Huaneng ooze north power plant in the north taihang, south river TZIDC intelligent positioner ABB dawen. TZIDC intelligent positioner ABB 207 state road, (jiaozuo - guangxi liuzhou) of jiaozuo-liuzhou railway, the east economic (henan jiyuan - shandong dongming) high-speed, high-speed economic law (jiyuan, luoyang), jiyang jin (jiyuan - shanxi jincheng) high-speed, respectively through the factory. In the domestic first use localization of large capacity supercritical coal-fired unit equipment, the first phase of coal-fired units installed two 600000 mw supercritical localization. Starts in September, 2002, opened in December 2004. As China's first 600000 mw supercritical coal-fired unit localization of relying on the power plant, henan huaneng ooze north power plant is designated by the state's first supercritical localization based on a project, close to the southeast shanxi and be coal base. Its construction, for the development of national industry, improve the level of China's major equipment localization, promote industrial upgrading, promote power structure adjustment and optimization is of great importance.
Due to ooze north power plant is located at the confluence of central China, north China, northwest power grid, to support the national networking, area resources optimization allocation plays an important role. Also seeps north power plant is listed as 21st century optimized design demonstration coal-fired power plant, its engineering design level and international level, the effect will be the future of our country play the part of demonstration role coal-fired power station design.
Qinbei power failure analysis of pneumatic positioner:
Our pneumatic damper for two units of the first phase of the original type of conventional mechanical locator and independent position feedback device, equipment control accuracy is low, poor reliability, mechanical type locator the spring tension adjusting screw to adjust the zero and full, its mechanical structure are susceptible to vibration influence, in the process of running multiple locator failure or feedback device failure occurs, affecting the system stability, in the early stage of the unit during the maintenance, the main external regulation actuator controller is reformed, will become a trinity of fission locator reforming intelligent controller, the work can not only greatly improve the equipment reliability and control accuracy, greatly reduce the defects during the operation of unit.
Reconstruction is completed, our factory site installation using the largest number of digital actuator positioner is friend Lin D3 digital locator, friends of Lin D3 digital actuator positioner consists of two parts, circuit parts and road, more failure due to gas path parts, the malfunction of the circuit part of the very few our factory caused by abnormal circuit part locator fault occurred just one example. Locator electric conversion part pneumatic block for the loss of its main materials diaphragm and seals for rubber products, has certain life cycle, long-term use of diaphragm and seals will be aging phenomenon, especially in the water, oil, etc. Will accelerate pneumatic diaphragm and seals in aging. Pneumatic block fault is the leading cause of our factory fault locator, especially some frequent pneumatic tone, continuous high load for a long time of work can be accelerated aging of pneumatic block.
In unit operation in the process of turbine high hydrophobic tone and actuator inputs such as boiler reduce warm tone has been in a state of adjustment, after automatic switch is very frequent, locator work continuously for a long time, intake and exhaust is very big, with the instrument gas into water, oil, impurities such as corresponding increase,
Had a great influence on the life of the gas circuit block. By the collapse of the fault locator gas circuit block found that film and seals have oil pollution and damage phenomenon. Because of pneumatic fittings in machining accuracy and quality of installation requirements is higher, maintenance staff temporarily unable to part of the gas circuit block the damaged to repair.
And continuous high load at the same job for long, the bad working environment is also a cause of the locator high failure rate, high plus normal hydrophobic tone as an example, the executing agency for straight travel, the body temperature is very high, the locator close distance from the body, baked in high temperature below the body cause the locator itself at higher temperature, high temperature and vibration on gas circuit block has a great influence and even the entire locator.
Locator after failure occurs, will be abnormal inlet and exhaust, different film location of different fault happens, cause abnormal fully open or close the actuator. Friends of Lin D3 intelligent positioner in continuous work for a period of time after the occasional unpredictable sudden shut phenomenon, under the condition of invariable in instruction valve shut down suddenly, after the change after the instruction to open valve positioner can also be put into normal use, but this will seriously affect the safe and stable operation of unit, so we will happen such failures of pneumatic actuators locator for transforming replacement.
A phase of the equipment is the domestic products of the late ninety s, has been in operation for many years, adjust with actuators are pneumatic actuators, often appear jams, leak, unreliable feedback signal, linear defects such as bad, make personnel in accordance with the operation of the damper the will of the action, or refuse to move, or fully open linear fitted is not good, to make the working condition of modulated exceeds the scope permitted, direct threat to the safe operation of the unit, in this case, the transformation was born of valve positioner, involving a period more than 1 #, 2 # unit of high and low, deaerator water level control, auxiliary steam, shaft seal pressure damper, high and low side pressure and reduce warm tone key parts, and other damper and the secondary air damper, etc.;
Our factory site there are three main forms of present use digital locator, are friends of Lin D3 trinity locator, actuator positioner ABB, Siemens locator. Through the comparison, the long-term use of ABB actuator positioner reliability is higher than the other two. We will gradually replace high failure rate with ABB locator friend Lin D3 locator. In view of the present locator failure rate is higher in this case, we will develop measures to strengthen the inspection site pneumatic actuators, according to the inlet and exhaust judging the working state of the locator, processing if it is abnormal. In the during the machine stop and on important or pneumatic actuator locators block for unified replacement, prevent units affected by the failures of the locator in the process of running units safe and stable operation in other power plant and the factory locator usage of research, found that ABB locator in other power plant equipment used widely and has been long time, work stability, failure rate, adjust sensitive features, well received by users. At the beginning of the factory, ooze north power plant valve positioner is along with the equipment, did not make any brand designated, 1 #, 2 # unit, a total of 250 valve positioner in loading, ABB locator original account for only 15% of the total, about 37, now through gradual transformation, ABB locator installed capacity has more than 130 units, in order to guarantee the safe and stable operation of the unit, and also in orderly to be modified, find other locator can't use it with ABB to replace locator, converted into quality is reliable output double air ABB locator.
Power plant valve positioner or have higher requirements, performance requirements are as follows:
1. Should be modular design, high accuracy intelligent valve positioner locator;
2. Cutting off power and signal to protect a function, namely in the case of without other equipment to realize fault signal power, when the valve has the function of the position, namely the stop in situ. Or optional with cutting off power and signal reset function, namely in the case of without other equipment to realize fault signal, power reset function, make the valve back to safety.
3. An automatic calibration and manual proofreading, local operating functions Set-up with automatic and manual proofreading (without extra equipment), operation function, can use the hand operator (for example: 275375691) for calibration
4. The input and output must be 4-20 ma current signal
5. Able to - 40... + 85 ° C degrees without any conditions
6. Has the ability to resist strong electromagnetic interference Has the ability to resist strong electromagnetic interference
7. Ability to resist shock: requirements of instruments have a stronger ability to resist vibration
8. Waterproof, dustproof protective class IP65
Where power failure protection is required:
High and low, deaerator is a key unit in the power plant system, high and low water level damper in quarter-turn work manner, with the function of the position losing electricity power plant requirements, namely when the valve positioner power supply disappears, should make the valve to keep the current position, in order to avoid once for DCS to 4 ~ 20 ma signal (DCS supply valve positioner AO not redundant) signal disappears, the high and low water level adjust the door quickly into full open or close position, and make the high and low water level fluctuations, may lead column height and solution, and cause accidents, we adopt which has the function of cutting off power and signal to protect an ABB TZIDC locator, without any additional current relay or solenoid valve can achieve fault signal protection, when the DCS signal disappears, the locator lock add damper cylinder gas source, thus realizing the position losing electricity function;