The hottest sipartps2 intelligent valve positioner

Application of sipartps2 intelligent valve positioner in Huaneng Dalian Power Plant

Huaneng Dalian Power Plant is located on the coast of Bohai Bay in the suburbs of Dalian, close to Dalian Economic and Technological Development Zone, and about 30 kilometers away from the city center. It is a large-scale thermal power plant built by using foreign capital and raising funds to run electricity in China. It now has an installed capacity of 1.4 million KW and is composed of four 350000 kW coal-fired units. The two thermal power generating units of phase I project use Japanese equipment, which were put into operation in September and December 1988 respectively, and have a power generation capacity of 700000 kW.; The second phase of the expansion project started in March 1996 and was put into operation successively in December 1998. At present, the electricity produced by Huaneng Dalian Power Plant is sold through northeast power grid. In recent years, the annual power generation of the plant has been more than 3.8 billion kwh, and the whole process of factory production has basically realized automatic control. At present, the power generation capacity of the plant has reached 1.05 million KW. Premier Li Peng and minister Shi Dazhen of the Ministry of electric power both put forward requirements for the plant to realize modern management, hoping to build Huaneng Dalian Power Plant into a model of a national power enterprise and reach the world-class level

sipart PS2 intelligent valve positioner has been applied in Huaneng Dalian power plant. However, due to the aging of the equipment used in phase I project for many years, the control level of some systems is relatively backward. In terms of thermal automatic regulation, there are too many failures and unreliability of peripheral control equipment. Most of the actuators used for regulation are pneumatic actuators, which are products of the 1980s. Their performance is poor, and the phenomena of regulating valve refusal and vibration occur from time to time, resulting in large regulation error. Some automation equipment can no longer meet the needs of the rapid development of automation system. In this case, the transformation of valve positioner came into being. This transformation first involves the transformation of phase I 2# unit, involving 6 sets of fan flow regulating valves, 10 sets of cold and hot air regulating dampers of coal mill, 4 sets of burner swing angle control, 6 sets of high and low bypass pressure and desuperheating water regulating valves, 20 sets of other regulating valves and 13 sets of secondary air dampers

II. Comparison between SIPART PS2 intelligent valve positioner and the requirements of the bid inviter:

the technical performance requirements of the manufacturer for the valve positioner and the performance comparison of Siemens SIPART PS2 intelligent valve positioner are as follows:

the bid inviter requires that Siemens SIPART PS2

1 should be a high-precision electronic positioning system; Digital electronic positioning system of highly integrated microprocessor

2 positioning and feedback can be integrated or installed separately

3 with automatic calibration and manual calibration, operation function with automatic calibration and manual calibration (without additional equipment), operation function

4 with air filter and necessary search where there is damage, pressure gauge filter can be added, pressure gauge can be optional (Modular)

5 its input The output must be ma current signal, and its input and output are 0/ma current signals (two-wire system and four wire system are optional)

6 can operate continuously without fault in - degree environment, and can operate continuously without fault in - degree environment

7 has the ability to resist strong electromagnetic interference

8 has the ability to resist temperature drift and the ability to resist temperature drift

9 is waterproof In addition to the above advantages, Siemens SIPART PS2 intelligent positioner also has the following characteristics:

the same type of valve positioner is used for the straight stroke and angular stroke actuators. The straight stroke and angular stroke only need to be set with a few simple parameters, which increases the interchangeability and flexibility of equipment application

simple installation, highly automated calibration, and maintenance free operation, which means saving time and convenient application

three keys and dual line LCD display can realize simple operation and programming

it has manual and automatic adjustment functions of zero position and stroke range

has optional or programmable output characteristics

has self diagnosis function

very little gas consumption

set value and limit value of control variable can be selected

the function of "close closing" of the valve can be set (unit: Provincial Department of economy and information technology, Provincial Department of science and technology, provincial market supervision bureau)

the dead zone can be set

adaptive program means that high-quality control can be achieved even in harsh environmental conditions

the influence of temperature and compressed air pressure on SIPART PS2 positioner can be ignored

III. problems encountered in the implementation of the project and solutions:

four burner swing angle valve positioners are installed, and the valve stroke reaches 400mm, so the conversion from large displacement of straight stroke to small displacement (measurable range) should be carried out. The original positioner used the way of spring plus pressure sensor, but the spring vibrated. This transformation used the way of inclined iron, which is to stick the travel guide rail of the valve positioner to the inclined iron, Converting the large displacement in the vertical direction into the small displacement in the horizontal direction, the operation knowledge of the torsion universal machine applied on site is good,

one high-pressure bypass temperature regulating valve and two low-pressure bypass temperature regulating valves also have the above problems. Because this valve is placed horizontally, in order to facilitate installation and reduce the weight of the measuring connector, the transformation adopts the way of universal joint, but there is a little error, However, for the range of 300mm, the error of 2~3mm can be ignored, and the field application is good

6 fan inlet regulating valves are in angular stroke working mode. Party A requires to have power loss position protection function, that is, when the power supply of the valve positioner disappears, the valve should be kept in the current position, so as to avoid that once the 4~20ma signal supplied by DCS (the Ao signal supplied by DCS to the valve positioner is not redundant) disappears, the fan inlet regulating valve will quickly enter the fully open or fully closed position, resulting in large pressure fluctuations in the boiler, which may cause the boiler to trip, For production accidents, we adopt the working mode of current relay and solenoid valve. When the signal of DCS disappears, the solenoid valve is used to lock the cylinder air source of the fan inlet regulating valve, so as to realize the function of power loss and position protection

during on-site commissioning, it should be noted that in the case of vibration, the dead zone of the valve positioner should be set. Otherwise, because the Siemens SIPART PS2 intelligent positioner uses microprocessing deformation, it can recover the given value and position feedback for comparison. If the microprocessor detects deviation, it uses a five step switching program to control the piezoelectric valve, and the piezoelectric valve converts the control command into gas