/m. The turbine was warmed up at a low speed. The warm-up time was reached. The target value was set to 2430 r/m and the speed was continued to increase. After the speed reaches this value, the engine is warmed up at a high speed. After 50 minutes, the warm-up time is up and the engine can continue to run. The operator sets the target value of 2950r/m, and the turbine rushes to 2950r/m under the control of the main valve. In this process, the critical speed should be exceeded, the actual speed of the turbine during the critical speed period, DEH automatically set the rate of increase of 500r/m/min, quickly pass through the critical speed, through the post-lift rate to restore the original set value.
After reaching a speed of 2950r/m, the operator presses the "high-profile door control" button to switch the valves of the main and high-profile doors. After the valve is switched, set the target value to 3000r/m and the ramp rate to 50r/m/min. The turbine will be rotated to 3000r/m under high-profile door control and stable with a positive and negative deviation of 2r/m. The conversion process ends. Satisfy the design and the working conditions of the unit.
3.5 Overspeed Test After the turbine speed is increased to 3000r/m, the overspeed test can be performed. The overspeed protection test consists of an overspeed protection key switch and a speed of 103%, a speed of 110%, and a mechanical overspeed. The overspeed protection key switch is set on the hard disk and divided into three blocks: test bit, overspeed protection input bit, and over speed protection cut-off bit. Prior to the test, the key switch is turned to the test position and the overspeed test can be performed.
â— "103%" test When the overspeed protection key switch is set to the test position, and the speed channel is normal, the 110% and mechanical overspeed test buttons are not to be pushed. Press the "103%" test button and the light is on. At this time, the DEH controller is allowed to operate. After setting the target value to 3100r/m and setting the target value to 3100r/m, the speed continues to increase. When the actual speed is increased to 3091r/m, the overspeed protection is activated, all the doors are closed, and the speed drops. At the same time, the controller automatically sets the target value to 3000r/m. Until the speed drops to the target value and the system recovers, adjust the door to open. The DEH design action value is 3090r/m, the deviation is within the allowable range and meets the requirements.
â— "110%" test After the 103% test is completed and the system is restored, 110% test is performed. Do not cast 103% and mechanical overspeed test button, press the "110%" test button, the light is on, this time DEH controller allows the operator to set the target value to 3310r/m, the target value is set to 3310r/m, after Continue to rise. When the actual speed rose to 3299r/m, the overspeed protection action, the controller issued AST signal, the main valve, adjust the door closed, the turbine trip. The DEH design action value is 3300r/m, the deviation is within the allowable range and meets the requirements.
â— The mechanical overspeed test system recovers, and after the speed is increased to 3000r/m, mechanical overspeed test is performed. Do not cast 103% and 110% test button, press the "Mechanical Overspeed" test button, the light is on, this time the DEH controller allows the operator to set the target value to 3400r/m, after the target value is set to 3400r/m, the speed Continue to rise. When the actual speed rises to 3238r/m, the machine over-speeds and the turbine trips. After the system is restored, the second mechanical overspeed test is performed. The action value is 3240r/m, and the deviation of the two actions is 2r/m. After negotiating with the power plant personnel and related units, the safety factor is greater and the mechanical speeding is maintained. .
3.6 Valve Tightness Test DEH-IIIA provides a test procedure for whether the main valve or high-profile door is closed tightly. In the case of unit speed of 3000r/m, the valve tightness test can be carried out to check whether the valve is tight.
â— The main valve tightness test Press the main valve tightness test button, the main valve is fully closed, adjust the valve fully open, the turbine speed began to decline, and finally fell to 500r/m, test pass, DEH program control is correct.
â— High-tune door tightness test Press the high-tight door tightness test button, the main valve is fully open, adjust the valve fully closed, the turbine speed starts to drop, and finally fell to 1942r/m, the speed does not drop, the test failed. This is a mechanical problem and the DEH program is properly controlled.
3.7 Load control The load control in a DEH system is a cascade adjustment system of three loops. The control of the trim gate controls the load of the unit. The three loops are: inner loop regulation level pressure loop (IMP); middle loop power regulation loop (MW); outer loop speed primary frequency modulation loop (WS). After the unit speed reaches 3000r/m, press the "Automatic Synchronization" button. At this time, the synchronization device can send synchronized increase or synchronous decrement to the DEH. The DEH can control the turbine speed to synchronous speed, which can be connected to the grid. After the grid connection, the initial load is about 5%. Stable for a period of time, first put into the power loop and load up. Power loop control is correct. Afterwards, the adjustment stage pressure loop and the primary frequency modulation loop were tested respectively, all of which meet the composite design requirements and the system is stable.
3.8 CCS Coordinated Control Units In the period of full load, CCS coordinated control mode was used. The operator presses the "remote control" button, the light is on, indicating that the control device has been put into coordinated control mode, and removes the DEH power, pressure regulator loop, and CCS completes the closed-loop control. The CCS sends a signal to increase or decrease the pulse. The DEH system receives normal signals and the load increases or decreases. At this point the operator has been unable to change the target value and variable load rate of the load. DEH automatically resumes operation in "automatic" mode when the cut is coordinated. After practical verification, this control method meets the design requirements.
Note: When CCS issues a load increase or decrease signal as a short pulse, the DEH load command is incremented by a fixed value each time it is issued. When CCS issues a long signal, during this period, the DEH load command is incremented by one time, until The CCS signal disappears.
3.9 The medium pressure extracting function unit is connected to the grid and the DEH is in full automatic mode. When the load is greater than 30MW (less than 20MW automatically exits), DEH can be used for medium pressure extraction. After power unit #8 unit was normal in the industrial heat network path, the medium pressure extraction test was carried out under full load of the unit. The operator presses the "Middle Pressure Extraction" button to enter the extraction mode. At this time, the operator can set the medium pressure extraction valve (EOV) to manual and open it. After the door is opened, the operator sets extraction steam. Press the target value and press the "Extraction pressure circuit" button. The extraction circuit is put in. The middle control door is gradually closed and the high-profile door is gradually opened until the extraction pressure of the medium pressure cylinder is the same as the target value. After tests, the DEH extraction function meets the production requirements and is consistent with the design.
Note: The medium pressure extraction valve (EOV) is always kept in the automatic mode and is in the closed state when the "medium pressure extraction pump input" button is not applied. It is not allowed to switch to the manual mode.
3.10 When the low-pressure extraction function unit is connected to the grid, the DEH is in automatic mode, and when the load is greater than 60MW (less than 50MW automatically exits), the DEH can be used for medium-pressure extraction. The logic design is similar to the medium pressure extraction function. The difference is that after the low pumping input, the low pressure adjustment valve (LV) will be turned off and the low pressure extraction valve will be opened at the same time until the extraction pressure of the low pressure cylinder is consistent with the set value. After tests, the DEH extraction function meets the production requirements and is consistent with the design.
3.11 Influence of extraction on load The extraction function of Unit #8 in Baoding Power Plant adopts the heat-setting method, and the input of dual-extraction circuits in the medium and low-pressure cylinders will inevitably cause unit load fluctuations and have a greater impact. In response to this, in the DEH function design, Xinhua added the influence of the extraction flow rate to the load flow rate in the steam flow circuit required for the load. When the extraction steam is put in, the steam flow required for the load and the actual load generate the power steam flow rate. Deviation, in order to stabilize the load, DEH automatically increases the high-profile door opening and increases the steam flow to keep the actual load consistent with the given load. When the extraction volume is relatively large, the high-profile door still cannot meet the load demand when it is fully opened. At this time, the steam flow rate given by the boiler is saturated, and the actual power generation of the generator does not meet the given requirements. Only the actual power generation can be used. quasi. Therefore, the control of Xinhua's DEH has actually achieved a partial decoupling function. Only when the extraction volume is relatively large and the boiler cannot reach the required steam volume, it is only at the same time that the steam extraction amount is satisfied, and the unit is actually The power generation method prevails.
4 system reliability design 4.1 dual fault-tolerant DEH-IIIA system uses redundant DPU configuration, system fault detection and discrimination by the fault-tolerant system. Failure types include: power failure, communication failure, differential failure, and channel detection failure. When the master DPU fails, the standby DPU runs automatically. Failure recovery, confirmed by the operator and then raised to automatic control operation. If both machines fail, the DEH system automatically switches to manual operation. The operator can maintain the current status of the unit or adjust the opening degree of the valve by hand. After the DPU recovers, it can be switched back to the automatic mode. Greatly improve the security and reliability of the system.
4.2 Three elections and two logical judgments 4.2.1 Speed: Three speed probes enter three speed boards respectively, and three roads enter the computer at the same time. After three elections, the machine enters the control loop.
4.2.2 The OPC control board is a three-selection system.
4.2.3 Other important analog measurements are dual transmitter measurements, two converter conversions, and two internal selections.
4.3 Parallel reserve design 4.3.1 Dual power supply: UPS power supply and security power supply.
4.3.2 Dual DC power supply, 1:1 redundancy.
4.3.3 OPC solenoid valve adopts double solenoid valve parallel system; AST solenoid valve adopts 4 solenoid valves, which are series and parallel structure.
4.3.4 Dual Data Communication.
4.4 System hardware/software anti-jamming measures 4.4.1 Analog input, using isolation amplifier to isolate external interference.
4.4.2 Switch input and output, using relay isolation and photoelectric isolation.
4.4.3 The use of input filtering: filter out the various types of interference signals.
5 Systematic evaluation The overall design of the DEH-IIIA system of Baoding Thermal Power Plant is relatively complete, it can fully meet the functional requirements of the turbine of the 100 MW unit, and the dual-channel extraction function of medium and low pressure is well realized. During the whole unit start-up and full-load trial run, all the functions such as steam turbine turning, grid-connected, load-lifting, full-load, and OPC experiment achieve high accuracy, and the system runs stably, and the protection action is normal. It is a safe and stable steam turbine digital electro-hydraulic control system.
Established in 1976 in China, JUXIN, are
considered as the first Conveyor and components: roller, frame, pulley
manufacturer in Hengshui, China. The rapid growth of the business in
China soon created the need for a distribution depot, therefore in 2007 a
new branch was put in place in Tianjin City The modern day JUXIN now
manufactures conveyor products to suit all supplies of mining, steel
plant, cement plant, quarry, crushing and screening equipment. Our
expertise and knowledge allows us to deliver fully on our promises of
providing quick answers to your enquiries, rapid service, high quality
products and above all, we are fully committed to be the best at what we
do Service Agents are also located in: UK, South Africa, Kenya,
Indonesia, Thailand, Kazakhstan All products are underpinned by
unmatched customer service and prompt, reliable delivery. Our internal
quality systems are designed to ensure that all orders are handled
quickly and are manufactured to the ultimate quality standards. Several
checking processes are in place prior to orders being released from the
factory. Many tightly controlled inspections occur during the production
processed.
DEH-IIIA System's Control and Debugging of 100MW Double Pumping Units
1 Overview Baoding Thermal Power Plant #8 unit is a 100MW double pumping (industrial extraction, heating extraction) unit, which uses a 450T/H circulating fluidized bed produced by Dongfang Boiler Works, and the turbine is CC100-8.83 produced by Shanghai Steam Turbine Works. / 0.981/0.196 type, DCS control system, steam turbine digital electro-hydraulic control system are XDPS distributed control system and DEH-IIIA system of Xinhua Control Engineering Co., Ltd. respectively. The DEH-IIIA control system consists of a computer control section and an EH hydraulic section. The control section mainly includes: a pair of basic control cabinets and terminal cabinets, engineering stations and operator stations. Engineer station, operator station and control DPU are connected through redundant data highway (Ethernet). Hand controller is connected to valve control card through hard wiring so that when DPU fails, valve position is directly controlled by manual operation disk, which increases safety. coefficient. The switching between redundant DPUs and hand-to-auto switching are all undisturbed switching for system control.